fix: handle ambiguous prompt transport failures

packages/ui/src/apps/AppEffects.tsx

@@ -22,13 +22,16 @@ const SyncOptimisticBridge: React.FC = () => {
   const sync = useSync();
   const addRef = React.useRef(sync.optimistic.add);
   const removeRef = React.useRef(sync.optimistic.remove);
+  const confirmRef = React.useRef(sync.optimistic.confirm);
   addRef.current = sync.optimistic.add;
   removeRef.current = sync.optimistic.remove;
+  confirmRef.current = sync.optimistic.confirm;
 
   React.useEffect(() => {
     setOptimisticRefs(
       (input) => addRef.current(input),
       (input) => removeRef.current(input),
+      (input) => confirmRef.current(input),
     );
   }, []);
 

packages/ui/src/hooks/useQueuedMessageAutoSend.ts

@@ -154,9 +154,6 @@ export function useQueuedMessageAutoSend(enabledOrOptions?: boolean | { enabled?
       if (!payload) {
         return;
       }
-      if (!payload.primaryText && payload.primaryAttachments.length === 0) {
-        return;
-      }
 
       // Use send config captured at queue time; fall back to current config
       const captured = payload.sendConfig;
@@ -176,9 +173,7 @@ export function useQueuedMessageAutoSend(enabledOrOptions?: boolean | { enabled?
           agent: resolved.agent,
           variant: resolved.variant,
         });
-
-        const removeFromQueue = useMessageQueueStore.getState().removeFromQueue;
-        removeFromQueue(sessionId, payload.queuedMessageId);
+        useMessageQueueStore.getState().removeFromQueue(sessionId, payload.queuedMessageId);
       } catch (error) {
         console.warn('[queue] queued auto-send failed:', error);
       } finally {

packages/ui/src/lib/opencode/client.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, mock, test } from 'bun:test';
+import { beforeEach, describe, expect, mock, test } from 'bun:test';
 
 type ConfigResponse = { data: Record<string, unknown> };
 
@@ -6,6 +6,15 @@ type ConfigResponse = { data: Record<string, unknown> };
 
 const configResolvers: Array<(response: ConfigResponse) => void> = [];
 let configCalls = 0;
+const promptAsyncCalls: unknown[][] = [];
+const promptAsyncResults: Array<unknown> = [];
+
+const promptAsyncMock = mock(async (...args: unknown[]) => {
+  promptAsyncCalls.push(args);
+  const next = promptAsyncResults.shift();
+  if (next instanceof Error) throw next;
+  return next ?? { response: new Response(null, { status: 200 }) };
+});
 
 mock.module('@opencode-ai/sdk/v2', () => ({
   createOpencodeClient: mock(() => ({
@@ -17,6 +26,9 @@ mock.module('@opencode-ai/sdk/v2', () => ({
         });
       }),
     },
+    session: {
+      promptAsync: promptAsyncMock,
+    },
   })),
 }));
 
@@ -47,6 +59,11 @@ mock.module('@/lib/startupTrace', () => ({
 
 const { opencodeClient } = await import(`./client?cache-test=${Date.now()}`);
 
+beforeEach(() => {
+  promptAsyncCalls.length = 0;
+  promptAsyncResults.length = 0;
+});
+
 describe('opencodeClient getConfig cache', () => {
   test('cleared stale in-flight requests do not repopulate cache or delete newer in-flight requests', async () => {
     const first = opencodeClient.getConfig('/workspace/project');
@@ -72,3 +89,54 @@ describe('opencodeClient getConfig cache', () => {
     expect(configCalls).toBe(2);
   });
 });
+
+describe('opencodeClient prompt retry behavior', () => {
+  const sendPrompt = (providerID = 'anthropic') => opencodeClient.sendMessage({
+    id: 'ses_1',
+    providerID,
+    modelID: 'claude-sonnet',
+    text: 'hello',
+  });
+
+  test('does not retry 504 prompt responses because the POST may already be accepted', async () => {
+    promptAsyncResults.push({ response: new Response('gateway timeout', { status: 504 }) });
+
+    let error: unknown = null;
+    try {
+      await sendPrompt('anthropic-504');
+    } catch (caught) {
+      error = caught;
+    }
+
+    expect(promptAsyncCalls.length).toBe(1);
+    expect(error instanceof Error ? error.message : String(error)).toContain('Failed to send message (504)');
+  });
+
+  test('does not retry transport failures because the tunnel may have lost only the response', async () => {
+    promptAsyncResults.push(new TypeError('Failed to fetch'));
+
+    let error: unknown = null;
+    try {
+      await sendPrompt('anthropic-network');
+    } catch (caught) {
+      error = caught;
+    }
+
+    expect(promptAsyncCalls.length).toBe(1);
+    expect(error instanceof Error ? error.message : String(error)).toContain('Failed to fetch');
+  });
+
+  test('does not retry 503 prompt responses because proxy errors can be ambiguous too', async () => {
+    promptAsyncResults.push({ response: new Response('starting', { status: 503 }) });
+
+    let error: unknown = null;
+    try {
+      await sendPrompt('anthropic-503');
+    } catch (caught) {
+      error = caught;
+    }
+
+    expect(promptAsyncCalls.length).toBe(1);
+    expect(error instanceof Error ? error.message : String(error)).toContain('Failed to send message (503)');
+  });
+});

