## What changed
- Add `create_session_with_limits` and session-scoped cell execution limits.
- Clamp execute and wait yield times to the session's `max_yield_time_ms`
without terminating the running cell.
- Negotiate support with remote code-mode hosts and include non-default limits
in `session/open`, while keeping unlimited sessions compatible with hosts and
providers that do not support limits.
## Testing
- Cover yield-time clamping, zero-timeout behavior, and isolation between
sessions.
- Cover wire serialization, capability negotiation, unsupported hosts, and
shared process-host execution.
GitOrigin-RevId: 9517321cd605bb87f93eeaa6ba331cc2e346e582
## Why
Large nested-tool callbacks can occupy a WebSocket and delay unrelated session
operations on the same code-mode connection.
## What changed
- Negotiate the optional `dual-websocket-v1` capability and pair a second,
token-scoped WebSocket with the control connection.
- Route nested-tool callbacks and their results over the bulk socket while
keeping session operations, notifications, and execution responses on the
control socket. Reject messages sent on the wrong lane.
- Preserve the single-connection transport when the capability is unavailable,
and bound pairing, queued callbacks, and deferred cross-socket messages.
- Defer callbacks that arrive before their execution-started response, and
return delegate errors without disconnecting the connection.
## Testing
Add protocol, transport, driver, and WebSocket integration coverage for
capability negotiation, lane routing, pairing failures, out-of-order messages,
and progress during large concurrent tool results.
GitOrigin-RevId: fa4504653e7cbf3c4ec930ae57aa0a41345bad66
## What changed
- Add `--code-mode-host ws://...` and `wss://...` support to `codex app-server`, gated by the `code_mode_host` feature. When omitted, app-server continues to start a local host.
- Share one remote WebSocket connection across the process's threads, using the configured HTTP client's proxy and TLS policy and preserving the existing framed host protocol.
- Reject invalid host URLs, bound WebSocket frame sizes, close connections cleanly, and return an error when a connection exceeds 1,024 pending delegate calls without disconnecting it.
## Testing
- Cover CLI validation, WebSocket protocol execution and shutdown, connection sharing across app-server threads, and delegate-call capacity recovery.
GitOrigin-RevId: 715e82d4d9db1e7e2f91b754a777dcab504e2ae4
## What changed
- Add a `--listen` option that accepts `stdio`, `stdio://`, or a
`ws://IP:PORT` endpoint, while retaining stdio as the default.
- Serve the existing length-prefixed protocol in binary WebSocket messages,
with isolated connections, shared host limits, and a `/readyz` endpoint.
- Reject browser-origin handshakes and contain malformed frames to the affected
connection.
## Testing
- Cover listen URL parsing and complete-frame encoding and decoding.
- Exercise readiness, cell execution, tool callbacks, large frames, concurrent
connections, malformed frames, and origin rejection through the WebSocket
listener.
GitOrigin-RevId: 01c8be4c6256b8ce4a3a0002440dcb3294e5f887
## Summary
- add an `EncodedFrame` type so IPC payloads are serialized and
size-checked before entering bounded queues
- add the V1 `operation/cancel` client-to-host message
- pin the new wire shape with protocol tests
## Why
The process-owned code-mode host needs bounded, pre-encoded outbound
messages and a best-effort cancellation signal. Keeping these wire
primitives in a protocol-only change lets their compatibility contract
be reviewed independently from either endpoint.
## Stack
This is **1 of 4** in the process-owned code-mode session stack. The
next PR targets this branch.
## Validation
- `just test -p codex-code-mode-protocol` — 22 passed
- `just fix -p codex-code-mode-protocol`
- `just fmt`
## Why
The process-owned code mode implementation needs an explicit, bounded
wire contract before either side depends on it. Keeping framing and
message semantics in `codex-code-mode-protocol` gives the client and
sidecar one shared source of truth and makes compatibility failures
detectable during connection setup.
## What changed
- adds a versioned client/host handshake with required and optional
capabilities
- defines operation requests and responses for session lifecycle and
cell control
- defines reverse delegate request, response, cancellation, and
cell-closure messages
- adds a four-byte little-endian length-prefixed JSON codec with a hard
frame cap
- rejects malformed frames, unknown fields, invalid identifiers, and
unsupported protocol states
- locks the wire representation down with explicit JSON round-trip tests
## Testing
- `just test -p codex-code-mode-protocol`
## Stack
Part 1 of 6. Followed by
[#29805](https://github.com/openai/codex/pull/29805).
## Summary
- add validated protocol-version, capability, and session identifier
types
- define explicit `ClientToHost` and `HostToClient` JSON envelopes for
connection negotiation and session open/close acknowledgements
- reject invalid states and unknown fields during decoding, with
explicit wire-format and round-trip coverage
## Why
This establishes the transport-neutral encoding shape needed to build
and test the new code-mode host incrementally. Cell, tool callback, and
failure-domain messages are intentionally deferred until their actors
and behavior tests establish the required semantics.
This is additive protocol scaffolding and does not change the current
production code-mode implementation.
## Validation
