## What changed
- Emit skill invocation analytics when a resource-backed skill is explicitly selected or its main resource is successfully read from the first page.
- Preserve provider-supplied skill IDs and user scope when available, and derive a stable ID from the main resource otherwise.
- Deduplicate repeated implicit reads of the same main resource within a turn.
## Testing
- Extend the orchestrator skill integration test to cover explicit and implicit invocation events, stable fallback IDs, failed reads, and repeated-read deduplication.
GitOrigin-RevId: 7d8453b31b5a2205847e65cda2c46183d6c97b45
## What changed
- Move `SkillLoadOutcome` and its implicit-path indexing into
`codex-skills-extension`.
- Import shared skill types directly from `codex-skills` and keep the skill
prompt size limit with the extension renderer that uses it.
- Remove `codex-core-skills` from the Cargo workspace and dependent crates.
GitOrigin-RevId: 4e9e84909fa2f692bcc94af990bb4671affd776f
## What changed
- Compact executor and orchestrator skill locators under metadata pressure, using provider-specific `e` and `o` aliases alongside host `r` aliases.
- Derive alias roots from executor discovery paths and orchestrator namespaces while preserving host plugin root handling.
- Centralize alias ordering, deduplication, and longest-prefix matching across skill providers.
## Testing
- Cover alias planning, cross-platform executor roots, and host plugin discovery.
GitOrigin-RevId: e7d15bd3891c08ae20170e96c4ad45c76d353707
## What changed
- Use `HostSkillRoot` throughout host root resolution and loading, including plugin roots.
- Remove the duplicate loader, root snapshot, and product-filtering implementation from `core-skills` now that loading is owned by the skills extension.
- Move and expand loader coverage for discovery, namespaces, filesystem routing, root merging, symlinks, and frontmatter parsing.
## Testing
- Added focused unit and integration tests under `ext/skills` and `skills` for the consolidated loader behavior.
GitOrigin-RevId: 214d06d59bf3033ee0f220ea5959ee4feff66782
## Why
Symlinked skills have a canonical `SKILL.md` path that can differ from the path
under the configured skill root. A catalog entry that advertises the discovery
path must still select the canonical skill.
## What changed
- Track each loaded skill's discovery path alongside its canonical identity.
- Render discovery paths in the skill catalog and accept either form for
structured selections and linked skill mentions.
- Preserve enabled-state checks, deduplication, and product filtering when
resolving discovery paths.
## Testing
Added loader, catalog, mention-resolution, and end-to-end turn coverage for
skills discovered through directory symlinks.
GitOrigin-RevId: bae539b766cc3782c7c121a4276c337699cbb509
## Why
Orchestrator skills with `allow_implicit_invocation: false` were still exposed in the model-visible skill catalog.
## What changed
- Hide explicit-only orchestrator skills from the prompt catalog while keeping them available for direct invocation.
- Include orchestrator resource-access metadata with injected instructions so `skills.read` can load referenced resources.
- Track visible and hidden discovery limits separately, and record discovery duration and resource-count metrics.
## Testing
Add an integration test that verifies an explicit-only orchestrator skill stays out of the prompt catalog, can be selected explicitly, and can read a referenced resource.
GitOrigin-RevId: 9cab5a61eb27c96bec9d1346c7dcdbc97376f7dc
## What changed
- Move host skill discovery, snapshot caching, and configuration handling from
`codex-core-skills` to `codex-skills-extension`.
- Rename `SkillsService` and `SkillsLoadInput` to `HostSkillsService` and
`HostSkillsLoadInput` to distinguish the host implementation from other skill
providers.
- Keep shared loading primitives and skill outcome modeling in
`codex-core-skills`.
GitOrigin-RevId: d81a21791d2ef8c066e157e7e538b8cb7ee4c24b
## What changed
- Add extension-owned discovery and namespace resolution for skills loaded directly through an `ExecutorFileSystem`.
- Preserve hidden and symlinked skills, nested plugin namespaces, optional `agents/openai.yaml` metadata, product restrictions, and deterministic ordering.
- Reuse the filesystem walk inventory and bound concurrent skill, metadata, and manifest reads.
- Route direct executor catalog loading through the new extension loader.
## Testing
- Cover namespace lookup, metadata probing, walk reuse, concurrent reads, and parity with the existing environment loader.
GitOrigin-RevId: 4e0b821eb84d03f0dc1c2dee7b2b9a072ee3fd44
## What changed
- Move parsing of pre-discovered executor skill bundles from `core-skills` to
the skills extension.
- Expose shared `SKILL.md` frontmatter parsing from `codex-skills` so direct
and pre-discovered loading use the same validation and repair behavior.