packages/ui/src/lib/opencode/client.ts

@@ -22,8 +22,6 @@ import {
   assertProviderCircuitClosed,
   recordProviderSuccess,
   recordProviderError,
-  shouldRetry,
-  getRetryDelayMs,
 } from "./provider-tracker";
 
 // Use relative path by default (works with both dev and nginx proxy server)
@@ -120,12 +118,6 @@ const ascendingId = (prefix: "msg"): string => {
   return `${prefix}_${hex}${randomBase62(ID_RANDOM_LENGTH)}`;
 };
 
-const isRetryableFetchError = (error: unknown): boolean => {
-  if (error instanceof DOMException && error.name === 'AbortError') return true;
-  if (error instanceof TypeError) return true;
-  return false;
-};
-
 const ensureAbsoluteBaseUrl = (candidate: string): string => {
   const normalized = typeof candidate === "string" && candidate.trim().length > 0 ? candidate.trim() : "/api";
 
@@ -764,8 +756,8 @@ class OpencodeService {
     };
     directory?: string | null;
   }): Promise<string> {
-    // Reuse one client-side message ID across retries. The server accepts this
-    // as the real user message ID, making ambiguous network retries idempotent.
+    // Use the optimistic/client-generated ID as the real user message ID so SSE
+    // can reconcile the echoed server message in-place.
     const messageId = params.messageId ?? ascendingId("msg");
 
     // Build parts array using SDK types (TextPartInput | FilePartInput) plus lightweight agent parts
@@ -848,74 +840,55 @@ class OpencodeService {
 
     assertProviderCircuitClosed(params.providerID);
 
-    let response!: Response;
+    let response: Response;
 
