fix(tui): standardize compact terminology (#41141 )

fix(tui): unify integration connection copy (#41137 )
chore: improve incremental typecheck performance (#40925 )
2026-08-07 17:49:53 -04:00 · 2026-08-07 16:26:14 -04:00 · 2026-08-07 16:11:51 -04:00 · 2026-08-07 15:34:36 -04:00 · 2026-08-07 14:06:37 -05:00 · 2026-08-07 13:43:00 -05:00
132 changed files with 616 additions and 951 deletions
@@ -368,11 +368,12 @@ Other provider exports listed above remain direct facades until they explicitly

 ## Provider options & HTTP overlays

-Three escape hatches in order of stability:
+Request options in order of stability:

 1. **`generation`** — portable knobs (`maxTokens`, `temperature`, `topP`, `topK`, penalties, seed, stop).
-2. **`providerOptions: { <provider>: {...} }`** — typed-at-the-facade provider-specific knobs (OpenAI `promptCacheKey`, Anthropic `thinking`, Gemini `thinkingConfig`, OpenRouter routing).
-3. **`http: { body, headers, query }`** — last-resort serializable overlays merged into the final HTTP request. Reach for this only when a stable typed path doesn't yet exist.
+2. **`promptCacheKey`** — stable cache affinity lowered by every protocol that supports it.
+3. **`providerOptions: { <provider>: {...} }`** — typed-at-the-facade provider-specific knobs (OpenAI `store`, Anthropic `thinking`, Gemini `thinkingConfig`, OpenRouter routing).
+4. **`http: { body, headers, query }`** — last-resort serializable overlays merged into the final HTTP request. Reach for this only when a stable typed path doesn't yet exist.

 Route/provider defaults are overridden by request-level values for each axis.

@@ -33,9 +33,10 @@ const model = OpenAI.configure({
 //
 //   - `generation`: common controls such as max tokens, temperature, topP/topK,
 //     penalties, seed, and stop sequences.
+//   - `promptCacheKey`: stable cache affinity for protocols that support it.
 //   - `providerOptions`: namespaced provider-native behavior. For example,
-//     OpenAI cache keys and store behavior, Anthropic thinking, Gemini thinking
-//     config, or OpenRouter routing/reasoning.
+//     OpenAI store behavior, Anthropic thinking, Gemini thinking config, or
+//     OpenRouter routing/reasoning.
 //   - `http`: last-resort serializable overlays for final request body, headers,
 //     and query params. Prefer typed `providerOptions` when a field is stable.
 //
@@ -45,9 +46,7 @@ const request = LLM.request({
  system: "You are concise and practical.",
  prompt: "Tell me a joke",
  generation: { maxTokens: 80, temperature: 0.7 },
-  providerOptions: {
-    openai: { promptCacheKey: "tutorial-joke" },
-  },
+  promptCacheKey: "tutorial-joke",
 })

 // 3. `generate` sends the request and collects the event stream into one
@@ -90,15 +90,10 @@ const OpenResponsesFunctionCallOutput = Schema.Union([
 ])

 export const InputItem = Schema.Union([
-  Schema.Struct({ role: Schema.tag("system"), id: Schema.optionalKey(Schema.String), content: Schema.String }),
-  Schema.Struct({
-    role: Schema.tag("user"),
-    id: Schema.optionalKey(Schema.String),
-    content: Schema.Array(OpenResponsesInputContent),
-  }),
+  Schema.Struct({ role: Schema.tag("system"), content: Schema.String }),
+  Schema.Struct({ role: Schema.tag("user"), content: Schema.Array(OpenResponsesInputContent) }),
  Schema.Struct({
    role: Schema.tag("assistant"),
-    id: Schema.optionalKey(Schema.String),
    content: Schema.Array(OpenResponsesOutputText),
    phase: Schema.optionalKey(MessagePhase),
  }),
@@ -106,23 +101,19 @@ export const InputItem = Schema.Union([
  OpenResponsesItemReference,
  Schema.Struct({
    type: Schema.tag("function_call"),
-    id: Schema.optionalKey(Schema.String),
    call_id: Schema.String,
    name: Schema.String,
    arguments: Schema.String,
  }),
  Schema.Struct({
    type: Schema.tag("function_call_output"),
-    id: Schema.optionalKey(Schema.String),
    call_id: Schema.String,
    output: OpenResponsesFunctionCallOutput,
  }),
 ])
 type OpenResponsesInputItem = Schema.Schema.Type<typeof InputItem>
-type ProviderInputItem = Readonly<Record<string, unknown>> & { readonly type: string; readonly id?: string }
 type LoweredInputItem =
  | OpenResponsesInputItem
-  | ProviderInputItem
  | {
      readonly role: "assistant"
      readonly content: ReadonlyArray<{ readonly type: "output_text"; readonly text: string }>
@@ -137,7 +128,7 @@ type OpenResponsesReasoningInput = {
  summary: Array<{ type: "summary_text"; text: string }>
  encrypted_content?: string | null
 }
-type OpenResponsesReasoningReplay = Omit<OpenResponsesReasoningInput, "id"> & { id?: string }
+type OpenResponsesReasoningReplay = Omit<OpenResponsesReasoningInput, "id">

 export const Tool = Schema.Struct({
  type: Schema.tag("function"),
@@ -263,11 +254,6 @@ export interface Extension {
    readonly request: LLMRequest
  }) => MediaInput | undefined
  readonly messagePhase?: (value: unknown) => MessagePhase | null | undefined
-  readonly lowerProviderItem?: (
-    part: ToolResultPart,
-    providerMetadataKey: string,
-    store: boolean | undefined,
-  ) => ProviderInputItem | undefined
 }

 const BASE: Extension = { id: ADAPTER, name: NAME }
@@ -324,17 +310,6 @@ export const lowerToolChoice = (protocolName: string, toolChoice: NonNullable<LL
    tool: (toolName) => ({ type: "function" as const, name: toolName }),
  })

-const metadataItemID = (
-  part: { readonly itemId?: string; readonly providerMetadata?: ProviderMetadata },
-  providerMetadataKey: string,
-) => {
-  if (part.itemId) return part.itemId
-  const metadata = part.providerMetadata?.[providerMetadataKey]
-  return ProviderShared.isRecord(metadata) && typeof metadata.itemId === "string" && metadata.itemId.length > 0
-    ? metadata.itemId
-    : undefined
-}
-
 const lowerToolCall = (part: ToolCallPart): OpenResponsesInputItem => ({
  type: "function_call",
  call_id: part.id,
@@ -344,23 +319,26 @@ const lowerToolCall = (part: ToolCallPart): OpenResponsesInputItem => ({

 const lowerReasoning = (part: ReasoningPart, providerMetadataKey: string): OpenResponsesReasoningInput | undefined => {
  const metadata = part.providerMetadata?.[providerMetadataKey]
-  const itemId = metadataItemID(part, providerMetadataKey)
-  if (!itemId) return undefined
+  if (!ProviderShared.isRecord(metadata) || typeof metadata.itemId !== "string" || metadata.itemId.length === 0)
+    return undefined
  const encryptedContent =
-    ProviderShared.isRecord(metadata) &&
-    (typeof metadata.reasoningEncryptedContent === "string" || metadata.reasoningEncryptedContent === null)
+    typeof metadata.reasoningEncryptedContent === "string" || metadata.reasoningEncryptedContent === null
      ? metadata.reasoningEncryptedContent
      : undefined
  return {
    type: "reasoning",
-    id: itemId,
+    id: metadata.itemId,
    summary: part.text.length > 0 ? [{ type: "summary_text", text: part.text }] : [],
    encrypted_content: encryptedContent,
  }
 }

-const hostedToolItemID = (part: ToolResultPart, providerMetadataKey: string) =>
-  metadataItemID(part, providerMetadataKey)
+const hostedToolItemID = (part: ToolResultPart, providerMetadataKey: string) => {
+  const metadata = part.providerMetadata?.[providerMetadataKey]
+  return ProviderShared.isRecord(metadata) && typeof metadata.itemId === "string" && metadata.itemId.length > 0
+    ? metadata.itemId
+    : undefined
+}

 const lowerMedia = Effect.fn("OpenResponses.lowerMedia")(function* (
  part: MediaPart,
@@ -419,18 +397,17 @@ const lowerToolResultOutput = Effect.fn("OpenResponses.lowerToolResultOutput")(f
 })

 const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (request: LLMRequest, extension: Extension) {
-  const options = OpenResponsesOptions.resolve(request)
  const system: LoweredInputItem[] =
    request.system.length === 0 ? [] : [{ role: "system", content: ProviderShared.joinText(request.system) }]
  const input: LoweredInputItem[] = [...system]
-  const store = options.store
+  const store = OpenResponsesOptions.resolve(request).store
  const providerMetadataKey = request.model.route.providerMetadataKey ?? "openresponses"

  for (const message of request.messages) {
    if (message.role === "system") {
      const part = yield* ProviderShared.wrappedSystemUpdate(extension.name, message)
      const previous = input.at(-1)
-      if (previous && "role" in previous && previous.role === "user" && Array.isArray(previous.content))
+      if (previous && "role" in previous && previous.role === "user")
        input[input.length - 1] = {
          role: "user",
          content: [...previous.content, { type: "input_text", text: part.text }],
@@ -450,24 +427,24 @@ const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (reques
    if (message.role === "assistant") {
      const content: TextPart[] = []
      const reasoningItems: Record<string, OpenResponsesReasoningReplay> = {}
-      const hostedToolItems = new Set<string>()
+      const reasoningReferences = new Set<string>()
+      const hostedToolReferences = new Set<string>()
      const flushText = () => {
        if (content.length === 0) return
-        const groups = content.reduce<
-          Array<{ phase: MessagePhase | null | undefined; itemId: string | undefined; parts: TextPart[] }>
-        >((groups, part) => {
-          const metadata = part.providerMetadata?.[providerMetadataKey]
-          const phase = ProviderShared.isRecord(metadata) ? messagePhase(metadata.phase, extension) : undefined
-          const itemId = metadataItemID(part, providerMetadataKey)
-          const group = groups.at(-1)
-          if (group && group.phase === phase && group.itemId === itemId) group.parts.push(part)
-          else groups.push({ phase, itemId, parts: [part] })
-          return groups
-        }, [])
+        const groups = content.reduce<Array<{ phase: MessagePhase | null | undefined; parts: TextPart[] }>>(
+          (groups, part) => {
+            const metadata = part.providerMetadata?.[providerMetadataKey]
+            const phase = ProviderShared.isRecord(metadata) ? messagePhase(metadata.phase, extension) : undefined
+            const group = groups.at(-1)
+            if (group && group.phase === phase) group.parts.push(part)
+            else groups.push({ phase, parts: [part] })
+            return groups
+          },
+          [],
+        )
        input.push(
          ...groups.map((group) => ({
            role: "assistant" as const,
-            ...(group.itemId === undefined ? {} : { id: group.itemId }),
            content: group.parts.map((part) => ({ type: "output_text" as const, text: part.text })),
            ...(group.phase === undefined ? {} : { phase: group.phase }),
          })),
@@ -483,6 +460,11 @@ const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (reques
          flushText()
          const reasoning = lowerReasoning(part, providerMetadataKey)
          if (!reasoning) continue
+          if (store !== false) {
+            if (!reasoningReferences.has(reasoning.id)) input.push({ type: "item_reference", id: reasoning.id })
+            reasoningReferences.add(reasoning.id)
+            continue
+          }
          const existing = reasoningItems[reasoning.id]
          if (existing) {
            existing.summary.push(...reasoning.summary)
@@ -492,7 +474,6 @@ const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (reques
          }
          const replay = {
            type: reasoning.type,
-            id: reasoning.id,
            summary: reasoning.summary,
            encrypted_content: reasoning.encrypted_content,
          }
@@ -509,18 +490,16 @@ const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (reques
        if (part.type === "tool-result" && part.providerExecuted === true) {
          flushText()
          const itemID = hostedToolItemID(part, providerMetadataKey)
-          const providerItem = extension.lowerProviderItem?.(part, providerMetadataKey, store)
-          if (providerItem && itemID && !hostedToolItems.has(itemID)) input.push(providerItem)
-          if (!providerItem && store !== false && itemID && !hostedToolItems.has(itemID))
+          if (store !== false && itemID && !hostedToolReferences.has(itemID))
            input.push({ type: "item_reference", id: itemID })
-          if (!providerItem && store === false && part.result.type === "content") {
+          if (store === false && part.result.type === "content") {
            const content: ReadonlyArray<Content> = part.result.value
            input.push({
              role: "user",
              content: yield* Effect.forEach(content, (item) => lowerToolResultContentItem(item, request, extension)),
            })
          }
-          if (itemID) hostedToolItems.add(itemID)
+          if (itemID) hostedToolReferences.add(itemID)
          continue
        }
        return yield* ProviderShared.unsupportedContent(extension.name, "assistant", [
@@ -560,7 +539,7 @@ const lowerOptions = (request: LLMRequest) => {
  return {
    ...(options.instructions ? { instructions: options.instructions } : {}),
    ...(options.store !== undefined ? { store: options.store } : {}),
-    ...(options.promptCacheKey ? { prompt_cache_key: options.promptCacheKey } : {}),
+    ...(request.promptCacheKey ? { prompt_cache_key: request.promptCacheKey } : {}),
    ...(options.include ? { include: options.include } : {}),
    ...(options.reasoningEffort || options.reasoningSummary
      ? { reasoning: { effort: options.reasoningEffort, summary: options.reasoningSummary } }
@@ -662,9 +641,9 @@ const onOutputTextDelta = (state: ParserState, event: Event, id: string): StepRe
  if (!event.delta) return [state, NO_EVENTS]
  const events: LLMEvent[] = []
  const phase = state.messagePhases[id]
-  const metadata = providerMetadata(state, { itemId: id, ...(phase === undefined ? {} : { phase }) })
-  const lifecycle = Lifecycle.textStart(state.lifecycle, events, id, metadata, id)
-  return [{ ...state, lifecycle: Lifecycle.textDelta(lifecycle, events, id, event.delta, metadata, id) }, events]
+  const metadata = phase === undefined ? undefined : providerMetadata(state, { phase })
+  const lifecycle = Lifecycle.textStart(state.lifecycle, events, id, metadata)
+  return [{ ...state, lifecycle: Lifecycle.textDelta(lifecycle, events, id, event.delta) }, events]
 }

 const onOutputTextDone = (state: ParserState, event: Event, id: string): StepResult => {
@@ -673,13 +652,7 @@ const onOutputTextDone = (state: ParserState, event: Event, id: string): StepRes
    return onOutputTextDelta(state, { ...event, delta: event.text }, id)
  }
  const events: LLMEvent[] = []
-  return [
-    {
-      ...state,
-      lifecycle: Lifecycle.textEnd(state.lifecycle, events, id, providerMetadata(state, { itemId: id }), id),
-    },
-    events,
-  ]
+  return [{ ...state, lifecycle: Lifecycle.textEnd(state.lifecycle, events, id) }, events]
 }

 export const onReasoningDelta = (state: ParserState, event: Event, itemID: string): StepResult => {
@@ -690,14 +663,7 @@ export const onReasoningDelta = (state: ParserState, event: Event, itemID: strin
  return [
    {
      ...state,
-      lifecycle: Lifecycle.reasoningDelta(
-        state.lifecycle,
-        events,
-        id,
-        event.delta,
-        providerMetadata(state, { itemId: itemID }),
-        itemID,
-      ),
+      lifecycle: Lifecycle.reasoningDelta(state.lifecycle, events, id, event.delta),
    },
    events,
  ]
@@ -739,13 +705,7 @@ const onOutputItemAdded = (state: ParserState, event: Event): StepResult => {
    return [
      {
        ...state,
-        lifecycle: Lifecycle.reasoningStart(
-          state.lifecycle,
-          events,
-          `${item.id}:0`,
-          reasoningMetadata(state, item),
-          item.id,
-        ),
+        lifecycle: Lifecycle.reasoningStart(state.lifecycle, events, `${item.id}:0`, reasoningMetadata(state, item)),
        reasoningItems: {
          ...state.reasoningItems,
          [item.id]: { encryptedContent: item.encrypted_content, summaryParts: { 0: "active" } },
@@ -764,7 +724,6 @@ const onOutputItemAdded = (state: ParserState, event: Event): StepResult => {
      lifecycle,
      tools: ToolStream.start(state.tools, item.id, {
        id: item.call_id ?? item.id,
-        itemId: item.id,
        name: item.name ?? "",
        input: item.arguments ?? "",
        providerMetadata: metadata,
@@ -772,12 +731,7 @@ const onOutputItemAdded = (state: ParserState, event: Event): StepResult => {
    },
    [
      ...events,
-      LLMEvent.toolInputStart({
-        id: item.call_id ?? item.id,
-        itemId: item.id,
-        name: item.name ?? "",
-        providerMetadata: metadata,
-      }),
+      LLMEvent.toolInputStart({ id: item.call_id ?? item.id, name: item.name ?? "", providerMetadata: metadata }),
    ],
  ]
 }
@@ -796,7 +750,6 @@ const onReasoningSummaryPartAdded = (state: ParserState, event: Event): StepResu
          events,
          `${event.item_id}:0`,
          providerMetadata(state, { itemId: event.item_id, reasoningEncryptedContent: null }),
-          event.item_id,
        ),
        reasoningItems: {
          ...state.reasoningItems,
@@ -817,7 +770,6 @@ const onReasoningSummaryPartAdded = (state: ParserState, event: Event): StepResu
          events,
          `${event.item_id}:${entry[0]}`,
          providerMetadata(state, { itemId: event.item_id }),
-          event.item_id,
        ),
      state.lifecycle,
    )
@@ -829,7 +781,6 @@ const onReasoningSummaryPartAdded = (state: ParserState, event: Event): StepResu
        events,
        `${event.item_id}:${event.summary_index}`,
        providerMetadata(state, { itemId: event.item_id, reasoningEncryptedContent: item.encryptedContent ?? null }),
-        event.item_id,
      ),
      reasoningItems: {
        ...state.reasoningItems,
@@ -865,7 +816,6 @@ const onReasoningSummaryPartDone = (state: ParserState, event: Event): StepResul
              events,
              `${event.item_id}:${event.summary_index}`,
              providerMetadata(state, { itemId: event.item_id }),
-              event.item_id,
            )
          : state.lifecycle,
      reasoningItems: {
@@ -920,8 +870,7 @@ const onOutputItemDone = Effect.fn("OpenResponses.onOutputItemDone")(function* (
          state.lifecycle,
          events,
          item.id,
-          providerMetadata(state, { itemId: item.id, ...(phase === undefined ? {} : { phase }) }),
-          item.id,
+          phase === undefined ? undefined : providerMetadata(state, { phase }),
        ),
        messageItems,
        messagePhases,
@@ -932,15 +881,9 @@ const onOutputItemDone = Effect.fn("OpenResponses.onOutputItemDone")(function* (

