fix(client): surface background service startup errors

Co-authored-by: Dax Raad <d@ironbay.co>

packages/ai/src/protocols/bedrock-converse.ts

@@ -348,7 +348,10 @@ const lowerMessages = Effect.fn("BedrockConverse.lowerMessages")(function* (
           continue
         }
       }
-      messages.push({ role: "user", content })
+      const previous = messages.at(-1)
+      if (previous?.role === "user")
+        messages[messages.length - 1] = { role: "user", content: [...previous.content, ...content] }
+      else messages.push({ role: "user", content })
       continue
     }
 
@@ -392,7 +395,10 @@ const lowerMessages = Effect.fn("BedrockConverse.lowerMessages")(function* (
       const cachePoint = BedrockCache.block(breakpoints, part.cache)
       if (cachePoint) content.push(cachePoint)
     }
-    messages.push({ role: "user", content })
+    const previous = messages.at(-1)
+    if (previous?.role === "user")
+      messages[messages.length - 1] = { role: "user", content: [...previous.content, ...content] }
+    else messages.push({ role: "user", content })
   }
 
   return messages

packages/ai/test/fixtures/recordings/bedrock-converse/continues-after-parallel-tool-results.json

@@ -0,0 +1,36 @@
+{
+  "version": 1,
+  "metadata": {
+    "tags": [
+      "prefix:bedrock-converse",
+      "provider:amazon-bedrock",
+      "protocol:bedrock-converse",
+      "tool",
+      "tool-loop",
+      "parallel"
+    ],
+    "name": "bedrock-converse/continues-after-parallel-tool-results",
+    "recordedAt": "2026-08-11T16:41:46.482Z"
+  },
+  "interactions": [
+    {
+      "transport": "http",
+      "request": {
+        "method": "POST",
+        "url": "https://bedrock-runtime.us-east-1.amazonaws.com/model/us.amazon.nova-micro-v1%3A0/converse-stream",
+        "headers": {
+          "content-type": "application/json"
+        },
+        "body": "{\"modelId\":\"us.amazon.nova-micro-v1:0\",\"messages\":[{\"role\":\"user\",\"content\":[{\"text\":\"Compare the weather in Paris and London.\"}]},{\"role\":\"assistant\",\"content\":[{\"toolUse\":{\"toolUseId\":\"weather_paris\",\"name\":\"get_weather\",\"input\":{\"city\":\"Paris\"}}},{\"toolUse\":{\"toolUseId\":\"weather_london\",\"name\":\"get_weather\",\"input\":{\"city\":\"London\"}}}]},{\"role\":\"user\",\"content\":[{\"toolResult\":{\"toolUseId\":\"weather_paris\",\"content\":[{\"json\":{\"temperature\":22,\"condition\":\"sunny\"}}],\"status\":\"success\"}},{\"toolResult\":{\"toolUseId\":\"weather_london\",\"content\":[{\"json\":{\"temperature\":14,\"condition\":\"rainy\"}}],\"status\":\"success\"}}]}],\"system\":[{\"text\":\"After receiving both tool results, reply exactly: Paris is sunny; London is rainy.\"}],\"inferenceConfig\":{\"maxTokens\":40,\"temperature\":0},\"toolConfig\":{\"tools\":[{\"toolSpec\":{\"name\":\"get_weather\",\"description\":\"Get current weather for a city.\",\"inputSchema\":{\"json\":{\"type\":\"object\",\"properties\":{\"city\":{\"type\":\"string\"}},\"required\":[\"city\"],\"additionalProperties\":false}}}}]}}"
+      },
+      "response": {
+        "status": 200,
+        "headers": {
+          "content-type": "application/vnd.amazon.eventstream"
+        },
+        "body": "AAAAqAAAAFKgEDvmCzpldmVudC10eXBlBwAMbWVzc2FnZVN0YXJ0DTpjb250ZW50LXR5cGUHABBhcHBsaWNhdGlvbi9qc29uDTptZXNzYWdlLXR5cGUHAAVldmVudHsicCI6ImFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6QUJDREVGR0hJSktMTU5PUFEiLCJyb2xlIjoiYXNzaXN0YW50In189ig4AAAAzgAAAFfGCE2ECzpldmVudC10eXBlBwARY29udGVudEJsb2NrRGVsdGENOmNvbnRlbnQtdHlwZQcAEGFwcGxpY2F0aW9uL2pzb24NOm1lc3NhZ2UtdHlwZQcABWV2ZW50eyJjb250ZW50QmxvY2tJbmRleCI6MCwiZGVsdGEiOnsidGV4dCI6IlBhcmlzIn0sInAiOiJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ekFCQ0RFRkdISUpLTE1OT1BRUlNUVVYifWttETIAAADDAAAAVz6YiTULOmV2ZW50LXR5cGUHABFjb250ZW50QmxvY2tEZWx0YQ06Y29udGVudC10eXBlBwAQYXBwbGljYXRpb24vanNvbg06bWVzc2FnZS10eXBlBwAFZXZlbnR7ImNvbnRlbnRCbG9ja0luZGV4IjowLCJkZWx0YSI6eyJ0ZXh0IjoiIGlzIn0sInAiOiJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ekFCQ0RFRkdISUpLTE0ifRHJ8Q0AAACqAAAAV6q6nAkLOmV2ZW50LXR5cGUHABFjb250ZW50QmxvY2tEZWx0YQ06Y29udGVudC10eXBlBwAQYXBwbGljYXRpb24vanNvbg06bWVzc2FnZS10eXBlBwAFZXZlbnR7ImNvbnRlbnRCbG9ja0luZGV4IjowLCJkZWx0YSI6eyJ0ZXh0IjoiIHN1bm55In0sInAiOiJhYmNkZWZnaGlqayJ98ZCy6gAAALAAAABXgOoTKgs6ZXZlbnQtdHlwZQcAEWNvbnRlbnRCbG9ja0RlbHRhDTpjb250ZW50LXR5cGUHABBhcHBsaWNhdGlvbi9qc29uDTptZXNzYWdlLXR5cGUHAAVldmVudHsiY29udGVudEJsb2NrSW5kZXgiOjAsImRlbHRhIjp7InRleHQiOiI7In0sInAiOiJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2In020bBKAAAAygAAAFcziOtECzpldmVudC10eXBlBwARY29udGVudEJsb2NrRGVsdGENOmNvbnRlbnQtdHlwZQcAEGFwcGxpY2F0aW9uL2pzb24NOm1lc3NhZ2UtdHlwZQcABWV2ZW50eyJjb250ZW50QmxvY2tJbmRleCI6MCwiZGVsdGEiOnsidGV4dCI6IiBMb25kb24ifSwicCI6ImFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6QUJDREVGR0hJSktMTU5PUCJ9ew04hAAAAK4AAABXXzo6yQs6ZXZlbnQtdHlwZQcAEWNvbnRlbnRCbG9ja0RlbHRhDTpjb250ZW50LXR5cGUHABBhcHBsaWNhdGlvbi9qc29uDTptZXNzYWdlLXR5cGUHAAVldmVudHsiY29udGVudEJsb2NrSW5kZXgiOjAsImRlbHRhIjp7InRleHQiOiIgaXMifSwicCI6ImFiY2RlZmdoaWprbG1ub3BxciJ9yK3bdAAAALcAAABXMsrPOgs6ZXZlbnQtdHlwZQcAEWNvbnRlbnRCbG9ja0RlbHRhDTpjb250ZW50LXR5cGUHABBhcHBsaWNhdGlvbi9qc29uDTptZXNzYWdlLXR5cGUHAAVldmVudHsiY29udGVudEJsb2NrSW5kZXgiOjAsImRlbHRhIjp7InRleHQiOiIgcmFpbnkifSwicCI6ImFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eCJ9JoCYVwAAALoAAABXyloLiws6ZXZlbnQtdHlwZQcAEWNvbnRlbnRCbG9ja0RlbHRhDTpjb250ZW50LXR5cGUHABBhcHBsaWNhdGlvbi9qc29uDTptZXNzYWdlLXR5cGUHAAVldmVudHsiY29udGVudEJsb2NrSW5kZXgiOjAsImRlbHRhIjp7InRleHQiOiIuIn0sInAiOiJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ekFCQ0RFRiJ9WJwR8wAAAMEAAABXRFjaVQs6ZXZlbnQtdHlwZQcAEWNvbnRlbnRCbG9ja0RlbHRhDTpjb250ZW50LXR5cGUHABBhcHBsaWNhdGlvbi9qc29uDTptZXNzYWdlLXR5cGUHAAVldmVudHsiY29udGVudEJsb2NrSW5kZXgiOjAsImRlbHRhIjp7InRleHQiOiIifSwicCI6ImFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6QUJDREVGR0hJSktMTU4ifYzp4V0AAAChAAAAVqptnY4LOmV2ZW50LXR5cGUHABBjb250ZW50QmxvY2tTdG9wDTpjb250ZW50LXR5cGUHABBhcHBsaWNhdGlvbi9qc29uDTptZXNzYWdlLXR5cGUHAAVldmVudHsiY29udGVudEJsb2NrSW5kZXgiOjAsInAiOiJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ekFCQyJ9AHyeLwAAAJUAAABRYKgWaws6ZXZlbnQtdHlwZQcAC21lc3NhZ2VTdG9wDTpjb250ZW50LXR5cGUHABBhcHBsaWNhdGlvbi9qc29uDTptZXNzYWdlLXR5cGUHAAVldmVudHsicCI6ImFiY2RlZmdoaWprbG1ub3BxcnN0Iiwic3RvcFJlYXNvbiI6ImVuZF90dXJuIn2HCXz0AAABBgAAAE6wWpX7CzpldmVudC10eXBlBwAIbWV0YWRhdGENOmNvbnRlbnQtdHlwZQcAEGFwcGxpY2F0aW9uL2pzb24NOm1lc3NhZ2UtdHlwZQcABWV2ZW50eyJtZXRyaWNzIjp7ImxhdGVuY3lNcyI6MTA5MH0sInAiOiJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ekFCQ0RFRkdISUpLTE1OT1BRUlNUVSIsInVzYWdlIjp7ImlucHV0VG9rZW5zIjo1MjEsIm91dHB1dFRva2VucyI6OSwic2VydmVyVG9vbFVzYWdlIjp7fSwidG90YWxUb2tlbnMiOjUzMH19Uwfxiw==",
+        "bodyEncoding": "base64"
+      }
+    }
+  ]
+}

