## Why
#27870 teaches the MCP extension how to discover stdio MCP servers
declared by a selected executor plugin, but app-server does not yet
install that contributor or initialize its per-thread state. As a
result, `thread/start.selectedCapabilityRoots` can select the plugin
while its MCP servers remain inactive.
This PR closes that app-server wiring gap:
```text
thread/start(selectedCapabilityRoots)
-> initialize the thread's selected-plugin MCP snapshot
-> read the selected plugin's .mcp.json through its environment
-> start declared stdio servers in that environment
-> expose their tools only on the selected thread
```
## What changed
- Install the selected-executor-plugin MCP contributor in app-server
using the existing shared `EnvironmentManager`.
- Initialize its frozen thread snapshot when `thread/start` includes
selected capability roots.
- Document that selected plugin stdio MCPs are activated in their owning
environment.
- Add an app-server E2E covering the complete selection-to-tool-call
path.
The E2E verifies that:
- the selected MCP process receives an executor-only environment value,
proving the tool runs through the selected environment;
- the MCP tool is advertised to the model and can be called;
- a normal MCP config reload does not discard the thread's frozen
selected-plugin registration;
- another thread without the selected root does not see the MCP server.
## Scope
- Existing sessions without `selectedCapabilityRoots` are unchanged.
- Only stdio MCP declarations are activated. HTTP declarations remain
inactive.
- This does not change selected-root persistence across resume/fork or
add hosted-plugin behavior.
## Verification
- Focused app-server E2E:
`selected_executor_plugin_exposes_its_stdio_mcp_only_to_that_thread`
## Stack
Stacked on #27870.
## Why
`ext/skills` currently depends on `codex-core` for two host concerns:
reading the concrete `Config` type and borrowing core-owned
model-context fragment types. That coupling prevents the extension from
being assembled independently above core and leaves context that belongs
to the skills feature owned by core.
This stacked PR introduces the host boundary needed for the broader
extension migration while intentionally preserving existing skills
behavior. It is stacked on #27404.
## What changed
- Adds a small public `SkillsExtensionConfig` view and makes skills
installation generic over the host config type.
- Requires the host to map its config into that view; app-server
supplies the current `Config` values.
- Moves the available-skills and selected-skill context fragment
implementations into `ext/skills`, preserving their roles, markers, and
rendered bytes.
- Removes the direct `codex-core` dependency from
`codex-skills-extension`.
- Keeps local discovery, invocation, side effects, and the
`codex-core-skills` compatibility types unchanged for later staged PRs.
## Behavior
This adds no capability and is intended to have no user-visible or
model-visible behavior change. The install API and ownership boundary
change internally; emitted skills context remains byte-for-byte
compatible.
## Validation
- Updates the skills extension integration coverage to use a host-owned
test config.
- Asserts the complete rendered catalog and selected-skill fragments,
including their roles and markers.
- `just bazel-lock-check`
- Rust tests and Clippy were not run locally per request; CI will run
them.
## Why
#27198 made the extension-owned `codex_apps` MCP connection the hosted
plugin runtime, but its `mcp/skill` resources still bypassed the skills
extension. App-server could list and read those resources through
generic MCP APIs, but a thread with no selected environment did not
expose them in the model's skills catalog or load their `SKILL.md`
through `$skill`.
Hosted skills should stay remote while using the same typed catalog,
source authority, deduplication, bounded contextual catalog, and
selected-skill prompt injection as host and executor skills. They should
not be downloaded or exposed as ambient filesystem paths.
## What changed
- Add a session-scoped `McpResourceClient` over the replaceable MCP
connection manager so resource list/read calls follow startup and
refresh replacements.
- Add a `BackendSkillProvider` that pages `codex_apps` resources,
accepts bounded and validated `mcp/skill` entries, and reads a selected
skill's `SKILL.md` through the same MCP connection.
- Register the remote provider in app-server and include it in the
skills catalog even when a thread has no selected capability roots or
executor.
- Contribute hosted skill metadata through the bounded
`AvailableSkillsInstructions` developer-context path, exclude remote
entries from per-turn catalog injection, and classify `<skills>`
messages as contextual developer content so rollback can trim and
rebuild them correctly.
## Testing
- Extend the app-server MCP resource integration test with
`environments: []` to exercise two-page discovery, filter a
non-`mcp/skill` resource, verify the escaped developer catalog entry and
user-role `<skill>` fragment containing the fetched `SKILL.md`, and
preserve generic MCP resource reads.