  if (item.type === "function_call") {
    if (!item.id || !item.call_id || !item.name) return [state, NO_EVENTS] satisfies StepResult
-    const metadata = providerMetadata(state, { itemId: item.id })
    const tools = state.tools[item.id]
      ? state.tools
-      : ToolStream.start(state.tools, item.id, {
-          id: item.call_id,
-          itemId: item.id,
-          name: item.name,
-          providerMetadata: metadata,
-        })
+      : ToolStream.start(state.tools, item.id, { id: item.call_id, name: item.name })
    const result =
      item.arguments === undefined
        ? yield* ToolStream.finish(state.id, tools, item.id)
@@ -970,7 +913,7 @@ const onOutputItemDone = Effect.fn("OpenResponses.onOutputItemDone")(function* (
      const lifecycle = Object.entries(reasoningItem.summaryParts)
        .filter((entry) => entry[1] === "active" || entry[1] === "can-conclude")
        .reduce(
-          (lifecycle, entry) => Lifecycle.reasoningEnd(lifecycle, events, `${item.id}:${entry[0]}`, metadata, item.id),
+          (lifecycle, entry) => Lifecycle.reasoningEnd(lifecycle, events, `${item.id}:${entry[0]}`, metadata),
          state.lifecycle,
        )
      const { [item.id]: _removed, ...reasoningItems } = state.reasoningItems
@@ -978,12 +921,12 @@ const onOutputItemDone = Effect.fn("OpenResponses.onOutputItemDone")(function* (
    }
    if (!state.lifecycle.reasoning.has(item.id)) {
      const lifecycle = Lifecycle.stepStart(state.lifecycle, events)
-      events.push(LLMEvent.reasoningStart({ id: item.id, itemId: item.id, providerMetadata: metadata }))
-      events.push(LLMEvent.reasoningEnd({ id: item.id, itemId: item.id, providerMetadata: metadata }))
+      events.push(LLMEvent.reasoningStart({ id: item.id, providerMetadata: metadata }))
+      events.push(LLMEvent.reasoningEnd({ id: item.id, providerMetadata: metadata }))
      return [{ ...state, lifecycle }, events] satisfies StepResult
    }
    return [
-      { ...state, lifecycle: Lifecycle.reasoningEnd(state.lifecycle, events, item.id, metadata, item.id) },
+      { ...state, lifecycle: Lifecycle.reasoningEnd(state.lifecycle, events, item.id, metadata) },
      events,
    ] satisfies StepResult
  }
@@ -132,6 +132,7 @@ export const bodyFields = {
  stream: Schema.Literal(true),
  stream_options: Schema.optional(Schema.Struct({ include_usage: Schema.Boolean })),
  store: Schema.optional(Schema.Boolean),
+  prompt_cache_key: Schema.optional(Schema.String),
  reasoning_effort: Schema.optional(OpenAIOptions.OpenAIReasoningEffort),
  max_completion_tokens: Schema.optional(Schema.Number),
  max_tokens: Schema.optional(Schema.Number),
@@ -509,6 +510,7 @@ const lowerOptions = (request: LLMRequest) => {
  const options = OpenAIOptions.resolve(request)
  return {
    ...(options.store !== undefined ? { store: options.store } : {}),
+    ...(request.promptCacheKey ? { prompt_cache_key: request.promptCacheKey } : {}),
    ...(options.reasoningEffort ? { reasoning_effort: options.reasoningEffort } : {}),
  }
 }
@@ -38,14 +38,10 @@ const OpenAIResponsesToolChoice = Schema.Union([
 const OpenAIResponsesInputItem = Schema.Union([
  Schema.Struct({
    role: Schema.tag("assistant"),
-    id: Schema.optionalKey(Schema.String),
    content: Schema.Array(Schema.Struct({ type: Schema.tag("output_text"), text: Schema.String })),
    phase: Schema.optionalKey(Schema.NullOr(OpenResponses.MessagePhase)),
  }),
  OpenResponses.InputItem,
-  Schema.StructWithRest(Schema.Struct({ type: Schema.String, id: Schema.optionalKey(Schema.String) }), [
-    Schema.Record(Schema.String, Schema.Unknown),
-  ]),
 ])

 const OpenAIResponsesCoreFields = {
@@ -84,25 +80,6 @@ const extension = {
      mime_type: media.mime,
    }
  },
-  lowerProviderItem: (part, providerMetadataKey, store) => {
-    const metadata = part.providerMetadata?.[providerMetadataKey]
-    if (!ProviderShared.isRecord(metadata) || !ProviderShared.isRecord(metadata.item)) return undefined
-    if (typeof metadata.item.type !== "string") return undefined
-    const id = typeof metadata.item.id === "string" ? metadata.item.id : undefined
-    // The public API requires stored state to replay image-generation items. In
-    // stateless mode, lower the generated file through the existing user-image fallback.
-    if (metadata.item.type === "image_generation_call" && store === false) return undefined
-    if (metadata.item.type === "image_generation_call")
-      return {
-        type: metadata.item.type,
-        ...(id === undefined ? {} : { id }),
-        ...(typeof metadata.item.status === "string" ? { status: metadata.item.status } : {}),
-        ...(typeof metadata.item.revised_prompt === "string" ? { revised_prompt: metadata.item.revised_prompt } : {}),
-        ...(typeof metadata.item.result === "string" ? { result: metadata.item.result } : {}),
-      }
-    const item: Record<string, unknown> & { type: string } = { ...metadata.item, type: metadata.item.type }
-    return item
-  },
 } satisfies OpenResponses.Extension

 const nativeImageToolInput = (tool: ToolDefinition) => {
@@ -218,29 +195,23 @@ const onHostedToolDone = Effect.fn("OpenAIResponses.onHostedToolDone")(function*
  item: HostedToolItem,
 ) {
  const tool = HOSTED_TOOLS[item.type]
-  const callMetadata = OpenResponses.providerMetadata(state, { itemId: item.id })
-  const resultMetadata = OpenResponses.providerMetadata(
-    state,
-    item.type === "image_generation_call" ? { itemId: item.id } : { itemId: item.id, item },
-  )
+  const providerMetadata = OpenResponses.providerMetadata(state, { itemId: item.id })
  const events: LLMEvent[] = []
  const lifecycle = Lifecycle.stepStart(state.lifecycle, events)
  events.push(
    LLMEvent.toolCall({
      id: item.id,
-      itemId: item.id,
      name: tool.name,
      input: tool.input(item),
      providerExecuted: true,
-      providerMetadata: callMetadata,
+      providerMetadata,
    }),
    LLMEvent.toolResult({
      id: item.id,
-      itemId: item.id,
      name: tool.name,
      result: yield* hostedToolResult(item),
      providerExecuted: true,
-      providerMetadata: resultMetadata,
+      providerMetadata,
    }),
  )
  return [{ ...state, lifecycle }, events] satisfies OpenResponses.StepResult
@@ -1,10 +1,4 @@
-import {
-  LLMEvent,
-  type FinishReasonDetails,
-  type ProviderMetadata,
-  type ResponseItemID,
-  type Usage,
-} from "../../schema"
+import { LLMEvent, type FinishReasonDetails, type ProviderMetadata, type Usage } from "../../schema"

 export interface State {
  readonly stepStarted: boolean
@@ -20,29 +14,16 @@ export const stepStart = (state: State, events: LLMEvent[]): State => {
  return { ...state, stepStarted: true }
 }

-export const textStart = (
-  state: State,
-  events: LLMEvent[],
-  id: string,
-  providerMetadata?: ProviderMetadata,
-  itemId?: ResponseItemID,
-): State => {
+export const textStart = (state: State, events: LLMEvent[], id: string, providerMetadata?: ProviderMetadata): State => {
  if (state.text.has(id)) return state
  const stepped = stepStart(state, events)
-  events.push(LLMEvent.textStart({ id, ...(itemId === undefined ? {} : { itemId }), providerMetadata }))
+  events.push(LLMEvent.textStart({ id, providerMetadata }))
  return { ...stepped, text: new Set([...stepped.text, id]) }
 }

-export const textDelta = (
-  state: State,
-  events: LLMEvent[],
-  id: string,
-  text: string,
-  providerMetadata?: ProviderMetadata,
-  itemId?: ResponseItemID,
-): State => {
-  const started = textStart(state, events, id, providerMetadata, itemId)
-  events.push(LLMEvent.textDelta({ id, ...(itemId === undefined ? {} : { itemId }), text, providerMetadata }))
+export const textDelta = (state: State, events: LLMEvent[], id: string, text: string): State => {
+  const started = textStart(state, events, id)
+  events.push(LLMEvent.textDelta({ id, text }))
  return started
 }

@@ -51,11 +32,10 @@ export const reasoningStart = (
  events: LLMEvent[],
  id: string,
  providerMetadata?: ProviderMetadata,
-  itemId?: ResponseItemID,
 ): State => {
  if (state.reasoning.has(id)) return state
  const stepped = stepStart(state, events)
-  events.push(LLMEvent.reasoningStart({ id, ...(itemId === undefined ? {} : { itemId }), providerMetadata }))
+  events.push(LLMEvent.reasoningStart({ id, providerMetadata }))
  return { ...stepped, reasoning: new Set([...stepped.reasoning, id]) }
 }

@@ -65,10 +45,9 @@ export const reasoningDelta = (
  id: string,
  text: string,
  providerMetadata?: ProviderMetadata,
-  itemId?: ResponseItemID,
 ): State => {
-  const started = reasoningStart(state, events, id, providerMetadata, itemId)
-  events.push(LLMEvent.reasoningDelta({ id, ...(itemId === undefined ? {} : { itemId }), text, providerMetadata }))
+  const started = reasoningStart(state, events, id, providerMetadata)
+  events.push(LLMEvent.reasoningDelta({ id, text, providerMetadata }))
  return started
 }

@@ -77,26 +56,19 @@ export const reasoningEnd = (
  events: LLMEvent[],
  id: string,
  providerMetadata?: ProviderMetadata,
-  itemId?: ResponseItemID,
 ): State => {
  if (!state.reasoning.has(id)) return state
  const stepped = stepStart(state, events)
-  events.push(LLMEvent.reasoningEnd({ id, ...(itemId === undefined ? {} : { itemId }), providerMetadata }))
+  events.push(LLMEvent.reasoningEnd({ id, providerMetadata }))
  const reasoning = new Set(stepped.reasoning)
  reasoning.delete(id)
  return { ...stepped, reasoning }
 }

-export const textEnd = (
-  state: State,
-  events: LLMEvent[],
-  id: string,
-  providerMetadata?: ProviderMetadata,
-  itemId?: ResponseItemID,
-): State => {
+export const textEnd = (state: State, events: LLMEvent[], id: string, providerMetadata?: ProviderMetadata): State => {
  if (!state.text.has(id)) return state
  const stepped = stepStart(state, events)
-  events.push(LLMEvent.textEnd({ id, ...(itemId === undefined ? {} : { itemId }), providerMetadata }))
+  events.push(LLMEvent.textEnd({ id, providerMetadata }))
  const text = new Set(stepped.text)
  text.delete(id)
  return { ...stepped, text }
@@ -33,7 +33,6 @@ export const ServiceTierSchema = Schema.Literals(ServiceTiers)
 export interface Resolved {
  readonly instructions?: string
  readonly store?: boolean
-  readonly promptCacheKey?: string
  readonly reasoningEffort?: string
  readonly reasoningSummary?: "auto" | "concise" | "detailed"
  readonly include?: ReadonlyArray<ResponseIncludable>
@@ -50,7 +49,6 @@ export const resolve = (request: LLMRequest): Resolved => {
  return {
    instructions: typeof input?.instructions === "string" ? input.instructions : undefined,
    store: typeof input?.store === "boolean" ? input.store : undefined,
-    promptCacheKey: typeof input?.promptCacheKey === "string" ? input.promptCacheKey : undefined,
    reasoningEffort: typeof input?.reasoningEffort === "string" ? input.reasoningEffort : undefined,
    reasoningSummary:
      reasoningSummary === "auto" || reasoningSummary === "concise" || reasoningSummary === "detailed"
@@ -1,12 +1,5 @@
 import { Effect } from "effect"
-import {
-  AIError,
-  LLMEvent,
-  type ProviderMetadata,
-  type ResponseItemID,
-  type ToolCall,
-  type ToolInputError,
-} from "../../schema"
+import { AIError, LLMEvent, type ProviderMetadata, type ToolCall, type ToolInputError } from "../../schema"
 import { eventError, parseToolInput, type ToolAccumulator } from "../shared"

 type StreamKey = string | number
@@ -17,7 +10,6 @@ type StreamKey = string | number
 * so far, not the parsed object.
 */
 export interface PendingTool extends ToolAccumulator {
-  readonly itemId?: ResponseItemID
  readonly providerExecuted?: boolean
  readonly providerMetadata?: ProviderMetadata
 }
@@ -60,7 +52,6 @@ const withoutTool = <K extends StreamKey>(tools: State<K>, key: K): State<K> =>
 const inputStart = (tool: PendingTool) =>
  LLMEvent.toolInputStart({
    id: tool.id,
-    ...(tool.itemId === undefined ? {} : { itemId: tool.itemId }),
    name: tool.name,
    providerExecuted: tool.providerExecuted ? true : undefined,
    providerMetadata: tool.providerMetadata,
@@ -69,7 +60,6 @@ const inputStart = (tool: PendingTool) =>
 const inputDelta = (tool: PendingTool, text: string) =>
  LLMEvent.toolInputDelta({
    id: tool.id,
-    ...(tool.itemId === undefined ? {} : { itemId: tool.itemId }),
    name: tool.name,
    text,
  })
@@ -80,7 +70,6 @@ const toolCall = (route: string, tool: PendingTool, inputOverride?: string) => {
    Effect.map((input): ToolCall | ToolInputError =>
      LLMEvent.toolCall({
        id: tool.id,
-        ...(tool.itemId === undefined ? {} : { itemId: tool.itemId }),
        name: tool.name,
        input,
        providerExecuted: tool.providerExecuted ? true : undefined,
@@ -93,7 +82,6 @@ const toolCall = (route: string, tool: PendingTool, inputOverride?: string) => {
        : Effect.succeed(
            LLMEvent.toolInputError({
              id: tool.id,
-              ...(tool.itemId === undefined ? {} : { itemId: tool.itemId }),
              name: tool.name,
              raw,
            }),
@@ -105,15 +93,7 @@ const toolCall = (route: string, tool: PendingTool, inputOverride?: string) => {
 const finishEvents = (tool: PendingTool, event: ToolCall | ToolInputError): ReadonlyArray<LLMEvent> =>
  event.type === "tool-input-error"
    ? [event]
-    : [
-        LLMEvent.toolInputEnd({
-          id: tool.id,
-          ...(tool.itemId === undefined ? {} : { itemId: tool.itemId }),
-          name: tool.name,
-          providerMetadata: tool.providerMetadata,
-        }),
-        event,
-      ]
+    : [LLMEvent.toolInputEnd({ id: tool.id, name: tool.name, providerMetadata: tool.providerMetadata }), event]

 /** Store the updated tool and produce the optional public delta event. */
 const appendTool = <K extends StreamKey>(
@@ -168,7 +148,6 @@ export const appendOrStart = <K extends StreamKey>(
    id,
    name,
    input: `${current?.input ?? ""}${delta.text}`,
-    itemId: current?.itemId,
    providerExecuted: current?.providerExecuted,
    providerMetadata: current?.providerMetadata,
  }
@@ -5,7 +5,6 @@ export interface OpenResponsesOptionsInput {
  readonly [key: string]: unknown
  readonly instructions?: string
  readonly store?: boolean
-  readonly promptCacheKey?: string
  readonly reasoningEffort?: ReasoningEffort
  readonly reasoningSummary?: "auto" | "concise" | "detailed"
  readonly include?: ReadonlyArray<ResponseIncludable>
@@ -17,7 +17,6 @@ const openAIProviderOptions = (options: OpenAIOptionsInput | undefined): Provide
  const openai = Object.fromEntries(
    definedEntries({
      store: options?.store,
-      promptCacheKey: options?.promptCacheKey,
      reasoningEffort: options?.reasoningEffort,
      reasoningSummary: options?.reasoningSummary,
      include: options?.include,
@@ -55,7 +55,6 @@ export interface OpenRouterOptions {
  readonly debug?: Readonly<{ echo_upstream_body?: boolean }>
  readonly models?: ReadonlyArray<string>
  readonly plugins?: ReadonlyArray<OpenRouterPlugin>
-  readonly promptCacheKey?: string
  readonly provider?: OpenRouterProviderRouting
  readonly reasoning?: Readonly<{
    enabled?: boolean
@@ -122,6 +121,7 @@ export const protocol = Protocol.make({
            ...body,
            messages,
            ...bodyOptions(request.providerOptions?.openrouter),
+            ...(request.promptCacheKey ? { prompt_cache_key: request.promptCacheKey } : {}),
          } as OpenRouterBody
        }),
      ),
@@ -161,7 +161,6 @@ const bodyOptions = (input: unknown) => {
    ...(isRecord(debug) ? { debug } : {}),
    ...(typeof user === "string" ? { user } : {}),
    ...(isRecord(reasoning) ? { reasoning } : {}),
-    ...(typeof promptCacheKey === "string" ? { prompt_cache_key: promptCacheKey } : {}),
  }
 }