packages/ai/test/provider/bedrock-converse.test.ts

@@ -255,6 +255,57 @@ describe("Bedrock Converse route", () => {
     }),
   )
 
+  it.effect("merges parallel tool results into one user message", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          id: "req_parallel_history",
+          model,
+          messages: [
+            Message.user("Compare the weather."),
+            Message.assistant([
+              ToolCallPart.make({ id: "tool_paris", name: "lookup", input: { city: "Paris" } }),
+              ToolCallPart.make({ id: "tool_london", name: "lookup", input: { city: "London" } }),
+            ]),
+            Message.tool({ id: "tool_paris", name: "lookup", result: { forecast: "sunny" } }),
+            Message.tool({ id: "tool_london", name: "lookup", result: { forecast: "rainy" } }),
+          ],
+          cache: "none",
+        }),
+      )
+
+      expect(prepared.body.messages).toEqual([
+        { role: "user", content: [{ text: "Compare the weather." }] },
+        {
+          role: "assistant",
+          content: [
+            { toolUse: { toolUseId: "tool_paris", name: "lookup", input: { city: "Paris" } } },
+            { toolUse: { toolUseId: "tool_london", name: "lookup", input: { city: "London" } } },
+          ],
+        },
+        {
+          role: "user",
+          content: [
+            {
+              toolResult: {
+                toolUseId: "tool_paris",
+                content: [{ json: { forecast: "sunny" } }],
+                status: "success",
+              },
+            },
+            {
+              toolResult: {
+                toolUseId: "tool_london",
+                content: [{ json: { forecast: "rainy" } }],
+                status: "success",
+              },
+            },
+          ],
+        },
+      ])
+    }),
+  )
+
   it.effect("lowers image content in tool-result messages", () =>
     Effect.gen(function* () {
       const prepared = yield* compileRequest(
@@ -1165,4 +1216,39 @@ describe("Bedrock Converse recorded", () => {
       )
     }),
   )
+
+  recorded.effect.with("continues after parallel tool results", { tags: ["tool", "tool-loop", "parallel"] }, () =>
+    Effect.gen(function* () {
+      const response = yield* LLMClient.generate(
+        LLM.request({
+          id: "recorded_bedrock_parallel_tool_results",
+          model: recordedModel(),
+          system: "After receiving both tool results, reply exactly: Paris is sunny; London is rainy.",
+          messages: [
+            Message.user("Compare the weather in Paris and London."),
+            Message.assistant([
+              ToolCallPart.make({ id: "weather_paris", name: weatherToolName, input: { city: "Paris" } }),
+              ToolCallPart.make({ id: "weather_london", name: weatherToolName, input: { city: "London" } }),
+            ]),
+            Message.tool({
+              id: "weather_paris",
+              name: weatherToolName,
+              result: { temperature: 22, condition: "sunny" },
+            }),
+            Message.tool({
+              id: "weather_london",
+              name: weatherToolName,
+              result: { temperature: 14, condition: "rainy" },
+            }),
+          ],
+          tools: [weatherTool],
+          cache: "none",
+          generation: { maxTokens: 40, temperature: 0 },
+        }),
+      )
+
+      expect(response.text.trim()).toBe("Paris is sunny; London is rainy.")
+      expect(response.finishReason?.normalized).toBe("stop")
+    }),
+  )
 })

packages/app/src/context/server-session-v2-reducer.test.ts

@@ -69,6 +69,63 @@ describe("v2 session reducer", () => {
     })
   })
 
+  test("prefers durable selection predecessors and derives them for older events", () => {
+    const source: SessionMessageInfo[] = [
+      { id: "msg_previous_agent", type: "agent-switched", agent: "build", time: { created: 1 } },
+      {
+        id: "msg_previous_model",
+        type: "model-switched",
+        model: { id: "old", providerID: "provider" },
+        time: { created: 1 },
+      },
+    ]
+    const reducer = createV2SessionReducer()
+
+    const agent = reducer.reduce(
+      source,
+      event({
+        ...base,
+        id: "evt_agent",
+        type: "session.agent.selected",
+        data: { sessionID: "ses_1", agent: "plan", previous: "review" },
+      }),
+    )
+    const model = reducer.reduce(
+      source,
+      event({
+        ...base,
+        id: "evt_model",
+        type: "session.model.selected",
+        data: {
+          sessionID: "ses_1",
+          model: { id: "new", providerID: "provider" },
+          previous: { id: "durable", providerID: "provider" },
+        },
+      }),
+    )
+    const legacyAgent = reducer.reduce(
+      source,
+      event({
+        ...base,
+        id: "evt_legacy_agent",
+        type: "session.agent.selected",
+        data: { sessionID: "ses_1", agent: "plan" },
+      }),
+    )
+
+    expect(agent?.messages.at(-1)).toMatchObject({ type: "agent-switched", agent: "plan", previous: "review" })
+    expect(model?.messages.at(-1)).toMatchObject({
+      type: "model-switched",
+      model: { id: "new" },
+      previous: { id: "durable" },
+    })
+    expect(legacyAgent?.messages.at(-1)).toMatchObject({
+      type: "agent-switched",
+      agent: "plan",
+      previous: "build",
+    })
+  })
+
   test("folds tool, retry, and completion events", () => {
     const reducer = createV2SessionReducer()
     let messages: SessionMessageInfo[] = []

packages/app/src/context/server-session-v2-reducer.ts

@@ -61,6 +61,12 @@ export function createV2SessionReducer() {
           type: "agent-switched",
           metadata: event.metadata,
           agent: event.data.agent,
+          previous:
+            event.data.previous ??
+            source.findLast(
+              (item): item is Extract<SessionMessageInfo, { type: "agent-switched" | "assistant" }> =>
+                item.type === "agent-switched" || item.type === "assistant",
+            )?.agent,
           time: { created: event.created },
         })
       case "session.model.selected":
@@ -69,10 +75,12 @@ export function createV2SessionReducer() {
           type: "model-switched",
           metadata: event.metadata,
           model: event.data.model,
-          previous: source.findLast(
-            (item): item is Extract<SessionMessageInfo, { type: "model-switched" | "assistant" }> =>
-              item.type === "model-switched" || item.type === "assistant",
-          )?.model,
+          previous:
+            event.data.previous ??
+            source.findLast(
+              (item): item is Extract<SessionMessageInfo, { type: "model-switched" | "assistant" }> =>
+                item.type === "model-switched" || item.type === "assistant",
+            )?.model,
           time: { created: event.created },
         })
       case "session.synthetic":

packages/cli/src/server-process.ts

@@ -39,6 +39,8 @@ export const run = Effect.fnUntraced(function* (options: Options) {
 })
 
 const processEffect = Effect.fnUntraced(function* (options: Options) {
+  const serviceErrorFormat = process.env.OPENCODE_SERVICE_ERROR_FORMAT
+  delete process.env.OPENCODE_SERVICE_ERROR_FORMAT
   const global = yield* Global.Service
   if (options.mode === "service") yield* Effect.sync(() => process.chdir(global.home))
   return yield* Effect.scoped(
@@ -127,15 +129,7 @@ const processEffect = Effect.fnUntraced(function* (options: Options) {
           if (serviceOptions === undefined || port === undefined || !addressInUse(error)) return Effect.fail(error)
           return recognizeIncumbent(serviceOptions, hostname, port).pipe(
             Effect.flatMap((found) =>
-              found
-                ? Effect.void
-                : Effect.fail(
-                    new Error(
-                      `Managed service port ${port} on ${hostname} is already in use by another process. ` +
-                        "Configure another port with `opencode service set port <port>` and start the service again.",
-                      { cause: error },
-                    ),
-                  ),
+              found ? Effect.void : managedPortInUse(hostname, port, error, serviceErrorFormat),
             ),
           )
         }),
@@ -214,6 +208,17 @@ function serviceURL(hostname: string, port: number) {
   return `http://${hostname.includes(":") ? `[${hostname}]` : hostname}:${port}`
 }
 
