[jonlwheat2-gif]

What was broken

npm run build:cli (scripts/build/prepublish.ts) crashes on Node ≥ 20 on Windows while bundling the ChatGPT Web (Codex) MCP bridge. The crash killed the CLI packaging step, so a user building from the source-only release ZIP (no prebuilt dist/) cannot produce a working global install.

Red evidence (Node v24.18.0, Windows, v3.8.50 source ZIP):

🔨 Bundling ChatGPT Web (Codex) MCP bridge...
    '--platform=node',
    '--packages=external',
    '--format=esm',
    '--outfile=dist/open-sse/vendor/codex-chatgpt-web/adapters/chatgpt-web/mcp-server.js'
  ],
  error: [Circular *1],
  status: null,
  signal: null,
  output: null,
  pid: 0,            ← child process never spawned
  ...
}

Node.js v24.18.0

Root cause

scripts/build/prepublish.ts:326 (old) called execFileSync(NPX_BIN, ...) directly — NPX_BIN is "npx.cmd" on win32. On Node ≥ 20, spawning a .cmd shim without shell: true throws EINVAL (CVE-2024-27980 spawn hardening). This is the exact failure mode the file's own header comment documents (lines 46–52), which is why runBuildTool() was introduced — it resolves the tool's JS entry and runs it with process.execPath, no shim, no shell. This one call site was missed by that refactor and is the only remaining raw NPX_BIN spawn in the file.

The fix (this PR)

scripts/build/prepublish.ts — route that one call through the existing runBuildTool():

Line	Before	After
326	execFileSync(NPX_BIN, [	runBuildTool("esbuild", "esbuild", [
328–336	["esbuild", "...mcp-server.ts", ...]	same args, unchanged
337	{ cwd: ROOT, stdio: "inherit" }	same options, unchanged

Full diff (6 lines changed, 3 added / 3 removed): the esbuild args and options are byte-identical; only the spawn mechanism changes.

What was tested

• Red: prepublish.ts crashes at this exact step on Node 24/Windows before the change (crash log above).
• Green: with the change, the full npm run build:cli completes — dist/server.js, dist/BUILD_SHA, and dist/open-sse/vendor/codex-chatgpt-web/adapters/chatgpt-web/mcp-server.js are all produced, and the resulting global install boots (omniroute --version → 3.8.50, server serves on :20128).
• Gates on this branch: eslint on the changed file → 0 errors; npm run typecheck:core → clean; check:changelog-integrity → OK vs origin/release/v3.8.51.

Scope

2 files, surgical:

• scripts/build/prepublish.ts (1 call site)
• changelog.d/fixes/11704-prepublish-npx-cmd-win32.md (fragment)

Fixes #11704.