@@ -47,6 +47,8 @@ const chatRoute = Route.make({
  protocol: OpenAIChat.protocol,
  endpoint: Endpoint.path("/chat/completions", { baseURL: OpenAICompatibleProfiles.profiles.xai.baseURL }),
  transport: OpenAICompatibleChat.route.transport,
+  headers: ({ request }): Record<string, string> =>
+    request.promptCacheKey ? { "x-grok-conv-id": request.promptCacheKey } : {},
 })

 export const routes = [responsesRoute, chatRoute]
@@ -1,5 +1,5 @@
 import { Schema } from "effect"
-import { ContentBlockID, FinishReason, ProviderMetadata, ResponseItemID, ToolCallID } from "./ids"
+import { ContentBlockID, FinishReason, ProviderMetadata, ToolCallID } from "./ids"
 import { Message, ToolCallPart, ToolOutput, ToolResultPart, ToolResultValue, type ContentPart } from "./messages"
 import { ProviderFailureClassification } from "./errors"

@@ -84,7 +84,6 @@ export type StepStart = Schema.Schema.Type<typeof StepStart>
 export const TextStart = Schema.Struct({
  type: Schema.tag("text-start"),
  id: ContentBlockID,
-  itemId: Schema.optional(ResponseItemID),
  providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.TextStart" })
 export type TextStart = Schema.Schema.Type<typeof TextStart>
@@ -93,7 +92,6 @@ export const TextDelta = Schema.Struct({
  type: Schema.tag("text-delta"),
  id: ContentBlockID,
  text: Schema.String,
-  itemId: Schema.optional(ResponseItemID),
  providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.TextDelta" })
 export type TextDelta = Schema.Schema.Type<typeof TextDelta>
@@ -101,7 +99,6 @@ export type TextDelta = Schema.Schema.Type<typeof TextDelta>
 export const TextEnd = Schema.Struct({
  type: Schema.tag("text-end"),
  id: ContentBlockID,
-  itemId: Schema.optional(ResponseItemID),
  providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.TextEnd" })
 export type TextEnd = Schema.Schema.Type<typeof TextEnd>
@@ -109,7 +106,6 @@ export type TextEnd = Schema.Schema.Type<typeof TextEnd>
 export const ReasoningStart = Schema.Struct({
  type: Schema.tag("reasoning-start"),
  id: ContentBlockID,
-  itemId: Schema.optional(ResponseItemID),
  providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.ReasoningStart" })
 export type ReasoningStart = Schema.Schema.Type<typeof ReasoningStart>
@@ -118,7 +114,6 @@ export const ReasoningDelta = Schema.Struct({
  type: Schema.tag("reasoning-delta"),
  id: ContentBlockID,
  text: Schema.String,
-  itemId: Schema.optional(ResponseItemID),
  providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.ReasoningDelta" })
 export type ReasoningDelta = Schema.Schema.Type<typeof ReasoningDelta>
@@ -126,7 +121,6 @@ export type ReasoningDelta = Schema.Schema.Type<typeof ReasoningDelta>
 export const ReasoningEnd = Schema.Struct({
  type: Schema.tag("reasoning-end"),
  id: ContentBlockID,
-  itemId: Schema.optional(ResponseItemID),
  providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.ReasoningEnd" })
 export type ReasoningEnd = Schema.Schema.Type<typeof ReasoningEnd>
@@ -135,7 +129,6 @@ export const ToolInputStart = Schema.Struct({
  type: Schema.tag("tool-input-start"),
  id: ToolCallID,
  name: Schema.String,
-  itemId: Schema.optional(ResponseItemID),
  providerExecuted: Schema.optional(Schema.Boolean),
  providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.ToolInputStart" })
@@ -144,7 +137,6 @@ export type ToolInputStart = Schema.Schema.Type<typeof ToolInputStart>
 export const ToolInputDelta = Schema.Struct({
  type: Schema.tag("tool-input-delta"),
  id: ToolCallID,
-  itemId: Schema.optional(ResponseItemID),
  name: Schema.String,
  text: Schema.String,
 }).annotate({ identifier: "LLM.Event.ToolInputDelta" })
@@ -154,7 +146,6 @@ export const ToolInputEnd = Schema.Struct({
  type: Schema.tag("tool-input-end"),
  id: ToolCallID,
  name: Schema.String,
-  itemId: Schema.optional(ResponseItemID),
  providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.ToolInputEnd" })
 export type ToolInputEnd = Schema.Schema.Type<typeof ToolInputEnd>
@@ -163,7 +154,6 @@ export type ToolInputEnd = Schema.Schema.Type<typeof ToolInputEnd>
 export const ToolInputError = Schema.Struct({
  type: Schema.tag("tool-input-error"),
  id: ToolCallID,
-  itemId: Schema.optional(ResponseItemID),
  name: Schema.String,
  raw: Schema.String,
 }).annotate({ identifier: "LLM.Event.ToolInputError" })
@@ -172,7 +162,6 @@ export type ToolInputError = Schema.Schema.Type<typeof ToolInputError>
 export const ToolCall = Schema.Struct({
  type: Schema.tag("tool-call"),
  id: ToolCallID,
-  itemId: Schema.optional(ResponseItemID),
  name: Schema.String,
  input: Schema.Unknown,
  providerExecuted: Schema.optional(Schema.Boolean),
@@ -183,7 +172,6 @@ export type ToolCall = Schema.Schema.Type<typeof ToolCall>
 export const ToolResult = Schema.Struct({
  type: Schema.tag("tool-result"),
  id: ToolCallID,
-  itemId: Schema.optional(ResponseItemID),
  name: Schema.String,
  result: ToolResultValue,
  output: Schema.optional(ToolOutput),
@@ -195,7 +183,6 @@ export type ToolResult = Schema.Schema.Type<typeof ToolResult>
 export const ToolError = Schema.Struct({
  type: Schema.tag("tool-error"),
  id: ToolCallID,
-  itemId: Schema.optional(ResponseItemID),
  name: Schema.String,
  message: Schema.String,
  error: Schema.optional(Schema.Defect()),
@@ -347,14 +334,12 @@ const responseUsage = (events: ReadonlyArray<LLMEvent>) =>
 interface ContentAssembly {
  readonly contentIndex: number
  readonly text: string
-  readonly itemId?: ResponseItemID
  readonly providerMetadata?: ProviderMetadata
 }

 interface ToolInputAssembly {
  readonly name: string
  readonly text: string
-  readonly itemId?: ResponseItemID
  readonly providerMetadata?: ProviderMetadata
 }

@@ -400,27 +385,11 @@ const appendEvent = (state: ResponseState, event: LLMEvent): ResponseState => {
  }
 }

-const textContent = (
-  text: string,
-  itemId: ResponseItemID | undefined,
-  providerMetadata: ProviderMetadata | undefined,
-): ContentPart => ({
-  type: "text",
-  text,
-  ...(itemId === undefined ? {} : { itemId }),
-  ...(providerMetadata === undefined ? {} : { providerMetadata }),
-})
+const textContent = (text: string, providerMetadata: ProviderMetadata | undefined): ContentPart =>
+  providerMetadata === undefined ? { type: "text", text } : { type: "text", text, providerMetadata }

-const reasoningContent = (
-  text: string,
-  itemId: ResponseItemID | undefined,
-  providerMetadata: ProviderMetadata | undefined,
-): ContentPart => ({
-  type: "reasoning",
-  text,
-  ...(itemId === undefined ? {} : { itemId }),
-  ...(providerMetadata === undefined ? {} : { providerMetadata }),
-})
+const reasoningContent = (text: string, providerMetadata: ProviderMetadata | undefined): ContentPart =>
+  providerMetadata === undefined ? { type: "reasoning", text } : { type: "reasoning", text, providerMetadata }

 const contentWith = (state: ResponseState, content: ReadonlyArray<ContentPart>): ResponseState => ({
  ...state,
@@ -435,32 +404,26 @@ const replaceContent = (state: ResponseState, index: number, part: ContentPart)
    state.message.content.map((item, itemIndex) => (itemIndex === index ? part : item)),
  )

-const ensureText = (
-  state: ResponseState,
-  id: string,
-  itemId?: ResponseItemID,
-  providerMetadata?: ProviderMetadata,
-): ResponseState => {
+const ensureText = (state: ResponseState, id: string, providerMetadata?: ProviderMetadata): ResponseState => {
  if (state.textParts[id]) return state
  return {
-    ...appendContent(state, textContent("", itemId, providerMetadata)),
+    ...appendContent(state, textContent("", providerMetadata)),
    textParts: {
      ...state.textParts,
-      [id]: { contentIndex: state.message.content.length, text: "", itemId, providerMetadata },
+      [id]: { contentIndex: state.message.content.length, text: "", providerMetadata },
    },
  }
 }

 const reduceTextDelta = (state: ResponseState, event: TextDelta): ResponseState => {
-  const started = ensureText(state, event.id, event.itemId, event.providerMetadata)
+  const started = ensureText(state, event.id, event.providerMetadata)
  const current = started.textParts[event.id]
  if (!current) return started
  const text = current.text + event.text
-  const itemId = event.itemId ?? current.itemId
  const providerMetadata = event.providerMetadata ?? current.providerMetadata
  return {
-    ...replaceContent(started, current.contentIndex, textContent(text, itemId, providerMetadata)),
-    textParts: { ...started.textParts, [event.id]: { ...current, text, itemId, providerMetadata } },
+    ...replaceContent(started, current.contentIndex, textContent(text, providerMetadata)),
+    textParts: { ...started.textParts, [event.id]: { ...current, text, providerMetadata } },
  }
 }

@@ -468,39 +431,32 @@ const reduceTextEnd = (state: ResponseState, event: TextEnd): ResponseState => {
  const current = state.textParts[event.id]
  if (!current) return state
  const providerMetadata = event.providerMetadata ?? current.providerMetadata
-  const itemId = event.itemId ?? current.itemId
  return {
-    ...replaceContent(state, current.contentIndex, textContent(current.text, itemId, providerMetadata)),
-    textParts: { ...state.textParts, [event.id]: { ...current, itemId, providerMetadata } },
+    ...replaceContent(state, current.contentIndex, textContent(current.text, providerMetadata)),
+    textParts: { ...state.textParts, [event.id]: { ...current, providerMetadata } },
  }
 }

-const ensureReasoning = (
-  state: ResponseState,
-  id: string,
-  itemId?: ResponseItemID,
-  providerMetadata?: ProviderMetadata,
-): ResponseState => {
+const ensureReasoning = (state: ResponseState, id: string, providerMetadata?: ProviderMetadata): ResponseState => {
  if (state.reasoningParts[id]) return state
  return {
-    ...appendContent(state, reasoningContent("", itemId, providerMetadata)),
+    ...appendContent(state, reasoningContent("", providerMetadata)),
    reasoningParts: {
      ...state.reasoningParts,
-      [id]: { contentIndex: state.message.content.length, text: "", itemId, providerMetadata },
+      [id]: { contentIndex: state.message.content.length, text: "", providerMetadata },
    },
  }
 }

 const reduceReasoningDelta = (state: ResponseState, event: ReasoningDelta): ResponseState => {
-  const started = ensureReasoning(state, event.id, event.itemId, event.providerMetadata)
+  const started = ensureReasoning(state, event.id, event.providerMetadata)
  const current = started.reasoningParts[event.id]
  if (!current) return started
  const text = current.text + event.text
-  const itemId = event.itemId ?? current.itemId
  const providerMetadata = event.providerMetadata ?? current.providerMetadata
  return {
-    ...replaceContent(started, current.contentIndex, reasoningContent(text, itemId, providerMetadata)),
-    reasoningParts: { ...started.reasoningParts, [event.id]: { ...current, text, itemId, providerMetadata } },
+    ...replaceContent(started, current.contentIndex, reasoningContent(text, providerMetadata)),
+    reasoningParts: { ...started.reasoningParts, [event.id]: { ...current, text, providerMetadata } },
  }
 }

@@ -508,10 +464,9 @@ const reduceReasoningEnd = (state: ResponseState, event: ReasoningEnd): Response
  const current = state.reasoningParts[event.id]
  if (!current) return state
  const providerMetadata = event.providerMetadata ?? current.providerMetadata
-  const itemId = event.itemId ?? current.itemId
  return {
-    ...replaceContent(state, current.contentIndex, reasoningContent(current.text, itemId, providerMetadata)),
-    reasoningParts: { ...state.reasoningParts, [event.id]: { ...current, itemId, providerMetadata } },
+    ...replaceContent(state, current.contentIndex, reasoningContent(current.text, providerMetadata)),
+    reasoningParts: { ...state.reasoningParts, [event.id]: { ...current, providerMetadata } },
  }
 }

@@ -519,7 +474,7 @@ const reduceToolInputStart = (state: ResponseState, event: ToolInputStart): Resp
  ...state,
  toolInputs: {
    ...state.toolInputs,
-    [event.id]: { name: event.name, text: "", itemId: event.itemId, providerMetadata: event.providerMetadata },
+    [event.id]: { name: event.name, text: "", providerMetadata: event.providerMetadata },
  },
 })

@@ -540,7 +495,6 @@ const reduceToolInputEnd = (state: ResponseState, event: ToolInputEnd): Response
      [event.id]: {
        ...current,
        name: event.name,
-        itemId: event.itemId ?? current.itemId,
        providerMetadata: event.providerMetadata ?? current.providerMetadata,
      },
    },
@@ -550,7 +504,6 @@ const reduceToolInputEnd = (state: ResponseState, event: ToolInputEnd): Response
 const toolCallContent = (event: ToolCall): ContentPart =>
  ToolCallPart.make({
    id: event.id,
-    ...(event.itemId === undefined ? {} : { itemId: event.itemId }),
    name: event.name,
    input: event.input,
    ...(event.providerExecuted === undefined ? {} : { providerExecuted: event.providerExecuted }),
@@ -560,7 +513,6 @@ const toolCallContent = (event: ToolCall): ContentPart =>
 const toolResultContent = (event: ToolResult): ContentPart =>
  ToolResultPart.make({
    id: event.id,
-    ...(event.itemId === undefined ? {} : { itemId: event.itemId }),
    name: event.name,
    result: event.result,
    ...(event.providerExecuted === undefined ? {} : { providerExecuted: event.providerExecuted }),
@@ -576,13 +528,13 @@ const reduceResponseState = (state: ResponseState, event: LLMEvent): ResponseSta
  const next = appendEvent(state, event)
  switch (event.type) {
    case "text-start":
-      return ensureText(next, event.id, event.itemId, event.providerMetadata)
+      return ensureText(next, event.id, event.providerMetadata)
    case "text-delta":
      return reduceTextDelta(next, event)
    case "text-end":
      return reduceTextEnd(next, event)
    case "reasoning-start":
-      return ensureReasoning(next, event.id, event.itemId, event.providerMetadata)
+      return ensureReasoning(next, event.id, event.providerMetadata)
    case "reasoning-delta":
      return reduceReasoningDelta(next, event)
    case "reasoning-end":
@@ -21,9 +21,6 @@ export type ProviderID = typeof ProviderID.Type
 export const ResponseID = Schema.String
 export type ResponseID = Schema.Schema.Type<typeof ResponseID>

-export const ResponseItemID = Schema.String
-export type ResponseItemID = Schema.Schema.Type<typeof ResponseItemID>
-
 export const ContentBlockID = Schema.String
 export type ContentBlockID = Schema.Schema.Type<typeof ContentBlockID>

@@ -1,6 +1,6 @@
 import { Schema } from "effect"
 import { Tool } from "@opencode-ai/schema/tool"
-import { JsonSchema, MessageRole, ProviderMetadata, ResponseItemID } from "./ids"
+import { JsonSchema, MessageRole, ProviderMetadata } from "./ids"
 import { CacheHint, CachePolicy, GenerationOptions, HttpOptions, LanguageModelSchema, ProviderOptions } from "./options"
 import { isRecord } from "../utils/record"

@@ -25,7 +25,6 @@ export const SystemPart = Object.assign(systemPartSchema, {
 export const TextPart = Schema.Struct({
  type: Schema.Literal("text"),
  text: Schema.String,
-  itemId: Schema.optional(ResponseItemID),
  cache: Schema.optional(CacheHint),
  metadata: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
  providerMetadata: Schema.optional(ProviderMetadata),
@@ -122,7 +121,6 @@ export const ToolCallPart = Object.assign(
  Schema.Struct({
    type: Schema.Literal("tool-call"),
    id: Schema.String,
-    itemId: Schema.optional(ResponseItemID),
    name: Schema.String,
    input: Schema.Unknown,
    providerExecuted: Schema.optional(Schema.Boolean),
@@ -140,7 +138,6 @@ export const ToolResultPart = Object.assign(
  Schema.Struct({
    type: Schema.Literal("tool-result"),
    id: Schema.String,
-    itemId: Schema.optional(ResponseItemID),
    name: Schema.String,
    result: ToolResultValue,
    providerExecuted: Schema.optional(Schema.Boolean),
@@ -157,7 +154,6 @@ export const ToolResultPart = Object.assign(
    ): ToolResultPart => ({
      type: "tool-result",
      id: input.id,
-      ...(input.itemId === undefined ? {} : { itemId: input.itemId }),
      name: input.name,
      result: ToolResultValue.make(input.result, input.resultType),
      providerExecuted: input.providerExecuted,
@@ -172,7 +168,6 @@ export type ToolResultPart = Schema.Schema.Type<typeof ToolResultPart>
 export const ReasoningPart = Schema.Struct({
  type: Schema.Literal("reasoning"),
  text: Schema.String,
-  itemId: Schema.optional(ResponseItemID),
  encrypted: Schema.optional(Schema.String),
  cache: Schema.optional(CacheHint),
  metadata: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
@@ -186,7 +181,7 @@ export const ContentPart = Schema.Union([TextPart, MediaPart, ToolCallPart, Tool
 export type ContentPart = Schema.Schema.Type<typeof ContentPart>

 export class Message extends Schema.Class<Message>("LLM.Message")({
-  id: Schema.optional(ResponseItemID),
+  id: Schema.optional(Schema.String),
  role: MessageRole,
  content: Schema.Array(ContentPart),
  metadata: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
@@ -277,6 +272,8 @@ export class LLMRequest extends Schema.Class<LLMRequest>("LLM.Request")({
  providerOptions: Schema.optional(ProviderOptions),
  http: Schema.optional(HttpOptions),
  cache: Schema.optional(CachePolicy),
+  // Stable cache affinity for protocols that support provider-managed prompt caching.
+  promptCacheKey: Schema.optional(Schema.String),
  metadata: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
 }) {}