-    for (let attempt = 0; attempt < 3; attempt++) {
-      try {
-        const result = await this.client.session.promptAsync({
-          sessionID: params.id,
-          ...(requestDirectory ? { directory: requestDirectory } : {}),
-          model: {
-            providerID: params.providerID,
-            modelID: params.modelID,
-          },
-          agent: params.agent,
-          variant: params.variant,
-          messageID: messageId,
-          ...(params.delivery ? { delivery: params.delivery } : {}),
-          ...(params.format ? { format: params.format } : {}),
-          parts,
-        });
-        if (result.response instanceof Response) {
-          response = result.response;
-        } else if (result.error) {
-          const status = (result as SdkResult<unknown>).response?.status || 500;
-          response = new Response(JSON.stringify(result.error), { status });
-        } else {
-          response = new Response(JSON.stringify(result.data ?? true), { status: 200 });
-        }
-      } catch (error) {
-        if (attempt < 2 && isRetryableFetchError(error)) {
-          const delay = getRetryDelayMs(attempt);
-          console.warn(
-            `[prompt] fetch failed for ${params.providerID}/${params.modelID} (attempt ${attempt + 1}/3), retrying in ${delay}ms`,
-            (error as Error)?.message
-          );
-          await new Promise((resolve) => setTimeout(resolve, delay));
-          continue;
-        }
-        recordProviderError(params.providerID);
-        throw error;
+    try {
+      const result = await this.client.session.promptAsync({
+        sessionID: params.id,
+        ...(requestDirectory ? { directory: requestDirectory } : {}),
+        model: {
+          providerID: params.providerID,
+          modelID: params.modelID,
+        },
+        agent: params.agent,
+        variant: params.variant,
+        messageID: messageId,
+        ...(params.delivery ? { delivery: params.delivery } : {}),
+        ...(params.format ? { format: params.format } : {}),
+        parts,
+      });
+      if (result.response instanceof Response) {
+        response = result.response;
+      } else if (result.error) {
+        const status = (result as SdkResult<unknown>).response?.status || 500;
+        response = new Response(JSON.stringify(result.error), { status });
+      } else {
+        response = new Response(JSON.stringify(result.data ?? true), { status: 200 });
       }
-
-      if (response.ok) {
-        recordProviderSuccess(params.providerID);
-        return messageId;
-      }
-
-      if (shouldRetry(params.providerID, response.status, attempt)) {
-        const delay = getRetryDelayMs(attempt);
-        console.warn(
-          `[prompt] ${response.status} for ${params.providerID}/${params.modelID} (attempt ${attempt + 1}/3), retrying in ${delay}ms`
-        );
-        await new Promise((resolve) => setTimeout(resolve, delay));
-        continue;
-      }
-
-      let detail = '';
-      try {
-        detail = await response.text();
-      } catch {
-        // ignore
-      }
-      const suffix = detail && detail.trim().length > 0 ? `: ${detail.trim()}` : '';
-      const error = new Error(`Failed to send message (${response.status})${suffix}`);
-      recordProviderError(params.providerID, response.status);
+    } catch (error) {
+      // Do not retry prompt_async after a transport failure: through a remote
+      // tunnel the POST may already be running server-side even though the
+      // client lost the response.
+      recordProviderError(params.providerID);
       throw error;
     }
-    // Defensive fallback — all loop paths return/throw, but TypeScript
-    // control flow analysis cannot prove exhaustiveness without this.
-    throw new Error('Failed to send message after retries');
+
+    if (response.ok) {
+      recordProviderSuccess(params.providerID);
+      return messageId;
+    }
+
+    let detail = '';
+    try {
+      detail = await response.text();
+    } catch {
+      // ignore
+    }
+    const suffix = detail && detail.trim().length > 0 ? `: ${detail.trim()}` : '';
+    const error = new Error(`Failed to send message (${response.status})${suffix}`) as Error & { status?: number };
+    error.status = response.status;
+    recordProviderError(params.providerID, response.status);
+    throw error;
   }
 
   async sendCommand(params: {

packages/ui/src/sync/session-actions.test.ts

@@ -10,6 +10,7 @@ let sessionRevertResult: { data?: unknown; error?: unknown; response?: { status?
 let questionReplyError: unknown | null = null
 let questionRejectError: unknown | null = null
 let sessionShareResult: { data?: unknown; error?: unknown; response?: { status?: number } } = {}
+let sessionMessagesResult: { data?: unknown; error?: unknown; response?: { status?: number } } = { data: [] }
 const globalUpsertedSessions: unknown[] = []
 
 const mockScopedClient = {
@@ -41,7 +42,7 @@ const mockSdk = {
   session: {
     messages: mock((params: Record<string, unknown>) => {
       replyCalls.push({ method: "session.messages", params })
-      return Promise.resolve({ data: [] })
+      return Promise.resolve(sessionMessagesResult)
     }),
     revert: mock((params: Record<string, unknown>) => {
       replyCalls.push({ method: "session.revert", params })
@@ -343,6 +344,7 @@ describe("optimisticSend target directory", () => {
   beforeEach(() => {
     replyCalls.length = 0
     scopedClientDirectories.length = 0
+    sessionMessagesResult = { data: [] }
   })
 
