## Why
Multi-agent delegation policy was split across `multiAgentMode`,
`features.multi_agent_mode`, and `usage_hint_enabled`. These controls
could disagree: a requested mode could be downgraded by the feature
flag, and disabling usage hints also disabled mode instructions.
Some clients also need multi-agent tools without adding
delegation-policy text to model context. The previous two-mode API could
not express that directly.
## What changed
`multiAgentMode` is now the only live delegation-policy control:
| Mode | Behavior |
| --- | --- |
| `none` | Keep multi-agent tools available without adding mode
instructions. |
| `explicitRequestOnly` | Only delegate after an explicit user request.
|
| `proactive` | Delegate when parallel work materially improves speed or
quality. |
- new threads default to `explicitRequestOnly`; omitting the mode on
later turns keeps the current value
- thread start, resume, fork, and settings responses always report the
concrete current mode instead of `null`
- mode selection remains sticky across turns and resume
- usage-hint text no longer controls whether mode instructions apply
- `features.multi_agent_mode` and `usage_hint_enabled` remain accepted
as ignored compatibility settings so existing configs continue to load
- app-server documentation and generated schemas describe the three-mode
API
## Tests
- `just test -p codex-core multi_agent_mode`
- `just test -p codex-core multi_agent_v2_config_from_feature_table`
- `just test -p codex-core spawn_agent_description`
- `just test -p codex-features`
- `just test -p codex-app-server-protocol`
- `just test -p codex-app-server multi_agent_mode`
## Why
The token-budget feature reports coarse remaining-context milestones,
but it does not give the model a configurable wrap-up prompt before
automatic compaction. A strict threshold-crossing check can also miss
resumed or reconfigured windows that are already inside the threshold.
## What changed
- Add structured `[features.token_budget]` configuration for an absolute
`reminder_threshold_tokens` and bounded `reminder_message_template`;
`{n_remaining}` is expanded when the reminder is delivered.
- Compute remaining tokens against the next effective auto-compaction
boundary, including scoped `body_after_prefix` accounting and the full
context-window limit.
- Make reminder delivery level-triggered before and after sampling, with
one-shot state owned by `AutoCompactWindow` and re-armed on compaction,
`new_context`, restore, or history replacement.
- Leave the existing initial full-window token-budget context, 25/50/75%
notices, and token-budget tools unchanged.
- Persist the resolved feature configuration in the session config lock
and regenerate the config schema.
## Validation
- `just test -p codex-core token_budget`
- `just test -p codex-core
token_budget_reminder_emits_after_crossing_compaction_threshold`
- `just test -p codex-core auto_compact_window`
- `just test -p codex-core
lock_contains_prompts_and_materializes_features`
- `just test -p codex-features`
- `just test -p codex-config`
## Why
Orchestrator-provided skills and Codex Apps MCP tools add model-visible
instructions, resources, and tools beyond the local workspace. Hosts
need config-level switches to disable those orchestrator-owned surfaces
independently, without disabling regular skills or regular MCP servers.
## What changed
- Adds `[orchestrator.skills].enabled` and `[orchestrator.mcp].enabled`
config entries, both defaulting to `true`.
- Includes the new settings in `config.schema.json` and in the config
lock so resolved thread configuration preserves the same orchestrator
exposure decisions.
- Threads `orchestrator.skills.enabled` through the app-server skills
extension so disabled orchestrator skills do not expose the `skills`
namespace or inject orchestrator skill context.
- Gates Codex Apps MCP exposure, app instructions, and app auth
eligibility on `orchestrator.mcp.enabled` while leaving non-Codex-Apps
MCP tools available.
- Updates the thread-manager sample config to disable both
orchestrator-owned surfaces.
## Verification
- Added config parsing, loading, defaulting, and schema coverage for the
new settings.
- Added MCP exposure coverage that `orchestrator.mcp.enabled = false`
removes Codex Apps tools while preserving regular MCP tools.
- Added app-server coverage that `orchestrator.skills.enabled = false`
prevents orchestrator skill tools, prompts, and resource reads from
reaching the model turn.
## What
This PR defines the structured configuration contract for shared rollout
token budgets (across ALL agent threads under 1 rollout).
