Codex Desktop Windows: node_repl trusted runtime fails with Access denied before Chrome bridge can run

Codex Desktop Windows: node_repl / trusted runtime fails before Chrome bridge can run

Summary

node_repl is broken in Codex Desktop on Windows before any Chrome plugin/native-host code can run. The Chrome extension and native host were independently verified present, but a minimal node_repl smoke test still fails. A lower-level MCP probe can initialize the node_repl server, but tools/call js fails when starting the Node runtime with Windows os error 5.

Environment

• Date observed: 2026-05-30
• Codex Desktop package path: C:\Program Files\WindowsApps\OpenAI.Codex_26.527.3686.0_x64__2p2nqsd0c76g0\...
• Codex app log version: app.version=0.135.0-alpha.1
• OS: Microsoft Windows NT 10.0.26200.0, x64
• Workspace: C:\Users\<user>\OneDrive\Documents\Codex\<workspace>
• MCP server: node_repl

User-visible failure

Original user request:

@Chrome list my open tabs

The request failed before any tab data could be returned. Later direct tests showed this is not a Chrome extension reinstall/native-host issue.

Things already verified / ruled out

A separate elevated check confirmed:

• Native host manifest exists:

C:\Users\<user>\AppData\Local\OpenAI\extension\com.openai.codexextension.json

• Registry key exists:

HKCU\Software\Google\Chrome\NativeMessagingHosts\com.openai.codexextension

• Registry points to the manifest path.
• Allowed origin matches the installed Codex Chrome extension origin.
• Codex Chrome Extension is installed and enabled in Chrome Default profile.

Current node_repl config

[mcp_servers.node_repl]
args = []
command = 'C:\Users\<user>\AppData\Local\OpenAI\Codex\bin\34ab3e1324cc55b5\node_repl.exe'
startup_timeout_sec = 120

[mcp_servers.node_repl.env]
NODE_REPL_NATIVE_PIPE_CONNECT_TIMEOUT_MS = "1000"
NODE_REPL_NODE_MODULE_DIRS = ""
NODE_REPL_NODE_PATH = 'C:\Users\<user>\AppData\Local\OpenAI\Codex\bin\5b9024f90663758b\node.exe'
NODE_REPL_TRUSTED_CODE_PATHS = 'C:\Users\<user>\.codex'
CODEX_HOME = 'C:\Users\<user>\.codex'
BROWSER_USE_AVAILABLE_BACKENDS = "chrome,iab"
BROWSER_USE_CODEX_APP_BUILD_FLAVOR = "prod"
CODEX_CLI_PATH = 'C:\Users\<user>\AppData\Local\OpenAI\Codex\bin\7dea4a003bc76627\codex.exe'

Reproduction evidence

Minimal live node_repl call:

nodeRepl.write('node_repl ok')

Result from Codex tool call:

tool call error: tool call failed for `node_repl/js`

Caused by:
    Transport closed

Lower-level manual MCP probe result:

STDOUT:
{"jsonrpc":"2.0","id":1,"result":{"protocolVersion":"2025-06-18","capabilities":{"experimental":{"codex/sandbox-state-meta":{}},"tools":{"listChanged":true}},"serverInfo":{"name":"rmcp","version":"1.5.0"},"instructions":"Use `js` to run JavaScript in the persistent Node-backed kernel..."}}
{"jsonrpc":"2.0","id":2,"result":{"content":[{"type":"text","text":"failed to start Node runtime: Access is denied. (os error 5)"}],"isError":true}}

STDERR:
2026-05-30T23:40:29.748951Z ERROR node_repl::diagnostics: codex app-server auth fetch failed auth_fetch_failure_reason="app_server_request_failed" auth_method=missing auth_token_state=missing auth_status_keys= auth_status_field_kinds=authStatus:missing codex_cli_path_env_present=true target_os="windows" target_arch="x86_64"

Earlier sandbox log failure from the same investigation:

setup refresh: spawning C:\Users\<user>\AppData\Local\OpenAI\Codex\bin\7dea4a003bc76627\codex-windows-sandbox-setup.exe
setup refresh: failed to spawn C:\Users\<user>\AppData\Local\OpenAI\Codex\bin\7dea4a003bc76627\codex-windows-sandbox-setup.exe: The requested operation requires elevation. (os error 740)

Normal shell tool commands in the same Codex Desktop session use the packaged setup helper and succeed:

C:\Program Files\WindowsApps\OpenAI.Codex_26.527.3686.0_x64__2p2nqsd0c76g0\app\resources\codex-windows-sandbox-setup.exe

Both setup-helper binaries were checked and appeared byte-identical by hash:

4BB5825D025721E7406A055D91B641DA4F08A947AE40AD43BE2A76FF190B55A2

Workarounds attempted

• Confirmed this is not caused by missing Chrome plugin or missing native host.
• Tried args = ["--disable-sandbox"]; Codex Desktop ignored the args value for the running MCP process.
• Tried removing / overriding CODEX_CLI_PATH; Codex Desktop still launched node_repl with the AppData Codex child path.
• Tried pointing CODEX_CLI_PATH to the packaged Codex CLI path; live process still used/cached the AppData path and Codex crashed during restart attempts.
• Tried a local stdio proxy that preserved sandboxing and only forced packaged CODEX_CLI_PATH; MCP initialize worked, but tools/call js still failed with Access is denied. (os error 5). The proxy config was rolled back.

Expected behavior

node_repl should be able to start the trusted Node runtime and execute a minimal JS call:

nodeRepl.write('node_repl ok')

After that, the Chrome skill should be able to call browser.user.openTabs().

Actual behavior

node_repl cannot start the Node runtime. The failure happens before Chrome extension/native-host communication is involved.

Request

Please investigate the Windows Codex Desktop trusted runtime / sandbox launch path for node_repl, especially why tools/call js returns failed to start Node runtime: Access is denied. (os error 5) while shell commands can refresh the sandbox successfully through the packaged codex-windows-sandbox-setup.exe.