   test("passes the prompt directory to optimistic state during session switch races", async () => {
@@ -438,6 +440,95 @@ describe("optimisticSend target directory", () => {
     expect((optimisticRemove as unknown as OptimisticRemoveCall).sessionID).toBe("session-race")
     expect(targetStore.getState().session_status["session-race"]?.type).toBe("idle")
   })
+
+  test("confirms an ambiguous send failure with a recent message refetch", async () => {
+    const targetStore = createStore({})
+    const childStores = createChildStores([["/target/project", targetStore]])
+    let optimisticRemove: OptimisticRemoveCall | null = null
+    let optimisticConfirm: OptimisticRemoveCall | null = null
+    let sentMessageID = ""
+
+    const { optimisticSend, setActionRefs, setOptimisticRefs } = await import("./session-actions")
+    setActionRefs(mockSdk as unknown as OpencodeClient, childStores, () => "/target/project")
+    setOptimisticRefs(
+      () => {},
+      (input) => {
+        optimisticRemove = input
+      },
+      (input) => {
+        optimisticConfirm = input
+      },
+    )
+
+    await optimisticSend({
+      sessionId: "session-confirmed",
+      directory: "/target/project",
+      content: "hello",
+      providerID: "provider",
+      modelID: "model",
+      send: async (messageID) => {
+        sentMessageID = messageID
+        sessionMessagesResult = {
+          data: [{
+            info: { id: messageID, role: "user", sessionID: "session-confirmed", time: { created: 1 } } as Message,
+            parts: [{ id: "server-part", type: "text", text: "hello" } as Part],
+          }],
+        }
+        const error = new Error("Failed to send message (504): gateway timeout") as Error & { status?: number }
+        error.status = 504
+        throw error
+      },
+    })
+
+    expect(optimisticRemove).toBe(null)
+    expect((optimisticConfirm as OptimisticRemoveCall | null)?.messageID).toBe(sentMessageID)
+    expect(replyCalls.find((call) => call.method === "session.messages")?.params.limit).toBe(30)
+    expect(targetStore.getState().message["session-confirmed"]?.[0]?.id).toBe(sentMessageID)
+    expect(targetStore.getState().part[sentMessageID]?.[0]?.id).toBe("server-part")
+  })
+
+  test("rolls back an ambiguous send failure when recent messages do not contain the sent ID", async () => {
+    const targetStore = createStore({})
+    const childStores = createChildStores([["/target/project", targetStore]])
+    let optimisticRemove: OptimisticRemoveCall | null = null
+    let optimisticConfirm: OptimisticRemoveCall | null = null
+
+    const { optimisticSend, setActionRefs, setOptimisticRefs } = await import("./session-actions")
+    setActionRefs(mockSdk as unknown as OpencodeClient, childStores, () => "/target/project")
+    setOptimisticRefs(
+      () => {},
+      (input) => {
+        optimisticRemove = input
+      },
+      (input) => {
+        optimisticConfirm = input
+      },
+    )
+
+    let caught: unknown = null
+    try {
+      await optimisticSend({
+        sessionId: "session-missing",
+        directory: "/target/project",
+        content: "hello",
+        providerID: "provider",
+        modelID: "model",
+        send: async () => {
+          const error = new Error("Failed to send message (504): gateway timeout") as Error & { status?: number }
+          error.status = 504
+          throw error
+        },
+      })
+    } catch (error) {
+      caught = error
+    }
+
+    expect(caught).toBeInstanceOf(Error)
+    expect((optimisticRemove as OptimisticRemoveCall | null)?.sessionID).toBe("session-missing")
+    expect(optimisticConfirm).toBe(null)
+    expect(replyCalls.filter((call) => call.method === "session.messages").every((call) => call.params.limit === 30)).toBe(true)
+    expect(targetStore.getState().session_status["session-missing"]?.type).toBe("idle")
+  })
 })
 
 describe("respondToPermission passes directory", () => {

packages/ui/src/sync/session-actions.ts

@@ -29,6 +29,9 @@ import {
 } from "@/lib/sessionReviewMetadata"
 
 const MESSAGE_REFETCH_LIMIT = 100
+const SEND_CONFIRMATION_REFETCH_LIMIT = 30
+const SEND_CONFIRMATION_REFETCH_ATTEMPTS = 2
+const SEND_CONFIRMATION_REFETCH_RETRY_MS = 150
 const MESSAGE_REFETCH_SKIP_PARTS = new Set(["patch", "step-start", "step-finish"])
 const UNREVERT_REFETCH_ATTEMPTS = 3
 const UNREVERT_REFETCH_RETRY_MS = 150
@@ -39,9 +42,11 @@ let _childStores: ChildStoreManager | null = null
 let _getDirectory: () => string = () => ""
 type OptimisticAddInput = { sessionID: string; directory?: string | null; message: Message; parts: Part[] }
 type OptimisticRemoveInput = { sessionID: string; directory?: string | null; messageID: string }
+type OptimisticConfirmInput = OptimisticRemoveInput
 
 let _optimisticAdd: ((input: OptimisticAddInput) => void) | null = null
 let _optimisticRemove: ((input: OptimisticRemoveInput) => void) | null = null
+let _optimisticConfirm: ((input: OptimisticConfirmInput) => void) | null = null
 
 const wait = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms))
 