```toml
[features.rollout_budget]
enabled = true
limit_tokens = 100000
reminder_interval_tokens = 10000
sampling_token_weight = 1.0
prefill_token_weight = 0.1
```
The reminder interval defaults to 10% of the rollout limit. Sampling and
prefill weights default to `1.0`.
## Scope
This PR only defines and validates configuration. It does not track
usage, inject reminders, or stop a rollout. Accounting and reminders are
implemented in the stacked follow-up #28494.
The existing `token_budget` feature remains unchanged. `rollout_budget`
has its own feature key and configuration type.
## Tests
The config test verifies that the structured fields resolve into
`RolloutBudgetConfig` and do not enable the existing `token_budget`
feature.
Local checks:
- `just write-config-schema`
- `just test -p codex-core load_config_resolves_rollout_budget`
- `cargo check -p codex-thread-manager-sample`
- `git diff --check`
The full workspace test suite was not run locally.
## Stack
- Base: #27191
- This PR is the third vertical and should be reviewed against
`jif/external-plugins-2`, not `main`.
## Why
#27191 moves the host-owned Apps MCP registration behind an extension
contributor, but deliberately preserves the existing endpoint-selection
feature while that contribution contract lands. App-server can therefore
resolve the server through extensions, yet the hosted plugin endpoint is
still selected through temporary `apps_mcp_path_override` plumbing.
That is not the long-term plugin model. A plugin can bundle skills,
connectors, MCP servers, and hooks, and those components do not all need
the same source or execution environment. In particular, an
authenticated HTTP MCP server can expose plugin capabilities directly
from a backend without an executor or an orchestrator filesystem.
This PR completes that hosted vertical. App-server's MCP extension now
owns the aggregate hosted plugin runtime at `/ps/mcp`. Connector actions
continue to arrive as MCP tools, while backend-provided skills arrive as
MCP resources and use Codex's existing resource list/read paths. No
second backend client, skill filesystem, or generic plugin activation
framework is introduced.
The backend route remains the hosted implementation. This change
replaces Codex's temporary endpoint-selection mechanism, not the service
behind the endpoint.
## What changed
### Hosted plugin runtime
The MCP extension now contributes `codex_apps` as the hosted plugin
runtime rather than as a configurable Apps endpoint:
- `https://chatgpt.com` resolves to
`https://chatgpt.com/backend-api/ps/mcp`;
- a bare custom ChatGPT base resolves to `/api/codex/ps/mcp`;
- the existing product-SKU header and ChatGPT authentication behavior
are preserved;
- executor availability is never consulted for this streamable HTTP
transport.
The same MCP connection carries both component shapes supported by the
hosted endpoint:
- connector actions are discovered and invoked as MCP tools;
- hosted skills are enumerated and read as MCP resources through the
existing `list_mcp_resources` and `read_mcp_resource` paths.
This keeps component access in the subsystem that already owns the
protocol instead of downloading backend skills into an orchestrator
filesystem or inventing a parallel hosted-skill client.
### Explicit runtime ordering
`McpManager` now resolves the reserved `codex_apps` entry in three
ordered phases:
1. install the legacy Apps fallback for compatibility;
2. apply ordered extension `Set` or `Remove` overlays;
3. apply the final ChatGPT-auth gate without synthesizing the server
again.
This ordering is important:
- an ordinary configured or plugin MCP server cannot claim the
auth-bearing `codex_apps` name;
- an extension-contributed hosted runtime wins over the fallback;
- an extension `Remove` remains authoritative;
- a host without the MCP extension retains the legacy Apps endpoint and
current local-only behavior.
The temporary `legacy_apps_mcp_loader_enabled` coordination flag is no
longer needed.
### Remove the path override
The `apps_mcp_path_override` feature and its runtime plumbing are
removed, including:
- the feature registry entry and structured feature config;
- `Config` and `McpConfig` fields;
- config schema output;
- config-lock materialization;
- URL override handling in `codex-mcp`.
Existing boolean and structured forms still deserialize as ignored
compatibility input. They are omitted from new serialized config, and
config-lock comparison normalizes the removed input so older locks
remain replayable.
### App-server coverage
App-server MCP fixtures now serve the hosted route at
`/api/codex/ps/mcp`. Existing resource-read and tool/elicitation flows
therefore exercise the extension-owned endpoint rather than succeeding
through the legacy fallback.
