## Why
A delegate bound at session creation cannot provide different callbacks for cells sharing that session. Each execution needs to retain its own delegate across yields and release it when the cell is cleaned up.
## What changed
- Pass `CodeModeSessionDelegate` to `execute` instead of session creation.
- Route tool calls, notifications, and cell closure callbacks through the execution's delegate in the in-process runtime and the gRPC and stdio transports.
- Retain delegates with pending executions and live cells, releasing them through closure and cancellation cleanup.
## Testing
Add coverage for distinct delegates across yielded cells, gRPC callbacks before cell admission, and delegate release after completion or abandoned execution cleanup. Update transport tests to verify callbacks reach the owning cell's delegate.
GitOrigin-RevId: 7469f52104b993e790a40c65fb800ad02b7fd606
## Why
Code mode wall time should measure the host operation itself, without including
client-side response delays or idle time between requests.
## What changed
- Measure each execute, wait, and terminate request in the code mode host.
- Carry the duration through the stdio and gRPC protocols and use it for
model-visible wall time.
- Emit a structured `codex.code_mode.host_timing` event correlated with the
conversation, turn, tool call, and cell.
## Testing
- Cover successful and failed execution timing, delayed response reads,
repeated waits, termination, and missing cells across stdio and gRPC.
- Verify timing survives protocol serialization and is reflected in app-server
model output and structured telemetry.
GitOrigin-RevId: d24af30c3fc5820521b4beba1f9970714dad6482
## What changed
- Forward notification text to the session delegate without applying the previous 1,024-byte limit or appending a truncation suffix.
- Update the gRPC host integration test to verify that oversized multibyte notification text is delivered unchanged.
GitOrigin-RevId: 9a9e24b359a07540f70ec4e98b28524db3f7a4a0
## What changed
- Use a never-resolving promise when verifying that a session continues to
enforce its yield limit after terminating a cell.
- Use `yield_control()` to create the yielded cell in the notification-draining
test instead of relying on timer scheduling.
GitOrigin-RevId: 01cdaa94e5b8b5c89c6fa98c4bbdb28a690678e0
## What changed
- Subscribe each gRPC code-mode session to nested tool calls and forward tool and notification callbacks to its delegate.
- Complete tool calls through the host while bounding oversized results and errors.
- Track callback ownership and cancellation so completed cells drain notifications, terminated cells cancel them, and shutdown revokes outstanding work.
- Validate callback identifiers, cell ownership, enabled tools, and pending callback limits without serializing independent callbacks or sessions.
## Testing
- Add integration and state tests for callback forwarding, completion ordering, cancellation, malformed callbacks, delegate panics, oversized results, and concurrent work.
GitOrigin-RevId: 005afbb90eea0eb77d746b930a1a96ca6dfcd4e7
Abhinav