@@ -100,9 +105,11 @@ export function setActionRefs(
 export function setOptimisticRefs(
   add: (input: OptimisticAddInput) => void,
   remove: (input: OptimisticRemoveInput) => void,
+  confirm?: (input: OptimisticConfirmInput) => void,
 ) {
   _optimisticAdd = add
   _optimisticRemove = remove
+  _optimisticConfirm = confirm ?? null
 }
 
 function sdk() {
@@ -189,6 +196,36 @@ function connectionLostError(): Error {
   return new Error(`Connection lost${suffix}. Please wait for reconnection.`)
 }
 
+function getErrorStatus(error: unknown): number | null {
+  if (!error || typeof error !== "object") return null
+  const direct = (error as { status?: unknown }).status
+  if (typeof direct === "number") return direct
+  const response = (error as { response?: { status?: unknown } }).response
+  return typeof response?.status === "number" ? response.status : null
+}
+
+function isAmbiguousSendFailure(error: unknown): boolean {
+  const status = getErrorStatus(error)
+  if (status === 503 || status === 504 || status === 408) return true
+  if (error instanceof TypeError) return true
+  if (error instanceof DOMException && (error.name === "AbortError" || error.name === "TimeoutError")) return true
+
+  const message = error instanceof Error
+    ? error.message.toLowerCase()
+    : typeof error === "string"
+      ? error.toLowerCase()
+      : ""
+
+  return message.includes("timeout")
+    || message.includes("timed out")
+    || message.includes("failed to fetch")
+    || message.includes("networkerror")
+    || message.includes("network error")
+    || message.includes("gateway timeout")
+    || message.includes("econnreset")
+    || message.includes("socket hang up")
+}
+
 // Wait briefly for the pipeline to re-establish connection before failing a
 // send. Transient reconnects (heartbeat race, WS→SSE fallback, brief network
 // blip) otherwise surface as a hard "Connection lost" toast even though the
@@ -722,6 +759,20 @@ export async function optimisticSend(input: {
   try {
     await input.send(messageID)
   } catch (error) {
+    const acceptedRecords = isAmbiguousSendFailure(error)
+      ? await fetchRecentSendConfirmationRecords(input.sessionId, messageID, targetDirectory)
+      : null
+
+    if (acceptedRecords) {
+      materializeConfirmedSendRecords(store, input.sessionId, messageID, acceptedRecords)
+      _optimisticConfirm?.({
+        sessionID: input.sessionId,
+        directory: targetDirectory,
+        messageID,
+      })
+      return
+    }
+
     // Rollback via optimistic infrastructure
     _optimisticRemove({
       sessionID: input.sessionId,
@@ -739,6 +790,60 @@ export async function optimisticSend(input: {
   }
 }
 