The stack also adds the missing `codex_chatgpt::connectors` re-export
for the manager-backed connector helper introduced in #27191.
## Compatibility
- App-server installs the extension and uses `/ps/mcp` for the hosted
runtime.
- CLI and other hosts that do not install the extension retain the
legacy Apps endpoint.
- Apps disabled or non-ChatGPT authentication removes `codex_apps` from
the effective runtime view.
- Existing local plugins, local skills, executor-selected skills,
configured MCP servers, and MCP OAuth behavior are otherwise unchanged.
- Backend plugin enablement remains account/workspace state owned by the
hosted endpoint; this PR does not add thread-local backend plugin
selection.
## Architectural fit
The stack now proves two independent runtime shapes:
1. #27184 resolves filesystem-backed skills through the executor that
owns a selected root.
2. #27191 and this PR resolve a backend-hosted HTTP MCP through an
extension with no executor.
Together they preserve the intended separation:
- selection identifies a plugin/root when explicit selection is needed;
- each component's owning extension resolves its concrete access
mechanism;
- execution stays with the runtime required by that component;
- existing skills, MCP, connector, and hook subsystems remain the
downstream consumers.
## Planned follow-ups
1. **Executor stdio MCP:** selecting an executor plugin registers a
manifest-declared stdio MCP server and executes it in the environment
that owns the plugin.
2. **Optional backend selection:** only if CCA needs thread-local
selection distinct from backend account/workspace enablement, add a
concrete backend-owned capability location and surface those selected
skills through the skills catalog.
3. **Connector metadata and hooks:** activate those plugin components
through their existing owning subsystems, with executor hooks remaining
environment-bound.
4. **Propagation and persistence:** define explicit resume, fork,
subagent, refresh, and environment-removal semantics once selected roots
have multiple real consumers.
5. **Local convergence:** migrate legacy local skill, MCP, connector,
and hook paths behind their owning extensions one vertical at a time,
then remove duplicate core managers and compatibility plumbing after
parity.
## Verification
Coverage in this change exercises:
- extension-owned `/backend-api/ps/mcp` registration without an
executor;
- preservation of the legacy endpoint in hosts without the extension;
- extension `Set` and `Remove` precedence over the legacy fallback;
- ChatGPT-auth gating for the reserved server;
- hosted MCP resource reads with and without an active thread;
- connector tool invocation and MCP elicitation through the hosted
route;
- ignored boolean and structured forms of the removed path override;
- config-lock replay compatibility for the removed feature.
`cargo check -p codex-features -p codex-mcp-extension -p
codex-app-server` passes. Tests and Clippy were not run locally under
the current development instruction; CI provides the full validation
pass.
## Summary
- accept non-empty model-defined reasoning effort values while
preserving built-in effort behavior
- propagate the non-Copy effort type through core, app-server, TUI,
telemetry, and persistence call sites
- preserve string wire encoding and expose an open-string schema for
clients
- update model selection and shortcut behavior for model-advertised
effort values
## Root cause
`ReasoningEffort` gained a string-backed custom variant, so it could no
longer implement `Copy` or rely on derived closed-enum serialization.
Existing consumers still moved effort values from shared references and
assumed a fixed built-in value set.
## Validation
- `just fmt`
- Local tests and compilation were not run per request; relying on CI.
## Why
Research and training setups need to control which tool namespaces
appear inside code mode's nested `tools` surface without disabling those
tools entirely. This makes it possible to train against a deliberately
reduced nested-tool setup while preserving the normal direct and
deferred tool paths.
## What
- Extend `features.code_mode` to accept structured configuration while
preserving the existing boolean syntax.
- Add an exact `excluded_tool_namespaces` list under
`[features.code_mode]`:
```toml
[features.code_mode]
enabled = true
excluded_tool_namespaces = ["mcp__codex_apps", "multi_agent_v1"]
```
- Filter matching canonical `ToolName` namespaces when constructing code
mode's nested router and code-mode-specific direct tool descriptions.
- Keep excluded tools registered, directly exposed in mixed code mode,
and discoverable through top-level `tool_search` when otherwise
eligible.