@@ -294,6 +291,7 @@ export namespace LLMRequest {
    providerOptions: request.providerOptions,
    http: request.http,
    cache: request.cache,
+    promptCacheKey: request.promptCacheKey,
    metadata: request.metadata,
  })

@@ -79,7 +79,7 @@ const result = (call: ToolCallPart, value: ToolResultValueType | ToolSettlement,
              id: call.id,
              name: call.name,
              result: settlement.result,
-              ...(call.providerMetadata === undefined ? {} : { providerMetadata: call.providerMetadata }),
+              providerMetadata: call.providerMetadata,
            }),
          ]
        : [
@@ -88,7 +88,7 @@ const result = (call: ToolCallPart, value: ToolResultValueType | ToolSettlement,
              name: call.name,
              result: settlement.result,
              output: settlement.output,
-              ...(call.providerMetadata === undefined ? {} : { providerMetadata: call.providerMetadata }),
+              providerMetadata: call.providerMetadata,
            }),
          ],
  }
@@ -44,7 +44,7 @@
        "headers": {
          "content-type": "application/json"
        },
-        "body": "{\"model\":\"gpt-5.5\",\"input\":[{\"role\":\"user\",\"content\":[{\"type\":\"input_text\",\"text\":\"Think briefly, then reply exactly with: Hello!\"}]},{\"type\":\"reasoning\",\"summary\":[],\"encrypted_content\":\"gAAAAABqEjXoGMCw3WDXpoD9151PEr2Lt8raW7KBKefQhZJGWx5f8jy152bApO6oE-Mr1BhUtfZNq3OPBVfSL4ioQ9bHREfujIBXgk9LUDBAz2Sle7KjOr9HaUV16A4HBiaFIRFjsHPS9G8yEySp1m6F1CD_WR6apyUGgugRh_y39EcOJmxPOzmiac5DVM6fraA1VpcGbqrZ1x2ANHFDOfnYTycPtPNTgzE7LjkYjDDWbT03uN1YxfP4pqjDVRzY14pA8bSZ8ys-pDv5kUFCAsw-OlU4jYKUXp-M8_6KTaRQP71LPwppt__zG_NJPfy-qUil4pOU8_NoxtxerHgLLXbfExZdzfpoGinoEjn7nj7BJDEtl-LNeNEb5c-1ZymNfVMp-Cs3fLEPkAV8rtHFtZ0MhE_07GKbGo7hTrOmkM4DydxmHsdWGNbXAG35cprslEA5P7p3GHFKnRs5hGs2eq-XcZ3yki64ZBOU_Tv6UR7nUH09gF1rdrJo3dpre6M00COwwdZ02zUP5KxCuI8FKu2jsZu9zgMVXDALsdtM5orTCVLXsn4rddWd111zE-vMjNmMMmktW2cHMjH7j1ooA-9P083koNVYiLi4UhMA64gTqgyl8MxkZekl7eFSMa7qk295NaHOKtFxzYYcZ9jdioCwSPSZ0ZZWLoNgrK7SWfRh0uaTHNcMZ3wq8ae6CguktIeVTCPTQAqJLQqd7AU0oOCKCJ7BWnC-L8UC6m7Pm9ZS958uUVeWBhgKHzMAGq9UeQB7IEeAcbMn3EDgOSfd8qCb8iwU9iG9dcu9axQwWU7pd7kd-T-He61W7z5wWgpx1KehWCxrN6kuKSo6p-uUfwVnJukreOn8BJNAzADQgz68bhmN9VGih7YcKVnLgwDwKditrjSd6-tfE0Baarj3jWENvT6ohY17R9FDrKS-2v8IIX6tGjoKJw8SRhaWLNv4vWlmxRgR0gdac3qumd0GKqsWSveNz01naA==\",\"id\":\"rs_0a0794dab3b8ec7d016a1235e7ce3881958a5eca32a36a14c5\"},{\"role\":\"assistant\",\"content\":[{\"type\":\"output_text\",\"text\":\"Hello!\"}]},{\"role\":\"user\",\"content\":[{\"type\":\"input_text\",\"text\":\"Now reply exactly with: Done.\"}]}],\"store\":false,\"include\":[\"reasoning.encrypted_content\"],\"reasoning\":{\"effort\":\"low\",\"summary\":\"auto\"},\"text\":{\"verbosity\":\"low\"},\"max_output_tokens\":40,\"stream\":true}"
+        "body": "{\"model\":\"gpt-5.5\",\"input\":[{\"role\":\"user\",\"content\":[{\"type\":\"input_text\",\"text\":\"Think briefly, then reply exactly with: Hello!\"}]},{\"type\":\"reasoning\",\"summary\":[],\"encrypted_content\":\"gAAAAABqEjXoGMCw3WDXpoD9151PEr2Lt8raW7KBKefQhZJGWx5f8jy152bApO6oE-Mr1BhUtfZNq3OPBVfSL4ioQ9bHREfujIBXgk9LUDBAz2Sle7KjOr9HaUV16A4HBiaFIRFjsHPS9G8yEySp1m6F1CD_WR6apyUGgugRh_y39EcOJmxPOzmiac5DVM6fraA1VpcGbqrZ1x2ANHFDOfnYTycPtPNTgzE7LjkYjDDWbT03uN1YxfP4pqjDVRzY14pA8bSZ8ys-pDv5kUFCAsw-OlU4jYKUXp-M8_6KTaRQP71LPwppt__zG_NJPfy-qUil4pOU8_NoxtxerHgLLXbfExZdzfpoGinoEjn7nj7BJDEtl-LNeNEb5c-1ZymNfVMp-Cs3fLEPkAV8rtHFtZ0MhE_07GKbGo7hTrOmkM4DydxmHsdWGNbXAG35cprslEA5P7p3GHFKnRs5hGs2eq-XcZ3yki64ZBOU_Tv6UR7nUH09gF1rdrJo3dpre6M00COwwdZ02zUP5KxCuI8FKu2jsZu9zgMVXDALsdtM5orTCVLXsn4rddWd111zE-vMjNmMMmktW2cHMjH7j1ooA-9P083koNVYiLi4UhMA64gTqgyl8MxkZekl7eFSMa7qk295NaHOKtFxzYYcZ9jdioCwSPSZ0ZZWLoNgrK7SWfRh0uaTHNcMZ3wq8ae6CguktIeVTCPTQAqJLQqd7AU0oOCKCJ7BWnC-L8UC6m7Pm9ZS958uUVeWBhgKHzMAGq9UeQB7IEeAcbMn3EDgOSfd8qCb8iwU9iG9dcu9axQwWU7pd7kd-T-He61W7z5wWgpx1KehWCxrN6kuKSo6p-uUfwVnJukreOn8BJNAzADQgz68bhmN9VGih7YcKVnLgwDwKditrjSd6-tfE0Baarj3jWENvT6ohY17R9FDrKS-2v8IIX6tGjoKJw8SRhaWLNv4vWlmxRgR0gdac3qumd0GKqsWSveNz01naA==\"},{\"role\":\"assistant\",\"content\":[{\"type\":\"output_text\",\"text\":\"Hello!\"}]},{\"role\":\"user\",\"content\":[{\"type\":\"input_text\",\"text\":\"Now reply exactly with: Done.\"}]}],\"store\":false,\"include\":[\"reasoning.encrypted_content\"],\"reasoning\":{\"effort\":\"low\",\"summary\":\"auto\"},\"text\":{\"verbosity\":\"low\"},\"max_output_tokens\":40,\"stream\":true}"
      },
      "response": {
        "status": 200,
@@ -8,6 +8,7 @@ import {
  type ProviderMetadata,
  type ToolCallPart,
  ToolResultPart,
+  type ToolResultValue,
  type Usage,
 } from "../../src/schema"
 import { type Tools, toDefinitions } from "../../src/tool"
@@ -60,10 +61,9 @@ export const runTools = <T extends Tools>(options: RunOptions<T>) =>
            ...dispatched.map(([call, dispatched]) =>
              Message.tool({
                id: call.id,
-                itemId: dispatched.events.find(LLMEvent.is.toolResult)?.itemId,
                name: call.name,
                result: dispatched.result,
-                providerMetadata: dispatched.events.find(LLMEvent.is.toolResult)?.providerMetadata,
+                providerMetadata: call.providerMetadata,
              }),
            ),
          ],
@@ -89,15 +89,9 @@ const stepState = (events: ReadonlyArray<LLMEvent>) => {

  for (const event of events) {
    if (event.type === "text-delta" || event.type === "reasoning-delta") {
-      appendText(assistantContent, event.type === "text-delta" ? "text" : "reasoning", event.text, event.itemId)
+      appendText(assistantContent, event.type === "text-delta" ? "text" : "reasoning", event.text)
    } else if (event.type === "text-end" || event.type === "reasoning-end") {
-      appendText(
-        assistantContent,
-        event.type === "text-end" ? "text" : "reasoning",
-        "",
-        event.itemId,
-        event.providerMetadata,
-      )
+      appendText(assistantContent, event.type === "text-end" ? "text" : "reasoning", "", event.providerMetadata)
    } else if (event.type === "tool-call") {
      assistantContent.push(event)
      if (!event.providerExecuted) toolCalls.push(event)
@@ -105,7 +99,6 @@ const stepState = (events: ReadonlyArray<LLMEvent>) => {
      assistantContent.push(
        ToolResultPart.make({
          id: event.id,
-          itemId: event.itemId,
          name: event.name,
          result: event.result,
          providerExecuted: true,
@@ -125,7 +118,6 @@ const appendText = (
  content: ContentPart[],
  type: "text" | "reasoning",
  text: string,
-  itemId?: string,
  providerMetadata?: ProviderMetadata,
 ) => {
  const last = content.at(-1)
@@ -133,12 +125,11 @@ const appendText = (
    content[content.length - 1] = {
      ...last,
      text: `${last.text}${text}`,
-      itemId: itemId ?? last.itemId,
      providerMetadata: providerMetadata ?? last.providerMetadata,
    }
    return
  }
-  content.push({ type, text, itemId, providerMetadata })
+  content.push({ type, text, providerMetadata })
 }

 const addUsage = (left: Usage | undefined, right: Usage | undefined): Usage | undefined => {
@@ -3,11 +3,11 @@ import { CloudflareWorkersAI } from "../../src/providers"

 const model = CloudflareWorkersAI.configure({ accountId: "account", apiKey: "test" }).model("model")

-LLM.request({ model, prompt: "Hello", providerOptions: { openai: { promptCacheKey: "cache" } } })
+LLM.request({ model, prompt: "Hello", promptCacheKey: "cache" })

 LLM.request({
  model,
  prompt: "Hello",
-  // @ts-expect-error Cloudflare's OpenAI-compatible prompt cache key must be a string.
-  providerOptions: { openai: { promptCacheKey: 1 } },
+  // @ts-expect-error Prompt cache keys must be strings.
+  promptCacheKey: 1,
 })
@@ -15,6 +15,8 @@ import {
 } from "../../src"
 import * as Azure from "../../src/providers/azure"
 import * as OpenAI from "../../src/providers/openai"
+import * as OpenAICompatible from "../../src/providers/openai-compatible"
+import * as XAI from "../../src/providers/xai"
 import * as OpenAIChat from "../../src/protocols/openai-chat"
 import { ProviderShared } from "../../src/protocols/shared"
 import { Auth, LLMClient } from "../../src/route"
@@ -154,6 +156,47 @@ describe("OpenAI Chat route", () => {
    }),
  )

+  it.effect("maps the request prompt cache key", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model: OpenAICompatible.configure({
+            baseURL: "https://api.compatible.test/v1",
+            apiKey: "test",
+          }).model("compatible-model"),
+          prompt: "Hello",
+          promptCacheKey: "session_123",
+        }),
+      )
+
+      expect(prepared.body.prompt_cache_key).toBe("session_123")
+    }),
+  )
+
+  it.effect("maps the xAI Chat prompt cache key to conversation affinity", () =>
+    LLMClient.generate(
+      LLM.request({
+        model: XAI.configure({ apiKey: "test", baseURL: "https://api.x.ai/v1" }).chat("grok-4.5"),
+        prompt: "Hello",
+        promptCacheKey: "session_123",
+      }),
+    ).pipe(
+      Effect.provide(
+        dynamicResponse((input) =>
+          Effect.gen(function* () {
+            const web = yield* HttpClientRequest.toWeb(input.request).pipe(Effect.orDie)
+            expect(web.headers.get("x-grok-conv-id")).toBe("session_123")
+            const body = decodeJson(yield* Effect.promise(() => web.text()))
+            expect(ProviderShared.isRecord(body) ? body.prompt_cache_key : undefined).toBe("session_123")
+            return input.respond(sseEvents(deltaChunk({}, "stop")), {
+              headers: { "content-type": "text/event-stream" },
+            })
+          }),
+        ),
+      ),
+    ),
+  )
+
  it.effect("passes through custom OpenAI-compatible reasoning effort strings", () =>
    Effect.gen(function* () {
      const prepared = yield* compileRequest(
@@ -45,7 +45,7 @@ describe("Open Responses-compatible route", () => {
          },
        },
      })
-      expect(prepared.body).toMatchObject({
+      expect(prepared.body).toEqual({
        model: "example-model",
        input: [
          { role: "system", content: "You are concise." },
@@ -53,8 +53,6 @@ describe("Open Responses-compatible route", () => {
        ],
        stream: true,
      })
-      expect(prepared.body.input[0]).not.toHaveProperty("id")
-      expect(prepared.body.input[1]).not.toHaveProperty("id")
    }),
  )

@@ -20,7 +20,7 @@ const cacheRequest = LLM.request({
  system: LARGE_CACHEABLE_SYSTEM,
  prompt: "Say hi.",
  generation: { maxTokens: 16, temperature: 0 },
-  providerOptions: { openai: { promptCacheKey: "recorded-cache-test" } },
+  promptCacheKey: "recorded-cache-test",
 })

 const recorded = recordedTests({
@@ -69,9 +69,6 @@ describe("OpenAI Responses route", () => {
        stream: true,
        max_output_tokens: 20,
        temperature: 0,
-        tool_choice: undefined,
-        tools: undefined,
-        top_p: undefined,
      })
    }),
  )
@@ -332,7 +329,7 @@ describe("OpenAI Responses route", () => {
      yield* LLMClient.generate(
        LLMRequest.update(request, {
          model: Azure.configure({
-            baseURL: "https://opencode-test.openai.azure.com/openai/",
+            baseURL: "https://opencode-test.openai.azure.com/openai/v1/",
            apiKey: "azure-key",
            headers: { authorization: "Bearer stale" },
          }).responses("gpt-4.1-mini"),
@@ -413,7 +410,7 @@ describe("OpenAI Responses route", () => {
        }),
      )

-      expect(prepared.body).toMatchObject({
+      expect(prepared.body).toEqual({
        model: "gpt-4.1-mini",
        input: [
          { role: "user", content: [{ type: "input_text", text: "What is the weather?" }] },
@@ -428,60 +425,6 @@ describe("OpenAI Responses route", () => {
        tools: undefined,
        top_p: undefined,
      })
-      const call = prepared.body.input.find((item) => "type" in item && item.type === "function_call")
-      const output = prepared.body.input.find((item) => "type" in item && item.type === "function_call_output")
-      expect(call?.id).toBeUndefined()
-      expect(output?.id).toBeUndefined()
-    }),
-  )
-
-  it.effect("does not generate response item ids for client-created history", () =>
-    Effect.sync(() => {
-      const canonical = LLM.request({
-        model,
-        messages: [
-          Message.assistant([
-            { type: "text", text: "Working." },
-            { type: "reasoning", text: "Thinking." },
-            ToolCallPart.make({ id: "call_1", name: "lookup", input: {} }),
-          ]),
-          Message.tool({ id: "call_1", name: "lookup", result: "done" }),
-        ],
-      })
-
-      expect(canonical.messages[0]?.id).toBeUndefined()
-      expect(canonical.messages[1]?.id).toBeUndefined()
-      expect(canonical.messages[0]?.content.every((part) => part.type === "media" || part.itemId === undefined)).toBe(
-        true,
-      )
-      expect(canonical.messages[1]?.content[0]).not.toHaveProperty("itemId")
-    }),
-  )
-
-  it.effect("preserves opaque assistant item ids without assigning ids to function items", () =>
-    Effect.gen(function* () {
-      const canonical = LLM.request({
-        model,
-        messages: [
-          Message.assistant([
-            { type: "text", text: "Calling.", itemId: "plain-text" },
-            ToolCallPart.make({ id: "call_1", itemId: "plain-call", name: "lookup", input: {} }),
-          ]),
-          Message.tool({ id: "call_1", itemId: "plain-output", name: "lookup", result: "done" }),
-        ],
-      })
-      const prepared = yield* compileRequest(canonical)
-
-      expect(canonical.messages[0]?.content.map((part) => (part.type === "media" ? undefined : part.itemId))).toEqual([
-        "plain-text",
-        "plain-call",
-      ])
-      expect(canonical.messages[1]?.content[0]).toMatchObject({ itemId: "plain-output" })
-      expect(prepared.body.input).toEqual([
-        { role: "assistant", id: "plain-text", content: [{ type: "output_text", text: "Calling." }] },
-        { type: "function_call", call_id: "call_1", name: "lookup", arguments: "{}" },
-        { type: "function_call_output", call_id: "call_1", output: '"done"' },
-      ])
    }),
  )