+async function fetchRecentSendConfirmationRecords(
+  sessionId: string,
+  messageID: string,
+  directory?: string | null,
+): Promise<Array<{ info: Message; parts?: Part[] }> | null> {
+  for (let attempt = 0; attempt < SEND_CONFIRMATION_REFETCH_ATTEMPTS; attempt += 1) {
+    if (attempt > 0) await wait(SEND_CONFIRMATION_REFETCH_RETRY_MS)
+    try {
+      const result = await sdk().session.messages({
+        sessionID: sessionId,
+        directory: directory ?? undefined,
+        limit: SEND_CONFIRMATION_REFETCH_LIMIT,
+      })
+      const records = (assertSdkSuccess(result, "session.messages") ?? [])
+        .filter((record: { info?: { id?: string } }) => !!record?.info?.id) as Array<{ info: Message; parts?: Part[] }>
+      if (records.some((record) => record.info.id === messageID)) {
+        return records
+      }
+    } catch {
+      // Confirmation is best-effort; if it fails, keep the original send error path.
+    }
+  }
+  return null
+}
+
+function materializeConfirmedSendRecords(
+  store: DirectoryStoreApi,
+  sessionId: string,
+  messageID: string,
+  records: Array<{ info: Message; parts?: Part[] }>,
+): void {
+  store.setState((state) => {
+    const currentMessages = state.message[sessionId]
+    const message = { ...state.message }
+    const part = { ...state.part }
+    if (currentMessages) {
+      const nextMessages = currentMessages.filter((message) => message.id !== messageID)
+      message[sessionId] = nextMessages
+    }
+    delete part[messageID]
+
+    const materialized = materializeSessionSnapshots(
+      { ...state, message, part },
+      sessionId,
+      records.map((record) => ({
+        info: stripMessageDiffSnapshots(record.info),
+        parts: record.parts ?? [],
+      })),
+      { skipPartTypes: MESSAGE_REFETCH_SKIP_PARTS },
+    )
+    return { message: materialized.message, part: materialized.part }
+  })
+}
+
 // ---------------------------------------------------------------------------
 // Abort
 // ---------------------------------------------------------------------------

packages/ui/src/sync/use-sync.ts

@@ -611,6 +611,13 @@ export function useSync() {
     [clearOptimistic, getOptimisticStore],
   )
 
+  const optimisticConfirm = useCallback(
+    (input: { sessionID: string; directory?: string | null; messageID: string }) => {
+      clearOptimistic(input.sessionID, input.messageID, input.directory)
+    },
+    [clearOptimistic],
+  )
+
   return useMemo(
     () => ({
       ensureSessionRenderable: syncSession,
@@ -622,8 +629,9 @@ export function useSync() {
       optimistic: {
         add: optimisticAdd,
         remove: optimisticRemove,
+        confirm: optimisticConfirm,
       },
     }),
-    [syncSession, loadMore, hasMore, isLoading, isComplete, optimisticAdd, optimisticRemove],
+    [syncSession, loadMore, hasMore, isLoading, isComplete, optimisticAdd, optimisticRemove, optimisticConfirm],
   )
 }

packages/web/server/index.js

@@ -602,6 +602,7 @@ Object.defineProperties(openCodeNetworkState, {
 const openCodeNetworkRuntime = createOpenCodeNetworkRuntime({
   state: openCodeNetworkState,
   getOpenCodeAuthHeaders,
+  configuredOpenCodeHostname: ENV_CONFIGURED_OPENCODE_HOSTNAME,
 });
 
 const waitForReady = (...args) => openCodeNetworkRuntime.waitForReady(...args);

packages/web/server/lib/opencode/network-runtime.js

@@ -2,8 +2,21 @@ export const createOpenCodeNetworkRuntime = (deps) => {
   const {
     state,
     getOpenCodeAuthHeaders,
+    configuredOpenCodeHostname = '127.0.0.1',
   } = deps;
 
+  const resolveConnectHostname = () => {
+    const raw = typeof configuredOpenCodeHostname === 'string' ? configuredOpenCodeHostname.trim() : '';
+    const hostname = raw || '127.0.0.1';
+    if (hostname === '0.0.0.0' || hostname === '::' || hostname === '[::]') {
+      return '127.0.0.1';
+    }
+    if (hostname.startsWith('[') && hostname.endsWith(']')) {
+      return hostname;
+    }
+    return hostname.includes(':') ? `[${hostname}]` : hostname;
+  };
+
   const normalizeApiPrefix = (prefix) => {
     if (!prefix) {
       return '';
@@ -77,7 +90,7 @@ export const createOpenCodeNetworkRuntime = (deps) => {
     const normalizedPath = path.startsWith('/') ? path : `/${path}`;
     const prefix = normalizeApiPrefix(prefixOverride !== undefined ? prefixOverride : '');
     const fullPath = `${prefix}${normalizedPath}`;
-    const base = state.openCodeBaseUrl ?? `http://localhost:${state.openCodePort}`;
+    const base = state.openCodeBaseUrl ?? `http://${resolveConnectHostname()}:${state.openCodePort}`;
     return `${base}${fullPath}`;
   };
 

packages/web/server/lib/opencode/network-runtime.test.js

@@ -2,36 +2,56 @@ import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { createOpenCodeNetworkRuntime } from './network-runtime.js';
 
