fix(core): request copilot raw usage chunks

packages/ai/src/protocols/openai-chat.ts

@@ -157,6 +157,7 @@ const OpenAIChatUsage = Schema.StructWithRest(
     prompt_tokens: optionalNull(Schema.Number),
     completion_tokens: optionalNull(Schema.Number),
     total_tokens: optionalNull(Schema.Number),
+    cost: optionalNull(Schema.Number),
     prompt_tokens_details: optionalNull(
       Schema.StructWithRest(
         Schema.Struct({
@@ -595,6 +596,7 @@ const mapUsage = (usage: OpenAIChatEvent["usage"]): Usage | undefined => {
     cacheWriteInputTokens: cacheWrite,
     reasoningTokens: reasoning,
     totalTokens: ProviderShared.totalTokens(input, output, usage.total_tokens ?? undefined),
+    cost: usage.cost ?? undefined,
     providerMetadata: { openai: usage },
   })
 }

packages/ai/src/schema/events.ts

@@ -56,6 +56,8 @@ export class Usage extends Schema.Class<Usage>("AI.Usage")({
   cacheWriteInputTokens: Schema.optional(Schema.Number),
   reasoningTokens: Schema.optional(Schema.Number),
   totalTokens: Schema.optional(Schema.Number),
+  /** Provider-reported cost for this physical request, normalized to USD. */
+  cost: Schema.optional(Schema.Number),
   providerMetadata: Schema.optional(ProviderMetadata),
 }) {
   /**

packages/ai/test/provider/openrouter.test.ts

@@ -246,6 +246,24 @@ describe("OpenRouter", () => {
     }),
   )
 
+  it.effect("reports OpenRouter's streamed USD cost", () =>
+    Effect.gen(function* () {
+      const model = OpenRouter.configure({ apiKey: "test-key" }).model("openai/gpt-4o-mini")
+      const response = yield* LLMClient.generate(LLM.request({ model, prompt: "Say hello." })).pipe(
+        Effect.provide(
+          fixedResponse(
+            sseEvents({
+              choices: [{ delta: { content: "Hello" }, finish_reason: "stop" }],
+              usage: { prompt_tokens: 10, completion_tokens: 2, total_tokens: 12, cost: 0.00123 },
+            }),
+          ),
+        ),
+      )
+
+      expect(response.usage?.cost).toBe(0.00123)
+    }),
+  )
+
   it.effect("fails on a mid-stream provider error", () =>
     Effect.gen(function* () {
       const model = OpenRouter.configure({ apiKey: "test-key" }).model("openai/gpt-4o-mini")

packages/core/src/aisdk.ts

@@ -343,7 +343,8 @@ function modelFromLanguage(info: Info, language: LanguageModelV3) {
     model: (input) =>
       LanguageModel.make({ ...input, provider: "provider" in input ? input.provider : info.providerID, route }),
     prepareTransport: (body) => Effect.succeed(body),
-    streamPrepared: (prepared) => streamLanguage(language, prepared as LanguageModelV3CallOptions),
+    streamPrepared: (prepared) =>
+      streamLanguage(language, prepared as LanguageModelV3CallOptions, info.providerID === Provider.ID.githubCopilot),
   }
   return LanguageModel.make({
     id: info.modelID ?? info.id,
@@ -427,6 +428,7 @@ function callOptions(request: LLMRequest): LanguageModelV3CallOptions {
     toolChoice: toolChoice(request.toolChoice),
     headers: request.http?.headers,
     providerOptions: providerOptions(request.providerOptions),
+    includeRawChunks: request.model.provider === ProviderID.make(Provider.ID.githubCopilot),
   }
 }
 
@@ -547,8 +549,15 @@ function providerOptions(input: LLMRequest["providerOptions"]): SharedV3Provider
   return Object.fromEntries(Object.entries(input).map(([key, value]) => [key, jsonObject(value)]))
 }
 
