[Bug]: Routed providers emit 'undeclared client tool Write' on Claude Code passthrough due to missing inboundWire exemption in passthrough-dispatch #6648

Client or integration

Claude Code

Area

Proxy and routing

Summary

When proxying Claude Code (or VS Code Claude Agent) through OpenCodex using the Anthropic inbound wire (inboundWire: "anthropic"), routed third-party providers (such as DeepSeek V3/V4.1, Qwen, etc. routed via openai-responses or passthrough) frequently fail during multi-turn coding sessions when the model calls standard Claude tools (e.g. Write, Edit, Bash, Read).

The proxy aborts the streaming session and returns:

API Error: routed provider emitted undeclared client tool "Write"; only request-declared tools may be called

Root Cause Analysis

There is an inconsistency in how the undeclared tool guard is enforced between the bridged adapter path and the passthrough dispatch path:

1. In src/server/responses/adapter-delivery.ts (lines 186 and 270), enforceDeclaredToolNames explicitly excludes Anthropic and Chat inbound wires:

   enforceDeclaredToolNames: options.inboundWire !== "chat" && options.inboundWire !== "anthropic",

   This is intentional, because Anthropic clients declare and execute their own client-side tool catalog (Write, Edit, Bash, etc.) under the Anthropic tool wire schema rather than Codex's internal declared wire tool representations.

2. However, in src/server/responses/passthrough-dispatch.ts (line 513), undeclaredToolGuardActive omitted the inbound wire check:

   undeclaredToolGuardActive = (
     declaredWireToolNames.size > 0
     || clientDeclaredNamelessCallTypes.size > 0
     || clientExplicitWireToolCatalog
   ) && route.provider.authMode !== "forward";

   Notice that options.inboundWire !== "chat" and options.inboundWire !== "anthropic" are missing.

3. Consequently, when a routed provider returns a tool call under passthrough-dispatch, undeclaredToolGuardActive evaluates to true. Because Claude's client tools (such as Write) are not in declaredWireToolNames, createUndeclaredToolCallGuardBlockRewrite trips and abruptly terminates the session with the error above.

Proposed Fix

1. Synchronize undeclaredToolGuardActive in src/server/responses/passthrough-dispatch.ts

Align the guard condition with adapter-delivery.ts:

--- a/src/server/responses/passthrough-dispatch.ts
+++ b/src/server/responses/passthrough-dispatch.ts
@@ -515,7 +515,10 @@ export async function dispatchPassthroughTurn(
         declaredWireToolNames.size > 0
         || clientDeclaredNamelessCallTypes.size > 0
         || clientExplicitWireToolCatalog
-      ) && route.provider.authMode !== "forward";
+      ) && route.provider.authMode !== "forward"
+      && options.inboundWire !== "chat"
+      && options.inboundWire !== "anthropic"
+      && inboundWire !== "anthropic";
       options.nativeControl?.configureToolAuthorization?.(
         undeclaredToolGuardActive,
         declaredWireToolNames,

2. (Optional Defense-in-Depth) Recognize Claude Code built-in tools in src/server/responses-undeclared-tool-guard.ts

When Codex code-mode shell execution is not active (!declared.has(CODE_MODE_EXEC_TOOL_NAME)), allow standard Claude Code client tools (Write, Edit, Read, Bash, etc.) through undeclaredNameInItem:

--- a/src/server/responses-undeclared-tool-guard.ts
+++ b/src/server/responses-undeclared-tool-guard.ts
@@ -93,6 +93,9 @@ function undeclaredNameInItem(
   const effectiveName = normalizeDeclaredToolName(name, declared, declaredBare, declaredCustom);
   if (declared.has(effectiveName)) return undefined;
+  if (CLAUDE_CODE_CLIENT_TOOLS.has(name) && !declared.has(CODE_MODE_EXEC_TOOL_NAME)) {
+    return undefined;
+  }
   return name;

3. (Optional) Case-insensitive normalization fallback in src/types/tools.ts

In normalizeDeclaredToolName, add a case-insensitive lookup fallback if exact case match fails.

Reproduction

1. Start OpenCodex proxy (ocx start --port 10100).
2. Route Anthropic wire requests to a non-forward routed provider (e.g., DeepSeek-V3 or DeepSeek-V4.1 via openai-responses or passthrough).
3. Connect Claude Code or VS Code Claude Agent to http://127.0.0.1:10100.
4. Prompt the model with a multi-step task that causes it to invoke the Write or Edit tool.
5. Observed: The turn fails immediately with API Error: routed provider emitted undeclared client tool "Write"; only request-declared tools may be called.
6. Expected: The tool call passes through to the client for local execution, just as it does in adapter-delivery.ts.

Version

@bitkyc08/opencodex 2.78.0

Operating system

Windows 11 (Build 26200)

Provider and model

Routed providers (e.g. DeepSeek-V3 / DeepSeek-V4.1 Flash) via Anthropic inbound wire

Logs or error output

API Error: routed provider emitted undeclared client tool "Write"; only request-declared tools may be called

Redacted configuration

{
  "routing": {
    "providers": {
      "deepseek": {
        "authMode": "api-key",
        "wire": "openai-responses"
      }
    }
  }
}

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