## What changed
Remove unused pending initial-yield state and its plumbing from cell completion handling. Route completion delivery through `send_cell_event`, retaining the completion event and original timestamp when an observer has disconnected.
## Testing
Extend `failed_completion_delivery_rebuffers_the_event` to verify that failed delivery attempts preserve output and report the full elapsed buffering duration on a later successful observation.
GitOrigin-RevId: eebe990a4f8258f1ccb12d0694945678f0cc3a8f
## What changed
- Add `CodeModeCellTiming` notifications for yielded executions, terminal waits, and unavailable cells, with thread, call, and cell identifiers.
- Measure how long completed results remain buffered before retrieval and carry `result_buffered_for` through the runtime, stdio protocol, and gRPC response metadata. Immediate delivery reports zero; waits without a completed result report no buffering measurement.
- Default missing buffering data to zero for compatibility with older hosts.
## Testing
Extend runtime tests to verify buffering duration with a paused clock and retrieval through termination. Add gRPC conversion tests for nanosecond precision, optional metadata, and the distinction between immediate delivery and no completed result.
GitOrigin-RevId: 60c0c5a3affa69ac3779bf1812fca50f5748af76
## Why
Yield signals and queued runtime events can detach an observer during termination, before the remaining output has been drained.
## What changed
Track the active yield signal separately from the observer so termination can disable yielding while keeping the observer attached. Ignore `Started`, `Pending`, and `YieldRequested` events during termination, allowing queued output to reach the observer in `CellEvent::Terminated`.
## Testing
Extend the termination regression test with an immediate yield timeout, a canceled yield signal, and queued start, yield, output, and completion events. Assert that both the termination caller and the initial observer receive the queued output in the terminated event.
GitOrigin-RevId: 1c08bdec06838123aaa102268da2f50b63ddea3f
## What changed
Add an optional `preempt` signal to `CodeModeSession::execute` and `CodeModeSession::wait` so callers can end an observation early while the cell continues running and remains available for later waits.
Support the signal in the in-process runtime and across both remote transports: `operation/yield` with the negotiated `yield-observation` capability for stdio, and `YieldObservation` for gRPC. Preserve signals received before gRPC observation registration, and retain normal timeout behavior for older hosts that lack support.
## Testing
Add runtime and transport tests covering early execute and wait yields followed by successful cell completion, yields before observation registration, and suppression of yield frames for older stdio hosts.
GitOrigin-RevId: 3f8049d8f0582be6b8f0832cc03f2d974a0b8f18
## Why
Fixed schema budgets can strip parameter descriptions from large MCP tools or render their Code Mode input types as `unknown`. Allow larger budgets to preserve that guidance.
## What changed
- Add `mcp_servers.<name>.tool_input_schema_max_bytes` to configure the UTF-8 byte threshold for best-effort input schema compaction, retaining the 5,000-byte default.
- Add `features.code_mode.tool_input_schema_max_bytes` for rendered input types. Use the largest of the 16,000-byte default, the Code Mode setting, and the ordinary MCP server's explicit setting.
- Apply rendering budgets to prompt declarations and the runtime tool catalog, and avoid reusing cached declarations after the Code Mode budget changes.
## Testing
Add coverage for UTF-8 compaction thresholds, budget precedence, configuration round trips, and preservation of parameter guidance in both the Code Mode prompt and `ALL_TOOLS`.
GitOrigin-RevId: 0ef2823a614d4794e636f518b09c0b03a5239b45
## Why
Creating a cell deep-copies every stored JSON value, including values the cell never loads. Storing a value also duplicates its payload between the cell's local state and pending writes.
## What changed
Use `Arc<JsonValue>` throughout the session store, cell runtime, and completion writes to share immutable payloads. Keep a separate map snapshot for each cell so later commits cannot change its view of stored values.
GitOrigin-RevId: 4535f0f2ed0c8f8cbfb8d24cf1cb44cbc74472b5
## What changed
- Move the V8 implementation into a dedicated `codex-code-mode-runtime` crate used by `codex-code-mode-host`, removing the embedded runtime fallback from the Codex process.
- Resolve the host executable from the active installation layout and check its availability before selecting tools.
- Fall back to direct tools with a one-time warning when optional code mode is unavailable. Keep `code_mode_only` and `disable_in_process_fallback` configurations fail-closed.
## Testing
- Cover host discovery for standalone and package layouts, including missing hosts and symlinks.
- Verify direct-tool fallback, one-time warnings, and fail-closed code-mode-only behavior.
GitOrigin-RevId: 5aa3c6f1db148b2231fc24089a2ee0e2b00dbddb
Channing Conger