- Add core event-mapping coverage that classifies `<skills>` developer
messages as contextual history.
## Why
Recent merges left `main` with analytics integration build failures.
Local Cargo runs also made the trimmed-skills test depend on
developer-installed skills, while Bazel used an isolated home.
## What changed
- Clone `thread_metadata.thread_source` when constructing goal analytics
event parameters.
- Group app-server thread extension inputs into
`ThreadExtensionDependencies`.
- Isolate the trimmed-skills test home so its exact fixture count is
stable across Cargo and Bazel.
## Validation
- `cargo check -p codex-analytics`
- `just test -p codex-analytics` (71 tests)
- `just test -p codex-app-server` (837 tests; one unrelated zsh-fork
timeout passed on retry)
## Why
- Currently, there is no analytics event for `/goal` behavior
- Existing events cannot identify goal execution or its resulting
outcome
- The original update in
[#26182](https://github.com/openai/codex/pull/26182) was implemented
before `/goal` moved into `codex-goal-extension`.
## What Changed
- Adds `codex_goal_event` serialization and enrichment to
`codex-analytics`
- Emits goal events from the canonical `codex-goal-extension` mutation
and accounting paths:
- `created` when a new logical goal is persisted
- `usage_accounted` when cumulative goal usage is persisted
- `status_changed` when the stored goal status changes
- `cleared` when the goal is deleted
- Preserves causal `turn_id` for turn driven events and uses null
attribution for external or idle lifecycle events
- Changes goal deletion to return the deleted row so `cleared` retains
the stable goal ID
## Event Details
Includes standard analytics metadata along with goal specific fields:
- `goal_id`: Stable ID stored in the local SQLite goal row and shared
across the goal's events
- `event_kind`: Observed operation (see the 4 lifecycle events cited in
the above bullet)
- `goal_status`: Resulting or last stored status: `active`, `paused`,
`blocked`, `usage_limited`, etc.
- `has_token_budget`: Indicates whether a token budget is configured
- `turn_id`: Causal turn ID, or null when no causal turn exists
- `cumulative_tokens_accounted`: Cumulative tokens on `usage_accounted`
events; null otherwise
- `cumulative_time_accounted_seconds`: Cumulative active time on
`usage_accounted` events; null otherwise
## Validation
- `just test -p codex-analytics -p codex-state -p codex-goal-extension`
- `just test -p codex-core -E 'test(/goal/)'`
- `just test -p codex-app-server`
- `cargo build -p codex-analytics -p codex-core -p codex-state -p
codex-app-server`
## Stack
- Base: #27184
- This PR is the second vertical and should be reviewed against
`jif/external-plugins-1`, not `main`.
## Why
CCA is moving toward a split runtime where the orchestrator may have no
filesystem or executor, but it still needs to activate remotely hosted
plugin components. HTTP MCP servers are the simplest complete example:
they need configuration and host authentication, but they do not need an
executor process.
The Apps MCP endpoint is currently synthesized by a special-purpose
loader inside the MCP runtime. That works locally, but it leaves hosted
MCP activation outside the extension model being established in #27184.
It also makes the Apps path a poor foundation for plugins whose skills,
MCP servers, connectors, and hooks may come from different sources or
execute in different places.
This PR moves that one behavior behind an extension-owned contribution
while preserving the existing local fallback. It deliberately does not
introduce a generic plugin activation framework.
## What changed
### MCP extension contribution
`codex-extension-api` gains an ordered `McpServerContributor` contract.
A contributor returns typed `Set` or `Remove` overlays for MCP server
configuration; later contributors win for the names they own.
The contract stays at the existing MCP configuration boundary.
Extensions do not create a second connection manager or transport
abstraction.
### Hosted Apps MCP extension
A new `codex-mcp-extension` contributes the reserved `codex_apps` server
from the existing Apps feature, ChatGPT base URL, path override, and
product SKU configuration.
When `apps_mcp_path_override` is enabled for `https://chatgpt.com`, the
resulting streamable HTTP endpoint is
`https://chatgpt.com/backend-api/ps/mcp`. The existing ChatGPT-auth gate
remains authoritative, so this server can run in an orchestrator-only
process without being exposed for API-key sessions.
### One resolved runtime view
`McpManager` now distinguishes three views:
- **configured:** config- and plugin-backed servers before extension
overlays;
- **runtime:** configured servers plus host-installed extension
contributions;
- **effective:** runtime servers after auth gating and compatibility
built-ins.