-function streamLanguage(language: LanguageModelV3, options: LanguageModelV3CallOptions) {
-  const state = { step: 0, toolNames: {} as Record<string, string> }
+interface StreamState {
+  step: number
+  toolNames: Record<string, string>
+  copilot: boolean
+  cost?: number
+}
+
+function streamLanguage(language: LanguageModelV3, options: LanguageModelV3CallOptions, copilot: boolean) {
+  const state: StreamState = { step: 0, toolNames: {}, copilot }
   return Stream.concat(
     Stream.make(LLMEvent.stepStart({ index: state.step })),
     Stream.unwrap(
@@ -571,17 +580,19 @@ function streamLanguage(language: LanguageModelV3, options: LanguageModelV3CallO
 }
 
 function streamPartEvents(
-  state: { step: number; toolNames: Record<string, string> },
+  state: StreamState,
   event: LanguageModelV3StreamPart,
 ): Effect.Effect<ReadonlyArray<LLMEvent>, AIError> {
   switch (event.type) {
     case "stream-start":
     case "response-metadata":
-    case "raw":
     case "file":
     case "source":
     case "tool-approval-request":
       return Effect.succeed([])
+    case "raw":
+      if (state.copilot) state.cost = copilotCost(event.rawValue) ?? state.cost
+      return Effect.succeed([])
     case "text-start":
       return Effect.succeed([
         LLMEvent.textStart({ id: event.id, providerMetadata: providerMetadata(event.providerMetadata) }),
@@ -672,16 +683,18 @@ function streamPartEvents(
         }),
       ])
     case "finish":
+      const normalized = usage(event.usage, state.cost)
+      state.cost = undefined
       return Effect.succeed([
         LLMEvent.stepFinish({
           index: state.step++,
           reason: { normalized: finishReason(event.finishReason), raw: event.finishReason.raw },
-          usage: usage(event.usage),
+          usage: normalized,
           providerMetadata: providerMetadata(event.providerMetadata),
         }),
         LLMEvent.finish({
           reason: { normalized: finishReason(event.finishReason), raw: event.finishReason.raw },
-          usage: usage(event.usage),
+          usage: normalized,
           providerMetadata: providerMetadata(event.providerMetadata),
         }),
       ])
@@ -690,7 +703,10 @@ function streamPartEvents(
   }
 }
 
-function usage(input: Extract<LanguageModelV3StreamPart, { type: "finish" }>["usage"]): UsageInput | undefined {
+function usage(
+  input: Extract<LanguageModelV3StreamPart, { type: "finish" }>["usage"],
+  cost?: number,
+): UsageInput | undefined {
   const output = {
     inputTokens: input.inputTokens.total,
     nonCachedInputTokens: input.inputTokens.noCache,
@@ -702,10 +718,22 @@ function usage(input: Extract<LanguageModelV3StreamPart, { type: "finish" }>["us
       input.inputTokens.total === undefined || input.outputTokens.total === undefined
         ? undefined
         : input.inputTokens.total + input.outputTokens.total,
+    cost,
   }
   return Object.values(output).some((value) => value !== undefined) ? output : undefined
 }
 
+function copilotCost(input: unknown): number | undefined {
+  if (!ProviderShared.isRecord(input)) return undefined
+  const raw = input
+  const response = ProviderShared.isRecord(raw.response) ? raw.response : undefined
+  const usage = raw.copilot_usage ?? response?.copilot_usage
+  if (!ProviderShared.isRecord(usage)) return undefined
+  const total = usage.total_nano_aiu
+  if (typeof total !== "number" || !Number.isFinite(total) || total < 0) return undefined
+  return total / 100_000_000_000
+}
+
 function finishReason(value: LanguageModelV3FinishReason): FinishReason {
   return value.unified === "other" ? "unknown" : value.unified
 }

packages/core/src/session/runner/llm.ts

@@ -272,10 +272,8 @@ const layer = Layer.effect(
         snapshot: startSnapshot,
         assistantMessageID,
       })
-      const stepUsage = (finish: NonNullable<StepRecord["finish"]>) => ({
-        cost: SessionUsage.calculateCost(resolved.cost, finish.tokens),
-        tokens: finish.tokens,
-      })
+      const stepUsage = (finish: NonNullable<StepRecord["finish"]>) =>
+        SessionUsage.record(finish.usage, resolved.cost)
 
       const captureStepEnd = Effect.fnUntraced(function* () {
         const snapshot = yield* snapshots.capture()

