bug(runtime): Code Mode on OpenAI Responses advertises maka_tool_search, which exec does not bind #5664

What happened

In Code Mode, with a connection routed through the OpenAI Responses adapter, the model cannot load any deferred tool. Its first exec call fails before any tool runs:

return await tools.maka_tool_search({ query: "ScheduledTask", limit: 1 });

{ "ok": false, "error": { "kind": "execution_error", "message": "not a function" }, "toolCalls": [] }

Because discovery fails, ScheduledTask (and every other deferred tool) is unreachable in that session. The user's request ("create a scheduled task for 10:00 today") ended with no task created.

Root cause. OpenAI Responses reserves tool_search, so #3958 renames the provider-bound tool to maka_tool_search (model-adapter.ts, startStream) and also rewrites every \btool_search\b in the system prompt via remapProviderToolNamesInText. In Code Mode the provider only sees exec; tool_search is nested inside it and bound in the QuickJS cell as tools.tool_search (code-mode.ts / nestableToolSnapshot). The prose rewrite still reaches the Code Mode catalog prompt (renderCodeModeCatalogPrompt, "After tool_search, …" plus the JSON catalog), so the model is told to call a name the cell never binds.

The existing Code Mode backend test (code-mode-backend.test.ts) does not use a Responses runtime, so it does not cover this combination.

How to reproduce

1. Enable Code Mode for new tasks (feat(settings): opt in to Code Mode for new tasks #5219).
2. Use a connection whose model runs on the OpenAI Responses adapter.
3. Ask for anything that needs a deferred tool, e.g. "create a scheduled task at 10:00 today".
4. The model calls tools.maka_tool_search(...) inside exec and gets not a function; toolCalls is empty.

Environment

• Maka Desktop 0.2.0-dev.48.20260923 (packaged)
• Windows 10 x64 (10.0.19042)
• Verified against source at apache/main@fef5b937a

Logs, screenshots, or additional context

Both conditions are required: Code Mode alone keeps tool_search; Responses alone exposes maka_tool_search as a real provider tool.