+function managedPortInUse(hostname: string, port: number, cause: unknown, format?: string) {
+  const message =
+    `Managed service port ${port} on ${hostname} is already in use by another process. ` +
+    "Configure another port with `opencode service set port <port>` and start the service again."
+  const failure = new Error(message, { cause })
+  if (format !== "plain") return Effect.fail(failure)
+  return Effect.sync(() => process.stderr.write(`OPENCODE_SERVICE_ERROR:${message}\n`)).pipe(
+    Effect.andThen(Effect.fail(failure)),
+  )
+}
+
 function truthy(value?: string) {
   return value === "1" || value?.toLowerCase() === "true"
 }

packages/client/src/effect/api/api.ts

@@ -339,7 +339,11 @@ export type Endpoint5_31Output =
           readonly type: "session.agent.selected"
           readonly durable: { readonly aggregateID: string; readonly seq: Event.Seq; readonly version: Event.Version }
           readonly location?: Location.Ref | undefined
-          readonly data: { readonly sessionID: Session.ID; readonly agent: Agent.ID }
+          readonly data: {
+            readonly sessionID: Session.ID
+            readonly agent: Agent.ID
+            readonly previous?: Agent.ID | undefined
+          }
         }
       | {
           readonly id: Event.ID
@@ -348,7 +352,11 @@ export type Endpoint5_31Output =
           readonly type: "session.model.selected"
           readonly durable: { readonly aggregateID: string; readonly seq: Event.Seq; readonly version: Event.Version }
           readonly location?: Location.Ref | undefined
-          readonly data: { readonly sessionID: Session.ID; readonly model: Model.Ref }
+          readonly data: {
+            readonly sessionID: Session.ID
+            readonly model: Model.Ref
+            readonly previous?: Model.Ref | undefined
+          }
         }
       | {
           readonly id: Event.ID

packages/client/src/effect/service.ts

@@ -1,9 +1,9 @@
 import { ServiceStatus } from "@opencode-ai/protocol/groups/health"
 import { Effect, FileSystem, Option, Schedule, Schema } from "effect"
-import { spawn, type ChildProcess } from "node:child_process"
 import { homedir } from "node:os"
 import { join } from "node:path"
 import type { DiscoverOptions, Endpoint, EnsureOptions, StopOptions } from "../service.js"
+import { ServiceProcess } from "../service-process.js"
 
 export * from "../service.js"
 /** Contents of the local service registration file. */
@@ -17,11 +17,6 @@ export type Info = import("../service.js").Info
 // is all a client needs to connect. The daemon's own configuration (port,
 // persisted password) is CLI-owned and never read here.
 
-type Contender = {
-  readonly child: ChildProcess
-  readonly error: () => Error | undefined
-}
-
 // Read-only lookup: registration file plus health check and version gate.
 // Never spawns; escalation to ensure() is the caller's policy.
 /** Discover a healthy, compatible local service without starting one. */
@@ -52,11 +47,12 @@ const discoverLocal = Effect.fnUntraced(function* (options: DiscoverOptions) {
 // becomes discoverable. A contender is never killed merely for slow startup.
 /** Ensure a healthy, compatible local service is running. */
 export const ensure = Effect.fn("service.ensure")(function* (options: EnsureOptions = {}) {
-  const contenders = new Set<Contender>()
+  const contenders = new Set<ServiceProcess.Contender>()
   let timeouts: { readonly info: Info; readonly count: number } | undefined
   let announced = false
   let lastSpawn = 0
   let spawnDelay = 5_000
+  let lastFailure: Error | undefined
   const announce = (reason: "missing" | "version-mismatch", previousVersion?: string) =>
     Effect.sync(() => {
       if (announced) return
@@ -67,15 +63,7 @@ export const ensure = Effect.fn("service.ensure")(function* (options: EnsureOpti
     const [command, ...args] = options.command ?? ["opencode", "serve", "--service"]
     if (command === undefined) return yield* Effect.fail(new Error("Missing service command"))
     return yield* Effect.try({
-      try: () => {
-        const child = spawn(command, args, { detached: true, stdio: "ignore" })
-        let error: Error | undefined
-        child.once("error", (cause) => {
-          error = new Error("Failed to start server", { cause })
-        })
-        child.unref()
-        return { child, error: () => error }
-      },
+      try: () => ServiceProcess.start(command, args),
       catch: (cause) => new Error("Failed to start server", { cause }),
     })
   })
@@ -108,8 +96,9 @@ export const ensure = Effect.fn("service.ensure")(function* (options: EnsureOpti
       return Option.none<LocalService>()
     } else if (lastSpawn === 0 && info !== undefined) lastSpawn = Date.now()
 
-    const finished = [...contenders].filter(contenderFinished)
-    const failure = finished.map(contenderFailure).find((error): error is Error => error !== undefined)
+    const finished = [...contenders].filter(ServiceProcess.finished)
+    const failure = finished.map(ServiceProcess.failure).find((error): error is Error => error !== undefined)
+    if (failure !== undefined) lastFailure = failure
     if (finished.some((item) => item.child.exitCode === 0)) {
       spawnDelay = Math.min(spawnDelay * 2, 30_000)
     }
@@ -129,24 +118,10 @@ export const ensure = Effect.fn("service.ensure")(function* (options: EnsureOpti
     }),
   )
   if (Option.isNone(found))
-    return yield* Effect.fail(new Error("Timed out waiting for the background service to start"))
+    return yield* Effect.fail(lastFailure ?? new Error("Timed out waiting for the background service to start"))
   return found.value.endpoint
 })
 
-function contenderFailure(contender: Contender) {
-  const error = contender.error()
-  if (error !== undefined) return error
-  if (contender.child.exitCode !== null && contender.child.exitCode !== 0)
-    return new Error(`Server process exited with code ${contender.child.exitCode}`)
-  if (contender.child.signalCode !== null)
-    return new Error(`Server process terminated by ${contender.child.signalCode}`)
-  return undefined
-}
-
-function contenderFinished(contender: Contender) {
-  return contender.error() !== undefined || contender.child.exitCode !== null || contender.child.signalCode !== null
-}
-
 /** Stop the registered local service. */
 export const stop = Effect.fn("service.stop")(function* (options: StopOptions = {}) {
   const existing = yield* find(options)

packages/client/src/promise/generated/types.ts

@@ -436,7 +436,7 @@ export type SessionAgentSelected = {
   type: "session.agent.selected"
   durable: { aggregateID: string; seq: number; version: 1 }
   location?: LocationRef
-  data: { sessionID: string; agent: string }
+  data: { sessionID: string; agent: string; previous?: string }
 }
 
 export type SessionModelSelected = {
@@ -446,7 +446,7 @@ export type SessionModelSelected = {
   type: "session.model.selected"
   durable: { aggregateID: string; seq: number; version: 1 }
   location?: LocationRef
-  data: { sessionID: string; model: ModelRef }
+  data: { sessionID: string; model: ModelRef; previous?: ModelRef }
 }
 
 export type SessionMoved = {

packages/client/src/promise/service.ts

@@ -1,8 +1,8 @@
 import { readFile } from "node:fs/promises"
-import { spawn, type ChildProcess } from "node:child_process"
 import { homedir } from "node:os"
 import { join } from "node:path"
 import type { DiscoverOptions, Endpoint, Info, EnsureOptions, StopOptions } from "../service.js"
+import { ServiceProcess } from "../service-process.js"
 import type { ServiceHealth, ServiceStopResponse } from "./generated/types.js"
 
 export * from "../service.js"
@@ -13,11 +13,6 @@ export * from "../service.js"
 // intentionally implemented with Node APIs so Promise clients do not need
 // Effect or @effect/platform-node at runtime.
 
-type Contender = {
-  readonly child: ChildProcess
-  readonly error: () => Error | undefined
-}
-
 /** Discover a healthy, compatible local service without starting one. */
 export async function discover(options: DiscoverOptions = {}) {
   return (await discoverLocal(options))?.endpoint
@@ -33,11 +28,12 @@ async function discoverLocal(options: DiscoverOptions) {
 /** Ensure a healthy, compatible local service is running. */
 export async function ensure(options: EnsureOptions = {}): Promise<Endpoint> {
   const deadline = Date.now() + 120_000
-  const contenders = new Set<Contender>()
+  const contenders = new Set<ServiceProcess.Contender>()
   let timeouts: { readonly info: Info; readonly count: number } | undefined
   let announced = false
   let lastSpawn = 0
   let spawnDelay = 5_000
+  let lastFailure: Error | undefined
 
   const announce = (reason: "missing" | "version-mismatch", previousVersion?: string) => {
     if (announced) return
@@ -47,21 +43,11 @@ export async function ensure(options: EnsureOptions = {}): Promise<Endpoint> {
   const spawnContender = () => {
     const [command, ...args] = options.command ?? ["opencode", "serve", "--service"]
     if (command === undefined) throw new Error("Missing service command")
-    try {
-      const child = spawn(command, args, { detached: true, stdio: "ignore" })
-      let error: Error | undefined
-      child.once("error", (cause) => {
-        error = new Error("Failed to start server", { cause })
-      })
-      child.unref()
-      return { child, error: () => error }
-    } catch (cause) {
-      throw new Error("Failed to start server", { cause })
-    }
+    return ServiceProcess.start(command, args)
   }
 
   while (true) {
-    if (Date.now() >= deadline) throw new Error("Timed out waiting for the background service to start")
+    if (Date.now() >= deadline) throw lastFailure ?? new Error("Timed out waiting for the background service to start")
     const registration = await registered(options.file, true)
     if (registration.timedOut && registration.info !== undefined) {
       timeouts = {
@@ -89,8 +75,9 @@ export async function ensure(options: EnsureOptions = {}): Promise<Endpoint> {
       }
     } else {
       if (lastSpawn === 0 && registration.info !== undefined) lastSpawn = Date.now()
-      const finished = [...contenders].filter(contenderFinished)
-      const failure = finished.map(contenderFailure).find((error) => error !== undefined)
+      const finished = [...contenders].filter(ServiceProcess.finished)
+      const failure = finished.map(ServiceProcess.failure).find((error) => error !== undefined)
+      if (failure !== undefined) lastFailure = failure
       if (finished.some((item) => item.child.exitCode === 0)) {
         spawnDelay = Math.min(spawnDelay * 2, 30_000)
       }
@@ -107,20 +94,6 @@ export async function ensure(options: EnsureOptions = {}): Promise<Endpoint> {
   }
 }
 