@@ -739,9 +682,9 @@ describe("OpenAI Responses route", () => {
        LLM.request({
          model: OpenAI.configure({ baseURL: "https://api.openai.test/v1/", apiKey: "test" }).model("gpt-5.2"),
          prompt: "think",
+          promptCacheKey: "session_123",
          providerOptions: {
            openai: {
-              promptCacheKey: "session_123",
              reasoningEffort: "high",
              reasoningSummary: "auto",
              include: ["reasoning.encrypted_content"],
@@ -860,17 +803,16 @@ describe("OpenAI Responses route", () => {
    }),
  )

-  it.effect("request OpenAI provider options override route defaults", () =>
+  it.effect("maps the request prompt cache key", () =>
    Effect.gen(function* () {
      const prepared = yield* compileRequest(
        LLM.request({
          model: OpenAI.configure({
            baseURL: "https://api.openai.test/v1/",
            apiKey: "test",
-            providerOptions: { openai: { promptCacheKey: "model_cache" } },
          }).model("gpt-4.1-mini"),
          prompt: "no cache",
-          providerOptions: { openai: { promptCacheKey: "request_cache" } },
+          promptCacheKey: "request_cache",
        }),
      )

@@ -921,21 +863,9 @@ describe("OpenAI Responses route", () => {
      expect(response.text).toBe("Hello!")
      expect(response.events).toEqual([
        { type: "step-start", index: 0 },
-        { type: "text-start", id: "msg_1", itemId: "msg_1", providerMetadata: { openai: { itemId: "msg_1" } } },
-        {
-          type: "text-delta",
-          id: "msg_1",
-          itemId: "msg_1",
-          text: "Hello",
-          providerMetadata: { openai: { itemId: "msg_1" } },
-        },
-        {
-          type: "text-delta",
-          id: "msg_1",
-          itemId: "msg_1",
-          text: "!",
-          providerMetadata: { openai: { itemId: "msg_1" } },
-        },
+        { type: "text-start", id: "msg_1" },
+        { type: "text-delta", id: "msg_1", text: "Hello" },
+        { type: "text-delta", id: "msg_1", text: "!" },
        { type: "text-end", id: "msg_1" },
        {
          type: "step-finish",
@@ -992,20 +922,17 @@ describe("OpenAI Responses route", () => {
        {
          type: "text",
          text: "Checking.",
-          itemId: "msg_commentary",
-          providerMetadata: { openai: { itemId: "msg_commentary", phase: "commentary" } },
+          providerMetadata: { openai: { phase: "commentary" } },
        },
        {
          type: "text",
          text: "Finished.",
-          itemId: "msg_final",
-          providerMetadata: { openai: { itemId: "msg_final", phase: "final_answer" } },
+          providerMetadata: { openai: { phase: "final_answer" } },
        },
        {
          type: "text",
          text: "Unclassified.",
-          itemId: "msg_null",
-          providerMetadata: { openai: { itemId: "msg_null", phase: null } },
+          providerMetadata: { openai: { phase: null } },
        },
      ])

@@ -1013,19 +940,16 @@ describe("OpenAI Responses route", () => {
      expect(prepared.body.input).toEqual([
        {
          role: "assistant",
-          id: "msg_commentary",
          content: [{ type: "output_text", text: "Checking." }],
          phase: "commentary",
        },
        {
          role: "assistant",
-          id: "msg_final",
          content: [{ type: "output_text", text: "Finished." }],
          phase: "final_answer",
        },
        {
          role: "assistant",
-          id: "msg_null",
          content: [{ type: "output_text", text: "Unclassified." }],
          phase: null,
        },
@@ -1118,24 +1042,12 @@ describe("OpenAI Responses route", () => {
      )

      expect(response.events.filter((event) => event.type.startsWith("text-"))).toEqual([
-        { type: "text-start", id: "msg_1", itemId: "msg_1", providerMetadata: { openai: { itemId: "msg_1" } } },
-        {
-          type: "text-delta",
-          id: "msg_1",
-          itemId: "msg_1",
-          text: "First",
-          providerMetadata: { openai: { itemId: "msg_1" } },
-        },
-        { type: "text-end", id: "msg_1", itemId: "msg_1", providerMetadata: { openai: { itemId: "msg_1" } } },
-        { type: "text-start", id: "msg_2", itemId: "msg_2", providerMetadata: { openai: { itemId: "msg_2" } } },
-        {
-          type: "text-delta",
-          id: "msg_2",
-          itemId: "msg_2",
-          text: "Second",
-          providerMetadata: { openai: { itemId: "msg_2" } },
-        },
-        { type: "text-end", id: "msg_2", itemId: "msg_2", providerMetadata: { openai: { itemId: "msg_2" } } },
+        { type: "text-start", id: "msg_1" },
+        { type: "text-delta", id: "msg_1", text: "First" },
+        { type: "text-end", id: "msg_1" },
+        { type: "text-start", id: "msg_2" },
+        { type: "text-delta", id: "msg_2", text: "Second" },
+        { type: "text-end", id: "msg_2" },
      ])
    }),
  )
@@ -1155,15 +1067,9 @@ describe("OpenAI Responses route", () => {
      expect(response.text).toBe("Hello")
      expect(response.events).toMatchObject([
        { type: "step-start", index: 0 },
-        { type: "reasoning-start", id: "rs_1", itemId: "rs_1", providerMetadata: { openai: { itemId: "rs_1" } } },
-        {
-          type: "reasoning-delta",
-          id: "rs_1",
-          itemId: "rs_1",
-          text: "thinking",
-          providerMetadata: { openai: { itemId: "rs_1" } },
-        },
-        { type: "text-start", id: "msg_1", itemId: "msg_1", providerMetadata: { openai: { itemId: "msg_1" } } },
+        { type: "reasoning-start", id: "rs_1" },
+        { type: "reasoning-delta", id: "rs_1", text: "thinking" },
+        { type: "text-start", id: "msg_1" },
        { type: "text-delta", id: "msg_1", text: "Hello" },
        { type: "reasoning-end", id: "rs_1" },
        { type: "text-end", id: "msg_1" },
@@ -1172,8 +1078,8 @@ describe("OpenAI Responses route", () => {
      ])
      expect(response.events.filter((event) => event.type === "finish")).toHaveLength(1)
      expect(response.message.content).toEqual([
-        { type: "reasoning", text: "thinking", itemId: "rs_1", providerMetadata: { openai: { itemId: "rs_1" } } },
-        { type: "text", text: "Hello", itemId: "msg_1", providerMetadata: { openai: { itemId: "msg_1" } } },
+        { type: "reasoning", text: "thinking" },
+        { type: "text", text: "Hello" },
      ])
    }),
  )
@@ -1204,7 +1110,6 @@ describe("OpenAI Responses route", () => {
        expect.objectContaining({
          type: "reasoning-end",
          id: "rs_1",
-          itemId: "rs_1",
          providerMetadata: { openai: { itemId: "rs_1", reasoningEncryptedContent: "encrypted-state" } },
        }),
      )
@@ -1245,34 +1150,19 @@ describe("OpenAI Responses route", () => {
        {
          type: "reasoning-start",
          id: "rs_1:0",
-          itemId: "rs_1",
          providerMetadata: { openai: { itemId: "rs_1", reasoningEncryptedContent: null } },
        },
-        {
-          type: "reasoning-delta",
-          id: "rs_1:0",
-          itemId: "rs_1",
-          text: "First",
-          providerMetadata: { openai: { itemId: "rs_1" } },
-        },
-        { type: "reasoning-end", id: "rs_1:0", itemId: "rs_1", providerMetadata: { openai: { itemId: "rs_1" } } },
+        { type: "reasoning-delta", id: "rs_1:0", text: "First" },
+        { type: "reasoning-end", id: "rs_1:0", providerMetadata: { openai: { itemId: "rs_1" } } },
        {
          type: "reasoning-start",
          id: "rs_1:1",
-          itemId: "rs_1",
          providerMetadata: { openai: { itemId: "rs_1", reasoningEncryptedContent: null } },
        },
-        {
-          type: "reasoning-delta",
-          id: "rs_1:1",
-          itemId: "rs_1",
-          text: "Second",
-          providerMetadata: { openai: { itemId: "rs_1" } },
-        },
+        { type: "reasoning-delta", id: "rs_1:1", text: "Second" },
        {
          type: "reasoning-end",
          id: "rs_1:1",
-          itemId: "rs_1",
          providerMetadata: { openai: { itemId: "rs_1", reasoningEncryptedContent: "encrypted-state" } },
        },
        { type: "step-finish", index: 0, reason: { normalized: "stop", raw: undefined } },
@@ -1310,8 +1200,8 @@ describe("OpenAI Responses route", () => {
      )

      expect(response.events.filter((event) => event.type === "reasoning-end")).toEqual([
-        { type: "reasoning-end", id: "rs_1:0", itemId: "rs_1", providerMetadata: { openai: { itemId: "rs_1" } } },
-        { type: "reasoning-end", id: "rs_1:1", itemId: "rs_1", providerMetadata: { openai: { itemId: "rs_1" } } },
+        { type: "reasoning-end", id: "rs_1:0", providerMetadata: { openai: { itemId: "rs_1" } } },
+        { type: "reasoning-end", id: "rs_1:1", providerMetadata: { openai: { itemId: "rs_1" } } },
      ])
    }),
  )
@@ -1359,7 +1249,7 @@ describe("OpenAI Responses route", () => {
                  { role: "user", content: [{ type: "input_text", text: "Summarize it." }] },
                ],
              })
-              expect(body.input[1]).toHaveProperty("id", "rs_1")
+              expect(body.input[1]).not.toHaveProperty("id")
              return input.respond(
                sseEvents(
                  { type: "response.output_text.delta", item_id: "msg_1", delta: "Parser now round-trips reasoning." },
@@ -1406,7 +1296,6 @@ describe("OpenAI Responses route", () => {
        { role: "assistant", content: [{ type: "output_text", text: "Before." }] },
        {
          type: "reasoning",
-          id: "rs_1",
          encrypted_content: "encrypted-state",
          summary: [{ type: "summary_text", text: "Checked order." }],
        },
@@ -1415,7 +1304,7 @@ describe("OpenAI Responses route", () => {
    }),
  )

-  it.effect("replays complete stored reasoning items with their id", () =>
+  it.effect("references stored reasoning items by id", () =>
    Effect.gen(function* () {
      const prepared = yield* compileRequest(
        LLM.request({
@@ -1433,14 +1322,7 @@ describe("OpenAI Responses route", () => {
        }),
      )

-      expect(prepared.body.input).toEqual([
-        {
-          type: "reasoning",
-          id: "rs_1",
-          summary: [{ type: "summary_text", text: "Checked the previous diff." }],
-          encrypted_content: undefined,
-        },
-      ])
+      expect(prepared.body.input).toEqual([{ type: "item_reference", id: "rs_1" }])
    }),
  )

@@ -1549,7 +1431,6 @@ describe("OpenAI Responses route", () => {
      expect(prepared.body.input).toEqual([
        {
          type: "reasoning",
-          id: "rs_1",
          encrypted_content: "encrypted-state",
          summary: [
            { type: "summary_text", text: "First" },
@@ -1629,7 +1510,6 @@ describe("OpenAI Responses route", () => {
        outputTokens: 1,
        nonCachedInputTokens: 5,
        cacheReadInputTokens: undefined,
-        cacheWriteInputTokens: undefined,
        reasoningTokens: undefined,
        totalTokens: 6,
        providerMetadata: { openai: { input_tokens: 5, output_tokens: 1 } },
@@ -1640,35 +1520,30 @@ describe("OpenAI Responses route", () => {
        {
          type: "tool-input-start",
          id: "call_1",
-          itemId: "item_1",
          name: "lookup",
          providerMetadata: { openai: { itemId: "item_1" } },
        },
        {
          type: "tool-input-delta",
          id: "call_1",
-          itemId: "item_1",
          name: "lookup",
          text: '{"query"',
        },
        {
          type: "tool-input-delta",
          id: "call_1",
-          itemId: "item_1",
          name: "lookup",
          text: ':"weather"}',
        },
        {
          type: "tool-input-end",
          id: "call_1",
-          itemId: "item_1",
          name: "lookup",
          providerMetadata: { openai: { itemId: "item_1" } },
        },
        {
          type: "tool-call",
          id: "call_1",
-          itemId: "item_1",
          name: "lookup",
          input: { query: "weather" },
          providerExecuted: undefined,
@@ -1688,17 +1563,6 @@ describe("OpenAI Responses route", () => {
          usage,
        },
      ])
-      expect(response.message.content).toEqual([
-        {
-          type: "tool-call",
-          id: "call_1",
-          itemId: "item_1",
-          name: "lookup",
-          input: { query: "weather" },
-          providerExecuted: undefined,
-          providerMetadata: { openai: { itemId: "item_1" } },
-        },
-      ])
    }),
  )

@@ -1731,7 +1595,6 @@ describe("OpenAI Responses route", () => {
      expect(response.events.find(LLMEvent.is.toolInputError)).toEqual({
        type: "tool-input-error",
        id: "call_1",
-        itemId: "item_1",
        name: "lookup",
        raw: '{"query":"partial',
      })
@@ -1788,7 +1651,6 @@ describe("OpenAI Responses route", () => {
        {
          type: "tool-call",
          id: "ws_1",
-          itemId: "ws_1",
          name: "web_search",
          input: { type: "search", query: "effect 4" },
          providerExecuted: true,
@@ -1797,35 +1659,11 @@ describe("OpenAI Responses route", () => {
        {
          type: "tool-result",
          id: "ws_1",
-          itemId: "ws_1",
          name: "web_search",
          result: { type: "json", value: item },
          providerExecuted: true,
-          providerMetadata: { openai: { itemId: "ws_1", item } },
-          output: undefined,
-        },
-      ])
-      expect(response.message.content).toEqual([
-        {
-          type: "tool-call",
-          id: "ws_1",
-          itemId: "ws_1",
-          name: "web_search",
-          input: { type: "search", query: "effect 4" },
-          providerExecuted: true,
          providerMetadata: { openai: { itemId: "ws_1" } },
        },
-        {
-          type: "tool-result",
-          id: "ws_1",
-          itemId: "ws_1",
-          name: "web_search",
-          result: { type: "json", value: item },
-          providerExecuted: true,
-          providerMetadata: { openai: { itemId: "ws_1", item } },
-          metadata: undefined,
-          cache: undefined,
-        },
      ])
    }),
  )
@@ -1903,7 +1741,6 @@ describe("OpenAI Responses route", () => {
      expect(toolCall).toEqual({
        type: "tool-call",
        id: "ci_1",
-        itemId: "ci_1",
        name: "code_interpreter",
        input: { code: "print(1+1)", container_id: "cnt_xyz" },
        providerExecuted: true,
@@ -1913,12 +1750,10 @@ describe("OpenAI Responses route", () => {
      expect(toolResult).toEqual({
        type: "tool-result",
        id: "ci_1",
-        itemId: "ci_1",
        name: "code_interpreter",
        result: { type: "json", value: item },
        providerExecuted: true,
-        providerMetadata: { openai: { itemId: "ci_1", item } },
-        output: undefined,
+        providerMetadata: { openai: { itemId: "ci_1" } },
      })
    }),
  )
@@ -162,7 +162,6 @@ describe("OpenRouter", () => {
              openrouter: {
                usage: true,
                reasoning: { effort: "high" },
-                promptCacheKey: "session_123",
                models: ["anthropic/claude-sonnet-4.6", "google/gemini-3.1-pro"],
                provider: { order: ["anthropic", "google"], require_parameters: true },
                plugins: [{ id: "response-healing" }],
@@ -174,6 +173,7 @@ describe("OpenRouter", () => {
            },
          }).model("anthropic/claude-3.7-sonnet:thinking"),
          prompt: "Think briefly.",
+          promptCacheKey: "session_123",
        }),
      )

@@ -49,43 +49,6 @@ describe("LLMResponse reducer", () => {
    expect(state.message.content).toEqual([{ type: "text", text: "partial" }])
  })

-  test("assembles response item identity and provider metadata", () => {
-    const response = LLMResponse.fromEvents([
-      LLMEvent.textStart({ id: "text-block", itemId: "msg_existing" }),
-      LLMEvent.textDelta({
-        id: "text-block",
-        itemId: "msg_existing",
-        text: "Answer",
-        providerMetadata: { openai: { itemId: "msg_existing" } },
-      }),
-      LLMEvent.textEnd({ id: "text-block", itemId: "msg_existing" }),
-      LLMEvent.reasoningStart({ id: "reasoning-block", itemId: "rs_existing" }),
-      LLMEvent.reasoningDelta({
-        id: "reasoning-block",
-        itemId: "rs_existing",
-        text: "Thought",
-        providerMetadata: { openai: { itemId: "rs_existing" } },
-      }),
-      LLMEvent.reasoningEnd({ id: "reasoning-block", itemId: "rs_existing" }),
-      LLMEvent.finish({ reason: { normalized: "stop" } }),
-    ])
-
-    expect(response?.message.content).toEqual([
-      {
-        type: "text",
-        text: "Answer",
-        itemId: "msg_existing",
-        providerMetadata: { openai: { itemId: "msg_existing" } },
-      },
-      {
-        type: "reasoning",
-        text: "Thought",
-        itemId: "rs_existing",
-        providerMetadata: { openai: { itemId: "rs_existing" } },
-      },
-    ])
-  })
-
  test("does not complete ended content without a terminal finish", () => {
    const state = reduce([
      LLMEvent.textStart({ id: "t1" }),
@@ -172,7 +172,7 @@ describe("LLMClient tools", () => {
      expect(calls).toEqual([{ id: "call_projected", parameters: { prefix: "count" }, output: { count: "2" } }])
      expect(dispatched.result).toEqual({ type: "text", value: "count:2" })
      expect(dispatched.output).toEqual({ structured: { count: "2" }, content: [{ type: "text", text: "count:2" }] })
-      expect(dispatched.events).toMatchObject([
+      expect(dispatched.events).toEqual([
        LLMEvent.toolResult({
          id: "call_projected",
          name: "projected",
@@ -180,7 +180,6 @@ describe("LLMClient tools", () => {
          output: { structured: { count: "2" }, content: [{ type: "text", text: "count:2" }] },
        }),
      ])
-      expect(dispatched.events[0]?.itemId).toBeUndefined()
    }),
  )