## Testing
- Add parity coverage for direct and pre-discovered executor skill catalogs,
including plugin namespaces, metadata, product policy, and warnings.
- Add a snapshot for the resulting pre-discovered executor catalog.
GitOrigin-RevId: c5f888226fa5600bd8b90f5682400da39a5db5ff
## Why
Host skill path aliases should follow the core skill loader's root discovery
order, independent of how catalog entries are sorted for rendering.
## What changed
- Propagate each host skill root's discovery position into its catalog entries.
- Assign `r0`, `r1`, and subsequent aliases from that position while leaving
entries without an explicit root order last.
## Testing
Added coverage for alias ordering in extension rendering and across consecutive
production turns.
GitOrigin-RevId: 9085a3843c91bf2ce78a378cf5ce4926e9c38eb8
## Why
Executor-backed skill resources must honor the active filesystem permission profile instead of reading outside its allowed roots.
## What changed
- Propagate each environment's filesystem sandbox context into `skills.read` calls.
- Apply turn-scoped permission grants when reading executor skill resources.
- Fail closed when no matching sandbox context exists or a restricted Windows read cannot be sandboxed.
- Preserve the existing resource size limit for both sandboxed and streamed reads.
## Testing
- Cover reads within permitted roots and reads that succeed after a permission grant.
- Verify denied references do not expose their contents and disabled Windows sandboxing is rejected.
GitOrigin-RevId: 5cc679b9385b0621665ff20cf5848863cc6396a4
## What changed
- Carry a plugin's local and remote identities together from plugin loading into
`SkillMetadata`.
- Resolve remote IDs from the installed-plugin snapshot when available, falling
back to persisted install metadata only when no snapshot exists.
- Include plugin identity in skill cache keys so identity changes refresh cached
skill metadata.
## Testing
- Cover snapshot and persisted identity resolution, local marketplace isolation,
cached skill refreshes, and propagation through plugin skill snapshots.
GitOrigin-RevId: aabeeb631a43361fe817358ace7f1ea8ba5db708
## What changed
- Add executor authority support to `skills.list` and `skills.read` for skills from selected capability roots.
- Allow `skills.read` to load package-relative resources referenced by an executor skill while keeping reads within the selected package.
- Paginate skill listings and resource contents with bounded response sizes and stale-cursor validation.
- Resolve executor filesystems per sampling step so skill tools use the active selected capability roots.
## Testing
- Extend the app-server executor skill test to list an executor skill, read its main `SKILL.md`, and read a paginated reference resource.
- Cover visibility filtering, metadata bounds, pagination, invalid cursors, package boundaries, and resource size limits.
GitOrigin-RevId: 1b5de95d5d1b9f79c34d2879d6e67f24401e9c29
## Why
Repeated absolute path prefixes consume the bounded skill catalog and can leave
less room for descriptions or later skills.
## What changed
- Track the discovery root for host skills and render shared roots as `r0`,
`r1`, and similar aliases when doing so improves the bounded catalog.
- Include a skill-roots table and alias-aware usage instructions whenever
compact paths are selected.
- Keep absolute, authority-aware locators when aliases provide no benefit or
the catalog contains non-host skills.
## Testing
Added unit and extension coverage for unpressured catalogs, constrained shared
paths, mixed-source catalogs, and plugin-cache root selection.
GitOrigin-RevId: 4196df2c52be27338796065cb2e6434efcfac6d5
## What changed
- Recognize root `plugin.json` files using the Agent Plugins 1.0 schema and map their portable metadata, `skills/`, and `mcp.json` into Codex plugin manifests.
- Apply Codex-specific apps, hooks, and interface settings from the inline `com.openai` extension, with `.codex-plugin/plugin.json` as a fallback overlay.
- Preserve legacy manifest precedence when a root `plugin.json` is unrelated, and reject unsupported Agent Plugins schema versions.
- Add a direct-child skill discovery mode that excludes nested skills and paths resolving outside the plugin root.
## Testing
- Cover manifest metadata, validation, extension precedence, legacy fallback, and direct-child skill path boundaries.
GitOrigin-RevId: eab24139f13a5cc5cb3ad3fb444d8e904511aca6
## Why
Core-compatible catalog rendering needs to preserve the core renderer's skill
priority, including when metadata budgets omit lower-priority entries.
## What changed
- Carry each host skill's `SkillScope` into its catalog entry.
- Under `CoreCompatible`, order visible skills by system, admin, repo, and user
scope, then by name and prompt resource ID.
- Preserve insertion order under `ExtensionCompatible`.
## Testing
Add coverage for propagating host skill scope and for both rendering policies.
GitOrigin-RevId: 9594a177edb2166abf1b5719c51a46fcee000600
## What changed
- Define and export skill metadata, policy, dependency, interface, and configuration rule types from `codex-skills`.