-function contenderFailure(contender: Contender) {
-  const error = contender.error()
-  if (error !== undefined) return error
-  if (contender.child.exitCode !== null && contender.child.exitCode !== 0)
-    return new Error(`Server process exited with code ${contender.child.exitCode}`)
-  if (contender.child.signalCode !== null)
-    return new Error(`Server process terminated by ${contender.child.signalCode}`)
-  return undefined
-}
-
-function contenderFinished(contender: Contender) {
-  return contender.error() !== undefined || contender.child.exitCode !== null || contender.child.signalCode !== null
-}
-
 /** Stop the registered local service. */
 export async function stop(options: StopOptions = {}) {
   const existing = await find(options)

packages/client/src/service-process.ts

@@ -0,0 +1,57 @@
+export * as ServiceProcess from "./service-process"
+
+import { spawn, type ChildProcess } from "node:child_process"
+
+const errorPrefix = "OPENCODE_SERVICE_ERROR:"
+
+export type Contender = {
+  readonly child: ChildProcess
+  readonly error: () => Error | undefined
+  readonly startupError: () => string
+}
+
+export function start(command: string, args: ReadonlyArray<string>) {
+  try {
+    const child = spawn(command, args, {
+      detached: true,
+      stdio: ["ignore", "ignore", "pipe"],
+      env: { ...process.env, OPENCODE_SERVICE_ERROR_FORMAT: "plain" },
+    })
+    let error: Error | undefined
+    let pending = ""
+    let startupError = ""
+    child.once("error", (cause) => {
+      error = new Error("Failed to start server", { cause })
+    })
+    child.stderr?.on("data", (chunk) => {
+      const lines = (pending + chunk.toString()).split(/\r?\n/)
+      pending = lines.pop()?.slice(-64 * 1024) ?? ""
+      const message = lines.findLast((line) => line.startsWith(errorPrefix))
+      if (message !== undefined) startupError = message.slice(errorPrefix.length)
+    })
+    unref(child.stderr)
+    child.unref()
+    return { child, error: () => error, startupError: () => startupError } satisfies Contender
+  } catch (cause) {
+    throw new Error("Failed to start server", { cause })
+  }
+}
+
+export function failure(contender: Contender) {
+  const error = contender.error()
+  if (error !== undefined) return error
+  if (contender.child.exitCode !== null && contender.child.exitCode !== 0)
+    return new Error(contender.startupError() || `Server process exited with code ${contender.child.exitCode}`)
+  if (contender.child.signalCode !== null)
+    return new Error(`Server process terminated by ${contender.child.signalCode}`)
+  return undefined
+}
+
+export function finished(contender: Contender) {
+  return contender.error() !== undefined || contender.child.exitCode !== null || contender.child.signalCode !== null
+}
+
+function unref(stream: ChildProcess["stderr"]) {
+  if (!stream || !("unref" in stream) || typeof stream.unref !== "function") return
+  stream.unref()
+}

packages/client/test/fixture/service.ts

@@ -3,6 +3,11 @@ import { appendFile, rename, writeFile } from "node:fs/promises"
 const [registration, mode, delay] = process.argv.slice(2)
 if (registration === undefined || mode === undefined) throw new Error("Missing service fixture arguments")
 if (mode === "failed") process.exit(1)
+if (mode === "failed-message") {
+  console.error("sensitive startup detail")
+  console.error("OPENCODE_SERVICE_ERROR:Managed service port is already in use")
+  process.exit(1)
+}
 if (mode === "record-start") {
   await writeFile(registration + ".started", "")
   process.exit(1)

packages/client/test/promise-service.test.ts

@@ -70,6 +70,19 @@ test("reports a failed registered service", async () => {
   )
 })
 
+test("reports the native contender's startup error", async () => {
+  const directory = await temp()
+  const registration = join(directory, "service.json")
+
+  await expect(
+    Service.ensure({
+      file: registration,
+      version: "test",
+      command: [process.execPath, fixture, registration, "failed-message"],
+    }),
+  ).rejects.toThrow(/^Managed service port is already in use$/)
+}, 10_000)
+
 test("evicts an unresponsive registered service before starting its replacement", async () => {
   const directory = await temp()
   const registration = join(directory, "service.json")

packages/client/test/service.test.ts

@@ -197,6 +197,20 @@ test("reports a contender that fails to start", async () => {
   ).rejects.toThrow("Server process exited with code 1")
 }, 10_000)
 
+test("reports the contender's startup error", async () => {
+  const directory = await temp()
+  const registration = join(directory, "service.json")
+  await expect(
+    run(
+      Service.ensure({
+        file: registration,
+        version: "test",
+        command: [process.execPath, fixture, registration, "failed-message"],
+      }),
+    ),
+  ).rejects.toThrow(/^Managed service port is already in use$/)
+}, 10_000)
+
 test("reports a contender terminated by a signal", async () => {
   const directory = await temp()
   const registration = join(directory, "service.json")

packages/core/script/migration.ts

@@ -194,11 +194,10 @@ async function formatTypescript(input: string) {
 
 function renderRegistry(names: string[]) {
   return `import type { DatabaseMigration } from "./migration"
+${names.map((name, index) => `import m${index.toString().padStart(2, "0")} from "./migration/${name}"`).join("\n")}
 
-export const migrations: DatabaseMigration.Migration[] = (
-  await Promise.all([
-${names.map((name) => `    import("./migration/${name}"),`).join("\n")}
-  ])
-).map((module) => module.default)
+export const migrations = [
+${names.map((_, index) => `  m${index.toString().padStart(2, "0")},`).join("\n")}
+] satisfies DatabaseMigration.Migration[]
 `
 }

packages/core/src/config/plugin/source.ts

@@ -153,10 +153,12 @@ const scan = Effect.fn("ConfigPluginSource.scan")(function* (
   })
 })
 
+const sourceDirectories = ["plugin", "plugins"] as const
+
 function discoverDirectory(fs: FSUtil.Interface, directory: string) {
   return Effect.gen(function* () {
     const files = yield* fs
-      .scan("{plugin,plugins}/*.{ts,js}", {
+      .scan(`{${sourceDirectories.join(",")}}/*.{ts,js}`, {
         cwd: directory,
         absolute: true,
         include: "file",
@@ -168,8 +170,6 @@ function discoverDirectory(fs: FSUtil.Interface, directory: string) {
   })
 }
 
-const sourceDirectories = ["plugin", "plugins"] as const
-
 function isPluginSource(entries: readonly Entry[], file: string) {
   return entries.some(
     (entry) =>

packages/core/src/credential.ts

@@ -1,12 +1,9 @@
 export * as Credential from "./credential"
 
-import { asc, eq, sql } from "drizzle-orm"
+import { asc, eq } from "drizzle-orm"
 import { Context, Effect, Layer, Schema } from "effect"
-import fs from "fs/promises"
-import path from "path"
 import { Credential } from "@opencode-ai/schema/credential"
 import { Integration } from "@opencode-ai/schema/integration"
-import { Global } from "@opencode-ai/util/global"
 import { Database } from "./database/database"
 import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
 import { CredentialTable } from "./credential/sql"
@@ -51,47 +48,6 @@ export interface Interface {
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/Credential") {}
 