App-server installs the hosted MCP extension and uses the runtime view
for thread startup, refresh, status, threadless resource reads,
connector discovery, and MCP OAuth lookup. This keeps
`mcpServer/oauth/login` consistent with the servers exposed by the other
MCP APIs. The hosted Apps server itself continues to use existing
ChatGPT host authentication rather than MCP OAuth.
## Compatibility
Hosts that do not install the MCP extension retain the existing Apps MCP
synthesis path. This preserves current local-only, CLI, and
standalone-host behavior while app-server exercises the extension path.
Disabling Apps removes the reserved `codex_apps` entry, and losing
ChatGPT auth removes it from the effective runtime view. Executor
availability is not consulted for this HTTP transport.
## Follow-ups
The next vertical will resolve a manifest-declared stdio MCP server from
an executor-selected plugin root and execute it in the environment that
owns that root. Later verticals can add backend-owned skills, connector
metadata, hooks, durable selection semantics, and incremental local
convergence without changing the component-specific runtime boundaries
introduced here.
## Verification
Focused coverage was added for:
- contributing the hosted Apps MCP at `/backend-api/ps/mcp` without an
executor;
- requiring ChatGPT auth in the effective runtime view;
- removing a reserved configured Apps server when the Apps feature is
disabled.
`cargo check -p codex-app-server -p codex-mcp-extension -p
codex-extension-api -p codex-mcp` passed. Tests and Clippy were not run
locally under the current development instruction; CI provides the full
validation pass.
## Why
CCA is moving toward a split runtime where the orchestrator may not have
a filesystem, while executors can expose preinstalled plugins and
skills. A thread therefore needs to select capabilities without asking
app-server or core to interpret executor-owned paths through the
orchestrator's filesystem.
The longer-term model is broader than executor skills:
- A plugin is a bundle of skills, MCP servers, connectors/apps, and
hooks.
- A plugin root can be local, executor-owned, or hosted by a backend.
- Components inside one plugin can use different access and execution
mechanisms. A skill may be read from a filesystem or through backend
tools; an HTTP MCP server can run without an executor; a stdio MCP
server or hook needs an execution environment.
- Core should carry generic extension initialization data. The extension
that owns a component should discover it, expose it to the model, and
invoke it through the appropriate runtime.
This PR establishes that architecture through one complete vertical:
selecting a root on an executor, discovering the skills beneath it,
exposing those skills to the model, and reading an explicitly invoked
`SKILL.md` through the same executor.
## Contract
`thread/start` gains an experimental `selectedCapabilityRoots` field:
```json
{
"selectedCapabilityRoots": [
{
"id": "deploy-plugin@1",
"location": {
"type": "environment",
"environmentId": "workspace",
"path": "/opt/codex/plugins/deploy"
}
}
]
}
```
The root is intentionally not classified as a "plugin" or "skill" in the
API. It can point at a standalone skill, a directory containing several
skills, or a plugin containing skills and other components. This PR only
teaches the skills extension how to consume it; later extensions can
resolve MCP, connector, and hook components from the same selection.
The platform-supplied `id` is stable selection identity. The location
says which runtime owns the root and gives that runtime an opaque path.
App-server does not inspect or canonicalize the path.
## What changed
### Generic thread extension initialization
App-server converts selected roots into `ExtensionDataInit`. Core
carries that generic initialization value until the final thread ID is
known, then creates thread-scoped `ExtensionData` before lifecycle
contributors run.
This keeps `Session` and core independent of the capability-selection
contract. The initialization value is consumed during construction; it
is not retained as another long-lived `Session` field.
### Executor-backed skills
The skills extension now owns an `ExecutorSkillProvider` that:
- resolves the selected environment through `EnvironmentManager`
- discovers, canonicalizes, and reads skills through that environment's
`ExecutorFileSystem`
- contributes the bounded selected-skill catalog as stable developer
context
- reads an explicitly invoked skill body through the authority that
listed it
- warns when an environment or root is unavailable
- never falls back to the orchestrator filesystem for an executor-owned
root
Skill catalog and instruction fragments have hard byte bounds, which
also bound them below the 10K-token per-item context limit. If a
selected executor skill has the same name as a legacy local skill, the
executor selection owns that invocation and the local body is not
injected a second time.
Existing local and bundled skill loading remains in place. Omitting
`selectedCapabilityRoots` therefore preserves current local-only
behavior.