- Derive deferred nested-tool guidance after namespace filtering so the
`exec` description does not advertise excluded-only deferred tools.
- Preserve the boolean/table representation when materializing config
locks and update the generated config schema.
## Testing
- `just test -p codex-features`
- `just test -p codex-config`
- `just test -p codex-core load_config_resolves_code_mode_config`
- `just test -p codex-core
lock_contains_prompts_and_materializes_features`
- `just test -p codex-core
excluded_deferred_namespaces_do_not_enable_nested_tool_guidance`
- `just test -p codex-core
code_mode_excludes_configured_nested_tool_namespaces`
- `cargo check -p codex-thread-manager-sample`
## Summary
Remove the deprecated `experimental_instructions_file` config setting
from the typed config surface and the remaining deprecation-notice
plumbing. `model_instructions_file` remains the supported setting and
its loading path is unchanged.
The setting was deprecated when it was renamed to
`model_instructions_file` on January 20, 2026 in
https://github.com/openai/codex/pull/9555.
## Changes
- Remove `experimental_instructions_file` from `ConfigToml` and
`ConfigProfile`.
- Delete the custom config-layer scan and session deprecation notice for
the removed setting.
- Stop clearing the removed field from generated session config locks.
- Remove the obsolete deprecation-notice test case while keeping
`model_instructions_file` coverage intact.
## Validation
- `just write-config-schema`
- `just fmt`
- `cargo test -p codex-config`
- `cargo test -p codex-core model_instructions_file`
- `just fix -p codex-core`
- `git diff --check`
Co-authored-by: Codex <noreply@openai.com>
## Summary
Get rid of the `experimental_use_freeform_apply_patch` config option,
since it is now encoded in model config. No deprecation message since it
has been experimental this entire time.
## Testing
- [x] Updated unit tests
---------
Co-authored-by: Codex <noreply@openai.com>
## Why
`multi_agent_v2` already allowed configuring the minimum `wait_agent`
timeout, but the default timeout and upper bound were still hard-coded.
That made it hard to tune waits for subagent mailbox activity in
sessions that need either faster wakeups or longer waits, and it meant
the model-visible `wait_agent` schema could not fully reflect the
resolved runtime limits.
## What Changed
- Added `features.multi_agent_v2.max_wait_timeout_ms` and
`features.multi_agent_v2.default_wait_timeout_ms` alongside the existing
`min_wait_timeout_ms` setting.
- Validated all three timeouts in config as `0..=3_600_000`, with
`min_wait_timeout_ms <= default_wait_timeout_ms <= max_wait_timeout_ms`.
- Thread and review session tool config now passes the resolved
min/default/max values into the `wait_agent` tool schema.
- `wait_agent` now uses the configured default when `timeout_ms` is
omitted and rejects explicit values outside the configured min/max range
instead of silently clamping them.
- Updated the generated config schema and config-lock test coverage for
the new fields.
## Summary
Adds include_collaboration_mode_instructions, which is a config
equivalent to include_permissions_instructions for collaboration modes.
Desired for situations where we want to disable this instruction from
entering the context
## Testing
- [x] Added unit test
## Why
`service_tier` in `config.toml` and profile config was still modeled as
an enum, which blocked newer or experimental service tier IDs even
though the runtime paths already carry string IDs.
This change makes the TOML-facing config accept string service tier IDs
directly while keeping the legacy `fast` alias behavior by normalizing
it to the request value `priority`.
## What Changed
- change the TOML-facing `service_tier` fields in global and profile
config to `Option<String>`
- keep config-load normalization so legacy `fast` still resolves to
`priority`
- persist resolved service tier strings directly in config locks so
arbitrary IDs round-trip cleanly
- regenerate the config schema and add config coverage for arbitrary
string IDs plus legacy `fast` normalization
## Verification
- added config tests for arbitrary string service tiers and legacy
`fast` normalization
- ran `just write-config-schema`
- CI
---------
Co-authored-by: Codex <noreply@openai.com>
## Why
`multi_agent_v2` usage hints sometimes need to reference resolved config
values such as the effective thread limit. Those values only exist after
config layering, defaulting, and feature materialization, so the raw
TOML alone was not enough to render them.