-export const importFromDatabase = Effect.fn("Credential.importFromDatabase")(function* (input: {
-  readonly path: string
-}) {
-  const database = yield* Database.Service
-  const filename = path.isAbsolute(input.path) ? input.path : path.join(Global.Path.data, input.path)
-  yield* Effect.promise(() => fs.access(filename))
-  yield* database.db.run(sql`ATTACH DATABASE ${filename} AS credential_snapshot`).pipe(Effect.orDie)
-  yield* Effect.gen(function* () {
-    yield* database.db.run(sql`DELETE FROM credential`)
-    // Snapshot OAuth credentials are access-token-only so the embedded host never rotates the user's refresh token.
-    yield* database.db.run(sql`
-        INSERT INTO credential (
-          id,
-          integration_id,
-          label,
-          value,
-          connector_id,
-          method_id,
-          active,
-          time_created,
-          time_updated
-        )
-        SELECT
-          id,
-          integration_id,
-          label,
-          CASE
-            WHEN json_extract(value, '$.type') = 'oauth'
-            THEN json_set(value, '$.refresh', '', '$.expires', 8640000000000000)
-            ELSE value
-          END,
-          connector_id,
-          method_id,
-          active,
-          time_created,
-          time_updated
-        FROM credential_snapshot.credential
-      `)
-  }).pipe(Effect.orDie, Effect.ensuring(database.db.run(sql`DETACH DATABASE credential_snapshot`).pipe(Effect.orDie)))
-})
-
 const layer = Layer.effect(
   Service,
   Effect.gen(function* () {

packages/core/src/database/database.ts

@@ -42,10 +42,10 @@ const databaseLayer = Layer.effect(
 export function layer(options: Options = { path: ":memory:" }) {
   return Layer.unwrap(
     Effect.gen(function* () {
-      const global = yield* Global.Service
       const provide = (filename: string) => databaseLayer.pipe(Layer.provide(sqliteLayer({ filename })))
       const filename = options.path ?? ":memory:"
       if (filename === ":memory:" || isAbsolute(filename)) return provide(filename)
+      const global = yield* Global.Service
       return provide(join(global.data, filename))
     }),
   )

packages/core/src/database/migration.gen.ts

@@ -1,47 +1,86 @@
 import type { DatabaseMigration } from "./migration"
+import m00 from "./migration/20260127222353_familiar_lady_ursula"
+import m01 from "./migration/20260211171708_add_project_commands"
+import m02 from "./migration/20260213144116_wakeful_the_professor"
+import m03 from "./migration/20260225215848_workspace"
+import m04 from "./migration/20260227213759_add_session_workspace_id"
+import m05 from "./migration/20260228203230_blue_harpoon"
+import m06 from "./migration/20260303231226_add_workspace_fields"
+import m07 from "./migration/20260309230000_move_org_to_state"
+import m08 from "./migration/20260312043431_session_message_cursor"
+import m09 from "./migration/20260323234822_events"
+import m10 from "./migration/20260410174513_workspace-name"
+import m11 from "./migration/20260413175956_chief_energizer"
+import m12 from "./migration/20260423070820_add_icon_url_override"
+import m13 from "./migration/20260427172553_slow_nightmare"
+import m14 from "./migration/20260428004200_add_session_path"
+import m15 from "./migration/20260501142318_next_venus"
+import m16 from "./migration/20260504145000_add_sync_owner"
+import m17 from "./migration/20260507164347_add_workspace_time"
+import m18 from "./migration/20260510033149_session_usage"
+import m19 from "./migration/20260511000411_data_migration_state"
+import m20 from "./migration/20260511173437_session-metadata"
+import m21 from "./migration/20260601010001_normalize_storage_paths"
+import m22 from "./migration/20260601202201_amazing_prowler"
+import m23 from "./migration/20260602002951_lowly_union_jack"
+import m24 from "./migration/20260602182828_add_project_directories"
+import m25 from "./migration/20260603001617_session_message_projection_indexes"
+import m26 from "./migration/20260603040000_session_message_projection_order"
+import m27 from "./migration/20260603141458_session_input_inbox"
+import m28 from "./migration/20260603160727_jittery_ezekiel_stane"
+import m29 from "./migration/20260604172448_event_sourced_session_input"
+import m30 from "./migration/20260605003541_add_session_context_snapshot"
+import m31 from "./migration/20260605042240_add_context_epoch_agent"
+import m32 from "./migration/20260611035744_credential"
+import m33 from "./migration/20260611192811_lush_chimera"
+import m34 from "./migration/20260612174303_project_dir_strategy"
+import m35 from "./migration/20260622142730_simplify_session_context_epoch"
+import m36 from "./migration/20260622170816_reset_v2_session_state"
+import m37 from "./migration/20260622202450_simplify_session_input"
+import m38 from "./migration/20260804233008_loose_psylocke"
+import m39 from "./migration/20260805200742_import_legacy_credentials"
+import m40 from "./migration/20260808023530_workspace_domain"
 
-export const migrations: DatabaseMigration.Migration[] = (
-  await Promise.all([
-    import("./migration/20260127222353_familiar_lady_ursula"),
-    import("./migration/20260211171708_add_project_commands"),
-    import("./migration/20260213144116_wakeful_the_professor"),
-    import("./migration/20260225215848_workspace"),
-    import("./migration/20260227213759_add_session_workspace_id"),
-    import("./migration/20260228203230_blue_harpoon"),
-    import("./migration/20260303231226_add_workspace_fields"),
-    import("./migration/20260309230000_move_org_to_state"),
-    import("./migration/20260312043431_session_message_cursor"),
-    import("./migration/20260323234822_events"),
-    import("./migration/20260410174513_workspace-name"),
-    import("./migration/20260413175956_chief_energizer"),
-    import("./migration/20260423070820_add_icon_url_override"),
-    import("./migration/20260427172553_slow_nightmare"),
-    import("./migration/20260428004200_add_session_path"),
-    import("./migration/20260501142318_next_venus"),
-    import("./migration/20260504145000_add_sync_owner"),
-    import("./migration/20260507164347_add_workspace_time"),
-    import("./migration/20260510033149_session_usage"),
-    import("./migration/20260511000411_data_migration_state"),
-    import("./migration/20260511173437_session-metadata"),
-    import("./migration/20260601010001_normalize_storage_paths"),
-    import("./migration/20260601202201_amazing_prowler"),
-    import("./migration/20260602002951_lowly_union_jack"),
-    import("./migration/20260602182828_add_project_directories"),
-    import("./migration/20260603001617_session_message_projection_indexes"),
-    import("./migration/20260603040000_session_message_projection_order"),
-    import("./migration/20260603141458_session_input_inbox"),
-    import("./migration/20260603160727_jittery_ezekiel_stane"),
-    import("./migration/20260604172448_event_sourced_session_input"),
-    import("./migration/20260605003541_add_session_context_snapshot"),
-    import("./migration/20260605042240_add_context_epoch_agent"),
-    import("./migration/20260611035744_credential"),
-    import("./migration/20260611192811_lush_chimera"),
-    import("./migration/20260612174303_project_dir_strategy"),
-    import("./migration/20260622142730_simplify_session_context_epoch"),
-    import("./migration/20260622170816_reset_v2_session_state"),
-    import("./migration/20260622202450_simplify_session_input"),
-    import("./migration/20260804233008_loose_psylocke"),
-    import("./migration/20260805200742_import_legacy_credentials"),
-    import("./migration/20260808023530_workspace_domain"),
-  ])
-).map((module) => module.default)
+export const migrations = [
+  m00,
+  m01,
+  m02,
+  m03,
+  m04,
+  m05,
+  m06,
+  m07,
+  m08,
+  m09,
+  m10,
+  m11,
+  m12,
+  m13,
+  m14,
+  m15,
+  m16,
+  m17,
+  m18,
+  m19,
+  m20,
+  m21,
+  m22,
+  m23,
+  m24,
+  m25,
+  m26,
+  m27,
+  m28,
+  m29,
+  m30,
+  m31,
+  m32,
+  m33,
+  m34,
+  m35,
+  m36,
+  m37,
+  m38,
+  m39,
+  m40,
+] satisfies DatabaseMigration.Migration[]

packages/core/src/database/v1-migration.ts

@@ -7,7 +7,7 @@ import { SessionV1 } from "@opencode-ai/schema/session-v1"
 import { SessionMessage } from "../session/message"
 import { SessionSchema } from "../session/schema"
 import { KVTable } from "../kv/sql"
-import { EventSequenceTable, EventTable } from "../event/sql"
+import { EventSequenceTable } from "../event/sql"
 import { eq, sql } from "drizzle-orm"
 import { Global } from "@opencode-ai/util/global"
 import { existsSync } from "node:fs"
@@ -161,6 +161,7 @@ type NextMessage = {
 
 const lock = Semaphore.makeUnsafe(1)
 const MIGRATION_STATE_KEY = "migration.v1-v2"
+const EVENT_DELETE_BATCH_SIZE = 1_000
 const decodeJson = Schema.decodeUnknownOption(Schema.UnknownFromJsonString)
 const decodeMessage = Schema.decodeUnknownOption(SessionV1.Info)
 const decodePart = Schema.decodeUnknownOption(SessionV1.Part)
@@ -485,7 +486,15 @@ export function run(options: Options = {}): Effect.Effect<RunResult, never, Data
           yield* db
             .transaction((tx) =>
               Effect.gen(function* () {
-                yield* tx.delete(EventTable).run()
+                while (true) {
+                  yield* tx.run(sql`
+                    DELETE FROM event
+                    WHERE rowid IN (SELECT rowid FROM event LIMIT ${EVENT_DELETE_BATCH_SIZE})
+                  `)
+                  const deleted = (yield* tx.get<{ value: number }>(sql`SELECT changes() AS value`))?.value ?? 0
+                  if (deleted < EVENT_DELETE_BATCH_SIZE) break
+                  yield* Effect.yieldNow
+                }
                 yield* tx
                   .insert(KVTable)
                   .values({ key: MIGRATION_STATE_KEY, value: { phase: "sessions" } })

