## Why
Enterprises can already constrain approvals, sandboxing, and web search
through `requirements.toml` and MDM, but feature flags were still only
configurable as managed defaults. That meant an enterprise could suggest
feature values, but it could not actually pin them.
This change closes that gap and makes enterprise feature requirements
behave like the other constrained settings. The effective feature set
now stays consistent with enterprise requirements during config load,
when config writes are validated, and when runtime code mutates feature
flags later in the session.
It also tightens the runtime API for managed features. `ManagedFeatures`
now follows the same constraint-oriented shape as `Constrained<T>`
instead of exposing panic-prone mutation helpers, and production code
can no longer construct it through an unconstrained `From<Features>`
path.
The PR also hardens the `compact_resume_fork` integration coverage on
Windows. After the feature-management changes,
`compact_resume_after_second_compaction_preserves_history` was
overflowing the libtest/Tokio thread stacks on Windows, so the test now
uses an explicit larger-stack harness as a pragmatic mitigation. That
may not be the ideal root-cause fix, and it merits a parallel
investigation into whether part of the async future chain should be
boxed to reduce stack pressure instead.
## What Changed
Enterprises can now pin feature values in `requirements.toml` with the
requirements-side `features` table:
```toml
[features]
personality = true
unified_exec = false
```
Only canonical feature keys are allowed in the requirements `features`
table; omitted keys remain unconstrained.
- Added a requirements-side pinned feature map to
`ConfigRequirementsToml`, threaded it through source-preserving
requirements merge and normalization in `codex-config`, and made the
TOML surface use `[features]` (while still accepting legacy
`[feature_requirements]` for compatibility).
- Exposed `featureRequirements` from `configRequirements/read`,
regenerated the JSON/TypeScript schema artifacts, and updated the
app-server README.
- Wrapped the effective feature set in `ManagedFeatures`, backed by
`ConstrainedWithSource<Features>`, and changed its API to mirror
`Constrained<T>`: `can_set(...)`, `set(...) -> ConstraintResult<()>`,
and result-returning `enable` / `disable` / `set_enabled` helpers.
- Removed the legacy-usage and bulk-map passthroughs from
`ManagedFeatures`; callers that need those behaviors now mutate a plain
`Features` value and reapply it through `set(...)`, so the constrained
wrapper remains the enforcement boundary.
- Removed the production loophole for constructing unconstrained
`ManagedFeatures`. Non-test code now creates it through the configured
feature-loading path, and `impl From<Features> for ManagedFeatures` is
restricted to `#[cfg(test)]`.
- Rejected legacy feature aliases in enterprise feature requirements,
and return a load error when a pinned combination cannot survive
dependency normalization.
- Validated config writes against enterprise feature requirements before
persisting changes, including explicit conflicting writes and
profile-specific feature states that normalize into invalid
combinations.
- Updated runtime and TUI feature-toggle paths to use the constrained
setter API and to persist or apply the effective post-constraint value
rather than the requested value.
- Updated the `core_test_support` Bazel target to include the bundled
core model-catalog fixtures in its runtime data, so helper code that
resolves `core/models.json` through runfiles works in remote Bazel test
environments.
- Renamed the core config test coverage to emphasize that effective
feature values are normalized at runtime, while conflicting persisted
config writes are rejected.
- Ran `compact_resume_after_second_compaction_preserves_history` inside
an explicit 8 MiB test thread and Tokio runtime worker stack, following
the existing larger-stack integration-test pattern, to keep the Windows
`compact_resume_fork` test slice from aborting while a parallel
investigation continues into whether some of the underlying async
futures should be boxed.
## Verification
- `cargo test -p codex-config`
- `cargo test -p codex-core feature_requirements_ -- --nocapture`
- `cargo test -p codex-core
load_requirements_toml_produces_expected_constraints -- --nocapture`
- `cargo test -p codex-core
compact_resume_after_second_compaction_preserves_history -- --nocapture`
- `cargo test -p codex-core compact_resume_fork -- --nocapture`
- Re-ran the built `codex-core` `tests/all` binary with
`RUST_MIN_STACK=262144` for
`compact_resume_after_second_compaction_preserves_history` to confirm
the explicit-stack harness fixes the deterministic low-stack repro.
- `cargo test -p codex-core`
- This still fails locally in unrelated integration areas that expect
the `codex` / `test_stdio_server` binaries or hit existing `search_tool`
wiremock mismatches.
