## What changed
When even the minimum skill catalog exceeds its metadata budget, render each
included entry without its description. This allows more skill names and
locators to fit before the remaining entries are omitted.
## Testing
Add coverage for extreme budget pressure and verify both the extension and
production-turn catalogs omit descriptions while staying within budget.
GitOrigin-RevId: 72cec10e9587beabbd3d8c6d53b931deb76824e6
## What changed
- Remove the step-scoped `ExtensionData` argument from context, turn-input, and tool contributors.
- Pass the host's optional `McpResourceClient` through `ThreadStartInput` so extensions can retain session capabilities explicitly.
- Keep the MCP resource client in skills-owned session state for catalog loading and skill tools.
GitOrigin-RevId: bafa77bcd998aff408d6a396c5fd9ac268c4cce4
## Why
Long skill descriptions can consume the catalog's metadata budget before later
skills are listed, hiding otherwise usable skills from the model.
## What changed
- Reserve space for every skill's name and locator when those minimum lines fit.
- Distribute the remaining token or character budget across descriptions in
round-robin order.
- Fall back to omitting entries only when the minimum catalog cannot fit.
## Testing
Added extension and production-turn coverage that verifies moderate budget
pressure keeps every catalog entry, shortens descriptions evenly, and avoids an
omission marker.
GitOrigin-RevId: 41971e4b47a86863b3839707b5cffcd8d83b888c
## Why
Startup prewarms and Guardian review sessions do not need workspace Git metadata. Collecting it for those requests performs redundant work, while user turns still need a fresh view of the repository.
## What changed
- Add a per-session Git enrichment policy.
- Skip enrichment for startup prewarm, preview, and Guardian review turns.
- Keep fresh enrichment enabled for regular sessions and one-shot delegated turns.
## Testing
- Cover prewarm and Guardian requests omitting workspace metadata while subsequent user turns observe repository changes.
- Cover concurrent repositories and worktrees retaining distinct metadata.
- Verify concurrent enrichment is coalesced and canceled enrichment can be retried.
GitOrigin-RevId: 4a68615288bb568c75f2e487d9c0776e3e80f191
## What changed
- Treat output-task closure as the signal that trailing output is complete, drain any remaining chunks before publishing command completion, and retain the grace period as a fallback.
- Wait for deferred network-denial classification before emitting the final command result.
- Serialize `write_stdin` interaction and completion events so an interaction that exits a process is published first, and avoid pruning processes while their terminal events are being finalized.
## Testing
- Add coverage for late output, missing output-close signals, late network denials, interaction/completion ordering, cross-platform aggregated output, and pruning during finalization.
GitOrigin-RevId: 46a118552bb1a4658b78aa5a5ca76eb8c5fba571
## What changed
- Use `McpConnectionSet` as the primary name for the collection of active MCP
server connections throughout `codex-mcp` and its callers.
- Keep `McpConnectionManager` as a backward-compatible type alias.
GitOrigin-RevId: 9753838b4fd0a0b6429a9c4af0c077137616f388
## What changed
- Include the Codex `session-id` and `thread-id` headers when starting realtime conversations over WebSocket or WebRTC.
- Add coverage confirming that WebRTC call creation forwards both identifiers while preserving the existing realtime request metadata and SDP payload.
GitOrigin-RevId: 668bee9a7d4797ad0a396e9ca4dc56b2c379cba7
## Why
ChatGPT token refresh requests need to follow the same configured routing policy as other authentication traffic, including environments that use the system proxy.
## What changed
- Require an `AuthRouteConfig` throughout login, logout, token refresh, personal access token, and agent identity flows.
- Build auth HTTP clients directly from that configuration instead of falling back to a default HTTP client when routing configuration is absent.
## Testing
- Add an integration test that refreshes a token through a cached system-proxy route and verifies the proxy receives the expected request.
GitOrigin-RevId: 7d54ab3219939a49921c51faf08cd4c2eabca51c
## Why
Turn diffs need to render paths from remote environments whose path convention may differ from the Codex host.
## What changed
- Preserve `PathUri` values through applied patch deltas, display-root discovery, and turn-diff tracking.
- Add host-independent relative-path rendering and normalize Windows drive-letter case in `PathUri`.
- Render paths relative to each environment's repository root while keeping Git diff headers slash-separated.
## Testing
- Cover POSIX, Windows, UNC, encoded-separator, and opaque URI relative paths.
- Verify an applied patch in a remote Windows working directory emits a portable unified diff.