packages/core/src/plugin/models-dev.ts

@@ -36,6 +36,7 @@ export const ModelsDevPlugin = define({
           draft.integrationID = Integration.ID.make(provider.info.id)
         })
         for (const model of provider.models) {
+          if (model.status === "deprecated") continue
           catalog.model.update(provider.info.id, model.id, (draft) => Object.assign(draft, model))
         }
       }

packages/core/src/session.ts

@@ -716,10 +716,11 @@ const layer = Layer.effect(
             .pipe(Effect.ignore, Effect.forkIn(scope, { startImmediately: true }), Effect.asVoid)
       }),
       switchAgent: Effect.fn("Session.switchAgent")(function* (input) {
-        yield* result.get(input.sessionID)
+        const session = yield* result.get(input.sessionID)
         yield* bus.publish(SessionEvent.AgentSelected, {
           sessionID: input.sessionID,
           agent: input.agent,
+          previous: session.agent,
         })
       }),
       switchModel: Effect.fn("Session.switchModel")(function* (input) {
@@ -733,6 +734,7 @@ const layer = Layer.effect(
         yield* bus.publish(SessionEvent.ModelSelected, {
           sessionID: input.sessionID,
           model: input.model,
+          previous: session.model,
         })
       }),
       rename: Effect.fn("Session.rename")(function* (input) {

packages/core/src/session/message-updater.ts

@@ -61,7 +61,7 @@ export function update(adapter: Adapter, event: SessionEvent.DurableEvent) {
       "session.usage.recorded": () => Effect.void,
       "session.agent.selected": (event) => {
         return Effect.gen(function* () {
-          const previous = yield* adapter.getAgent()
+          const previous = event.data.previous ?? (yield* adapter.getAgent())
           yield* adapter.appendMessage(
             SessionMessage.AgentSelected.make({
               id: SessionMessage.ID.fromEvent(event.id),
@@ -76,7 +76,7 @@ export function update(adapter: Adapter, event: SessionEvent.DurableEvent) {
       },
       "session.model.selected": (event) => {
         return Effect.gen(function* () {
-          const previous = yield* adapter.getModel()
+          const previous = event.data.previous ?? (yield* adapter.getModel())
           yield* adapter.appendMessage(
             SessionMessage.ModelSelected.make({
               id: SessionMessage.ID.fromEvent(event.id),

packages/core/src/session/runner/to-llm-message.ts

@@ -65,15 +65,15 @@ const userAttachmentContent = (files: readonly FileAttachment[]) => {
   )
   if (eligible.length < 2) return files.flatMap(attachmentContent)
 
-  const seen = new Map<string, string[]>()
+  const seen = new Map<string, Set<string>>()
   return files.flatMap((file) => {
     if (!imageMimes.has(file.mime) || file.source.type !== "inline" || !file.mention?.text)
       return attachmentContent(file)
     const metadata = JSON.stringify([file.mime, file.name ?? null, file.description ?? null, file.mention.text])
-    const matches = seen.get(metadata)
-    if (matches?.includes(file.data)) return []
-    if (matches) matches.push(file.data)
-    if (!matches) seen.set(metadata, [file.data])
+    const payloads = seen.get(metadata) ?? new Set<string>()
+    if (payloads.has(file.data)) return []
+    payloads.add(file.data)
+    seen.set(metadata, payloads)
     return attachmentContent(file)
   })
 }

packages/core/src/tool/plugin/question.ts

@@ -21,7 +21,7 @@ Usage notes:
 - If you recommend a specific option, make that the first option in the list and add "(Recommended)" at the end of the label`
 
 export const Input = Schema.Struct({
-  questions: Schema.NonEmptyArray(Question.Prompt).annotate({ description: "Questions to ask" }),
+  questions: Schema.Array(Question.Prompt).check(Schema.isNonEmpty()).annotate({ description: "Questions to ask" }),
 })
 
 export const Output = Schema.Struct({

packages/core/test/credential.test.ts

@@ -1,15 +1,11 @@
 import { describe, expect } from "bun:test"
-import { Effect, Layer } from "effect"
+import { Effect } from "effect"
 import { Credential } from "@opencode-ai/core/credential"
-import { Database } from "@opencode-ai/core/database/database"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
 import { Integration } from "@opencode-ai/core/integration"
 import { testEffect } from "./lib/effect"
-import { tmpdir } from "./fixture/tmpdir"
-import path from "path"
 
-const it = testEffect(Layer.empty)
-const credentialLayer = LayerNode.compile(Credential.node)
+const it = testEffect(LayerNode.compile(Credential.node))
 
 describe("Credential", () => {
   it.effect("stores, updates, lists, and removes credentials", () =>
@@ -35,56 +31,6 @@ describe("Credential", () => {
 
       yield* credentials.remove(replacement.id)
       expect(yield* credentials.list(integrationID)).toEqual([])
-    }).pipe(Effect.provide(credentialLayer)),
-  )
-
-  it.effect("imports a read-only credential snapshot", () =>
-    Effect.acquireRelease(
-      Effect.promise(() => tmpdir("opencode-credential-snapshot-")),
-      (directory) => Effect.promise(() => directory[Symbol.asyncDispose]()),
-    ).pipe(
-      Effect.flatMap((directory) => {
-        const filename = path.join(directory.path, "source.sqlite")
-        const source = LayerNode.compile(Credential.node, [[Database.node, Database.configured({ path: filename })]])
-        const keyIntegration = Integration.ID.make("openai")
-        const oauthIntegration = Integration.ID.make("github-copilot")
-        return Effect.gen(function* () {
-          yield* Effect.gen(function* () {
-            const credentials = yield* Credential.Service
-            yield* credentials.create({
-              integrationID: keyIntegration,
-              value: Credential.Key.make({ type: "key", key: "secret" }),
-            })
-            yield* credentials.create({
-              integrationID: oauthIntegration,
-              value: Credential.OAuth.make({
-                type: "oauth",
-                methodID: Integration.MethodID.make("oauth"),
-                access: "access",
-                refresh: "refresh",
-                expires: 1,
-              }),
-            })
-          }).pipe(Effect.provide(source), Effect.scoped)
-
-          yield* Effect.gen(function* () {
-            yield* Credential.importFromDatabase({ path: filename })
-            const credentials = yield* Credential.Service
-            expect((yield* credentials.list(keyIntegration))[0]?.value).toEqual(
-              Credential.Key.make({ type: "key", key: "secret" }),
-            )
-            expect((yield* credentials.list(oauthIntegration))[0]?.value).toEqual(
-              Credential.OAuth.make({
-                type: "oauth",
-                methodID: Integration.MethodID.make("oauth"),
-                access: "access",
-                refresh: "",
-                expires: 8640000000000000,
-              }),
-            )
-          }).pipe(Effect.provide(LayerNode.compile(LayerNode.group([Credential.node, Database.node]))), Effect.scoped)
-        })
-      }),
-    ),
+    }),
   )
 })

packages/core/test/plugin/models-dev.test.ts

@@ -215,6 +215,66 @@ describe("ModelsDevPlugin", () => {
     }),
   )
 
+  it.effect("omits deprecated models from the catalog", () =>
+    Effect.gen(function* () {
+      const integrations = yield* Integration.Service
+      const catalog = yield* Catalog.Service
+      const providerID = Provider.ID.make("acme")
+      const activeID = Model.ID.make("current")
+      const deprecatedID = Model.ID.make("legacy")
+      const model = {
+        modelID: activeID,
+        providerID,
+        name: "Current",
+        capabilities: { tools: true, input: [], output: [] },
+        variants: [],
+        time: { released: Date.parse("2026-01-01") },
+        cost: [],
+        status: "active",
+        enabled: true,
+        limit: { context: 128_000, output: 32_000 },
+      } satisfies Omit<Model.Info, "id">
+      const snapshots = [
+        {
+          info: {
+            id: providerID,
+            name: "Acme",
+            package: Provider.aisdk("@ai-sdk/openai-compatible"),
+          },
+          environment: [],
+          models: [
+            { id: activeID, ...model },
+            {
+              id: deprecatedID,
+              ...model,
+              modelID: deprecatedID,
+              name: "Legacy",
+              status: "deprecated" as const,
+            },
+          ],
+        },
+      ] satisfies readonly ModelsDev.Snapshot[]
+
+      yield* ModelsDevPlugin.effect(
+        host({
+          catalog: catalogHost(catalog),
+          integration: integrationHost(integrations),
+        }),
+      ).pipe(
+        Effect.provideService(
+          ModelsDev.Service,
+          ModelsDev.Service.of({
+            get: () => Effect.succeed(snapshots),
+            refresh: () => Effect.void,
+          }),
+        ),
+      )
+
+      expect(yield* catalog.model.get(providerID, activeID)).toBeDefined()
+      expect(yield* catalog.model.get(providerID, deprecatedID)).toBeUndefined()
+    }),
+  )
+
   it.effect("registers key methods for providers with environment variables", () =>
     Effect.gen(function* () {
       const integrations = yield* Integration.Service