@@ -198,7 +197,7 @@ describe("LLMClient tools", () => {
        LLMEvent.toolCall({ id: "call_1", name: "tool", input: {}, providerMetadata }),
      )

-      expect(dispatched.events).toMatchObject([
+      expect(dispatched.events).toEqual([
        LLMEvent.toolResult({
          id: "call_1",
          name: "tool",
@@ -207,13 +206,12 @@ describe("LLMClient tools", () => {
          providerMetadata,
        }),
      ])
-      expect(dispatched.events[0]?.itemId).toBeUndefined()

      const failed = yield* ToolRuntime.dispatch(
        {},
-        LLMEvent.toolCall({ id: "call_2", itemId: "fc_failed", name: "missing", input: {}, providerMetadata }),
+        LLMEvent.toolCall({ id: "call_2", name: "missing", input: {}, providerMetadata }),
      )
-      expect(failed.events).toMatchObject([
+      expect(failed.events).toEqual([
        LLMEvent.toolError({
          id: "call_2",
          name: "missing",
@@ -227,27 +225,6 @@ describe("LLMClient tools", () => {
          providerMetadata,
        }),
      ])
-      const errorItemID = failed.events.find(LLMEvent.is.toolError)?.itemId
-      const resultItemID = failed.events.find(LLMEvent.is.toolResult)?.itemId
-      expect(errorItemID).toBeUndefined()
-      expect(resultItemID).toBeUndefined()
-    }),
-  )
-
-  it.effect("does not derive a function output item id from the function call item id", () =>
-    Effect.gen(function* () {
-      const tool = Tool.make({
-        description: "Return text.",
-        parameters: Schema.Struct({}),
-        success: Schema.String,
-        execute: () => Effect.succeed("hello"),
-      })
-      const dispatched = yield* ToolRuntime.dispatch(
-        { tool },
-        LLMEvent.toolCall({ id: "call_1", itemId: "fc_existing", name: "tool", input: {} }),
-      )
-
-      expect(dispatched.events.find(LLMEvent.is.toolResult)?.itemId).toBeUndefined()
    }),
  )

@@ -460,7 +437,7 @@ describe("LLMClient tools", () => {
      )

      expect(dispatched.result).toEqual(callerOwned)
-      expect(dispatched.events).toMatchObject([
+      expect(dispatched.events).toEqual([
        LLMEvent.toolResult({
          id: "call_1",
          name: "eventful",
@@ -468,7 +445,6 @@ describe("LLMClient tools", () => {
          output: { structured: { ok: true }, content: [] },
        }),
      ])
-      expect(dispatched.events[0]?.itemId).toBeUndefined()
    }),
  )

@@ -22,5 +22,6 @@
    }
  },
  "include": ["src", "package.json"],
-  "exclude": ["dist", "ts-dist"]
+  "exclude": ["dist", "ts-dist"],
+  "references": [{ "path": "../core" }]
 }
@@ -11,7 +11,7 @@
    "fix-node-pty": "bun run script/fix-node-pty.ts",
    "benchmark:location": "bun run script/benchmark-location.ts",
    "test": "bun test --only-failures",
-    "typecheck": "tsgo --noEmit"
+    "typecheck": "tsgo -b tsconfig.json tsconfig.tests.json"
  },
  "bin": {
    "opencode": "./bin/opencode"
@@ -132,14 +132,16 @@ function renderMigration(name: string, sql: string) {
  return `import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: ${JSON.stringify(name)},
  up(tx) {
    return Effect.gen(function* () {
 ${renderStatements(sql)}
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
 `
 }

@@ -147,13 +149,15 @@ function renderSchema(sql: string) {
  return `import { Effect } from "effect"
 import type { DatabaseMigration } from "./migration"

-export default {
+const schema: Omit<DatabaseMigration.Migration, "id"> = {
  up(tx) {
    return Effect.gen(function* () {
 ${renderStatements(sql)}
    })
  },
-} satisfies Omit<DatabaseMigration.Migration, "id">
+}
+
+export default schema
 `
 }

@@ -191,10 +195,10 @@ async function formatTypescript(input: string) {
 function renderRegistry(names: string[]) {
  return `import type { DatabaseMigration } from "./migration"

-export const migrations = (
+export const migrations: DatabaseMigration.Migration[] = (
  await Promise.all([
 ${names.map((name) => `    import("./migration/${name}"),`).join("\n")}
  ])
-).map((module) => module.default) satisfies DatabaseMigration.Migration[]
+).map((module) => module.default)
 `
 }
@@ -263,6 +263,7 @@ function mapOpenRouterOptions(settings: Readonly<Record<string, unknown>>) {
          "extraBody",
          "fetch",
          "headers",
+          "promptCacheKey",
          "timeout",
        ].includes(key),
    ),
@@ -279,7 +280,6 @@ function mapXAIOptions(settings: Readonly<Record<string, unknown>>) {
  const options = {
    ...(typeof settings.reasoningEffort === "string" ? { reasoningEffort: settings.reasoningEffort } : {}),
    ...(typeof settings.store === "boolean" ? { store: settings.store } : {}),
-    ...(typeof settings.promptCacheKey === "string" ? { promptCacheKey: settings.promptCacheKey } : {}),
  }
  if (Object.keys(options).length === 0) return {}
  return { providerOptions: { xai: options } }
@@ -126,7 +126,7 @@ ${render(current)}`
 const key = Instructions.Key.make("core/codemode")
 const codec = Schema.toCodecJson(CodeModeCatalog.Summary)

-export const make = (entries?: ReadonlyArray<CodeModeCatalog.Entry>): Instructions.Instructions => {
+export const make = (entries?: ReadonlyArray<CodeModeCatalog.Entry>): Instructions.List => {
  const catalog = entries === undefined ? Instructions.removed : CodeModeCatalog.summarize(entries)
  return Instructions.make({
    key,
@@ -1,6 +1,6 @@
 import type { DatabaseMigration } from "./migration"

-export const migrations = (
+export const migrations: DatabaseMigration.Migration[] = (
  await Promise.all([
    import("./migration/20260127222353_familiar_lady_ursula"),
    import("./migration/20260211171708_add_project_commands"),
@@ -43,4 +43,4 @@ export const migrations = (
    import("./migration/20260804233008_loose_psylocke"),
    import("./migration/20260805200742_import_legacy_credentials"),
  ])
-).map((module) => module.default) satisfies DatabaseMigration.Migration[]
+).map((module) => module.default)
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260127222353_familiar_lady_ursula",
  up(tx) {
    return Effect.gen(function* () {
@@ -104,4 +104,6 @@ export default {
      yield* tx.run(`CREATE INDEX \`todo_session_idx\` ON \`todo\` (\`session_id\`);`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,11 +1,13 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260211171708_add_project_commands",
  up(tx) {
    return Effect.gen(function* () {
      yield* tx.run(`ALTER TABLE \`project\` ADD \`commands\` text;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260213144116_wakeful_the_professor",
  up(tx) {
    return Effect.gen(function* () {
@@ -20,4 +20,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260225215848_workspace",
  up(tx) {
    return Effect.gen(function* () {
@@ -16,4 +16,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260227213759_add_session_workspace_id",
  up(tx) {
    return Effect.gen(function* () {
@@ -9,4 +9,6 @@ export default {
      yield* tx.run(`CREATE INDEX \`session_workspace_idx\` ON \`session\` (\`workspace_id\`);`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260228203230_blue_harpoon",
  up(tx) {
    return Effect.gen(function* () {
@@ -27,4 +27,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260303231226_add_workspace_fields",
  up(tx) {
    return Effect.gen(function* () {
@@ -12,4 +12,6 @@ export default {
      yield* tx.run(`ALTER TABLE \`workspace\` DROP COLUMN \`config\`;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260309230000_move_org_to_state",
  up(tx) {
    return Effect.gen(function* () {
@@ -12,4 +12,6 @@ export default {
      yield* tx.run(`ALTER TABLE \`account\` DROP COLUMN \`selected_org_id\`;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260312043431_session_message_cursor",
  up(tx) {
    return Effect.gen(function* () {
@@ -13,4 +13,6 @@ export default {
      yield* tx.run(`CREATE INDEX \`part_message_id_id_idx\` ON \`part\` (\`message_id\`,\`id\`);`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260323234822_events",
  up(tx) {
    return Effect.gen(function* () {
@@ -23,4 +23,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260410174513_workspace-name",
  up(tx) {
    return Effect.gen(function* () {
@@ -26,4 +26,6 @@ export default {
      yield* tx.run(`PRAGMA foreign_keys=ON;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260413175956_chief_energizer",
  up(tx) {
    return Effect.gen(function* () {
@@ -21,4 +21,6 @@ export default {
      yield* tx.run(`CREATE INDEX \`session_entry_time_created_idx\` ON \`session_entry\` (\`time_created\`);`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260423070820_add_icon_url_override",
  up(tx) {
    return Effect.gen(function* () {
@@ -11,4 +11,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260427172553_slow_nightmare",
  up(tx) {
    return Effect.gen(function* () {
@@ -27,4 +27,6 @@ export default {
      yield* tx.run(`DROP TABLE \`session_entry\`;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,11 +1,13 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260428004200_add_session_path",
  up(tx) {
    return Effect.gen(function* () {
      yield* tx.run(`ALTER TABLE \`session\` ADD \`path\` text;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260501142318_next_venus",
  up(tx) {
    return Effect.gen(function* () {
@@ -9,4 +9,6 @@ export default {
      yield* tx.run(`ALTER TABLE \`session\` ADD \`model\` text;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,11 +1,13 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260504145000_add_sync_owner",
  up(tx) {
    return Effect.gen(function* () {
      yield* tx.run(`ALTER TABLE \`event_sequence\` ADD \`owner_id\` text;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,11 +1,13 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260507164347_add_workspace_time",
  up(tx) {
    return Effect.gen(function* () {
      yield* tx.run(`ALTER TABLE \`workspace\` ADD \`time_used\` integer NOT NULL DEFAULT 0;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260510033149_session_usage",
  up(tx) {
    return Effect.gen(function* () {
@@ -53,4 +53,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260511000411_data_migration_state",
  up(tx) {
    return Effect.gen(function* () {
@@ -13,4 +13,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260511173437_session-metadata",
  up(tx) {
    return Effect.gen(function* () {
@@ -13,4 +13,6 @@ export default {
      yield* tx.run(`ALTER TABLE \`session\` ADD \`metadata\` text;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260601010001_normalize_storage_paths",
  up(tx) {
    return Effect.gen(function* () {
@@ -19,4 +19,6 @@ export default {
      )
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,11 +1,13 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260601202201_amazing_prowler",
  up(tx) {
    return Effect.gen(function* () {
      yield* tx.run(`DROP TABLE \`permission\`;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260602002951_lowly_union_jack",
  up(tx) {
    return Effect.gen(function* () {
@@ -21,4 +21,6 @@ export default {
      )
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260602182828_add_project_directories",
  up(tx) {
    return Effect.gen(function* () {
@@ -17,4 +17,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260603001617_session_message_projection_indexes",
  up(tx) {
    return Effect.gen(function* () {
@@ -16,4 +16,6 @@ export default {
      )
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260603040000_session_message_projection_order",
  up(tx) {
    return Effect.gen(function* () {
@@ -16,4 +16,6 @@ export default {
      )
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260603141458_session_input_inbox",
  up(tx) {
    return Effect.gen(function* () {
@@ -22,4 +22,6 @@ export default {
      )
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260603160727_jittery_ezekiel_stane",
  up(tx) {
    return Effect.gen(function* () {
@@ -17,4 +17,6 @@ export default {
      )
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260604172448_event_sourced_session_input",
  up(tx) {
    return Effect.gen(function* () {
@@ -44,4 +44,6 @@ export default {
      )
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260605003541_add_session_context_snapshot",
  up(tx) {
    return Effect.gen(function* () {
@@ -18,4 +18,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,11 +1,13 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260605042240_add_context_epoch_agent",
  up(tx) {
    return Effect.gen(function* () {
      yield* tx.run(`ALTER TABLE \`session_context_epoch\` ADD \`agent\` text DEFAULT 'build' NOT NULL;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260611035744_credential",
  up(tx) {
    return Effect.gen(function* () {
@@ -22,4 +22,6 @@ export default {
      )
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260611192811_lush_chimera",
  up(tx) {
    return Effect.gen(function* () {
@@ -22,4 +22,6 @@ export default {
      `)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260612174303_project_dir_strategy",
  up(tx) {
    return Effect.gen(function* () {
@@ -26,4 +26,6 @@ export default {
      yield* tx.run(`PRAGMA foreign_keys=ON;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260622142730_simplify_session_context_epoch",
  up(tx) {
    return Effect.gen(function* () {
@@ -10,4 +10,6 @@ export default {
      yield* tx.run(`ALTER TABLE \`session_context_epoch\` DROP COLUMN \`revision\`;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260622170816_reset_v2_session_state",
  up(tx) {
    return Effect.gen(function* () {
@@ -12,4 +12,6 @@ export default {
      yield* tx.run(`DELETE FROM \`event_sequence\`;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260622202450_simplify_session_input",
  up(tx) {
    return Effect.gen(function* () {
@@ -14,4 +14,6 @@ export default {
      yield* tx.run(`DELETE FROM \`workspace\`;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "../migration"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260804233008_loose_psylocke",
  up(tx) {
    return Effect.gen(function* () {
@@ -135,4 +135,6 @@ export default {
      yield* tx.run(`DROP TABLE \`session_input\`;`)
    })
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration
@@ -30,12 +30,14 @@ const decodeJson = Schema.decodeUnknownOption(Schema.UnknownFromJsonString)
 const decodeValue = Schema.decodeUnknownOption(LegacyValue)
 const wellKnownSourcesKey = "wellknown:sources"

-export default {
+const migration: DatabaseMigration.Migration = {
  id: "20260805200742_import_legacy_credentials",
  up(tx) {
    return importLegacyCredentials(tx, path.join(Global.Path.data, "auth.json"))
  },
-} satisfies DatabaseMigration.Migration
+}
+
+export default migration

 export function importLegacyCredentials(tx: Parameters<DatabaseMigration.Migration["up"]>[0], filepath: string) {
  return Effect.gen(function* () {
@@ -1,7 +1,7 @@
 import { Effect } from "effect"
 import type { DatabaseMigration } from "./migration"

-export default {
+const schema: Omit<DatabaseMigration.Migration, "id"> = {
  up(tx) {
    return Effect.gen(function* () {
      yield* tx.run(`
@@ -248,4 +248,6 @@ export default {
      )
    })
  },
-} satisfies Omit<DatabaseMigration.Migration, "id">
+}
+
+export default schema
@@ -18,7 +18,7 @@ const Files = Schema.Array(File)
 const key = Instructions.Key.make("core/instructions")

 export interface Interface {
-  readonly load: () => Effect.Effect<Instructions.Instructions>
+  readonly load: () => Effect.Effect<Instructions.List>
 }

 export const Options = Schema.Struct({
@@ -8,7 +8,7 @@ import { SessionSchema } from "../session/schema"
 import { Instructions } from "./index"

 export interface Interface {
-  readonly load: (sessionID: SessionSchema.ID) => Effect.Effect<Instructions.Instructions>
+  readonly load: (sessionID: SessionSchema.ID) => Effect.Effect<Instructions.List>
 }

 export class Service extends Context.Service<Service, Interface>()("@opencode/InstructionBuiltIns") {}
@@ -53,7 +53,7 @@ export declare namespace Source {
 }

 /** Ordered sources; identical values render identical bytes. */
-export type Instructions = ReadonlyArray<Source>
+export type List = ReadonlyArray<Source>

 export type ReadResult = ReadonlyArray<{
  readonly key: Key
@@ -82,10 +82,10 @@ export class DuplicateKeyError extends Schema.TaggedErrorClass<DuplicateKeyError
  }
 }

-export const empty: Instructions = []
+export const empty: List = []

 /** Closes a typed definition into one `Source`, so differently typed sources compose. */
-export function make<A>(source: Source.Definition<A>): Instructions {
+export function make<A>(source: Source.Definition<A>): List {
  const decode = Schema.decodeUnknownOption(source.codec)
  const encode = Schema.encodeSync(source.codec)
  const initial = (value: A) => requireText(source.key, "initial", source.render.initial(value))
@@ -121,7 +121,7 @@ export function make<A>(source: Source.Definition<A>): Instructions {
  ]
 }

-export function combine(values: ReadonlyArray<Instructions>): Instructions {
+export function combine(values: ReadonlyArray<List>): List {
  const sources = values.flat()
  const keys = new Set<Key>()
  for (const source of sources) {
@@ -131,7 +131,7 @@ export function combine(values: ReadonlyArray<Instructions>): Instructions {
  return sources
 }

-export function read(value: Instructions): Effect.Effect<ReadResult> {
+export function read(value: List): Effect.Effect<ReadResult> {
  return Effect.forEach(
    value,
    (source) => source.read.pipe(Effect.map((observed) => ({ key: source.key, value: observed }))),
@@ -158,7 +158,7 @@ export function diff(observed: ReadResult, previous?: Values): Effect.Effect<Adm
  return Effect.succeed({ delta, blobs })
 }

