fix(opencode): surface content-filter finish reason as visible error (#31745)

Co-authored-by: Aiden Cline <aidenpcline@gmail.com>

packages/core/src/v1/session.ts

@@ -52,6 +52,9 @@ export const ContextOverflowError = NamedError.create("ContextOverflowError", {
   message: Schema.String,
   responseBody: Schema.optional(Schema.String),
 })
+export const ContentFilterError = NamedError.create("ContentFilterError", {
+  message: Schema.String,
+})
 
 export class OutputFormatText extends Schema.Class<OutputFormatText>("OutputFormatText")({
   type: Schema.Literal("text"),
@@ -388,6 +391,7 @@ const AssistantErrorSchema = Schema.Union([
   AbortedError.EffectSchema,
   StructuredOutputError.EffectSchema,
   ContextOverflowError.EffectSchema,
+  ContentFilterError.EffectSchema,
   APIError.EffectSchema,
 ]).annotate({ discriminator: "name" })
 type AssistantError = Schema.Schema.Type<typeof AssistantErrorSchema>

packages/opencode/src/session/prompt.ts

@@ -1355,6 +1355,18 @@ export const layer = Layer.effect(
 
             const finished = handle.message.finish && !["tool-calls", "unknown"].includes(handle.message.finish)
             if (finished && !handle.message.error) {
+              // Surface any content-filter finish (e.g. Anthropic stop_reason:
+              // refusal) as an error. These turns may have produced no visible
+              // output at all — previously the session went idle silently — or
+              // partial text that was cut off by the provider's filter.
+              if (handle.message.finish === "content-filter") {
+                handle.message.error = new SessionV1.ContentFilterError({
+                  message: "The response was blocked by the provider's content filter",
+                }).toObject()
+                yield* sessions.updateMessage(handle.message)
+                yield* events.publish(Session.Event.Error, { sessionID, error: handle.message.error })
+                return "break" as const
+              }
               if (format.type === "json_schema") {
                 handle.message.error = new SessionV1.StructuredOutputError({
                   message: "Model did not produce structured output",

packages/opencode/test/lib/llm-server.ts

@@ -493,6 +493,14 @@ export class Reply {
     return this
   }
 
+  contentFilter() {
+    this.#finish = "content_filter"
+    this.#hang = false
+    this.#error = undefined
+    this.#reset = false
+    return this
+  }
+
   toolCalls() {
     this.#finish = "tool_calls"
     this.#hang = false

packages/opencode/test/session/prompt.test.ts

@@ -506,6 +506,52 @@ it.instance("loop calls LLM and returns assistant message", () =>
   }),
 )
 
+it.instance("loop surfaces content-filter finishes as session errors", () =>
+  Effect.gen(function* () {
+    const { llm } = yield* useServerConfig(providerCfg)
+    const events = yield* EventV2Bridge.Service
+    const prompt = yield* SessionPrompt.Service
+    const sessions = yield* Session.Service
+    const chat = yield* sessions.create({ title: "Pinned" })
+    const errors: NonNullable<SessionV1.Assistant["error"]>[] = []
+    const expected = {
+      name: "ContentFilterError",
+      data: { message: "The response was blocked by the provider's content filter" },
+    } satisfies NonNullable<SessionV1.Assistant["error"]>
+    const off = yield* events.listen((event) => {
+      if (event.type !== Session.Event.Error.type) return Effect.void
+      const data = event.data as typeof Session.Event.Error.data.Type
+      if (data.sessionID === chat.id && data.error) errors.push(data.error)
+      return Effect.void
+    })
+
+    yield* prompt.prompt({
+      sessionID: chat.id,
+      agent: "build",
+      noReply: true,
+      parts: [{ type: "text", text: "hello" }],
+    })
+    yield* llm.push(reply().text("partial response").contentFilter())
+
+    const result = yield* prompt.loop({ sessionID: chat.id })
+    const stored = yield* MessageV2.get({ sessionID: chat.id, messageID: result.info.id })
+    yield* off
+
+    expect(yield* llm.hits).toHaveLength(1)
+    expect(result.info.role).toBe("assistant")
+    expect(stored.info.role).toBe("assistant")
+    if (result.info.role === "assistant" && stored.info.role === "assistant") {
+      expect(result.info.finish).toBe("content-filter")
+      expect(result.info.error).toEqual(expected)
+      expect(stored.info.error).toEqual(result.info.error)
+      expect(errors).toContainEqual(expected)
+    }
+    expect(result.parts).toEqual(
+      expect.arrayContaining([expect.objectContaining({ type: "text", text: "partial response" })]),
+    )
+  }),
+)
+
 it.instance("loop stops provider overflow instead of auto-compacting when disabled", () =>
   Effect.gen(function* () {
     const { llm } = yield* useServerConfig((url) => ({

packages/sdk/js/src/v2/gen/types.gen.ts

@@ -308,6 +308,13 @@ export type ContextOverflowError = {
   }
 }
 
+export type ContentFilterError = {
+  name: "ContentFilterError"
+  data: {
+    message: string
+  }
+}
+
 export type ApiError = {
   name: "APIError"
   data: {
@@ -339,6 +346,7 @@ export type AssistantMessage = {
     | MessageAbortedError
     | StructuredOutputError
     | ContextOverflowError
+    | ContentFilterError
     | ApiError
   parentID: string
   modelID: string
@@ -1249,6 +1257,7 @@ export type GlobalEvent = {
             | MessageAbortedError
             | StructuredOutputError
             | ContextOverflowError
+            | ContentFilterError
             | ApiError
         }
       }
@@ -4920,6 +4929,7 @@ export type EventSessionError = {
       | MessageAbortedError
       | StructuredOutputError
       | ContextOverflowError
+      | ContentFilterError
       | ApiError
   }
 }

packages/sdk/openapi.json

@@ -14375,6 +14375,27 @@
         "required": ["name", "data"],
         "additionalProperties": false
       },
+      "ContentFilterError": {
+        "type": "object",
+        "properties": {
+          "name": {
+            "type": "string",
+            "enum": ["ContentFilterError"]
+          },
+          "data": {
+            "type": "object",
+            "properties": {
+              "message": {
+                "type": "string"
+              }
+            },
+            "required": ["message"],
+            "additionalProperties": false
+          }
+        },
+        "required": ["name", "data"],
+        "additionalProperties": false
+      },
       "APIError": {
         "type": "object",
         "properties": {
@@ -14468,6 +14489,9 @@
               {
                 "$ref": "#/components/schemas/ContextOverflowError"
               },
+              {
+                "$ref": "#/components/schemas/ContentFilterError"
+              },
               {
                 "$ref": "#/components/schemas/APIError"
               }
@@ -17399,6 +17423,9 @@
                           {
                             "$ref": "#/components/schemas/ContextOverflowError"
                           },
+                          {
+                            "$ref": "#/components/schemas/ContentFilterError"
+                          },
                           {
                             "$ref": "#/components/schemas/APIError"
                           }
@@ -29058,6 +29085,9 @@
                   {
                     "$ref": "#/components/schemas/ContextOverflowError"
                   },
+                  {
+                    "$ref": "#/components/schemas/ContentFilterError"
+                  },
                   {
                     "$ref": "#/components/schemas/APIError"
                   }