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

@@ -654,7 +654,7 @@ describe("Session.create", () => {
       expect(yield* session.get(created.id)).toMatchObject({ agent: "plan" })
       expect(
         Array.from(yield* logEvents(session, created.id, true).pipe(Stream.drop(1), Stream.take(1), Stream.runCollect)),
-      ).toMatchObject([{ type: "session.agent.selected", data: { agent: "plan" } }])
+      ).toMatchObject([{ type: "session.agent.selected", data: { agent: "plan", previous: "build" } }])
       expect(yield* session.messages({ sessionID: created.id, order: "asc" })).toMatchObject([
         { type: "agent-switched", agent: "plan", previous: "build" },
       ])
@@ -678,7 +678,12 @@ describe("Session.create", () => {
   it.effect("switches the selected model through the durable Session event", () =>
     Effect.gen(function* () {
       const session = yield* Session.Service
-      const created = yield* session.create({ location })
+      const previous = Model.Ref.make({
+        id: Model.ID.make("haiku"),
+        providerID: Provider.ID.anthropic,
+        variant: Model.VariantID.make("default"),
+      })
+      const created = yield* session.create({ location, model: previous })
       const model = Model.Ref.make({
         id: Model.ID.make("sonnet"),
         providerID: Provider.ID.anthropic,
@@ -692,7 +697,10 @@ describe("Session.create", () => {
         yield* logEvents(session, created.id, true).pipe(Stream.drop(1), Stream.take(1), Stream.runCollect),
       )
       expect(bus).toMatchObject([{ type: "session.model.selected" }])
-      expect(bus[0]?.data).toEqual({ sessionID: created.id, model })
+      expect(bus[0]?.data).toEqual({ sessionID: created.id, model, previous })
+      expect(yield* session.messages({ sessionID: created.id, order: "asc" })).toMatchObject([
+        { type: "model-switched", model, previous },
+      ])
     }),
   )
 

packages/core/test/tool-question.test.ts

@@ -89,6 +89,30 @@ const it = testEffect(
 )
 
 describe("QuestionTool", () => {
+  it.effect("emits one item schema for the nonempty questions array", () =>
+    Effect.gen(function* () {
+      captured = undefined
+      const registry = yield* Tool.Service
+      const definition = (yield* toolDefinitions(registry)).find((tool) => tool.name === QuestionTool.name)
+
+      expect(definition?.inputSchema).toHaveProperty("properties.questions.type", "array")
+      expect(definition?.inputSchema).toHaveProperty("properties.questions.minItems", 1)
+      expect(definition?.inputSchema).toHaveProperty("properties.questions.items")
+      expect(definition?.inputSchema).not.toHaveProperty("properties.questions.prefixItems")
+      expect(
+        yield* executeTool(registry, {
+          sessionID,
+          ...toolIdentity,
+          call: { type: "tool-call", id: "call-question-empty", name: QuestionTool.name, input: { questions: [] } },
+        }),
+      ).toMatchObject({
+        status: "error",
+        error: { type: "tool.execution", message: expect.stringContaining("Invalid tool input") },
+      })
+      expect(capturedInput()).toBeUndefined()
+    }),
+  )
+
   it.effect("omits a catalog-denied question and enforces its leaf permission", () =>
     Effect.gen(function* () {
       captured = undefined

packages/core/test/v1-migration.test.ts

@@ -11,7 +11,7 @@ import { Project } from "@opencode-ai/core/project"
 import { ProjectTable } from "@opencode-ai/core/project/sql"
 import { AbsolutePath } from "@opencode-ai/core/schema"
 import { Global } from "@opencode-ai/util/global"
-import { Effect, Layer, Logger, Schedule, Schema, Scope } from "effect"
+import { Effect, Fiber, Layer, Logger, Schedule, Schema, Scope } from "effect"
 import { eq, sql } from "drizzle-orm"
 import type { SqlClient } from "effect/unstable/sql/SqlClient"
 import { tmpdir } from "./fixture/tmpdir"
@@ -798,6 +798,35 @@ describe("V1Migration database workflow", () => {
     )
   })
 
+  test("yields while clearing stale events in batches", async () => {
+    await database(
+      Effect.gen(function* () {
+        const { db } = yield* Database.Service
+        yield* db.run(sql`INSERT INTO event_sequence (aggregate_id, seq) VALUES ('stale', 2500)`)
+        yield* db.run(sql`
+          WITH RECURSIVE rows(value) AS (
+            VALUES(1)
+            UNION ALL
+            SELECT value + 1 FROM rows WHERE value < 2500
+          )
+          INSERT INTO event (id, aggregate_id, seq, created, type, data)
+          SELECT printf('event_%04d', value), 'stale', value, 1, 'session.renamed.1', '{}'
+          FROM rows
+        `)
+        let yielded = false
+        const heartbeat = yield* Effect.yieldNow.pipe(
+          Effect.andThen(Effect.sync(() => (yielded = true))),
+          Effect.forkChild({ startImmediately: true }),
+        )
+
+        expect(yield* V1Migration.run()).toEqual({ status: "completed" })
+        expect(yielded).toBe(true)
+        yield* Fiber.join(heartbeat)
+        expect(yield* db.get<{ value: number }>(sql`SELECT COUNT(*) AS value FROM event`)).toEqual({ value: 0 })
+      }),
+    )
+  })
+
   test("imports previous V2 sessions and messages as part of the migration", async () => {
     await using tmp = await tmpdir()
     const filename = path.join(tmp.path, "opencode-next.db")

packages/merman/src/core/spatial.ts

@@ -77,20 +77,21 @@ export function spatialPathSpans(points: readonly DiagramPoint[]): SpatialSpan[]
     .sort(([left], [right]) => left - right)
     .flatMap(([y, xs]) => {
       const sorted = [...xs].sort((left, right) => left - right)
+      const [first, ...rest] = sorted
+      if (first === undefined) return []
       const spans: SpatialSpan[] = []
-      let start = sorted[0]
-      let end = start
-      if (start === undefined) return spans
-      for (const x of sorted.slice(1)) {
-        if (x === end! + 1) {
+      let start = first
+      let end = first
+      for (const x of rest) {
+        if (x === end + 1) {
           end = x
           continue
         }
-        spans.push(normalizedSpan(y, start, end!))
+        spans.push(normalizedSpan(y, start, end))
         start = x
         end = x
       }
-      spans.push(normalizedSpan(y, start, end!))
+      spans.push(normalizedSpan(y, start, end))
       return spans
     })
 }

packages/protocol/openapi.json

@@ -14373,6 +14373,9 @@
               },
               "agent": {
                 "type": "string"
+              },
+              "previous": {
+                "type": "string"
               }
             },
             "required": ["sessionID", "agent"],
@@ -14441,6 +14444,9 @@
               },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
+              },
+              "previous": {
+                "$ref": "#/components/schemas/Model.Ref"
               }
             },
             "required": ["sessionID", "model"],

packages/schema/src/session-event.ts

@@ -69,6 +69,7 @@ export const AgentSelected = Event.durable({
   schema: {
     ...Base,
     agent: Agent.ID,
+    previous: Agent.ID.pipe(optional),
   },
 })
 export type AgentSelected = typeof AgentSelected.Type
@@ -79,6 +80,7 @@ export const ModelSelected = Event.durable({
   schema: {
     ...Base,
     model: Model.Ref,
+    previous: Model.Ref.pipe(optional),
   },
 })
 export type ModelSelected = typeof ModelSelected.Type

packages/sdk-next/README.md

@@ -13,22 +13,6 @@ const session = yield * opencode.sessions.get({ sessionID })
 
 It also exports `Tool` for plugins that add tools with `ctx.tool.transform(...)`. Embedded plugins run through the ordinary discovery flow and register tools into each Location's `ToolRegistry` through the normal `Tools.Service.register(...)` path. Closing the owning Effect Scope releases router resources, location services, fibers, and scoped tool registrations.
 
-Use credentials already stored by the local OpenCode installation while keeping
-SDK sessions in memory:
-
-```ts
-const opencode =
-  yield *
-  OpenCode.create({
-    credentials: OpenCode.Credentials.fromLocalDatabase(),
-  })
-```
-
-The SDK copies credentials from `OPENCODE_DB` or `opencode.db` in OpenCode's
-data directory. The source database is never updated.
-OAuth credentials are copied without a usable refresh token; if the access
-token is rejected, re-authenticate with OpenCode and create a new SDK host.
-
 `sessions.events({ sessionID, after })` replays durable events after the optional aggregate sequence, then emits newly committed durable events. `sessions.interrupt(...)` targets execution owned by this host, and `sessions.message(...)` retrieves one projected Session message.
 