-export function renderInitial(value: Instructions, values: Readonly<Record<string, Schema.Json>>) {
+export function renderInitial(value: List, values: Readonly<Record<string, Schema.Json>>) {
  return render(
    value.flatMap((source) => {
      if (!Object.hasOwn(values, source.key)) return []
@@ -169,7 +169,7 @@ export function renderInitial(value: Instructions, values: Readonly<Record<strin
 }

 export function renderUpdate(
-  value: Instructions,
+  value: List,
  previous: Readonly<Record<string, Schema.Json>>,
  delta: Readonly<Record<string, Option.Option<Schema.Json>>>,
 ) {
@@ -55,7 +55,7 @@ const update = (previous: ReadonlyArray<Summary>, current: ReadonlyArray<Summary
 }

 export interface Interface {
-  readonly load: (agent: Agent.Selection) => Effect.Effect<Instructions.Instructions>
+  readonly load: (agent: Agent.Selection) => Effect.Effect<Instructions.List>
 }

 export class Service extends Context.Service<Service, Interface>()("@opencode/McpInstructions") {}
@@ -54,7 +54,7 @@ const update = (previous: ReadonlyArray<typeof Summary.Type>, current: ReadonlyA
 }

 export interface Interface {
-  readonly load: () => Effect.Effect<Instructions.Instructions>
+  readonly load: () => Effect.Effect<Instructions.List>
 }

 export class Service extends Context.Service<Service, Interface>()("@opencode/ReferenceInstructions") {}
@@ -11,6 +11,7 @@ import { llmClient } from "../effect/app-node-platform"
 import { SessionEvent } from "./event"
 import type { SessionMessage } from "./message"
 import { SessionModelHeaders } from "./model-headers"
+import { SessionPromptCacheKey } from "./prompt-cache-key"
 import { App } from "../app"
 import { SessionRunnerModel } from "./runner/model"
 import { SessionSchema } from "./schema"
@@ -258,6 +259,7 @@ const make = (dependencies: Dependencies) => {
      .stream(
        LLM.request({
          model: plan.model,
+          promptCacheKey: SessionPromptCacheKey.make(plan.session.id),
          http: { headers: SessionModelHeaders.make(plan.session, dependencies.app) },
          messages: [Message.user(plan.prompt)],
          tools: [],
@@ -25,7 +25,7 @@ import { SessionStore } from "./store"
 export interface Selection {
  readonly session: SessionSchema.Info
  readonly agent: Agent.Selection & { readonly info: Agent.Info }
-  readonly instructions: Instructions.Instructions
+  readonly instructions: Instructions.List
  readonly tools: Tool.Snapshot
 }

@@ -11,6 +11,7 @@ import { SessionContext } from "./context"
 import { SessionGenerate } from "./generate"
 import { SessionHistory } from "./history"
 import { SessionModelHeaders } from "./model-headers"
+import { SessionPromptCacheKey } from "./prompt-cache-key"
 import { SessionRunnerModel } from "./runner/model"
 import PROMPT_DEFAULT from "./runner/prompt/base.txt"
 import { toLLMMessages } from "./runner/to-llm-message"
@@ -31,9 +32,6 @@ export const layer = Layer.effect(
        const model = yield* models.resolve(selection.session)
        const history = yield* SessionHistory.preview(database.db, selection.session.id, selection.instructions)
        const providerMetadataKey = model.model.route.providerMetadataKey ?? model.model.provider
-        const promptCacheKey = /^ses_[0-9a-f]{64}$/.test(selection.session.id)
-          ? selection.session.id.slice(4)
-          : selection.session.id
        const tools = selection.tools
        const toolDefinitions = tools.definitions
        const toolsByName = new Map(toolDefinitions.map((tool) => [tool.name, tool]))
@@ -71,7 +69,7 @@ export const layer = Layer.effect(
          LLM.request({
            model: model.model,
            http: { headers: SessionModelHeaders.make(selection.session, app) },
-            providerOptions: { [providerMetadataKey]: { promptCacheKey } },
+            promptCacheKey: SessionPromptCacheKey.make(selection.session.id),
            system: contextEvent.system,
            messages: contextEvent.messages,
            tools: hookedTools,
@@ -74,7 +74,7 @@ export const load = Effect.fn("SessionHistory.load")(function* (db: DatabaseServ
 export const entriesForRunner = Effect.fn("SessionHistory.entriesForRunner")(function* (
  db: DatabaseService,
  sessionID: SessionSchema.ID,
-  instructions: Instructions.Instructions,
+  instructions: Instructions.List,
 ) {
  return yield* db
    .transaction(() =>
@@ -92,7 +92,7 @@ export const entriesForRunner = Effect.fn("SessionHistory.entriesForRunner")(fun
 export const preview = Effect.fn("SessionHistory.preview")(function* (
  db: DatabaseService,
  sessionID: SessionSchema.ID,
-  instructions: Instructions.Instructions,
+  instructions: Instructions.List,
 ) {
  const observed = yield* Instructions.read(instructions)
  return yield* db
@@ -25,7 +25,7 @@ export interface Interface {
  }) => Effect.Effect<void, InstructionEntry.ValueTooLargeError>
  readonly remove: (input: { readonly sessionID: SessionSchema.ID; readonly key: Key }) => Effect.Effect<void>
  /** Produces one Instructions source per stored entry, keyed `api/<key>`. */
-  readonly load: (sessionID: SessionSchema.ID) => Effect.Effect<Instructions.Instructions>
+  readonly load: (sessionID: SessionSchema.ID) => Effect.Effect<Instructions.List>
 }

 export class Service extends Context.Service<Service, Interface>()("@opencode/InstructionEntry") {}
@@ -20,7 +20,7 @@ export interface Observation extends Instructions.Admission {

 export const observe = Effect.fn("InstructionState.observe")(function* (
  db: DatabaseService,
-  instructions: Instructions.Instructions,
+  instructions: Instructions.List,
  sessionID: SessionSchema.ID,
 ): Effect.fn.Return<Observation, Instructions.InitializationBlocked> {
  const [observed, stored] = yield* Effect.all([Instructions.read(instructions), find(db, sessionID)], {
@@ -38,7 +38,7 @@ export const observe = Effect.fn("InstructionState.observe")(function* (
 export const commit = Effect.fn("InstructionState.commit")(function* (
  db: DatabaseService,
  bus: Bus.Interface,
-  instructions: Instructions.Instructions,
+  instructions: Instructions.List,
  observation: Observation,
 ) {
  if (!observation.initial && Object.keys(observation.delta).length === 0) return
@@ -62,7 +62,7 @@ export const commit = Effect.fn("InstructionState.commit")(function* (

 const renderUpdateText = Effect.fnUntraced(function* (
  db: DatabaseService,
-  instructions: Instructions.Instructions,
+  instructions: Instructions.List,
  observation: Observation,
 ) {
  const replaced = Object.entries(observation.previous).filter(([key]) => Object.hasOwn(observation.delta, key))
@@ -77,7 +77,7 @@ const renderUpdateText = Effect.fnUntraced(function* (
 export const prepare = Effect.fn("InstructionState.prepare")(function* (
  db: DatabaseService,
  bus: Bus.Interface,
-  instructions: Instructions.Instructions,
+  instructions: Instructions.List,
  sessionID: SessionSchema.ID,
 ) {
  yield* commit(db, bus, instructions, yield* observe(db, instructions, sessionID))
@@ -162,7 +162,7 @@ export const reset = Effect.fn("InstructionState.reset")(function* (db: Database
 export const initial = Effect.fn("InstructionState.initial")(function* (
  db: DatabaseService,
  sessionID: SessionSchema.ID,
-  instructions: Instructions.Instructions,
+  instructions: Instructions.List,
 ) {
  const state = yield* find(db, sessionID)
  if (!state) return yield* Effect.die(new Error(`Instruction state not found during assembly: ${sessionID}`))
@@ -181,7 +181,7 @@ export const current = Effect.fn("InstructionState.current")(function* (
 export const preview = Effect.fn("InstructionState.preview")(function* (
  db: DatabaseService,
  sessionID: SessionSchema.ID,
-  instructions: Instructions.Instructions,
+  instructions: Instructions.List,
  observed: Instructions.ReadResult,
 ) {
  const state = yield* find(db, sessionID)
@@ -15,6 +15,7 @@ import { QuestionTool } from "../tool/plugin/question"
 import { Tool } from "../tool"
 import { SessionContext } from "./context"
 import { SessionModelHeaders } from "./model-headers"
+import { SessionPromptCacheKey } from "./prompt-cache-key"
 import { PromptCacheDiagnostics } from "./prompt-cache-diagnostics"
 import { MAX_STEPS_PROMPT } from "./runner/max-steps"
 import PROMPT_DEFAULT from "./runner/prompt/base.txt"
@@ -181,7 +182,6 @@ export const layer = Layer.effect(
      // The final Step keeps definitions available to protocols with native "none",
      // preserving their prompt cache prefix. Calls are still rejected at execution.
      const tools = input.context.tools
-      const promptCacheKey = /^ses_[0-9a-f]{64}$/.test(session.id) ? session.id.slice(4) : session.id
      const system = [agent.info.system ? agent.info.system : PROMPT_DEFAULT, input.context.initial]
        .filter((part) => part.length > 0)
        .map(SystemPart.make)
@@ -220,7 +220,7 @@ export const layer = Layer.effect(
        http: {
          headers: SessionModelHeaders.make(session, app),
        },
-        providerOptions: { [providerMetadataKey]: { promptCacheKey } },
+        promptCacheKey: SessionPromptCacheKey.make(session.id),
        system: context.system,
        messages: boundImages(unsupportedParts(context.messages, resolved.capabilities)),
        tools: Array.from(hooked, ([name, tool]) => ({ ...tool, name })),
@@ -0,0 +1,6 @@
+export * as SessionPromptCacheKey from "./prompt-cache-key"
+
+import { SessionSchema } from "./schema"
+
+export const make = (sessionID: SessionSchema.ID) =>
+  /^ses_[0-9a-f]{64}$/.test(sessionID) ? sessionID.slice(4) : sessionID
@@ -116,11 +116,7 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
  })
  const currentAssistantMessageID = () =>
    stepStarted ? Effect.succeed(assistantMessageID) : Effect.die(new Error("Tool event before assistant step start"))
-  const providerState = (metadata: ProviderMetadata | undefined, itemId?: string) => {
-    const state = metadata?.[input.providerMetadataKey]
-    if (itemId === undefined) return state
-    return { ...(typeof state === "object" && state !== null && !Array.isArray(state) ? state : {}), itemId }
-  }
+  const providerState = (metadata: ProviderMetadata | undefined) => metadata?.[input.providerMetadataKey]
  const fragments = (
    name: string,
    ended: (id: string, value: string, ordinal: number, state?: Record<string, unknown>) => Effect.Effect<void>,
@@ -344,7 +340,7 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
        return
      case "text-start":
        outputStarted = true
-        const startedTextOrdinal = yield* text.start(event.id, providerState(event.providerMetadata, event.itemId))
+        const startedTextOrdinal = yield* text.start(event.id, providerState(event.providerMetadata))
        yield* bus.publish(SessionEvent.Text.Started, {
          sessionID: input.sessionID,
          assistantMessageID: yield* startAssistant(),
@@ -352,11 +348,7 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
        })
        return
      case "text-delta":
-        const deltaTextOrdinal = yield* text.append(
-          event.id,
-          event.text,
-          providerState(event.providerMetadata, event.itemId),
-        )
+        const deltaTextOrdinal = yield* text.append(event.id, event.text, providerState(event.providerMetadata))
        yield* bus.publish(SessionEvent.Text.Delta, {
          sessionID: input.sessionID,
          assistantMessageID: yield* currentAssistantMessageID(),
@@ -365,26 +357,23 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
        })
        return
      case "text-end":
-        yield* text.end(event.id, providerState(event.providerMetadata, event.itemId))
+        yield* text.end(event.id, providerState(event.providerMetadata))
        return
      case "reasoning-start":
        outputStarted = true
-        const startedReasoningOrdinal = yield* reasoning.start(
-          event.id,
-          providerState(event.providerMetadata, event.itemId),
-        )
+        const startedReasoningOrdinal = yield* reasoning.start(event.id, providerState(event.providerMetadata))
        yield* bus.publish(SessionEvent.Reasoning.Started, {
          sessionID: input.sessionID,
          assistantMessageID: yield* startAssistant(),
          ordinal: startedReasoningOrdinal,
-          state: providerState(event.providerMetadata, event.itemId),
+          state: providerState(event.providerMetadata),
        })
        return
      case "reasoning-delta":
        const deltaReasoningOrdinal = yield* reasoning.append(
          event.id,
          event.text,
-          providerState(event.providerMetadata, event.itemId),
+          providerState(event.providerMetadata),
        )
        yield* bus.publish(SessionEvent.Reasoning.Delta, {
          sessionID: input.sessionID,
@@ -394,7 +383,7 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
        })
        return
      case "reasoning-end":
-        yield* reasoning.end(event.id, providerState(event.providerMetadata, event.itemId))
+        yield* reasoning.end(event.id, providerState(event.providerMetadata))
        return
      case "tool-input-start":
        outputStarted = true
@@ -438,7 +427,7 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
          id: event.id,
          input: asRecord(event.input),
          executed: tool.providerExecuted,
-          state: providerState(event.providerMetadata, event.itemId),
+          state: providerState(event.providerMetadata),
        })
        return
      }
@@ -456,7 +445,7 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
        }
        tool.settled = true
        const executed = event.providerExecuted === true || tool.providerExecuted
-        const resultState = providerState(event.providerMetadata, event.itemId)
+        const resultState = providerState(event.providerMetadata)
        if (event.result.type === "error") {
          yield* bus.publish(SessionEvent.Tool.Failed, {
            sessionID: input.sessionID,
@@ -496,7 +485,7 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
              : { type: "tool.execution", message: event.message },
          ...failureSnapshot(tool),
          executed: tool.providerExecuted,
-          resultState: providerState(event.providerMetadata, event.itemId),
+          resultState: providerState(event.providerMetadata),
        })
        return
      }
@@ -521,7 +510,8 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp

  const progress = Effect.fnUntraced(function* (id: string, update: Tool.Metadata) {
    const tool = tools.get(id)
-    if (!tool?.called || tool.settled) return yield* Effect.die(new Error(`Tool progress outside running call: ${id}`))
+    if (!tool?.called || tool.settled)
+      return yield* Effect.die(new Error(`Tool progress outside running call: ${id}`))
    tool.progress = update
    yield* bus.publish(SessionEvent.Tool.Progress, {
      sessionID: input.sessionID,
@@ -532,7 +522,11 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
  })

  /** Publishes one canonical terminal event for a locally executed tool call. */
-  const toolExecution = Effect.fnUntraced(function* (id: string, name: string, result: Tool.Result) {
+  const toolExecution = Effect.fnUntraced(function* (
+    id: string,
+    name: string,
+    result: Tool.Result,
+  ) {
    const tool = tools.get(id)
    if (!tool?.called) return yield* Effect.die(new Error(`Tool execution before call: ${id}`))
    if (tool.name !== name)
@@ -1,10 +1,4 @@
-import {
-  Message,
-  ToolCallPart,
-  ToolResultPart,
-  type ContentPart,
-  type ProviderMetadata,
-} from "@opencode-ai/ai"
+import { Message, ToolCallPart, ToolResultPart, type ContentPart, type ProviderMetadata } from "@opencode-ai/ai"
 import { Option, Schema } from "effect"
 import type { Model } from "../../model"
 import { SessionMessage } from "../message"
@@ -72,46 +66,27 @@ const providerMetadata = (
  state: Record<string, unknown> | undefined,
 ): ProviderMetadata | undefined => (state === undefined ? undefined : { [provider]: state })

-const responseItemID = (state: Record<string, unknown> | undefined) =>
-  typeof state?.itemId === "string" ? state.itemId : undefined
-
-const portableProviderState = (state: Record<string, unknown> | undefined) => {
-  if (state === undefined || !("itemId" in state)) return state
-  const { itemId: _itemId, ...portable } = state
-  return portable
-}
-
 const toolInput = (tool: SessionMessage.AssistantTool) =>
  tool.state.status === "streaming"
    ? Option.getOrElse(decodeToolInput(tool.state.input), () => tool.state.input)
    : tool.state.input

-const toolCall = (
-  tool: SessionMessage.AssistantTool,
-  itemId: string | undefined,
-  providerMetadata: ProviderMetadata | undefined,
-): ContentPart =>
+const toolCall = (tool: SessionMessage.AssistantTool, providerMetadata: ProviderMetadata | undefined): ContentPart =>
  ToolCallPart.make({
    id: tool.id,
-    ...(itemId === undefined ? {} : { itemId }),
    name: tool.name,
    input: toolInput(tool),
    providerExecuted: tool.executed,
    providerMetadata,
  })