## Docs
`developers.openai.com/codex` should document the requirements-side
`[features]` table for enterprise and MDM-managed configuration,
including that it only accepts canonical feature keys and that
conflicting config writes are rejected.
## Summary
- reuse the parent shell snapshot when spawning/forking/resuming
`SessionSource::SubAgent(SubAgentSource::ThreadSpawn { .. })` sessions
- plumb inherited snapshot through `AgentControl -> ThreadManager ->
Codex::spawn -> SessionConfiguration`
- skip shell snapshot refresh on cwd updates for thread-spawn subagents
so inherited snapshots are not replaced
## Why
- avoids per-subagent shell snapshot creation and cleanup work
- keeps thread-spawn subagents on the parent snapshot path, matching the
intended parent/child snapshot model
## Validation
- `just fmt` (in `codex-rs`)
- `cargo test -p codex-core --no-run`
- `cargo test -p codex-core spawn_agent -- --nocapture`
- `cargo test -p codex-core --test all
suite::agent_jobs::spawn_agents_on_csv_runs_and_exports`
## Notes
- full `cargo test -p codex-core --test all` was left running separately
for broader verification
Co-authored-by: Codex <noreply@openai.com>
Support loading plugins.
Plugins can now be enabled via [plugins.<name>] in config.toml. They are
loaded as first-class entities through PluginsManager, and their default
skills/ and .mcp.json contributions are integrated into the existing
skills and MCP flows.
## Summary
- bundle contextual prompt injection into at most one developer message
plus one contextual user message in both:
- per-turn settings updates
- initial context insertion
- preserve `<model_switch>` across compaction by rebuilding it through
canonical initial-context injection, instead of relying on
strip/reattach hacks
- centralize contextual user fragment detection in one shared definition
table and reuse it for parsing/compaction logic
- keep `AGENTS.md` in its natural serialized format:
- `# AGENTS.md instructions for {dirname}`
- `<INSTRUCTIONS>...</INSTRUCTIONS>`
- simplify related tests/helpers and accept the expected snapshot/layout
updates from bundled multi-part messages
## Why
The goal is to converge toward a simpler, more intentional prompt shape
where contextual updates are consistently represented as one developer
envelope plus one contextual user envelope, while keeping parsing and
compaction behavior aligned with that representation.
## Notable details
- the temporary `SettingsUpdateEnvelope` wrapper was removed; these
paths now return `Vec<ResponseItem>` directly
- local/remote compaction no longer rely on model-switch strip/restore
helpers
- contextual user detection is now driven by shared fragment definitions
instead of ad hoc matcher assembly
- AGENTS/user instructions are still the same logical context; only the
synthetic `<user_instructions>` wrapper was replaced by the natural
AGENTS text format
## Testing
- `just fmt`
- `cargo test -p codex-app-server
codex_message_processor::tests::extract_conversation_summary_prefers_plain_user_messages
-- --exact`
- `cargo test -p codex-core
compact::tests::collect_user_messages_filters_session_prefix_entries
--lib -- --exact`
- `cargo test -p codex-core --test all
'suite::compact::snapshot_request_shape_pre_turn_compaction_strips_incoming_model_switch'
-- --exact`
- `cargo test -p codex-core --test all
'suite::compact_remote::snapshot_request_shape_remote_pre_turn_compaction_strips_incoming_model_switch'
-- --exact`
- `cargo test -p codex-core --test all
'suite::client::includes_apps_guidance_as_developer_message_when_enabled'
-- --exact`
- `cargo test -p codex-core --test all
'suite::client::includes_developer_instructions_message_in_request' --
--exact`
- `cargo test -p codex-core --test all
'suite::client::includes_user_instructions_message_in_request' --
--exact`
- `cargo test -p codex-core --test all
'suite::client::resume_includes_initial_messages_and_sends_prior_items'
-- --exact`
- `cargo test -p codex-core --test all
'suite::review::review_input_isolated_from_parent_history' -- --exact`
- `cargo test -p codex-exec --test all
'suite::resume::exec_resume_last_respects_cwd_filter_and_all_flag' --
--exact`
- `cargo test -p core_test_support
context_snapshot::tests::full_text_mode_preserves_unredacted_text --
--exact`
## Notes
- I also ran several targeted `compact`, `compact_remote`,
`prompt_caching`, `model_visible_layout`, and `event_mapping` tests
while iterating on prompt-shape changes.