 The same constructor is available as a service Layer:

packages/sdk-next/src/opencode.ts

@@ -1,27 +1,11 @@
 import { OpenCode } from "@opencode-ai/client/effect"
-import { Credential } from "@opencode-ai/core/credential"
-import { Database } from "@opencode-ai/core/database/database"
 import { SdkPlugins } from "@opencode-ai/core/plugin/sdk"
 import { createEmbeddedRoutes } from "@opencode-ai/server/routes"
 import type { ServerOptions } from "@opencode-ai/server/options"
 import { Context, Effect, Layer, ManagedRuntime } from "effect"
 import { FetchHttpClient, HttpEffect, HttpRouter, HttpServer } from "effect/unstable/http"
 
-export type CredentialSource = {
-  readonly path: string
-}
-
-export const Credentials = {
-  fromLocalDatabase: (input: Partial<CredentialSource> = {}): CredentialSource => ({
-    path: input.path ?? process.env.OPENCODE_DB ?? "opencode.db",
-  }),
-}
-
-export type CreateOptions = ServerOptions & {
-  readonly credentials?: CredentialSource
-}
-
-export const create = Effect.fn("OpenCode.create")(function* (options: CreateOptions = {}) {
+export const create = Effect.fn("OpenCode.create")(function* (options: ServerOptions = {}) {
   const runtime = yield* Effect.acquireRelease(
     Effect.sync(() =>
       ManagedRuntime.make(
@@ -35,10 +19,6 @@ export const create = Effect.fn("OpenCode.create")(function* (options: CreateOpt
     (runtime) => runtime.disposeEffect,
   )
   const context = yield* runtime.contextEffect
-  if (options.credentials) {
-    const database = Context.get(context, Database.Service)
-    yield* Credential.importFromDatabase(options.credentials).pipe(Effect.provideService(Database.Service, database))
-  }
   const plugins = Context.get(context, SdkPlugins.Service)
   const router = Context.get(context, HttpRouter.HttpRouter)
   const handler = HttpEffect.toWebHandler(router.asHttpEffect())

packages/sdk-next/test/embedded.test.ts

@@ -2,9 +2,6 @@ import fs from "fs/promises"
 import path from "path"
 import { expect } from "bun:test"
 import { Deferred, Effect, Latch, Layer, Option, Ref, Schema, Stream } from "effect"
-import { Credential } from "@opencode-ai/core/credential"
-import { Database } from "@opencode-ai/core/database/database"
-import { LayerNode } from "../../util/src/effect/layer-node"
 import { testEffect } from "../../core/test/lib/effect"
 import { tmpdir } from "../../core/test/fixture/tmpdir"
 import type { OpenCodeEvent } from "../src"
@@ -28,30 +25,6 @@ const sessionID = (fixture: Fixture) => fixture.sdk.Session.ID.create()
 const location = (fixture: Fixture) =>
   fixture.sdk.Location.Ref.make({ directory: fixture.sdk.AbsolutePath.make(fixture.directory) })
 
-it.live("starts with credentials copied from the local database", () =>
-  withEmbedded("opencode-embedded-credentials-", (fixture) =>
-    Effect.gen(function* () {
-      const filename = path.join(fixture.directory, "credentials.sqlite")
-      const integrationID = fixture.sdk.Integration.ID.make("snapshot-test")
-      yield* Effect.gen(function* () {
-        const credentials = yield* Credential.Service
-        yield* credentials.create({
-          integrationID,
-          label: "Local",
-          value: Credential.Key.make({ type: "key", key: "secret" }),
-        })
-      }).pipe(
-        Effect.provide(LayerNode.compile(Credential.node, [[Database.node, Database.configured({ path: filename })]])),
-        Effect.scoped,
-      )
-      const opencode = yield* fixture.sdk.OpenCode.create({
-        credentials: fixture.sdk.OpenCode.Credentials.fromLocalDatabase({ path: filename }),
-      })
-      expect((yield* opencode.health.get()).healthy).toBe(true)
-    }),
-  ),
-)
-
 it.live("exposes app metadata to plugins", () =>
   withEmbedded("opencode-embedded-app-", (fixture) =>
     Effect.gen(function* () {

packages/server/src/handlers/model.ts

@@ -12,6 +12,19 @@ export const ModelHandler = HttpApiBuilder.group(Api, "server.model", (handlers)
       .handle(
         "model.list",
         Effect.fn(function* () {
+          const plugins = yield* PluginSupervisor.Service
+          yield* plugins.flush.pipe(
+            Effect.timeoutOrElse({
+              duration: "5 seconds",
+              orElse: () =>
+                Effect.fail(
+                  new ServiceUnavailableError({
+                    message: "Model catalog initialization timed out",
+                    service: "model.catalog",
+                  }),
+                ),
+            }),
+          )
           const catalog = yield* Catalog.Service
           return yield* response(catalog.model.available())
         }),

packages/server/test/model.test.ts

@@ -0,0 +1,57 @@
+import fs from "node:fs/promises"
+import path from "node:path"
+import { expect } from "bun:test"
+import { Effect } from "effect"
+import { HttpServer } from "effect/unstable/http"
+import { tmpdir } from "../../core/test/fixture/tmpdir"
+import { it } from "../../core/test/lib/effect"
+import { ServerProcess } from "../src/process"
+
+it.live("waits for plugin initialization before listing models", () =>
+  Effect.acquireUseRelease(
+    Effect.promise(() => tmpdir("opencode-model-endpoint-")),
+    (tmp) =>
+      Effect.gen(function* () {
+        yield* Effect.promise(() =>
+          fs.writeFile(
+            path.join(tmp.path, "opencode.json"),
+            JSON.stringify({
+              providers: {
+                custom: {
+                  package: "aisdk:@ai-sdk/openai-compatible",
+                  settings: { apiKey: "secret" },
+                  models: { chat: {} },
+                },
+              },
+            }),
+          ),
+        )
+        const server = yield* ServerProcess.start<never, never>({
+          hostname: "127.0.0.1",
+          port: 0,
+          password: "secret",
+          app: { version: "test-version" },
+          database: { path: ":memory:" },
+          config: { directory: tmp.path },
+          fs: { filewatcher: false },
+        })
+        const url = new URL("/api/model", HttpServer.formatAddress(server.address))
+        url.searchParams.set("location[directory]", tmp.path)
+        const response = yield* Effect.promise(() =>
+          fetch(url, { headers: { authorization: `Basic ${btoa("opencode:secret")}` } }),
+        )
+
+        expect(response.status).toBe(200)
+        const body: unknown = yield* Effect.promise(() => response.json())
+        if (!isRecord(body) || !Array.isArray(body["data"])) throw new Error("Expected a model list response")
+        expect(
+          body["data"].some((model) => isRecord(model) && model["providerID"] === "custom" && model["id"] === "chat"),
+        ).toBeTrue()
+      }),
+    (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
+  ),
+)
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null && !Array.isArray(value)
+}

packages/tui/src/component/session-tabs.tsx

@@ -62,13 +62,9 @@ function createMarquee(hovered: () => string | undefined, animations: () => bool
   const leading = createAnimatable({ opacity: 0 }, { enabled: animations, transition: tween({ duration: 0.25 }) })
 
   createEffect(() => {
-    if (!hovered()) {
-      setOffset(0)
-      leading.jump({ opacity: 0 })
-      return
-    }
     setOffset(0)
     leading.jump({ opacity: 0 })
+    if (!hovered()) return
     let interval: ReturnType<typeof setInterval> | undefined
     const delay = setTimeout(() => {
       setOffset(1)

packages/tui/src/prompt/attachment.ts

@@ -25,14 +25,14 @@ function deduplicateByIdentity<T>(
   items: readonly T[],
   identity: (item: T) => { metadata: string; payload: string } | undefined,
 ) {
-  const seen = new Map<string, string[]>()
+  const seen = new Map<string, Set<string>>()
   return items.filter((item) => {
     const key = identity(item)
     if (!key) return true
-    const matches = seen.get(key.metadata)
-    if (matches?.includes(key.payload)) return false
-    if (matches) matches.push(key.payload)
-    if (!matches) seen.set(key.metadata, [key.payload])
+    const payloads = seen.get(key.metadata) ?? new Set<string>()
+    if (payloads.has(key.payload)) return false
+    payloads.add(key.payload)
+    seen.set(key.metadata, payloads)
     return true
   })
 }
@@ -42,7 +42,7 @@ export function deduplicatePromptImages(files: readonly PromptFile[] | undefined
   return deduplicateByIdentity(files, (file) =>
     file.uri.startsWith("data:image/") && file.mention?.text
       ? {
-          metadata: JSON.stringify([attachmentMetadata(file), file.mention.text]),
+          metadata: JSON.stringify([file.name ?? null, file.description ?? null, file.mention.text]),
           payload: file.uri,
         }
       : undefined,

packages/www/openapi.json

@@ -14373,6 +14373,9 @@
               },
               "agent": {
                 "type": "string"
+              },
+              "previous": {
+                "type": "string"
               }
             },
             "required": ["sessionID", "agent"],
@@ -14441,6 +14444,9 @@
               },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
+              },
+              "previous": {
+                "$ref": "#/components/schemas/Model.Ref"
               }
             },
             "required": ["sessionID", "model"],

packages/www/public/openapi.json

@@ -14373,6 +14373,9 @@
               },
               "agent": {
                 "type": "string"
+              },
+              "previous": {
+                "type": "string"
               }
             },
             "required": ["sessionID", "agent"],
@@ -14441,6 +14444,9 @@
               },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
+              },
+              "previous": {
+                "$ref": "#/components/schemas/Model.Ref"
               }
             },
             "required": ["sessionID", "model"],