GitOrigin-RevId: 526f70ae36a40627de5496d375310d12295b69bb
## What changed
- Send the streaming SSE request-body drain test through `HttpClientFactory`.
- Replace the test-support crate's direct `reqwest` dependency with
`codex-http-client`.
- Remove `core_test_support` from the temporary direct-`reqwest` exceptions.
GitOrigin-RevId: 16ea4309d0b575592c2e59991eb6dce18d9467ed
## What changed
- Assign IDs to client-created response items in every session, including streamed items, forked history, compaction results, and non-OpenAI provider requests.
- Preserve server-provided IDs and stable generated IDs across persisted and resumed conversations while continuing to omit unprefixed server IDs from outbound requests.
- Retire `features.item_ids` as a configurable feature. Existing configuration and CLI toggles remain accepted as compatibility no-ops.
## Testing
- Cover default ID assignment, persistence and resume behavior, remote compaction, provider requests, WebSocket requests, and removed-feature compatibility.
GitOrigin-RevId: 7a09e2d07d2606c2ef1e8e2283d36cb555557eae
## Why
`codex-http-client` is the intended owner of direct `reqwest` usage.
## What changed
- Build Codex's default and route-aware clients with `HttpClientBuilder`, and return `HttpClient` directly to API, model discovery, auth, remote control, skills, and extension callers.
- Preserve custom CA, proxy, Cloudflare cookie, sandbox, and request-logging policies while removing `codex-login`'s direct `reqwest` dependency.
- Use shared HTTP types for auth headers, status codes, transport errors, and login-server tests.
## Testing
- Add a Linux integration test verifying that a regular Responses API turn traverses the configured system proxy.
GitOrigin-RevId: 714695fb80762d2083e2f7a6414183e2b3b63854
## Why
A fixed character limit does not account for the different context-window sizes supported by models.
## What changed
- Budget extension-rendered skill metadata at 2% of the resolved model context window, capped at 4,000 tokens.
- Keep the existing 8,000-character fallback when model context metadata is unavailable.
- Include the omission marker in the budget and still emit it when no skill entry fits.
- Apply the same resolved budget to executor and host skill catalogs assembled for a turn.
## Testing
- Cover proportional and capped budgets, multibyte fallback accounting, and omission-marker behavior.
- Verify through the production turn path that larger model context windows include more catalog entries without exceeding the computed budget.
GitOrigin-RevId: 4667293f1594de4dd605b32b9fa4255d26772c0f
## Why
Elevated Windows sandboxes need stable managed-proxy ports while preserving the network policy and environment attribution of each sandboxed process.
## What changed
- Keep shared HTTP and SOCKS5 loopback ingress listeners alive across managed-proxy instances.
- Add a per-route restricting SID to elevated sandbox tokens and dispatch incoming connections to the matching proxy policy after attributing the client process.
- Reject connections without exactly one registered route, remove routes when their proxy handle is dropped, and keep unsandboxed Windows launches off the managed ingress.
- Provision the elevated sandbox with the configured proxy ports and local-binding setting, honoring the selected profile and CLI overrides.
## Testing
- Add Windows unit tests for TCP ownership attribution, route selection, restricting-token propagation, and setup settings.
- Add an end-to-end Windows test covering stable ports, isolated environment policies, HTTP and SOCKS5 routing, and route teardown.
GitOrigin-RevId: 783fac6e0f904dc9bb1955b75d4a5895e8bb9690
## Why
Default read-only protections for project metadata should apply when paths such
as `.git`, `.agents`, and `.codex` exist, without causing sandbox setup to
materialize missing paths as ACL targets.
## What changed
- Add an optional `missing_path_behavior` to filesystem sandbox entries and
mark default project-metadata protections with `skip`.
- Preserve the behavior through permission transforms and exec/MCP protocol
serialization while keeping existing path wire variants stable.
- Ignore skip-missing entries when projecting configuration or Windows sandbox
overrides, while retaining explicit metadata carveouts.
## Testing
- Cover protocol round trips for path and special-path entries.
- Verify default metadata protections and Windows explicit carveout handling.
GitOrigin-RevId: 6df13dadacdd131c44aab9f15a967c81051355c1
## What changed
- Add `shell_environment_policy.filters`, mapping environment-variable patterns to `include` or `exclude`, while continuing to accept the legacy `exclude` and `include_only` arrays.
- Merge filter keys case-insensitively across config layers so higher-precedence entries can override individual patterns. Switching representations replaces the other representation instead of combining them.
