## What changed
Add `codex tcp-tunnel --diagnostics-json` to emit versioned, newline-delimited JSON diagnostics on stderr. Records classify startup, CONNECT, transport, and control failures without exposing credentials, addresses, headers, or raw error messages. Rejected CONNECT records may include a validated `http_status`.
Distinguish terminal failures from recoverable stream and transport events, flush terminal records before returning a generic error, and preserve stdout readiness and credential acknowledgments. Keep human-readable diagnostics as the default and document the version 1 schema and consumer fallback rules.
## Testing
Add tests for bounded output, error-chain suppression, terminal flushing, control error classification, CONNECT status validation, legacy behavior, and flag parsing. Extend the reconnect test to exercise a rejected CONNECT followed by a successful connection in JSON mode.
GitOrigin-RevId: 350f67fe8e3f313e8a6d3bb0fd891952b77647fd
## What changed
Add `codex tcp-tunnel` and the `codex-tcp-tunnel` crate to forward loopback TCP connections to an explicit target through a TLS-verified HTTP/3 CONNECT proxy.
- Require the proxy origin to match an approved HTTPS origin in a supplied policy file.
- Read bearer tokens and optional bounded, non-forwarding `x-` headers from stdin. Support token updates for new connections, `LISTENING` and `AUTH_UPDATED` notifications, and shutdown when the control pipe closes in token-update mode.
- Preserve the listener across proxy reconnects without replaying TCP streams, and let accepted streams continue while a proxy drains.
## Testing
Add tests for hidden CLI parsing, proxy and target validation, credential renewal, control-pipe closure, and invalid input without secret disclosure. A local HTTP/3 proxy test covers token replacement, transport recovery without stream replay, and graceful draining.
GitOrigin-RevId: c6af3025301c61e9fe90940cf5a6df0039465e69
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