-const createRuntime = () => createOpenCodeNetworkRuntime({
+const originalFetch = globalThis.fetch;
+
+const createRuntime = (overrides = {}) => createOpenCodeNetworkRuntime({
   state: {
     openCodePort: 4096,
     openCodeBaseUrl: null,
     openCodeApiPrefix: '',
     openCodeApiPrefixDetected: false,
     openCodeApiDetectionTimer: null,
+    ...overrides.state,
   },
   getOpenCodeAuthHeaders: () => ({}),
+  configuredOpenCodeHostname: overrides.configuredOpenCodeHostname,
 });
 
 describe('OpenCode network runtime', () => {
   afterEach(() => {
     vi.useRealTimers();
-    vi.unstubAllGlobals();
+    globalThis.fetch = originalFetch;
   });
 
-  it('clears the probe abort timer when readiness fetch rejects', async () => {
-    vi.useFakeTimers();
-    vi.setSystemTime(0);
-    vi.stubGlobal('fetch', vi.fn(async () => {
+  it('returns false when readiness fetch rejects', async () => {
+    globalThis.fetch = vi.fn(async () => {
       throw new Error('offline');
-    }));
+    });
 
     const runtime = createRuntime();
     const readyPromise = runtime.waitForReady('http://127.0.0.1:4096', 1);
 
-    await vi.advanceTimersByTimeAsync(100);
     await expect(readyPromise).resolves.toBe(false);
+  });
 
-    expect(vi.getTimerCount()).toBe(0);
+  it('builds managed OpenCode URLs against IPv4 loopback by default', () => {
+    const runtime = createRuntime();
+
+    expect(runtime.buildOpenCodeUrl('/provider')).toBe('http://127.0.0.1:4096/provider');
+  });
+
+  it('keeps external OpenCode base URLs authoritative', () => {
+    const runtime = createRuntime({
+      state: { openCodeBaseUrl: 'http://remote.example:4096' },
+    });
+
+    expect(runtime.buildOpenCodeUrl('/provider')).toBe('http://remote.example:4096/provider');
+  });
+
+  it('normalizes wildcard and IPv6 OpenCode bind hosts for local connects', () => {
+    expect(createRuntime({ configuredOpenCodeHostname: '0.0.0.0' }).buildOpenCodeUrl('/provider'))
+      .toBe('http://127.0.0.1:4096/provider');
+    expect(createRuntime({ configuredOpenCodeHostname: '::1' }).buildOpenCodeUrl('/provider'))
+      .toBe('http://[::1]:4096/provider');
   });
 });

packages/web/server/lib/opencode/proxy.js

@@ -181,6 +181,7 @@ export const registerOpenCodeProxy = (app, deps) => {
     os,
     path,
     OPEN_CODE_READY_GRACE_MS,
+    LONG_REQUEST_TIMEOUT_MS,
     getRuntime,
     getOpenCodeAuthHeaders,
     buildOpenCodeUrl,
@@ -291,13 +292,48 @@ export const registerOpenCodeProxy = (app, deps) => {
       return externalBase;
     }
 
-    if (runtimeState.openCodePort) {
-      return `http://localhost:${runtimeState.openCodePort}`;
-    }
-
     return FALLBACK_PROXY_TARGET;
   };
 