- Reject mixed, duplicate, or malformed filter definitions in enabled layers, config writes, and reloads, while retaining the previous session configuration when a reload is invalid.
- Make config-manager reads and writes representation-aware and preserve existing formatting when updating individual policy values.
## Testing
Add coverage for parsing, schema constraints, layered merging, validation and diagnostics, config writes, override metadata, and invalid session reloads.
GitOrigin-RevId: e15464bca53e6e7ef31fcc97537fda60ed5d670a
## What changed
Remove ignored tests for cloud-task composer rendering, delegated approval
forwarding, and unified-exec session pruning, along with their unused imports.
GitOrigin-RevId: 66ae0d3b672f6471a52ba0479bbd8119e12182f1
## Why
Sandbox wrappers replaced the process launch command and did not carry an
`ExecParams.arg0` override through to the inner process.
## What changed
- Route sandboxed Unix launches with a custom `arg0` through a helper mode that
re-execs the requested program with the override.
- Expose the helper executable to the filesystem sandbox and dispatch its mode
from Codex and exec-server test binaries.
## Testing
Add coverage for the prepared sandbox command and an end-to-end remote process
that verifies both the custom `arg0` and filesystem restrictions.
GitOrigin-RevId: c9f8eef3906d184e670184c2eeed250d5895a9ca
## Why
Goal-first and forked threads could create rollouts without recording their
effective thread settings. Resuming those threads after a restart could then
use current configuration instead of the settings selected when the thread was
created.
## What changed
- Persist a `thread_settings_applied` item when a goal first materializes a
rollout, including a follow-up snapshot if settings changed concurrently.
- Append each fork's effective settings after its copied history so they take
precedence over inherited settings during resume.
- Centralize conversion from `ThreadConfigSnapshot` to
`ThreadSettingsSnapshot`.
## Testing
Added coverage that restarts the app server and verifies goal-first and forked
threads retain their respective `approvals_reviewer` settings.
GitOrigin-RevId: 6cb9aaae73bbe9ca432831cff7e826f95ffd6d01
## Why
Patch approval events can take longer than the default test event timeout.
## What changed
Wait up to 15 seconds for a patch approval request or turn completion in the
approval test helper, while preserving the existing event checks and assertions.
GitOrigin-RevId: 73a50538482b5a88ccf0be07f8fad21000e54699
## What changed
- Add model-catalog approval message variants for `never` and `unless_trusted`.
- Select the catalog message that matches the active approval policy, while retaining the existing built-in text when that variant is absent.
- Treat an explicitly empty variant as an instruction to suppress the built-in approval text, consistent with `on_request` messages.
## Testing
- Cover variant selection, fallback and empty-message behavior, catalog deserialization, and the initial permissions message sent to the model.
GitOrigin-RevId: a0f8d41a08645f39b80093be53f200eeee18ca25
## Why
Sandboxed process launch through the exec server was unsupported on Windows.
## What changed
- Add a shared native process launcher that selects the Windows sandbox session backend when required and otherwise launches PTY or pipe-based processes.
- Pass Windows permission, workspace-root, proxy, filesystem-override, and desktop settings through exec-server process preparation.
- Preserve piped stdin and inherited file descriptors across the shared launch path.
## Testing
- Verify that a remote Windows sandbox process accepts stdin while blocking a write under a read-only policy.
- Enable workspace-root sandbox tests on native Windows while continuing to skip environments that cannot emulate Windows sandbox semantics.
GitOrigin-RevId: 6719ccbe87ad0d5a57af56503e3f23f894c60a71
## What changed
- Remove the `spawn_agents_on_csv` and `report_agent_job_result` tools and their agent-job runtime and state models.
- Drop the legacy `agent_jobs` and `agent_job_items` tables during state database migration.
- Keep `features.enable_fanout` and `agents.job_max_runtime_seconds` accepted as no-op compatibility settings while omitting them from the generated configuration schema.
## Testing
- Verify upgrades remove both legacy agent-job tables.
- Verify the removed feature and configuration keys still parse without taking effect.
GitOrigin-RevId: 8cc3337da78c67162229f02f40a747f503542646
## What changed
- Make the MCP connection manager's event sender optional.
- Skip startup notifications when a caller has no session event stream.
- Decline interactive MCP elicitations in that mode while allowing the
underlying operation to continue.
- Update threadless resource reads, status snapshots, and connector discovery
to use the channel-free path.