## What changed
- allow
`features.multi_agent_v2.{usage_hint_text,root_agent_usage_hint_text,subagent_usage_hint_text}`
to use `{{ ... }}` placeholders backed by the materialized effective
config
- fail config loading with a targeted error when a referenced
placeholder does not exist or does not resolve to a scalar value
- move resolved-config materialization into a shared helper so config
interpolation and config-lock export/replay both serialize the same
resolved feature, memory, and agent settings
## Example
```
[features.multi_agent_v2]
enabled = true
usage_hint_text = "lorem {{ features.multi_agent_v2.max_concurrent_threads_per_session }} ipsum"
```
gets rendered as
```
"description": String("... \lorem 4 ipsum"),
```
## Why
For reproducibility. A hand-written `config.toml` is not enough to
recreate what a Codex session actually ran with because layered config,
CLI overrides, defaults, feature aliases, resolved feature config,
prompt setup, and model-catalog/session values can all affect the final
runtime behavior.
This PR adds an effective config lockfile path: one run can export the
resolved session config, and a later run can replay that lockfile and
fail early if the regenerated effective config drifts.
## What Changed
- Add a dedicated `ConfigLockfileToml` wrapper with top-level lockfile
metadata plus the replayable config:
```toml
version = 1
codex_version = "..."
[config]
# effective ConfigToml fields
```
- Keep lockfile metadata out of regular `ConfigToml`; replay loads
`ConfigLockfileToml` and then uses its nested `config` as the
authoritative config layer.
- Add `debug.config_lockfile.export_dir` to write
`<thread_id>.config.lock.toml` when a root session starts.
- Add `debug.config_lockfile.load_path` to replay a saved lockfile and
validate the regenerated session lockfile against it.
- Add `debug.config_lockfile.allow_codex_version_mismatch` to optionally
tolerate Codex binary version drift while still comparing the rest of
the lockfile.
- Add `debug.config_lockfile.save_fields_resolved_from_model_catalog` so
lock creation can either save model-catalog/session-resolved fields or
intentionally leave those fields dynamic.
- Build lockfiles from the effective config plus resolved runtime values
such as model selection, reasoning settings, prompts, service tier, web
search mode, feature states/config, memories config, skill instructions,
and agent limits.
- Materialize feature aliases and custom feature config into the
lockfile so replay compares canonical resolved behavior instead of
user-authored alias shape.
- Strip profile/debug/file-include/environment-specific inputs from
generated lockfiles so they contain replayable values rather than the
inputs that produced those values.
- Surface JSON-RPC server error code/data in app-server client and TUI
bootstrap errors so config-lock replay failures include the actual TOML
diff.
- Regenerate the config schema for the new debug config keys.
## Review Notes
The main flow is split across these files:
- `config/src/config_toml.rs`: lockfile/debug TOML shapes.
- `core/src/config/mod.rs`: loading `debug.config_lockfile.*`, replaying
a lockfile as a config layer, and preserving the expected lockfile for
validation.
- `core/src/session/config_lock.rs`: exporting the current session
lockfile and materializing resolved session/config values.
- `core/src/config_lock.rs`: lockfile parsing, metadata/version checks,
replay comparison, and diff formatting.
## Usage
Export a lockfile from a normal session:
```sh
codex -c 'debug.config_lockfile.export_dir="/tmp/codex-locks"'
```
Export a lockfile without saving model-catalog/session-resolved fields:
```sh
codex -c 'debug.config_lockfile.export_dir="/tmp/codex-locks"' \
-c 'debug.config_lockfile.save_fields_resolved_from_model_catalog=false'
```
Replay a saved lockfile in a later session:
```sh
codex -c 'debug.config_lockfile.load_path="/tmp/codex-locks/<thread_id>.config.lock.toml"'
```
If replay resolves to a different effective config, startup fails with a
TOML diff.
To tolerate Codex binary version drift during replay:
```sh
codex -c 'debug.config_lockfile.load_path="/tmp/codex-locks/<thread_id>.config.lock.toml"' \
-c 'debug.config_lockfile.allow_codex_version_mismatch=true'
```
## Limitations
This does not support custom rules/network policies.
## Verification
- `cargo test -p codex-core config_lock`
- `cargo test -p codex-config`
- `cargo test -p codex-thread-manager-sample`
rka-oai