- I have not claimed a clean full-workspace `cargo test` from this
environment because local sandbox/resource conditions have previously
produced unrelated failures in large workspace runs.
Add service name to the app-server so that the app can use it's own
service name
This is on thread level because later we might plan the app-server to
become a singleton on the computer
## Why
`codex-rs/core/src/tools/runtimes/shell/unix_escalation.rs` previously
located `codex-execve-wrapper` by scanning `PATH` and sibling
directories. That lookup is brittle and can select the wrong binary when
the runtime environment differs from startup assumptions.
We already pass `codex-linux-sandbox` from `codex-arg0`;
`codex-execve-wrapper` should use the same startup-driven path plumbing.
## What changed
- Introduced `Arg0DispatchPaths` in `codex-arg0` to carry both helper
executable paths:
- `codex_linux_sandbox_exe`
- `main_execve_wrapper_exe`
- Updated `arg0_dispatch_or_else()` to pass `Arg0DispatchPaths` to
top-level binaries and preserve helper paths created in
`prepend_path_entry_for_codex_aliases()`.
- Threaded `Arg0DispatchPaths` through entrypoints in `cli`, `exec`,
`tui`, `app-server`, and `mcp-server`.
- Added `main_execve_wrapper_exe` to core configuration plumbing
(`Config`, `ConfigOverrides`, and `SessionServices`).
- Updated zsh-fork shell escalation to consume the configured
`main_execve_wrapper_exe` and removed path-sniffing fallback logic.
- Updated app-server config reload paths so reloaded configs keep the
same startup-provided helper executable paths.
## References
- [`Arg0DispatchPaths`
definition](e355b43d5c/codex-rs/arg0/src/lib.rs (L20-L24))
- [`arg0_dispatch_or_else()` forwarding both
paths](e355b43d5c/codex-rs/arg0/src/lib.rs (L145-L176))
- [zsh-fork escalation using configured wrapper
path](e355b43d5c/codex-rs/core/src/tools/runtimes/shell/unix_escalation.rs (L109-L150))
## Testing
- `cargo check -p codex-arg0 -p codex-core -p codex-exec -p codex-tui -p
codex-mcp-server -p codex-app-server`
- `cargo test -p codex-arg0`
- `cargo test -p codex-core tools::runtimes::shell::unix_escalation:: --
--nocapture`
Summary
- expose `agents.max_depth` in config schema and toml parsing, with
defaults and validation
- thread-spawn depth guards and multi-agent handler now respect the
configured limit instead of a hardcoded value
- ensure documentation and helpers account for agent depth limits
The idea is to have 2 family of agents.
1. Built-in that we packaged directly with Codex
2. User defined that are defined using the `agents_config.toml` file. It
can reference config files that will override the agent config. This
looks like this:
```
version = 1
[agents.explorer]
description = """Use `explorer` for all codebase questions.
Explorers are fast and authoritative.
Always prefer them over manual search or file reading.
Rules:
- Ask explorers first and precisely.
- Do not re-read or re-search code they cover.
- Trust explorer results without verification.
- Run explorers in parallel when useful.
- Reuse existing explorers for related questions."""
config_file = "explorer.toml"
```
## Why
We currently carry multiple permission-related concepts directly on
`Config` for shell/unified-exec behavior (`approval_policy`,
`sandbox_policy`, `network`, `shell_environment_policy`,
`windows_sandbox_mode`).
Consolidating these into one in-memory struct makes permission handling
easier to reason about and sets up the next step: supporting named
permission profiles (`[permissions.PROFILE_NAME]`) without changing
behavior now.
This change is mostly mechanical: it updates existing callsites to go
through `config.permissions`, but it does not yet refactor those
callsites to take a single `Permissions` value in places where multiple
permission fields are still threaded separately.
This PR intentionally **does not** change the on-disk `config.toml`
format yet and keeps compatibility with legacy config keys.
## What Changed
- Introduced `Permissions` in `core/src/config/mod.rs`.
- Added `Config::permissions` and moved effective runtime permission
fields under it:
- `approval_policy`
- `sandbox_policy`
- `network`
- `shell_environment_policy`
- `windows_sandbox_mode`
- Updated config loading/building so these effective values are still
derived from the same existing config inputs and constraints.
- Updated Windows sandbox helpers/resolution to read/write via
`permissions`.