packages/core/src/session/runner/publish-llm-event.ts

@@ -35,7 +35,7 @@ export interface StepRecord {
   /** Present once the provider finished the step normally. */
   readonly finish?: {
     readonly finish: Extract<LLMEvent, { type: "step-finish" }>["reason"]["normalized"]
-    readonly tokens: ReturnType<typeof SessionUsage.tokens>
+    readonly usage: Extract<LLMEvent, { type: "step-finish" }>["usage"]
   }
   readonly calls: ReadonlyArray<{
     readonly id: string
@@ -495,7 +495,7 @@ export const createLLMEventPublisher = (bus: Pick<Bus.Interface, "publish">, inp
       case "step-finish":
         yield* flush()
         if (stepSettlement) return yield* Effect.die(new Error("Duplicate step finish"))
-        stepSettlement = { finish: event.reason.normalized, tokens: SessionUsage.tokens(event.usage) }
+        stepSettlement = { finish: event.reason.normalized, usage: event.usage }
         if (event.reason.normalized === "content-filter") {
           providerFailed = true
           yield* failAssistant({ type: "provider.content-filter", message: "Provider blocked the response" })

packages/core/src/session/usage.ts

@@ -17,7 +17,6 @@ export const tokens = (usage: Usage | undefined): TokenUsage.Info => ({
   },
 })
 
-// TODO(#35765): Use Copilot's reported billed amount once billing has a dedicated typed runtime contract.
 export function calculateCost(costs: Model.Info["cost"], usage: TokenUsage.Info) {
   const context = usage.input + usage.cache.read + usage.cache.write
   const tier = costs
@@ -38,7 +37,14 @@ export type Recorded = { readonly tokens: TokenUsage.Info; readonly cost: Money.
 
 export const record = (usage: Usage | undefined, costs: Model.Info["cost"]): Recorded => {
   const normalized = tokens(usage)
-  return { tokens: normalized, cost: calculateCost(costs, normalized) }
+  const reported = usage?.cost
+  return {
+    tokens: normalized,
+    cost:
+      reported !== undefined && Number.isFinite(reported) && reported >= 0
+        ? Money.USD.make(reported)
+        : calculateCost(costs, normalized),
+  }
 }
 
 export const add = (a: Recorded, b: Recorded): Recorded => ({

packages/core/test/aisdk.test.ts

@@ -1,5 +1,5 @@
 import { APICallError } from "@ai-sdk/provider"
-import type { LanguageModelV3, LanguageModelV3StreamPart } from "@ai-sdk/provider"
+import type { LanguageModelV3, LanguageModelV3CallOptions, LanguageModelV3StreamPart } from "@ai-sdk/provider"
 import { AISDK } from "@opencode-ai/core/aisdk"
 import { SessionRunnerRetry } from "@opencode-ai/core/session/runner/retry"
 import { toSessionError } from "@opencode-ai/core/session/to-session-error"
@@ -23,21 +23,26 @@ const model = (packageName: string, settings: Record<string, unknown> = {}) =>
     limit: { context: 100, output: 20 },
   })
 
-const streamModel = (events: ReadonlyArray<LanguageModelV3StreamPart>): LanguageModelV3 => ({
+const streamModel = (
+  events: ReadonlyArray<LanguageModelV3StreamPart>,
+  inspect?: (options: LanguageModelV3CallOptions) => void,
+): LanguageModelV3 => ({
   specificationVersion: "v3",
   provider: "test",
   modelId: "test",
   supportedUrls: {},
   doGenerate: () => Promise.reject(new Error("Unexpected non-streaming request")),
-  doStream: () =>
-    Promise.resolve({
+  doStream: (options) => {
+    inspect?.(options)
+    return Promise.resolve({
       stream: new ReadableStream({
         start(controller) {
           events.forEach((event) => controller.enqueue(event))
           controller.close()
         },
       }),
-    }),
+    })
+  },
 })
 
 const usage = {
@@ -375,6 +380,41 @@ it.effect("emits malformed AI SDK tool input without executing it", () =>
   }),
 )
 