- Update core, plugin, and extension consumers to use the shared models while retaining compatibility re-exports from `codex-core-skills`.
- Share product-restriction handling between host and environment skill metadata.
## Testing
- Add unit coverage for default and explicit implicit-invocation and product policies.
GitOrigin-RevId: 9093469f8fff8e2d902dc9781235f64709827a87
## Why
Selected capability roots can contribute plugins, MCP servers, connectors, and
skills. Discovering each contribution separately requires repeated access to the
executor filesystem.
## What changed
- Add the `capabilityRoots/discoverV1` exec-server RPC to scan selected roots and
materialize recognized plugin manifests, configuration files, skill
instructions, and skill metadata in one bounded request.
- Add the opt-in `executor_capability_discovery` feature, with a thread-scoped
cache and per-step snapshot shared by MCP and skill discovery.
- Parse MCP, connector, and skill contributions from the materialized snapshot,
including serving cached skill instructions without another filesystem read.
## Testing
- Cover discovery limits, manifest precedence, root-local failures, cache reuse,
plugin contributions, and parity with the existing environment skill loader.
GitOrigin-RevId: f98fd2321cafb58c596db02da1f83c09d8eb375d
## Why
After #28918, selected skill roots are `PathUri`, but the executor skill
provider still converts them to the app-server host's `AbsolutePathBuf`.
A foreign Windows root therefore cannot be discovered by a Unix host,
and the inverse has the same problem.
This PR keeps executor skill discovery and reads on the filesystem that
owns the selected root while reusing the existing skill rules.
## What changed
- Generalize the existing skill traversal to operate on `PathUri`
through `ExecutorFileSystem`, preserving its depth, directory, symlink,
and sibling-metadata concurrency behavior.
- Add a small environment skill loader that reuses the shared discovery,
frontmatter validation, dependency parsing, product policy, and
prompt-visibility rules.
- Keep the environment id and entrypoint `PathUri` in the skill catalog,
then route `skills.read` back through the same environment filesystem.
- Preserve the executor's path convention when deriving catalog handles,
including literal backslashes in POSIX filenames.
- Resolve plugin namespaces from nearby manifests through URI-native
filesystem reads.
- Cover foreign Windows roots, executor-owned reads, namespaces,
metadata, policy, and path identity.
```text
selected root (PathUri)
|
v
shared discovery over ExecutorFileSystem
|
v
environment-bound catalog entry --skills.read--> same ExecutorFileSystem
```
No second filesystem abstraction or duplicate traversal implementation
is introduced.
## Stack
1. #29614 — add lexical `PathUri` containment.
2. #29620 — share URI-native manifest path resolution.
3. #28918 — keep selected plugin roots and resources URI-native.
4. **This PR** — load executor skills without host path conversion.
5. #29628 — resolve executor MCP working directories without host path
conversion.
## Why
Selected capability roots belong to the executor filesystem, not the
app-server host. Converting their path strings into the host's native
`Path` breaks whenever the two machines use different path conventions,
such as a Windows executor behind a Unix app-server.
This PR establishes `PathUri` as the selected-plugin boundary so the
executor remains authoritative for its paths.
## What changed
- Require `selectedCapabilityRoots[].location.path` to be a canonical
`file:` URI and deserialize it directly as `PathUri`; native path
strings are rejected.
- Update the app-server schema, generated TypeScript, examples, and
request coverage for the URI contract.
- Keep selected roots, resolved plugin locations, manifest paths, and
manifest resources as `PathUri`.
- Inspect and read plugin roots and manifests only through the selected
environment's `ExecutorFileSystem`.
- Parse executor manifests with the shared URI-native parser from #29620
instead of projecting them onto the host filesystem.
- Enforce resource containment lexically and preserve the root URI's
POSIX or Windows path convention.
- Cover foreign Windows plugin roots and URI-native manifest resources.
```text
thread/start
selectedCapabilityRoots[].location.path = "file:///C:/plugins/demo"
| PathUri
v
ExecutorFileSystem
|
+--> plugin.json
+--> manifest resources
```
This PR stops at the shared selected-plugin representation. The next two
PRs remove the remaining host-path projections in the skill and MCP
consumers.
## Stack
1. #29614 — add lexical `PathUri` containment.
2. #29620 — share URI-native manifest path resolution.
3. **This PR** — keep selected plugin roots and resources URI-native.
4. #29626 — load executor skills without host path conversion.
5. #29628 — resolve executor MCP working directories without host path
conversion.
## Why
Skill descriptions are used in model-visible lists: the default
available-skills catalog that supports implicit selection, and the
on-demand `skills.list` tool response used to discover orchestrator
skills. A single overlong description should not consume a
disproportionate share of either list.