## Testing
- Extend the app-server MCP resource test to verify that a threadless resource
read declines an elicitation and still returns the resource contents.
GitOrigin-RevId: 65fea152adbc02a78e09a40cae4134b6dccffd34
## What changed
- Change `ReviewDecision::Denied` to carry a rejection string and update the generated protocol schemas.
- Preserve specific rejection reasons through command, patch, network, MCP, delegated, and automatic approval flows so tool results can return them to the model.
- Distinguish invalid approval responses from user declines and truncate oversized rejection messages before adding them to model context.
## Testing
- Add coverage for denial serialization, invalid app-server approval responses, dropped automatic reviews, network rejection propagation, and rejection-message truncation.
GitOrigin-RevId: d48a55643aa03c7ecfa08a8e4b669913eec5464a
## Why
Mid-turn auto-compaction queued `SessionStart` hooks but continued sampling
before running them. This delayed hook-provided context and ignored requests to
stop the continuation.
## What changed
Drain pending session-start hooks immediately after successful mid-turn
auto-compaction. End the turn when a hook requests a stop; otherwise include
its additional context in the next sampling request.
## Testing
Added coverage for repeated compactions in one turn, context delivery without
leaking hooks into the next user turn, and stop requests that block sampling.
GitOrigin-RevId: c57708a792fb47d98d95c38d7d91bcd9f235be84
## What changed
- Add `additionalContextLimit` to command hook configuration for events that can emit `additionalContext`.
- Apply the limit independently to each hook's context before it is sent to the model. Unset values retain the 2,500-token default, while `0` disables spilling for that hook.
- Expose configured limits through app-server hook and requirements responses, and show them in the TUI hooks browser.
## Testing
- Cover JSON and TOML parsing, discovery and hashing, per-hook spilling behavior, app-server responses, and TUI rendering.
GitOrigin-RevId: 55ddc2dbbdf9067dceee3e1968c03617bbf6bcea
## What changed
- Point the default Codex Apps MCP server at `ps/mcp` instead of the legacy Apps endpoint for both `backend-api` and `api/codex` base URLs.
- Use the same server configuration for Codex Apps and the hosted plugin runtime.
- Update MCP integration tests and test-server routing to expect the plugin-service path.
GitOrigin-RevId: 939f20dcff67ba6f79c11b328bfc624b25e3aac2
## Why
Audio attachments could be dropped from tool outputs and reconstructed thread history, while inline base64 payload size could overstate their model context cost.
## What changed
- Preserve remote and local audio attachments in legacy user-message events and thread history.
- Keep audio from function and custom tool outputs when the model supports it and the output fits the truncation budget; otherwise replace it with an omission marker.
- Estimate inline audio cost from its duration, with a serialized-size fallback for malformed or unsupported data URLs, so compaction and truncation use model-visible cost instead of raw base64 size.
- Replace audio in messages and tool outputs with an explanatory placeholder for models without audio input support.
## Testing
Add coverage for history round trips, dynamic tool responses, modality filtering, duration-based context estimates, output-budget truncation, and remote compaction.
GitOrigin-RevId: 5ed4628850a668f8383b7cd73db71b144cc02cd1
## What changed
Remove the fallback that replaced image content in the latest tool output with
`Invalid image` and retried the model request. Invalid-image responses now use
the existing bad-request error path without modifying conversation history.
GitOrigin-RevId: f4ea782f16c5451feb261694caa73b77f24c3e4e
## What changed
- Remove unused APIs and test helpers across the Rust workspace.
- Route Linux sandbox test setup through the shared exec request path.
- Drop dependencies that became unnecessary after the cleanup.
GitOrigin-RevId: 48fd9b2b1575bad7add0819786b4d8ec88d8486f
## Why
zsh prints tied scalar/array exports such as `PATH` and `path` with `-T`
metadata. The snapshot filter rejected that syntax, so commands available only
through the configured `PATH` could not be resolved from a restored snapshot.
## What changed
- Recognize writable tied exports and retain them in zsh shell snapshots.
- Skip readonly exports so restoring a snapshot does not make variables such as
`PATH` immutable.
## Testing
Added macOS coverage for restoring a tied `PATH`, handling entries with spaces,
deduplicating path entries, excluding readonly tied exports, and resolving a
command available only through the restored snapshot.
GitOrigin-RevId: 297cfae3368230c7f6fe5ef84f0a10b35a2c802c
## What changed
- On session startup, remove exact `allow` entries from `rules/default.rules`
for command prefixes that Codex no longer suggests as policy amendments.