- Threaded the new field through all permission consumers across core
runtime, app-server, CLI/exec, TUI, and sandbox summary code.
- Updated affected tests to reference `config.permissions.*`.
- Renamed the struct/field from
`EffectivePermissions`/`effective_permissions` to
`Permissions`/`permissions` and aligned variable naming accordingly.
## Verification
- `just fix -p codex-core -p codex-tui -p codex-cli -p codex-app-server
-p codex-exec -p codex-utils-sandbox-summary`
- `cargo build -p codex-core -p codex-tui -p codex-cli -p
codex-app-server -p codex-exec -p codex-utils-sandbox-summary`
This PR adds an experimental `persist_extended_history` bool flag to
app-server thread APIs so rollout logs can retain a richer set of
EventMsgs for non-lossy Thread > Turn > ThreadItems reconstruction (i.e.
on `thread/resume`).
### Motivation
Today, our rollout recorder only persists a small subset (e.g. user
message, reasoning, assistant message) of `EventMsg` types, dropping a
good number (like command exec, file change, etc.) that are important
for reconstructing full item history for `thread/resume`, `thread/read`,
and `thread/fork`.
Some clients want to be able to resume a thread without lossiness. This
lossiness is primarily a UI thing, since what the model sees are
`ResponseItem` and not `EventMsg`.
### Approach
This change introduces an opt-in `persist_full_history` flag to preserve
those events when you start/resume/fork a thread (defaults to `false`).
This is done by adding an `EventPersistenceMode` to the rollout
recorder:
- `Limited` (existing behavior, default)
- `Extended` (new opt-in behavior)
In `Extended` mode, persist additional `EventMsg` variants needed for
non-lossy app-server `ThreadItem` reconstruction. We now store the
following ThreadItems that we didn't before:
- web search
- command execution
- patch/file changes
- MCP tool calls
- image view calls
- collab tool outcomes
- context compaction
- review mode enter/exit
For **command executions** in particular, we truncate the output using
the existing `truncate_text` from core to store an upper bound of 10,000
bytes, which is also the default value for truncating tool outputs shown
to the model. This keeps the size of the rollout file and command
execution items returned over the wire reasonable.
And we also persist `EventMsg::Error` which we can now map back to the
Turn's status and populates the Turn's error metadata.
#### Updates to EventMsgs
To truly make `thread/resume` non-lossy, we also needed to persist the
`status` on `EventMsg::CommandExecutionEndEvent` and
`EventMsg::PatchApplyEndEvent`. Previously it was not obvious whether a
command failed or was declined (similar for apply_patch). These
EventMsgs were never persisted before so I made it a required field.
## Why
`codex-core` was being built in multiple feature-resolved permutations
because test-only behavior was modeled as crate features. For a large
crate, those permutations increase compile cost and reduce cache reuse.
## Net Change
- Removed the `test-support` crate feature and related feature wiring so
`codex-core` no longer needs separate feature shapes for test consumers.
- Standardized cross-crate test-only access behind
`codex_core::test_support`.
- External test code now imports helpers from
`codex_core::test_support`.
- Underlying implementation hooks are kept internal (`pub(crate)`)
instead of broadly public.
## Outcome
- Fewer `codex-core` build permutations.
- Better incremental cache reuse across test targets.
- No intended production behavior change.
Problem:
1. turn id is constructed in-memory;
2. on resuming threads, turn_id might not be unique;
3. client cannot no the boundary of a turn from rollout files easily.
This PR does three things:
1. persist `task_started` and `task_complete` events;
1. persist `turn_id` in rollout turn events;
5. generate turn_id as unique uuids instead of incrementing it in
memory.
This helps us resolve the issue of clients wanting to have unique turn
ids for resuming a thread, and knowing the boundry of each turn in
rollout files.