+it.effect("normalizes Copilot billed usage to USD", () =>
+  Effect.gen(function* () {
+    const aisdk = yield* AISDK.Service
+    let options: LanguageModelV3CallOptions | undefined
+    yield* aisdk.hook.sdk((event) => {
+      event.sdk = {
+        languageModel: () =>
+          streamModel(
+            [
+              {
+                type: "raw",
+                rawValue: { type: "message_delta", copilot_usage: { total_nano_aiu: 4_473_525_000 } },
+              },
+              { type: "finish", finishReason: { unified: "stop", raw: "end_turn" }, usage },
+            ],
+            (input) => {
+              options = input
+            },
+          ),
+      }
+    })
+
+    const resolved = yield* aisdk.model({
+      ...model("@ai-sdk/github-copilot"),
+      providerID: Provider.ID.githubCopilot,
+    })
+    const response = yield* LLMClient.generate(LLM.request({ model: resolved, prompt: "Hello" })).pipe(
+      Effect.provide(client),
+    )
+
+    expect(options?.includeRawChunks).toBeTrue()
+    expect(response.usage?.cost).toBeCloseTo(0.04473525)
+  }),
+)
+
 it.effect("keeps malformed provider-executed AI SDK input terminal", () =>
   Effect.gen(function* () {
     const aisdk = yield* AISDK.Service

packages/core/test/session-runner-tool-events.test.ts

@@ -1,7 +1,6 @@
 import { expect, test } from "bun:test"
 import { Cause, Effect, Exit, Schema } from "effect"
 import { LLMEvent } from "@opencode-ai/ai"
-import { Money } from "@opencode-ai/schema/money"
 import { Bus } from "@opencode-ai/core/bus"
 import { Event } from "@opencode-ai/schema/event"
 import { Agent } from "@opencode-ai/core/agent"
@@ -13,6 +12,7 @@ import { Provider } from "@opencode-ai/core/provider"
 import { RelativePath } from "@opencode-ai/core/schema"
 import { Snapshot } from "@opencode-ai/core/snapshot"
 import { createLLMEventPublisher } from "@opencode-ai/core/session/runner/publish-llm-event"
+import { SessionUsage } from "@opencode-ai/core/session/usage"
 
 const sessionID = Session.ID.make("ses_tool_event_test")
 const base64 = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAAB"
@@ -280,6 +280,7 @@ test("content-filter finish retains failure evidence until step closeout", async
           nonCachedInputTokens: 8,
           outputTokens: 3,
           reasoningTokens: 1,
+          cost: 1.25,
         },
       }),
     ),
@@ -289,13 +290,13 @@ test("content-filter finish retains failure evidence until step closeout", async
   const settlement = publisher.record().finish
   expect(settlement).toMatchObject({
     finish: "content-filter",
-    tokens: { input: 8, output: 2, reasoning: 1 },
+    usage: { nonCachedInputTokens: 8, outputTokens: 3, reasoningTokens: 1, cost: 1.25 },
   })
   if (!settlement) throw new Error("Expected content-filter settlement")
+  const recorded = SessionUsage.record(settlement.usage, [])
   await Effect.runPromise(
     publisher.publishStepFailure({
-      cost: Money.USD.make(1.25),
-      tokens: settlement.tokens,
+      ...recorded,
       snapshot: Snapshot.ID.make("tree-end"),
       files: [RelativePath.make("src/changed.ts")],
     }),

packages/core/test/session-usage.test.ts

@@ -0,0 +1,28 @@
+import { expect, test } from "bun:test"
+import { Usage } from "@opencode-ai/ai"
+import { Money } from "@opencode-ai/schema/money"
+import { SessionUsage } from "@opencode-ai/core/session/usage"
+
+const costs = [
+  {
+    input: Money.USDPerMillionTokens.make(1),
+    output: Money.USDPerMillionTokens.make(2),
+    cache: { read: Money.USDPerMillionTokens.zero, write: Money.USDPerMillionTokens.zero },
+  },
+]
+
+test("prefers provider-reported cost", () => {
+  expect(SessionUsage.record(new Usage({ nonCachedInputTokens: 1_000_000, cost: 0.25 }), costs).cost).toBe(
+    Money.USD.make(0.25),
+  )
+  expect(SessionUsage.record(new Usage({ nonCachedInputTokens: 1_000_000, cost: 0 }), costs).cost).toBe(Money.USD.zero)
+})
+
+test("falls back to catalog pricing for invalid reported cost", () => {
+  expect(SessionUsage.record(new Usage({ nonCachedInputTokens: 1_000_000, cost: Number.NaN }), costs).cost).toBe(
+    Money.USD.make(1),
+  )
+  expect(SessionUsage.record(new Usage({ nonCachedInputTokens: 1_000_000, cost: -1 }), costs).cost).toBe(
+    Money.USD.make(1),
+  )
+})