+  const normalizeProxyTimeout = (value) => {
+    return Number.isFinite(value) && value > 0 ? value : 4 * 60 * 1000;
+  };
+
+  const PROXY_REQUEST_TIMEOUT_MS = normalizeProxyTimeout(LONG_REQUEST_TIMEOUT_MS);
+  const PROXY_TIMEOUT_MARKER = Symbol('openchamberProxyTimedOut');
+
+  const isProxyTimeoutError = (error) => {
+    const code = typeof error?.code === 'string' ? error.code : '';
+    const message = typeof error?.message === 'string' ? error.message.toLowerCase() : '';
+    return code === 'ETIMEDOUT'
+      || code === 'ESOCKETTIMEDOUT'
+      || message.includes('timeout')
+      || message.includes('timed out');
+  };
+
+  const sendProxyErrorResponse = (res, statusCode) => {
+    if (!res || res.headersSent || res.writableEnded || typeof res.status !== 'function') {
+      return false;
+    }
+    res.status(statusCode).json({ error: statusCode === 504 ? 'OpenCode upstream timed out' : 'OpenCode service unavailable' });
+    return true;
+  };
+
+  const applyProxyResponseDeadline = (req, res, next) => {
+    const timeout = setTimeout(() => {
+      req[PROXY_TIMEOUT_MARKER] = true;
+      if (sendProxyErrorResponse(res, 504)) {
+        res.once('finish', () => req.destroy?.());
+      }
+    }, PROXY_REQUEST_TIMEOUT_MS);
+    timeout.unref?.();
+
+    const clear = () => clearTimeout(timeout);
+    res.once('finish', clear);
+    res.once('close', clear);
+    next();
+  };
+
   const forwardSseRequest = async (req, res) => {
     const abortController = new AbortController();
     const closeUpstream = () => abortController.abort();
@@ -665,6 +701,8 @@ export const registerOpenCodeProxy = (app, deps) => {
     target: resolveProxyTarget(),
     changeOrigin: true,
     pathRewrite: { '^/api': '' },
+    timeout: PROXY_REQUEST_TIMEOUT_MS,
+    proxyTimeout: PROXY_REQUEST_TIMEOUT_MS,
     // Dynamic target — port can change after restart
     router: () => resolveProxyTarget(),
     on: {
@@ -700,11 +738,13 @@ export const registerOpenCodeProxy = (app, deps) => {
           }
         }
       },
-      error: (err, _req, res) => {
+      error: (err, req, res) => {
         console.error('[proxy] OpenCode proxy error:', err.message);
-        if (res && !res.headersSent && typeof res.status === 'function') {
-          res.status(503).json({ error: 'OpenCode service unavailable' });
+        if (req?.[PROXY_TIMEOUT_MARKER]) {
+          return;
         }
+        const statusCode = isProxyTimeoutError(err) ? 504 : 503;
+        sendProxyErrorResponse(res, statusCode);
       },
     },
   });
@@ -724,5 +764,6 @@ export const registerOpenCodeProxy = (app, deps) => {
     next();
   });
 
+  app.use('/api', applyProxyResponseDeadline);
   app.use('/api', apiProxy);
 };

packages/web/server/opencode-proxy.test.js

@@ -536,4 +536,42 @@ describe('OpenCode proxy SSE forwarding', () => {
     expect(data.body).toEqual(payload);
     expect(Number(data.contentLength)).toBeGreaterThan(0);
   });
+
+  it('uses the long proxy timeout budget for slow upstream responses', async () => {
+    const upstream = express();
+    upstream.get('/slow', (_req, _res) => {
+      // Leave the response open so the proxy timeout path is exercised.
+    });
+    upstreamServer = await listen(upstream);
+    const upstreamPort = upstreamServer.address().port;
+    const externalBaseUrl = `http://127.0.0.1:${upstreamPort}`;
+
+    const app = express();
+    registerOpenCodeProxy(app, {
+      fs: {},
+      os: {},
+      path,
+      OPEN_CODE_READY_GRACE_MS: 0,
+      LONG_REQUEST_TIMEOUT_MS: 50,
+      getRuntime: () => ({
+        openCodePort: upstreamPort,
+        openCodeBaseUrl: externalBaseUrl,
+        isOpenCodeReady: true,
+        openCodeNotReadySince: 0,
+        isRestartingOpenCode: false,
+      }),
+      getOpenCodeAuthHeaders: () => ({}),
+      buildOpenCodeUrl: (requestPath) => `${externalBaseUrl}${requestPath}`,
+      ensureOpenCodeApiPrefix: () => {},
+    });
+    proxyServer = await listen(app);
+    const proxyPort = proxyServer.address().port;
+
+    const response = await fetch(`http://127.0.0.1:${proxyPort}/api/slow`, {
+      signal: AbortSignal.timeout(2000),
+    });
+
+    expect(response.status).toBe(504);
+    await expect(response.json()).resolves.toMatchObject({ error: 'OpenCode upstream timed out' });
+  });
 });