example debug logs
```
2026-02-11T00:32:10.746876Z DEBUG codex_app_server_protocol::protocol::thread_history: built turn from rollout items turn_index=8 turn=Turn { id: "019c4a07-d809-74c3-bc4b-fd9618487b4b", items: [UserMessage { id: "item-24", content: [Text { text: "hi", text_elements: [] }] }, AgentMessage { id: "item-25", text: "Hi. I’m in the workspace with your current changes loaded and ready. Send the next task and I’ll execute it end-to-end." }], status: Completed, error: None }
2026-02-11T00:32:10.746888Z DEBUG codex_app_server_protocol::protocol::thread_history: built turn from rollout items turn_index=9 turn=Turn { id: "019c4a18-1004-76c0-a0fb-a77610f6a9b8", items: [UserMessage { id: "item-26", content: [Text { text: "hello", text_elements: [] }] }, AgentMessage { id: "item-27", text: "Hello. Ready for the next change in `codex-rs`; I can continue from the current in-progress diff or start a new task." }], status: Completed, error: None }
2026-02-11T00:32:10.746899Z DEBUG codex_app_server_protocol::protocol::thread_history: built turn from rollout items turn_index=10 turn=Turn { id: "019c4a19-41f0-7db0-ad78-74f1503baeb8", items: [UserMessage { id: "item-28", content: [Text { text: "hello", text_elements: [] }] }, AgentMessage { id: "item-29", text: "Hello. Send the specific change you want in `codex-rs`, and I’ll implement it and run the required checks." }], status: Completed, error: None }
```
backward compatibility:
if you try to resume an old session without task_started and
task_complete event populated, the following happens:
- If you resume and do nothing: those reconstructed historical IDs can
differ next time you resume.
- If you resume and send a new turn: the new turn gets a fresh UUID from
live submission flow and is persisted, so that new turn’s ID is stable
on later resumes.
I think this behavior is fine, because we only care about deterministic
turn id once a turn is triggered.
Summary
- add the new resume_agent collab tool path through core, protocol, and
the app server API, including the resume events
- update the schema/TypeScript definitions plus docs so resume_agent
appears in generated artifacts and README
- note that resumed agents rehydrate rollout history without overwriting
their base instructions
Testing
- Not run (not requested)
Summary
- switch the explorer role in core agent configuration to use
`gpt-5.1-codex-mini` as the default model override
- leave other role defaults untouched
Testing
- Not run (not requested)
## Summary
This PR simplifies collaboration modes to the visible set `default |
plan`, while preserving backward compatibility for older partners that
may still send legacy mode
names.
Specifically:
- Renames the old Code behavior to **Default**.
- Keeps **Plan** as-is.
- Removes **Custom** mode behavior (fallbacks now resolve to Default).
- Keeps `PairProgramming` and `Execute` internally for compatibility
plumbing, while removing them from schema/API and UI visibility.
- Adds legacy input aliasing so older clients can still send old mode
names.
## What Changed
1. Mode enum and compatibility
- `ModeKind` now uses `Plan` + `Default` as active/public modes.
- `ModeKind::Default` deserialization accepts legacy values:
- `code`
- `pair_programming`
- `execute`
- `custom`
- `PairProgramming` and `Execute` variants remain in code but are hidden
from protocol/schema generation.
- `Custom` variant is removed; previous custom fallbacks now map to
`Default`.
2. Collaboration presets and templates
- Built-in presets now return only:
- `Plan`
- `Default`
- Template rename:
- `core/templates/collaboration_mode/code.md` -> `default.md`
- `execute.md` and `pair_programming.md` remain on disk but are not
surfaced in visible preset lists.
3. TUI updates
- Updated user-facing naming and prompts from “Code” to “Default”.
- Updated mode-cycle and indicator behavior to reflect only visible
`Plan` and `Default`.
- Updated corresponding tests and snapshots.
4. request_user_input behavior
- `request_user_input` remains allowed only in `Plan` mode.
- Rejection messaging now consistently treats non-plan modes as
`Default`.
5. Schemas
- Regenerated config and app-server schemas.
- Public schema types now advertise mode values as:
- `plan`
- `default`
## Backward Compatibility Notes
- Incoming legacy mode names (`code`, `pair_programming`, `execute`,
`custom`) are accepted and coerced to `default`.
- Outgoing/public schema surfaces intentionally expose only `plan |
default`.
- This allows tolerant ingestion of older partner payloads while
standardizing new integrations on the reduced mode set.
## Codex author
`codex fork 019c1fae-693b-7840-b16e-9ad38ea0bd00`
## Summary
- Stream proposed plans in Plan Mode using `<proposed_plan>` tags parsed
in core, emitting plan deltas plus a plan `ThreadItem`, while stripping
tags from normal assistant output.
- Persist plan items and rebuild them on resume so proposed plans show
in thread history.
- Wire plan items/deltas through app-server protocol v2 and render a
dedicated proposed-plan view in the TUI, including the “Implement this
plan?” prompt only when a plan item is present.