- Record the migration in `.sandbox_migration` so it runs only once, preserving
rules created after the migration.
- Skip the migration when user and project exec policy rules are ignored.
- Expand the protected prefix list across shells, interpreters, package runners,
and destructive or privilege-related commands.
## Testing
- Cover selective removal, case-insensitive matching, one-time behavior, and the
startup path with ignored policy rules.
GitOrigin-RevId: a0c60e3f82b9630e621fd034b40462e3ab775102
## What changed
- Add an optional `initialItems` field to `thread/realtime/start` for seeding
realtime V3 session history with `user`, `developer`, and `assistant` text.
- Encode the items in Frameless Bidi session bootstrap payloads for websocket
and WebRTC transports while preserving existing payloads when the list is
omitted or empty.
- Reject non-empty initial items for V1 and V2, more than 128 items, any item
over 8,192 estimated tokens, or a combined total over 8,192 estimated tokens.
## Testing
- Cover protocol serialization, app-server forwarding, websocket and WebRTC
payloads, empty-list compatibility, version checks, and size limits.
GitOrigin-RevId: 09af367f9a07543e3f8d59b7fa5387f932dc5a6a
## What changed
- Add `audio` to the model input modalities exposed by the protocol and generated app-server schemas.
- Preserve audio in prompts for models that advertise audio input, and replace historical audio with an omission marker for models that do not.
## Testing
- Cover prompt normalization with and without audio support.
- Extend the model-switching integration test to verify that switching from a multimodal model to a text-only model strips prior image and audio content.
GitOrigin-RevId: c18e47ad602720216303ff9abb5bca4d508391ee
## What changed
- Model permission instructions as a world-state section keyed by a stable hash of their rendered developer message.
- Re-emit permission context when its model-visible contents change or the retained fragment is missing, while avoiding duplicates when matching instructions already exist in history, including bundled developer messages.
- Normalize CRLF line endings when hashing world-state fragments so equivalent content produces the same snapshot.
## Testing
- Add snapshot coverage for unchanged, changed, absent, and unknown permission state.
- Cover bundled retained permissions and restored world-state baselines during rollout reconstruction.
GitOrigin-RevId: 7d8d212460c1690ca617859f66dcd825987f1e23
## Why
Audio variants were available in the user-input protocol but were replaced with unsupported-input placeholders instead of being sent to the model.
## What changed
- Serialize audio data URLs as `input_audio` content and convert local `wav`, `mp3`, `m4a`, `webm`, and `ogg` files to labeled data URLs.
- Validate and canonicalize base64 audio before requests, enforce the 50 MiB input limit, and replace invalid, unsupported, or oversized audio with explanatory text.
- Preserve audio attachments when mapping response items back to user-message events and document the app-server input variants.
## Testing
- Add unit coverage for local-file conversion, data URL validation, size and format errors, event mapping, and attachment extraction.
- Add client tests that verify data URL and local audio payloads sent to the Responses API.
GitOrigin-RevId: f72cd6b6e43ab12757eeb47621b1d670594ac7d9
## What changed
- Add `HistoryPosition` to identify a source thread and an exclusive rollout
prefix by ordinal and JSONL byte offset.
- Add optional `history_base` metadata to `SessionMeta` so a thread can record
an inherited prefix of another paginated rollout.
- Default missing `history_base` metadata to `None` and omit it when unset to
preserve compatibility with existing rollout metadata.
## Testing
- Verify that legacy session metadata without `history_base` deserializes with
no inherited history position.
GitOrigin-RevId: 3b2b07a2dfee793d3b37b0a60529f856f167dbc1
## What changed
- Add `codexResponseHandoffMode` to `thread/realtime/start` for V3 sessions, with `thinking` as the default and `commentary` and `bemTags` routing modes.
- Map BEM `analysis` and `commentary` output to the commentary channel and `final` output to the speakable channel, while preserving the original BEM envelope. Unrecognized output falls back to speakable.
- Mark explicit speech appends as speakable and stop adding the legacy `"Agent Final Message"` prefix to V3 handoffs. V1 and V2 continue to ignore the new setting.
## Testing
- Cover channel selection for every routing mode, streamed BEM header parsing, fallback behavior, explicit speech, and V1 compatibility.
GitOrigin-RevId: 1974578257488f2914b252c9c1990ba38831c96b
## What changed
- Add the `SessionEnd` hook event to hook configuration, protocol schemas, analytics, and the hooks browser.