-const toolResult = (
-  tool: SessionMessage.AssistantTool,
-  itemId: string | undefined,
-  providerMetadata: ProviderMetadata | undefined,
-) => {
+const toolResult = (tool: SessionMessage.AssistantTool, providerMetadata: ProviderMetadata | undefined) => {
  if (tool.state.status === "completed") {
    // TODO: Materialize remote and managed URIs before provider-history lowering.
    const content = tool.state.content
    const single = content.length === 1 ? content[0] : undefined
    return ToolResultPart.make({
      id: tool.id,
-      ...(itemId === undefined ? {} : { itemId }),
      name: tool.name,
      result:
        single?.type === "text"
@@ -124,7 +99,6 @@ const toolResult = (
  if (tool.state.status === "error") {
    return ToolResultPart.make({
      id: tool.id,
-      ...(itemId === undefined ? {} : { itemId }),
      name: tool.name,
      result: { error: tool.state.error, content: tool.state.content ?? [] },
      resultType: "error",
@@ -144,13 +118,7 @@ const assistant = (message: SessionMessage.Assistant, model: Model.Ref, provider
        {
          type: "text",
          text: item.text,
-          itemId: reuseProviderMetadata ? responseItemID(item.state) : undefined,
-          providerMetadata: sameProvider
-            ? providerMetadata(
-                providerMetadataKey,
-                reuseProviderMetadata ? item.state : portableProviderState(item.state),
-              )
-            : undefined,
+          providerMetadata: sameProvider ? providerMetadata(providerMetadataKey, item.state) : undefined,
        },
      ]
    if (item.type === "reasoning")
@@ -159,7 +127,6 @@ const assistant = (message: SessionMessage.Assistant, model: Model.Ref, provider
            {
              type: "reasoning",
              text: item.text,
-              itemId: responseItemID(item.state),
              providerMetadata: providerMetadata(providerMetadataKey, item.state),
            },
          ]
@@ -171,7 +138,6 @@ const assistant = (message: SessionMessage.Assistant, model: Model.Ref, provider
      (sameModel && item.executed === true && (item.state.status === "completed" || item.state.status === "error"))
    const call = toolCall(
      item,
-      reuseToolProviderMetadata ? responseItemID(item.providerState) : undefined,
      reuseToolProviderMetadata ? providerMetadata(providerMetadataKey, item.providerState) : undefined,
    )
    if (item.executed !== true) return [call]
@@ -179,11 +145,6 @@ const assistant = (message: SessionMessage.Assistant, model: Model.Ref, provider
    // replay must survive a model switch within the same provider.
    const result = toolResult(
      item,
-      reuseToolProviderMetadata
-        ? responseItemID(item.providerResultState ?? (item.executed === true ? item.providerState : undefined))
-        : sameProvider && item.executed === true
-          ? responseItemID(item.providerResultState)
-          : undefined,
      reuseToolProviderMetadata
        ? providerMetadata(providerMetadataKey, item.providerResultState ?? item.providerState)
        : sameProvider && item.executed === true && item.providerResultState !== undefined
@@ -202,8 +163,9 @@ const assistant = (message: SessionMessage.Assistant, model: Model.Ref, provider
    .map((item) =>
      toolResult(
        item,
-        responseItemID(item.providerResultState) ?? `fco_${item.id}`,
-        reuseProviderMetadata ? providerMetadata(providerMetadataKey, item.providerResultState) : undefined,
+        reuseProviderMetadata
+          ? providerMetadata(providerMetadataKey, item.providerResultState ?? item.providerState)
+          : undefined,
      ),
    )
    .filter((message) => message !== undefined)
@@ -242,7 +204,7 @@ function toLLMMessage(message: SessionMessage.Info, model: Model.Ref, providerMe
    case "skill":
      return [Message.make({ id: message.id, role: "user", content: message.text, metadata: message.metadata })]
    case "system":
-      return [Message.make({ id: message.id, role: "system", content: message.text })]
+      return [Message.system(message.text)]
    case "shell":
      return [
        Message.make({
@@ -57,7 +57,7 @@ const update = (previous: ReadonlyArray<Summary>, current: ReadonlyArray<Summary
 }

 export interface Interface {
-  readonly load: (agent: Agent.Selection) => Effect.Effect<Instructions.Instructions>
+  readonly load: (agent: Agent.Selection) => Effect.Effect<Instructions.List>
 }

 export class Service extends Context.Service<Service, Interface>()("@opencode/SkillInstructions") {}
@@ -22,7 +22,7 @@ export abstract class NamedError extends Error {
    return NamedError.createSchemaClass(name, Schema.isSchema(data) ? data : Schema.Struct(data))
  }

-  private static createSchemaClass<Name extends string, DataSchema extends Schema.Top>(name: Name, data: DataSchema) {
+  public static createSchemaClass<Name extends string, DataSchema extends Schema.Top>(name: Name, data: DataSchema) {
    const schema = Schema.Struct({
      name: Schema.Literal(name),
      data,
@@ -179,7 +179,6 @@ describe("AISDKNative", () => {
        models: ["anthropic/claude-sonnet-4.6"],
        provider: { only: ["anthropic"], require_parameters: true },
        reasoning: { effort: "high" },
-        promptCacheKey: "session_123",
        future_option: { enabled: true },
      }),
    ).toEqual({
@@ -190,7 +189,6 @@ describe("AISDKNative", () => {
            models: ["anthropic/claude-sonnet-4.6"],
            provider: { only: ["anthropic"], require_parameters: true },
            reasoning: { effort: "high" },
-            promptCacheKey: "session_123",
            future_option: { enabled: true },
          },
        },
@@ -271,7 +269,6 @@ describe("AISDKNative", () => {
        baseURL: "https://xai.example/v1",
        reasoningEffort: "custom",
        store: true,
-        promptCacheKey: "cache-key",
      }),
    ).toEqual({
      package: "@opencode-ai/ai/providers/xai",
@@ -282,7 +279,6 @@ describe("AISDKNative", () => {
          xai: {
            reasoningEffort: "custom",
            store: true,
-            promptCacheKey: "cache-key",
          },
        },
      },
@@ -68,7 +68,7 @@ const instructionEvents = (db: Database.Interface["db"], sessionID: SessionSchem
    .all()
    .pipe(Effect.orDie)

-const preview = (db: Database.Interface["db"], sessionID: SessionSchema.ID, instructions: Instructions.Instructions) =>
+const preview = (db: Database.Interface["db"], sessionID: SessionSchema.ID, instructions: Instructions.List) =>
  Instructions.read(instructions).pipe(
    Effect.flatMap((observed) => InstructionState.preview(db, sessionID, instructions, observed)),
  )
@@ -10,7 +10,7 @@ export const state = (values: Readonly<Record<string, Schema.Json>>): State => (
 const hashes = (values: Readonly<Record<string, Schema.Json>>): Instructions.Values =>
  Object.fromEntries(Object.entries(values).map(([key, value]) => [key, Instructions.hash(value)]))

-export const readInitial = (instructions: Instructions.Instructions) =>
+export const readInitial = (instructions: Instructions.List) =>
  Effect.gen(function* () {
    const admission = yield* Instructions.read(instructions).pipe(Effect.flatMap(Instructions.diff))
    const current = state(
@@ -23,7 +23,7 @@ export const readInitial = (instructions: Instructions.Instructions) =>
    return { ...current, text: Instructions.renderInitial(instructions, current.values) }
  })

-export const readUpdate = (instructions: Instructions.Instructions, previous: State) =>
+export const readUpdate = (instructions: Instructions.List, previous: State) =>
  Effect.gen(function* () {
    const admission = yield* Instructions.read(instructions).pipe(
      Effect.flatMap((observed) => Instructions.diff(observed, hashes(previous.values))),
@@ -236,6 +236,7 @@ it.effect("manual compaction summarizes short context instead of no-op", () =>
    expect(Array.from(yield* Fiber.join(delta)).map((event) => event.data.text)).toEqual(["manual summary"])

    expect(requests).toHaveLength(1)
+    expect(requests[0]?.promptCacheKey).toBe(sessionID)
    expect(requests[0]?.http?.headers).toEqual({
      "x-session-affinity": sessionID,
      "X-Session-Id": sessionID,
@@ -296,7 +296,7 @@ it.effect("generates from fresh settled Session context without durable mutation
    expect(requests[0]?.system[0]?.text).toBe("Hooked system")
    expect(requests[0]?.system.map((part) => part.text)).toContain("Initial context")
    expect(requests[0]?.http?.headers).toMatchObject({ "X-Session-Id": sessionID })
-    expect(requests[0]?.providerOptions).toMatchObject({ openai: { promptCacheKey: sessionID } })
+    expect(requests[0]?.promptCacheKey).toBe(sessionID)
    const instructionUpdates = requests[0]?.messages.flatMap((message) =>
      message.role === "system"
        ? message.content.flatMap((content) => (content.type === "text" ? [content.text] : []))
@@ -110,13 +110,7 @@ describe("toLLMMessages", () => {
    )

    expect(messages.map((message) => message.role)).toEqual(["system", "user", "user", "user", "user"])
-    expect(messages[0]).toEqual(
-      Message.make({
-        id: "msg_system",
-        role: "system",
-        content: [{ type: "text", text: "Updated context\n\nOther context" }],
-      }),
-    )
+    expect(messages[0]).toEqual(Message.system("Updated context\n\nOther context"))
    expect(messages[1]).toEqual(
      Message.make({
        id: id("user"),
@@ -482,7 +476,6 @@ Recent work
      {
        type: "tool-result",
        id: "completed",
-        itemId: "fco_completed",
        name: "read",
        result: {
          type: "content",
@@ -520,7 +513,6 @@ Recent work
      {
        type: "reasoning",
        text: "Think",
-        itemId: "rs_1",
        providerMetadata: { provider: { itemId: "rs_1", reasoningEncryptedContent: "encrypted-state" } },
      },
    ])
@@ -610,7 +602,6 @@ Recent work
      {
        type: "tool-call",
        id: "hosted-completed",
-        itemId: "call_completed",
        name: "web_search",
        input: { query: "Effect" },
        providerExecuted: true,
@@ -619,7 +610,6 @@ Recent work
      {
        type: "tool-result",
        id: "hosted-completed",
-        itemId: "result_completed",
        name: "web_search",
        result: { type: "text", value: '{"found":true}' },
        providerExecuted: true,
@@ -630,7 +620,6 @@ Recent work
      {
        type: "tool-call",
        id: "hosted-failed",
-        itemId: "call_failed",
        name: "web_search",
        input: { query: "Effect" },
        providerExecuted: true,
@@ -639,7 +628,6 @@ Recent work
      {
        type: "tool-result",
        id: "hosted-failed",
-        itemId: "result_failed",
        name: "web_search",
        result: {
          type: "error",
@@ -710,7 +698,6 @@ Recent work
      {
        type: "tool-call",
        id: "hosted-old-model",
-        itemId: undefined,
        name: "web_search",
        input: { query: "Effect" },
        providerExecuted: true,
@@ -719,7 +706,6 @@ Recent work
      {
        type: "tool-result",
        id: "hosted-old-model",
-        itemId: "hosted-old-model",
        name: "web_search",
        result: { type: "text", value: '{"status":"completed"}' },
        providerExecuted: true,
@@ -732,7 +718,6 @@ Recent work
      {
        type: "tool-call",
        id: "local-old-model",
-        itemId: undefined,
        name: "read",
        input: { path: "README.md" },
        providerExecuted: false,
@@ -743,7 +728,6 @@ Recent work
      {
        type: "tool-result",
        id: "local-old-model",
-        itemId: "fco_local-old-model",
        name: "read",
        result: { type: "text", value: "Hello" },
        providerExecuted: false,
@@ -24,7 +24,9 @@ const capture = (providerMetadataKey = "anthropic", options?: { readonly interru
      const publish = Effect.sync(() => {
        const event = { id: Event.ID.create(), type: definition.type, data } as Event.Payload<typeof definition>
        published.push({
-          type: definition.durable ? Bus.versionedType(definition.type, definition.durable.version) : definition.type,
+          type: definition.durable
+            ? Bus.versionedType(definition.type, definition.durable.version)
+            : definition.type,
          data,
        })
        return event
@@ -64,10 +66,9 @@ const hostedResult = LLMEvent.toolResult({

 test("local tool success serializes media base64 once through canonical content", async () => {
  const { published, publisher } = capture()
-  const localCall = LLMEvent.toolCall({ ...call, itemId: "fc_call-image" })
-  await Effect.runPromise(publisher.publish(localCall))
+  await Effect.runPromise(publisher.publish(call))
  await Effect.runPromise(
-    publisher.toolExecution(localCall.id, localCall.name, {
+    publisher.toolExecution(call.id, call.name, {
      output: { type: "media", mime: "image/png" },
      content: [
        { type: "text", text: "Image read successfully" },
@@ -83,11 +84,6 @@ test("local tool success serializes media base64 once through canonical content"
  expect(success?.data).not.toHaveProperty("result")
  expect(success?.data).not.toHaveProperty("output")

-  const called = published.find((event) => event.type === "session.tool.called.1")?.data
-  expect(called).toMatchObject({ state: { itemId: "fc_call-image" } })
-  expect(success?.data).not.toHaveProperty("resultState")
-  expect(JSON.stringify(success?.data)).not.toContain('"itemId":"fc_call-image"')
-
  expect(success?.data).toMatchObject({
    content: [
      { type: "text", text: "Image read successfully" },
@@ -230,7 +226,9 @@ test("provider-executed tool metadata is flattened using the route key", async (
 test("binary failure emits no success event", async () => {
  const { published, publisher } = capture()
  await Effect.runPromise(publisher.publish(call))
-  await Effect.runPromise(publisher.failTool(call.id, { type: "tool.execution", message: "Cannot read binary file" }))
+  await Effect.runPromise(
+    publisher.failTool(call.id, { type: "tool.execution", message: "Cannot read binary file" }),
+  )
  expect(published.some((event) => event.type === "session.tool.success.2")).toBe(false)
  expect(published.some((event) => event.type === "session.tool.failed.2")).toBe(true)
 })
@@ -558,15 +558,6 @@ const messageTexts = (request: LLMRequest, role: "user" | "system") =>
 const userTexts = (request: LLMRequest) => messageTexts(request, "user")
 const systemTexts = (request: LLMRequest) => messageTexts(request, "system")
 const messageRoles = (request: LLMRequest | undefined) => request?.messages.map((message) => message.role)
-const withoutItemIDs = (messages: LLMRequest["messages"]) =>
-  messages.map((message) => ({
-    role: message.role,
-    content: message.content.map((part) => {
-      if (!("itemId" in part)) return part
-      const { itemId: _itemId, ...content } = part
-      return content
-    }),
-  }))

 const recordedEventTypes = (id: Session.ID) =>
  Effect.gen(function* () {
@@ -865,8 +856,8 @@ describe("SessionRunnerLLM", () => {
      yield* Fiber.join(renamed)

      expect(requests).toHaveLength(5)
-      expect(withoutItemIDs(requests[2]!.messages)).toContainEqual(withoutItemIDs([Message.user("First prompt")])[0])
-      expect(withoutItemIDs(requests[4]!.messages)).toContainEqual(withoutItemIDs([Message.user("First prompt")])[0])
+      expect(requests[2]?.messages).toContainEqual(Message.user("First prompt"))
+      expect(requests[4]?.messages).toContainEqual(Message.user("First prompt"))
      expect((yield* session.get(sessionID)).title).toBe("Generated title")
    }),
  )
@@ -891,7 +882,7 @@ describe("SessionRunnerLLM", () => {
      // A hook-removed call fails independently and continues while step allowance remains.
      expect(requests).toHaveLength(2)
      expect(requests[0]?.system.map((part) => part.text)).toEqual(["Hooked system"])
-      expect(withoutItemIDs(requests[0]!.messages)).toEqual(withoutItemIDs([Message.user("Hooked message")]))
+      expect(requests[0]?.messages).toEqual([Message.user("Hooked message")])
      expect(requests[0]?.tools.map((tool) => tool.name)).not.toContain("echo")
      expect(requests[0]?.tools.map((tool) => tool.name)).not.toContain("unregistered")
      expect(executions).toEqual([])
@@ -1316,14 +1307,12 @@ describe("SessionRunnerLLM", () => {
      systemBaseline = "Changed context"
      yield* runPrompt(session, "Second")

-      const firstSnapshot = PromptCacheDiagnostics.snapshot(requests[0]!)
-      const secondSnapshot = PromptCacheDiagnostics.snapshot(requests[1]!)
-      expect(PromptCacheDiagnostics.compare(firstSnapshot, secondSnapshot)).toEqual({
-        status: "append-only",
-        previousMessages: 1,
-        currentMessages: 3,
-      })
-      expect(secondSnapshot.messages[0]).toEqual(firstSnapshot.messages[0])
+      expect(
+        PromptCacheDiagnostics.compare(
+          PromptCacheDiagnostics.snapshot(requests[0]),
+          PromptCacheDiagnostics.snapshot(requests[1]),
+        ),
+      ).toEqual({ status: "append-only", previousMessages: 1, currentMessages: 3 })
      expect(requests.map((request) => request.system.map((part) => part.text))).toEqual([
        [defaultSystem, "Initial context"],
        [defaultSystem, "Initial context"],
@@ -2543,24 +2532,9 @@ describe("SessionRunnerLLM", () => {
        {
          type: "reasoning",
          text: "Encrypted thought",
-          itemId: "rs_1",
          providerMetadata: { openai: { itemId: "rs_1", reasoningEncryptedContent: "encrypted-state" } },
        },
      ])
-
-      yield* admit(session, "Continue again")
-      yield* TestLLM.push([])
-      yield* session.resume(sessionID)
-
-      expect(requests[2]?.messages[1]?.content.map((part) => ("itemId" in part ? part.itemId : undefined))).toEqual(
-        requests[1]?.messages[1]?.content.map((part) => ("itemId" in part ? part.itemId : undefined)),
-      )
-      expect(
-        PromptCacheDiagnostics.compare(
-          PromptCacheDiagnostics.snapshot(requests[1]!),
-          PromptCacheDiagnostics.snapshot(requests[2]!),
-        ),
-      ).toEqual({ status: "append-only", previousMessages: 3, currentMessages: 4 })
    }),
  )

@@ -2639,7 +2613,6 @@ describe("SessionRunnerLLM", () => {
        {
          type: "tool-call",
          id: "hosted-search",
-          itemId: "hosted-search",
          name: "web_search",
          input: { query: "Effect" },
          providerExecuted: true,
@@ -3281,7 +3254,7 @@ describe("SessionRunnerLLM", () => {
      yield* stream.started

      expect(requests).toHaveLength(2)
-      expect(requests.map((request) => request.providerOptions?.openai?.promptCacheKey)).toEqual([
+      expect(requests.map((request) => request.promptCacheKey)).toEqual([
        sessionID,
        otherSessionID,
      ])
@@ -3312,7 +3285,7 @@ describe("SessionRunnerLLM", () => {
      yield* session.resume(longSessionID)
      yield* session.resume(otherLongSessionID)

-      const keys = requests.map((request) => request.providerOptions?.openai?.promptCacheKey)
+      const keys = requests.map((request) => request.promptCacheKey)
      expect(keys).toEqual([longSessionID.slice(4), otherLongSessionID.slice(4)])
      expect(keys.every((key) => typeof key === "string" && key.length === 64)).toBe(true)
      expect(keys[0]).not.toBe(keys[1])
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
opencode-agent[bot]	0b84e24e65	fix(tui): standardize compact terminology (#41141 )	2026-08-07 16:26:14 -04:00
opencode-agent[bot]	3776975d5c	fix(tui): unify integration connection copy (#41137 )	2026-08-07 16:11:51 -04:00
James Long	d2c99ba97c	chore: improve incremental typecheck performance (#40925 ) Co-authored-by: exe.dev user <exedev@jlongster-site.exe.xyz>	2026-08-07 15:34:36 -04:00
Aiden Cline	6f3a3600b9	fix(ai): forward chat cache keys (#41131 )	2026-08-07 14:06:37 -05:00
Aiden Cline	9ca650f97c	refactor(ai): promote prompt cache key (#39965 )	2026-08-07 13:43:00 -05:00