kimi web: terminal creation fails in the packaged binary (node-pty native assets not bundled; deeper hang after fixing)

What happens

With the packaged single-file CLI (install.ps1 / SEA build), start kimi web and create a terminal from the web UI (or via the API):

POST /api/v1/sessions/{session_id}/terminals
{"runtime_id":"local","shell":"cmd.exe","cols":80,"rows":24}

The request fails with code 50001:

Failed to load native module: conpty.node, checked: build/Release, build/Debug, prebuilds/win32-x64:
Error [ERR_UNKNOWN_BUILTIN_MODULE]: No such built-in module: ./prebuilds/win32-x64//conpty.node

Web terminals are therefore completely unusable in the packaged binary (dev mode via pnpm dev:cli is unaffected). Confirmed on 0.39.0, Windows 11 x64.

Root cause (layer 1)

• HostTerminalService.spawn (agent-core-v2/.../hostTerminalService.ts) lazily runs await import('node-pty').
• node-pty's JS is bundled into the SEA blob, but its native prebuilds (prebuilds/<target>/*.node, plus winpty-agent.exe / conpty/OpenConsole.exe / conpty.dll on Windows, spawn-helper on darwin) are not registered in apps/kimi-code/scripts/native/native-deps.mjs (only clipboard and pi-tui are), so they never ship as native assets.
• Additionally, inside the SEA main script the bundled require(dir+"/"+name+".node") in node-pty/lib/utils.js runs as the builtin-only require variant and throws ERR_UNKNOWN_BUILTIN_MODULE before Module._load can intercept it — so apps/kimi-code/src/native/module-hook.ts (which currently only redirects pi-tui patterns) never sees the request.

What we tried (layer 1 fixed, layer 2 found)

We implemented the pi-tui-style fix locally:

1. Registered node-pty in native-deps.mjs with per-target prebuild files (plus 0o755 for darwin spawn-helper).
2. Extended module-hook.ts with a redirect for node-pty prebuilds/<target>/ requires to the extracted cache copy.
3. Added a small bundler plugin that rewrites the exact require(dir + "/" + name + ".node") call site in node-pty/lib/utils.js to createRequire(pathToFileURL(__filename).href)(...), failing the build loudly if a node-pty upgrade moves the call site.

Result: the 50001 error is gone — conpty.node now loads from the extracted native-asset cache, and test:native:smoke passes. But terminal creation then hangs the entire server event loop (no error response; the process stays alive but stops answering requests).

Current leading hypothesis: node-pty spawns new Worker(__dirname/worker/conoutSocketWorker.js) in its Windows conout connection, and that worker file does not exist inside the SEA bundle — the repo already solves the same problem for its own workers (minidb/search workers are extracted to disk as runtime files). The conout worker likely needs the same treatment (extract + rewrite the script path at bundle time), though a blocking fs.openSync on the conin pipe hasn't been ruled out.

Control experiment: the extracted node-pty (same cache copy) spawns cmd.exe successfully under plain node, so the .node binaries and sidecars themselves are fine — the hang is specific to the SEA process context.

We're happy to PR the layer-1 fix and/or continue with the worker extraction under maintainer guidance — whichever you prefer.

Start with apps/kimi-code/scripts/native/native-deps.mjs and apps/kimi-code/src/native/module-hook.ts, then inspect node-pty/lib/utils.js and its worker path. Run test:native:smoke and reproduce terminal creation in the packaged SEA binary, comparing it with plain node. Done means packaged Windows terminal creation returns successfully without hanging the server.