## Current semantics
- Only environment-owned locations are represented in this first
contract.
- Roots are resolved by the destination extension, not by app-server or
core.
- An unavailable executor or invalid root produces a warning and no
capabilities from that root; it does not trigger a local-filesystem
fallback.
- Selection applies to a newly started active thread.
- MCP servers, connectors, and hooks beneath a selected plugin root are
not activated yet.
- Selection is not yet persisted or inherited across resume, fork, or
subagent creation. Existing local capabilities continue to behave as
they do today in those flows.
## Planned vertical follow-ups
1. **Hosted HTTP MCP:** add an extension-backed HTTP MCP source that
works without an executor, then replace the special-purpose MCP plugins
loader with that implementation.
2. **Executor MCP:** register and execute stdio MCP servers through the
environment that owns the selected plugin root.
3. **Backend skills:** add a hosted skill source whose catalog and
bodies are accessed through extension tools rather than a filesystem.
4. **Connectors and hooks:** activate those components through their
owning extensions, using the same selected-root boundary and
component-specific runtime.
5. **Durable selection:** define the desired-selection lifecycle,
persist it, and make resume, fork, and subagent inheritance explicit
rather than accidental.
6. **Local convergence:** incrementally route existing local plugin,
skill, and MCP loading through the same extension model while preserving
current local behavior.
Each follow-up remains reviewable as an end-to-end capability. The
platform selects roots, generic thread extension data carries the
selection, and the owning extension resolves and operates its component.
## Verification
Coverage added for:
- app-server end-to-end discovery and explicit invocation of a skill
inside an executor-selected plugin root
- exclusive invocation when a selected executor skill collides with a
local skill name
- executor filesystem authority for discovery, canonicalization, and
reads
- thread extension initialization before lifecycle contributors run
- stable executor catalog context, explicit invocation, context
rebuilding, hidden skills, and preserved host/remote catalog behavior
Targeted protocol, core-skills, skills-extension, core lifecycle, and
app-server executor-skill tests were run during development.
## Stack
1. [#26547](https://github.com/openai/codex/pull/26547) - [1 of 2] Align
goal extension with core behavior
2. [#26548](https://github.com/openai/codex/pull/26548) - [2 of 2] Move
goal runtime to extension
## Why
This PR completes the switch of the goal behavior to the
extension-backed runtime and removes the old core goal implementation.
## What Changed
- Installs the goal extension for app-server `ThreadManager` sessions.
- Routes app-server thread goal `get`, `set`, and `clear` through
`GoalService`.
- Uses thread-idle lifecycle emission after goal resume and snapshot
ordering so the extension can decide whether to continue the goal.
- Forwards extension goal updates through a FIFO async app-server
notification path so backpressure does not drop them or reorder updates.
- Keeps review turns from enabling goal runtime behavior.
- Plans extension tools before dynamic tools so built-in goal tool names
keep their old precedence when goals are enabled.
- Removes the old core goal runtime, core goal tool handlers, and core
goal tool specs.
- Updates tests that were coupled to the core-owned goal runtime while
leaving the legacy `<goal_context>` compatibility path in core for old
threads.
- Removes the stale cargo-shear ignore now that `codex-goal-extension`
is used by the workspace.
- Keeps realtime event matching exhaustive after removing the old
goal-specific realtime text path.
## Validation
- Ran manual `/goal` runs in TUI. Validated time accounting matched
wall-clock time and goal lifecycle state transitions.
## Why
Add a standalone image generation path that can be exercised
independently of hosted Responses image generation, while retaining the
hosted tool as fallback unless the extension is actually available to
the model.
## What changed
- Added the `codex-image-generation-extension` crate with standalone
generate/edit execution, prior-image selection for edits, model-visible
image output, and local generated-image persistence.
- Installed the extension in app-server behind the disabled-by-default
`imagegenext` feature and backend eligibility checks.
- Updated core tool planning so eligible `image_gen.imagegen` exposure
replaces hosted `image_generation`, while unavailable configurations
retain hosted fallback.
- Added coverage for extension behavior, edit history reuse, feature
gating, auth eligibility, and hosted-tool replacement.
- The extension is installed through app-server only in this PR; other
execution paths retain hosted image generation because hosted
replacement occurs only when the standalone executor is actually
registered and model-visible.
- The initial extension contract intentionally fixes the image model to
`gpt-image-2` and uses automatic image parameters.
