fix(acp): surface prompt errors (#34061)

packages/opencode/src/acp/error.ts

@@ -46,6 +46,7 @@ export class UnsupportedOperationError extends Schema.TaggedErrorClass<Unsupport
 export class ServiceFailureError extends Schema.TaggedErrorClass<ServiceFailureError>()("ACPServiceFailureError", {
   safeMessage: Schema.String,
   service: Schema.optional(Schema.String),
+  errorName: Schema.optional(Schema.String),
 }) {}
 
 export type Error =
@@ -81,7 +82,13 @@ export function toRequestError(error: Error) {
     case "ACPUnsupportedOperationError":
       return RequestError.methodNotFound(error.method)
     case "ACPServiceFailureError":
-      return RequestError.internalError({ service: error.service }, error.safeMessage)
+      return RequestError.internalError(
+        {
+          ...(error.service ? { service: error.service } : {}),
+          ...(error.errorName ? { errorName: error.errorName } : {}),
+        },
+        error.safeMessage,
+      )
   }
 }
 

packages/opencode/src/acp/service.ts

@@ -30,7 +30,7 @@ import {
   type SetSessionModeResponse,
 } from "@agentclientprotocol/sdk"
 import { InstallationVersion } from "@opencode-ai/core/installation/version"
-import type { Message, OpencodeClient, SessionMessageResponse } from "@opencode-ai/sdk/v2"
+import type { AssistantMessage, Message, OpencodeClient, SessionMessageResponse } from "@opencode-ai/sdk/v2"
 import { Context, Effect, Layer, ManagedRuntime } from "effect"
 import * as ACPError from "./error"
 import { buildConfigOptions, parseModelSelection } from "./config-option"
@@ -521,7 +521,7 @@ export function make(input: {
           "session",
         )
         yield* sendUsageUpdate(input.usage, input.sdk, input.connection, current.id, current.cwd)
-        return promptResponse(response.info, params.messageId)
+        return yield* promptResponse(response.info, params.messageId)
       }
 
       const known = snapshot.availableCommands.find((item) => item.name === command.name)
@@ -543,7 +543,7 @@ export function make(input: {
           "session",
         )
         yield* sendUsageUpdate(input.usage, input.sdk, input.connection, current.id, current.cwd)
-        return promptResponse(response.info, params.messageId)
+        return yield* promptResponse(response.info, params.messageId)
       }
 
       if (command.name === "compact") {
@@ -563,7 +563,7 @@ export function make(input: {
       }
 
       yield* sendUsageUpdate(input.usage, input.sdk, input.connection, current.id, current.cwd)
-      return promptResponse(undefined, params.messageId)
+      return yield* promptResponse(undefined, params.messageId)
     }),
     cancel,
   }
@@ -695,7 +695,8 @@ type MessageInfo = {
   readonly agent?: Message["agent"]
 }
 
-type AssistantInfo = UsageService.AssistantTokenCost | undefined
+type AssistantError = NonNullable<AssistantMessage["error"]>
+type AssistantInfo = (UsageService.AssistantTokenCost & Pick<AssistantMessage, "error">) | undefined
 
 function request<T>(fn: () => Promise<T | SdkResponse<T>>, service?: string) {
   return Effect.tryPromise({
@@ -811,13 +812,60 @@ function detectSlashCommand(parts: ReturnType<typeof promptContentToParts>) {
   return { name, args: rest.join(" ").trim() }
 }
 
-function promptResponse(info: AssistantInfo, messageId: string | null | undefined): PromptResponse {
-  return {
-    stopReason: "end_turn",
-    ...(info ? { usage: UsageService.buildUsage(info) } : {}),
+const promptResponse = Effect.fn("ACP.promptResponse")(function* (
+  info: AssistantInfo,
+  messageId: string | null | undefined,
+) {
+  if (!info?.error) {
+    return {
+      stopReason: "end_turn" as const,
+      ...(info ? { usage: UsageService.buildUsage(info) } : {}),
+      ...(messageId ? { userMessageId: messageId } : {}),
+      _meta: {},
+    }
+  }
+
+  const base = {
+    usage: UsageService.buildUsage(info),
     ...(messageId ? { userMessageId: messageId } : {}),
     _meta: {},
   }
+
+  if (info.error.name === "MessageAbortedError") {
+    return {
+      stopReason: "cancelled" as const,
+      ...base,
+    }
+  }
+
+  if (info.error.name === "MessageOutputLengthError") {
+    return {
+      stopReason: "max_tokens" as const,
+      ...base,
+    }
+  }
+
+  if (info.error.name === "ContentFilterError") {
+    return {
+      stopReason: "refusal" as const,
+      ...base,
+    }
+  }
+
+  if (info.error.name === "ProviderAuthError") {
+    return yield* new ACPError.AuthRequiredError({ providerId: info.error.data.providerID })
+  }
+
+  return yield* new ACPError.ServiceFailureError({
+    service: "session",
+    safeMessage: promptErrorMessage(info.error),
+    errorName: info.error.name,
+  })
+})
+
+function promptErrorMessage(error: AssistantError) {
+  if ("message" in error.data && typeof error.data.message === "string") return error.data.message
+  return "OpenCode prompt failed"
 }
 
 function sendUsageUpdate(