## Why
Code Mode sessions always used client-side output handling, leaving server truncation settings and observation budgets unused.
## What changed
- Honor each session's `output_truncation` setting in the runtime and both host transports, and advertise the bounded-output capability.
- Apply `max_output_tokens` independently to execute, wait, and terminate responses in server mode. Keep client mode as the default when the setting is omitted.
- Use bounded output collection and rendering in server mode, preserving head and tail output with omission notices. Include script errors in the output budget while retaining failure status and a separate diagnostic capped at 64 KiB.
- Estimate audio tokens without the Tokio-dependent cache when rendering bounded output.
## Testing
Add runtime and host regression tests for session mode selection, per-request budgets, output overflow, oversized images, zero-token audio output, diagnostic preservation, and termination under output backpressure.
GitOrigin-RevId: 3d9661edcdd2dde31526bb92eb83fa0614f0fa88
## What changed
Add session options for client- or server-owned output truncation and optional `max_output_tokens` budgets for wait and terminate observations. Introduce `TerminateRequest` and update session implementations and callers to use it.
Extend the stdio and gRPC schemas with optional truncation settings and budgets, and define the `bounded-output-v1` capability. Existing sessions retain client-side truncation; providers reject server mode by default. This change defines the contracts without enabling server-side truncation.
## Testing
Extend protocol serialization coverage for `outputTruncation: "server"` while preserving existing wire shapes when optional fields are absent.
GitOrigin-RevId: 22145897ea16d385c5ba9e7549109f7a669fceb4
## 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
A catchable exception lets JavaScript continue after `exit()`, including in `catch`, `finally`, and queued promise callbacks. Exiting should finish the cell successfully without further output or state changes.
## What changed
- Terminate V8 execution when `exit()` is called and complete the cell even if its module promise remains pending.
- Guard host callbacks against effects after exit, including when getters or value conversion request exit.
- Preserve stored writes made before exit and suppress errors when exit occurs during exception formatting.
## Testing
Add regression tests for synchronous and asynchronous exit, timers, parallel promises, value conversion, exception getters, and resuming after a yield and tool response. Verify that only prior output and stored writes survive, and separately exercise host guards while JavaScript continues running.
GitOrigin-RevId: e9487ba65ef0358612c5009bd26953b786a12798
## Why
Reentering V8 during termination can replace uncatchable cancellation with a catchable JavaScript exception, allowing a script to continue after cancellation.
## What changed
Skip JSON conversion and exception throwing while V8 execution is terminating, preserving cancellation through `image()` getters and JSON fallback.
## Testing
Add regression coverage for cancellation during JSON fallback and reentrant image getters, including prompt termination through the standalone host and continued usability of another session. Extend serialization error tests to cover failing image getters alongside circular JSON.
GitOrigin-RevId: f03dd131a62724106fad96111292ddf5b9dc99f6
## Why
JavaScript objects containing Serde's reserved JSON keys can be reinterpreted during deserialization, allowing nested `RawValue` markers to bypass the parser's normal recursion limit.
## What changed
Reject `$serde_json::private::RawValue` and `$serde_json::private::Number` object keys before passing V8's serialized JSON to `serde_json`. Report a `reserved JSON object key` serialization error while continuing to allow marker text in strings and longer keys.
## Testing
Add runtime regression coverage for nested and escaped marker keys, recursion limits, normal JSON conversion, and session recovery without overwriting stored values. Extend the host-backed integration test to verify that stored values remain available across turns after rejection.
GitOrigin-RevId: 27ddce08e1ffe98ec9dffe02473a815ceae2cc89
## What changed
Expose two JavaScript globals for consuming results as inputs settle:
- `as_settled(promises)` returns an async iterator of fulfilled and rejected records in settlement order, preserving queued results while the consumer is busy.
- `stream_settled(promises, emit)` delivers those records to a callback, awaiting each invocation and propagating callback errors.
Records include an `index`, a `status`, and either a `value` or a `reason`. Iterable inputs use positional indices; `Map` inputs retain their keys. Both helpers accept promises, thenables, and plain values.
## Testing
Add runtime coverage for ordering, input types, object identity, callback behavior, early iteration exit, and termination. Add stdio and gRPC host tests for partial results across waits, plus a scenario snapshot verifying fulfilled and rejected records reach the model.
GitOrigin-RevId: cddc9f3679ae04f2421e154caa0417afb15f550d
## Why
Tokio's paused clock can auto-advance while tests await the V8 thread. The service tests need explicit control over time when checking yield limits and grace periods.
## What changed
- Hold virtual time with a blocking-task guard that is released when dropped.
- Replace bounded polling loops with tool-start notifications and direct awaits of response tasks.
- Return an error from the test helper if the cell closes before a nested tool starts.
## Testing
Add tests covering tool-start acknowledgement when a cell throws or is terminated before invoking a nested tool, including assertions on the resulting cell responses.
GitOrigin-RevId: c221c0501ec0354052102c0211cc651008babff3
## 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
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
Passing `undefined` to a tool could fail JSON parsing because V8 stringifies it as the non-JSON text `undefined`.
## What changed
Return no JSON value for JavaScript `undefined`, so explicit `undefined` tool arguments behave like omitted arguments. Attempts to `store` an undefined value report the existing serializability error and preserve the previous stored value.
## Testing
Add regression coverage for storing `undefined` over an existing `null` value, and extend the current-time tool test to cover `{}`, omitted arguments, and explicit `undefined`.
GitOrigin-RevId: 071050ebb2ecc44c8f08453cf8523b4d21728c7e
## Why
Audio models cannot reliably encode tool-generated clips shorter than 25 ms.
## What changed
- Measure the available audio frames in base64-encoded PCM and IEEE float WAV outputs.
- Replace clips under 25 ms with explanatory text while preserving surrounding Code Mode output.
- Leave clips at or above the threshold and unrecognized audio formats unchanged.
## Testing
- Cover the duration boundary across multiple sample rates and all supported `audio()` input forms.
- Verify bounded and truncated WAV chunks, output after `yield_control()`, and end-to-end mixed text and audio output.
GitOrigin-RevId: 342b4bdbc65db4238580f9cdc372763c2576eca5
## 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
- Cover object serialization through the `text()` helper directly in the code
mode runtime suite.
- Remove redundant core integration coverage for serialized text and rejected
image outputs.
GitOrigin-RevId: f465b8361e9d725a7246994d9c41e9d01c969011
## What changed
Replace the core integration test for allowed `globalThis` properties with an
in-process code-mode runtime test. The test continues to fail when the runtime
exposes a global outside the allowlist without requiring the core network test
harness.
GitOrigin-RevId: f33846ae2bb35e6779b5bec0a3f0ba5729eb707d
## What changed
Move circular-value coverage for the `text()` helper from the core integration
suite to the in-process code mode runtime tests. Verify that stringification
returns no content and surfaces the V8 circular-structure error without needing
a mock server or network access.
GitOrigin-RevId: d506591af5ae8ce0a8c7305d633a7b0f2e458335
## 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
## 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
Sean Huang