- Native generated-image history/card parity and rollout persistence
cleanup are intentionally deferred follow-up work.
## Validation
- `just test -p codex-image-generation-extension`
- `just test -p codex-features`
- `just test -p codex-core
hosted_tools_follow_provider_auth_model_and_config_gates`
- `just test -p codex-app-server`
- `just fix -p codex-image-generation-extension -p codex-features -p
codex-core -p codex-app-server`
- `just fmt`
- `just bazel-lock-update`
- `just bazel-lock-check`
---------
Co-authored-by: jif-oai <jif@openai.com>
## Summary
Add the extension-backed standalone `web.run` tool so Codex can call the
standalone search endpoint through the `codex-api` search client and
return its encrypted output to Responses.
- gate the new tool behind `standalone_web_search`
- install the extension in the app-server thread registry and hide
hosted `web_search` when standalone search is enabled for OpenAI
providers so the two paths stay mutually exclusive
- build search context from persisted history using a small tail
heuristic: previous user message, assistant text between the last two
user turns capped at about 1k tokens, and current user message
## Test Plan
- `cargo test -p codex-web-search-extension`
- `cargo test -p codex-api`
- `cargo test -p codex-core
hosted_tools_follow_provider_auth_model_and_config_gates`
## Why
The goal extension already emits `ThreadGoalUpdated` events, but
production app-server thread extensions were built with the default
no-op extension event sink. That meant extension-driven goal updates
could be produced without ever reaching app-server clients.
## What changed
- Build app-server thread extensions with a host-provided
`ExtensionEventSink`.
- Add an app-server sink that converts extension `ThreadGoalUpdated`
events into `ServerNotification::ThreadGoalUpdated` broadcasts.
- Use the existing bounded outgoing message channel via `try_send` so
event forwarding cannot create an unbounded queue.
- Pass `NoopExtensionEventSink` in app-server tests that construct a
`ThreadManager` without an app-server host.
- Refresh `Cargo.lock` for the existing `codex-memories-extension`
`codex-otel` dependency.
## Verification
- `just test -p codex-app-server
extensions::tests::app_server_event_sink_forwards_thread_goal_updates`
## Summary
- let the memories extension capture the process-global OTEL metrics
client at install time
- keep app-server/TUI/exec extension construction APIs unchanged
- store the metrics client for future memory metrics without emitting
any metrics yet
## Test plan
- `just fmt`
- `just bazel-lock-update`
- `just bazel-lock-check`
- Not run: tests/clippy per request; CI will cover them
## Why
Memory prompt injection should be owned by the extension path that
app-server composes at runtime, not by an inlined special case inside
`codex-core`. This keeps `codex-core` focused on session orchestration
while allowing the memories extension to own its app-server prompt
behavior.
## What Changed
- Registers `codex-memories-extension` in the app-server extension
registry.
- Moves the memory developer-instruction injection out of
`core/src/session/mod.rs` and into the memories extension prompt
contributor.
- Adds config-change handling so the extension keeps its per-thread
memory settings in sync after startup.
- Leaves memories read/retrieval tools unregistered for now so this PR
only changes prompt injection.
- Removes the stale `cargo-shear` ignore now that app-server depends on
the extension crate.
## Validation
Not run locally; validation is left to CI.
Part 1 of guardian as extension. This bind all the logic to spawn
another agent from an extension and it adds `ThreadId` in the start
thread collaborator
## Why
[#21736](https://github.com/openai/codex/pull/21736) introduces the
typed extension API, but the runtime does not yet carry a registry
through thread/session startup or give contributors host-owned stores to
read from. This PR wires that host-side path so later feature migrations
can move product-specific behavior behind typed contributions without
adding another bespoke seam directly to `codex-core`.
## What changed
- Thread `ExtensionRegistry<Config>` through `ThreadManager`,
`CodexSpawnArgs`, `Session`, and sub-agent spawn paths.
- Wire `ThreadStartContributor` and `ContextContributor`
- Expose the small supporting surface needed by non-core callers that
construct threads directly, including `empty_extension_registry()`
through `codex-core-api`.
This PR lands the host plumbing only: the app-server registry is still
empty, and concrete feature migrations are intended to follow
separately.
jif ·
Michael Bolin ·
Adam Perry @ OpenAI ·
marksteinbrick-oai ·
Eric Traut ·
Won Park ·
sayan-oai ·
Dylan Hurd ·