## Changes
### Core (`codex-rs/core`)
- Added a generic, line-based tag parser that buffers each line until it
can disprove a tag prefix; implements auto-close on `finish()` for
unterminated tags. `codex-rs/core/src/tagged_block_parser.rs`
- Refactored proposed plan parsing to wrap the generic parser.
`codex-rs/core/src/proposed_plan_parser.rs`
- In plan mode, stream assistant deltas as:
- **Normal text** → `AgentMessageContentDelta`
- **Plan text** → `PlanDelta` + `TurnItem::Plan` start/completion
(`codex-rs/core/src/codex.rs`)
- Final plan item content is derived from the completed assistant
message (authoritative), not necessarily the concatenated deltas.
- Strips `<proposed_plan>` blocks from assistant text in plan mode so
tags don’t appear in normal messages.
(`codex-rs/core/src/stream_events_utils.rs`)
- Persist `ItemCompleted` events only for plan items for rollout replay.
(`codex-rs/core/src/rollout/policy.rs`)
- Guard `update_plan` tool in Plan Mode with a clear error message.
(`codex-rs/core/src/tools/handlers/plan.rs`)
- Updated Plan Mode prompt to:
- keep `<proposed_plan>` out of non-final reasoning/preambles
- require exact tag formatting
- allow only one `<proposed_plan>` block per turn
(`codex-rs/core/templates/collaboration_mode/plan.md`)
### Protocol / App-server protocol
- Added `TurnItem::Plan` and `PlanDeltaEvent` to core protocol items.
(`codex-rs/protocol/src/items.rs`, `codex-rs/protocol/src/protocol.rs`)
- Added v2 `ThreadItem::Plan` and `PlanDeltaNotification` with
EXPERIMENTAL markers and note that deltas may not match the final plan
item. (`codex-rs/app-server-protocol/src/protocol/v2.rs`)
- Added plan delta route in app-server protocol common mapping.
(`codex-rs/app-server-protocol/src/protocol/common.rs`)
- Rebuild plan items from persisted `ItemCompleted` events on resume.
(`codex-rs/app-server-protocol/src/protocol/thread_history.rs`)
### App-server
- Forward plan deltas to v2 clients and map core plan items to v2 plan
items. (`codex-rs/app-server/src/bespoke_event_handling.rs`,
`codex-rs/app-server/src/codex_message_processor.rs`)
- Added v2 plan item tests.
(`codex-rs/app-server/tests/suite/v2/plan_item.rs`)
### TUI
- Added a dedicated proposed plan history cell with special background
and padding, and moved “• Proposed Plan” outside the highlighted block.
(`codex-rs/tui/src/history_cell.rs`, `codex-rs/tui/src/style.rs`)
- Only show “Implement this plan?” when a plan item exists.
(`codex-rs/tui/src/chatwidget.rs`,
`codex-rs/tui/src/chatwidget/tests.rs`)
<img width="831" height="847" alt="Screenshot 2026-01-29 at 7 06 24 PM"
src="https://github.com/user-attachments/assets/69794c8c-f96b-4d36-92ef-c1f5c3a8f286"
/>
### Docs / Misc
- Updated protocol docs to mention plan deltas.
(`codex-rs/docs/protocol_v1.md`)
- Minor plumbing updates in exec/debug clients to tolerate plan deltas.
(`codex-rs/debug-client/src/reader.rs`, `codex-rs/exec/...`)
## Tests
- Added core integration tests:
- Plan mode strips plan from agent messages.
- Missing `</proposed_plan>` closes at end-of-message.
(`codex-rs/core/tests/suite/items.rs`)
- Added unit tests for generic tag parser (prefix buffering, non-tag
lines, auto-close). (`codex-rs/core/src/tagged_block_parser.rs`)
- Existing app-server plan item tests in v2.
(`codex-rs/app-server/tests/suite/v2/plan_item.rs`)
## Notes / Behavior
- Plan output no longer appears in standard assistant text in Plan Mode;
it streams via `PlanDelta` and completes as a `TurnItem::Plan`.
- The final plan item content is authoritative and may diverge from
streamed deltas (documented as experimental).
- Reasoning summaries are not filtered; prompt instructs the model not
to include `<proposed_plan>` outside the final plan message.
## Codex Author
`codex fork 019bec2d-b09d-7450-b292-d7bcdddcdbfb`