- Run matching hooks for root threads during shutdown, including app-server archive, delete, idle unload, and graceful shutdown. Flush the transcript first and provide the session ID, transcript path, working directory, and `reason: "other"`.
- Keep teardown bounded: hook output is advisory, the default timeout is one second, configured timeouts are capped at three seconds, and async hooks run synchronously with a warning.
## Testing
- Cover transcript availability, matcher selection, timeout normalization, ignored control output, subagent exclusion, archive/delete ordering, and graceful shutdown of multiple loaded threads.
GitOrigin-RevId: 5d19a658677a137caf836ed5042dcb43f5eb6d1a
## What changed
- Represent whether realtime is active as a persisted world-state section.
- Emit start and end instructions from world-state transitions, including when
reconstructing context after resume.
- Retain existing realtime start fragments and avoid emitting another start when
custom instructions change while realtime remains active.
## Testing
- Add snapshot coverage for absent, unknown, active, and inactive realtime state
transitions.
- Cover realtime start and end updates plus resuming with changed custom start
instructions.
GitOrigin-RevId: ec670b8132b0f1c9317738bfdeb272069927d91d
## What changed
- Add a thread-owned `McpRuntime` that atomically publishes connection-set
replacements and owns shutdown.
- Route `McpResourceClient` snapshots and cache keys through that runtime so
extension clients observe refreshed MCP servers.
- Keep model-step configuration snapshots separate from ownership of live MCP
connections.
## Testing
- Add coverage that captures an extension's session resource client, refreshes
the MCP server configuration, and verifies that the existing client sees the
newly published server.
GitOrigin-RevId: 351b2e25594b8eb6b91e50ff8d06b7d49768ae1c
## What changed
- Model collaboration mode as a world-state section whose persisted snapshot is
the active mode.
- Emit collaboration instructions when the mode changes, while ignoring
instruction text changes within the same mode.
- Restore persisted collaboration instructions when they are missing from
retained history, including after a fork.
## Testing
- Add snapshot coverage for initial, unchanged, changed, and unknown mode state.
- Cover retained-history restoration and same-mode instruction changes.
GitOrigin-RevId: ffd1683499f09acef6516b0bfcb5bcb4d3f28df4
## What changed
- Treat an empty custom `multi_agent_mode_hint_text` as having no instructions to emit.
- Avoid adding an empty multi-agent mode message both on the initial turn and when the configured hint changes after resuming a session.
## Testing
- Update the empty-hint integration test to assert that no mode message is sent.
- Add resume coverage that verifies changing a custom hint to an empty string emits no update.
GitOrigin-RevId: 8033292115936fac2cf22f85141278595804ee61
## What changed
Add a Unix integration test that starts two `exec-server` environments with
separate workspace roots. Verify that each environment can write within its own
workspace while cross-workspace writes are denied.
GitOrigin-RevId: 98f2f58b97c1dcca8e103702b067c65d4eeed0c4
## Why
The shared core test harness does not need to spawn a login shell for every
test, and approval scenarios exercise tool behavior rather than rollout
persistence.
## What changed
- Disable `ShellSnapshot` by default in `test_codex()`; snapshot-specific tests
can continue to opt in explicitly.
- Give each approval scenario a named in-memory thread store so it does not use
durable rollout storage.
GitOrigin-RevId: 787670857aa4f77d5fc442ec1e0bfe6d22314f63
## What changed
- Stream V3 agent message deltas to `delegation.context.append` at 200 ms intervals instead of waiting for each completed message.
- Send commentary without a prefix and label final or phase-less V1/V3 output with `"Agent Final Message":`.
- Bound streamed output while preserving both its beginning and final tail when truncation is required.
- Remove `codexResponseHandoffPrefix` from `thread/realtime/start`; unknown fields from older clients remain ignored.
## Testing
- Cover incremental V3 commentary and final output, Unicode-safe truncation, V1/V3 phase labeling, and legacy request compatibility.
GitOrigin-RevId: 633c18b5eb9a4f5756a264b63b7bfc185b073951
## What changed
- Add `<source>transcript_tail_flush</source>` to realtime delegation payloads
emitted when a session flushes its remaining transcript tail.
- Keep explicit realtime handoff payloads unchanged.
- Render both delegation variants through a shared contextual user fragment.
## Testing
- Update realtime conversation tests to cover tagged transcript-tail flushes and
preserve the existing handoff format and XML escaping behavior.
GitOrigin-RevId: 33f70d16cf45b3af8068565c4cf2b1785be3f1d9