Enforcing the 1024-character limit while loading or migrating skills is
the wrong boundary: it rejects otherwise-valid skills and discards
metadata that non-model consumers and full skill reads may need. Skill
metadata and `SKILL.md` content should remain intact; the cap belongs at
model-visible list rendering boundaries.
## What changed
- Preserve full `description` and `metadata.short-description` values
when loading skills.
- Preserve full external-agent command descriptions during
`source-command-*` migration instead of skipping commands solely because
their descriptions exceed 1024 characters.
- Preserve full normalized orchestrator descriptions in the underlying
skills catalog.
- Cap each description at 1024 Unicode characters when rendering the
default available-skills context in `codex-core-skills` and
`codex-skills-extension`.
- Apply the same cap when serializing descriptions in the model-visible
`skills.list` response.
- Render truncated descriptions as 1021 original characters plus `...`.
- Leave explicit `$skill` injection, `skills.read`, underlying metadata,
and on-disk `SKILL.md` files unchanged and full-fidelity.
## Implicit skill selection
Codex injects a bounded catalog containing each implicitly allowed
skill's name, description, and source locator, together with
instructions to use a skill when the task clearly matches its
description. The model makes that semantic choice; after selecting a
skill, it reads the full `SKILL.md` from its filesystem or provider
resource. Explicit `$skill` mentions remain a separate path that injects
the full skill instructions. For orchestrator skills, `skills.list`
provides bounded discovery metadata before `skills.read` returns the
full selected resource.
## Test plan
- `just test -p codex-core-skills`
- `just test -p codex-skills-extension`
- `just test -p codex-external-agent-migration`
The focused regressions verify that overlong metadata is preserved at
load and migration boundaries while default available-skills rendering
and `skills.list` output produce the 1021-character prefix plus `...`.
## Summary
- Preserve raw plugin skill-root snapshots in the matching loaded-plugin
cache entry, keyed by the effective plugin root identity including
namespace.
- Pass those snapshots through `SkillsLoadInput` as an optional preload,
so session startup reuses plugin parsing while ordinary skill loads pass
`None`.
- Keep plugin skill loading cohesive: the existing loaders accept the
optional snapshots directly, and uncached or marketplace-detail paths do
not create a cache.
## Why
Plugin discovery already parses plugin skills to determine available
capabilities. Cold session startup then scanned and parsed the same
roots again while building the skills snapshot.
This solves the same duplicate-work problem as #28623 while keeping
ownership narrow: `PluginsManager` creates and owns
`PluginSkillSnapshots` only for its loaded-plugin cache entry;
`SkillsService` consumes an optional clone. Entry replacement or
clearing naturally drops the snapshots, with no separate generation,
capacity policy, or watcher coupling.
## Validation
- `cargo clippy -p codex-core-skills --all-targets -- -D warnings`
- `just test -p codex-core-plugins
skills_service_reuses_skills_parsed_during_plugin_load`
- `just test -p codex-core-skills
namespaces_plugin_skills_using_provided_namespace`
- `just fmt`
## What changed
- retain the parsed plugin manifest namespace on loaded plugins
- carry that namespace through `PluginSkillRoot` and `SkillRoot`
- use the provided namespace when qualifying plugin skill names
- include the namespace in the skills cache key
## Why
Plugin loading has already parsed `plugin.json`, but skill parsing
currently walks every `SKILL.md` ancestor and probes/reads the manifest
again to reconstruct the same namespace. Passing the parsed namespace
removes those repeated filesystem calls, which are particularly costly
on remote filesystems.
Context:
https://openai.slack.com/archives/C0ARA9GF5D4/p1781639496496439?thread_ts=1781202444.891669&cid=C0ARA9GF5D4
## Impact
Plugin skill names remain unchanged. A regression test uses a
deliberately different on-disk manifest name to verify that plugin roots
use the provided parsed namespace.
## Validation
- `just test -p codex-core-skills -p codex-core-plugins -p codex-plugin
-p codex-utils-plugins` (352 passed)
- `just fix -p codex-core-skills -p codex-core-plugins -p codex-plugin
-p codex-utils-plugins`
- `just fmt`
## Why
Host skill discovery was still exposed as a manager even though it is a
process-owned service shared by sessions, the app-server catalog, and
file-watcher invalidation. The skills extension also consumed an ad hoc
loaded-skills wrapper instead of a named immutable snapshot.
## What changed
- replace `SkillsManager` with concrete `SkillsService`
- make the service cache and return immutable `HostSkillsSnapshot`
values
- migrate the skills extension host provider to the snapshot boundary
- migrate app-server catalog, watcher, and invalidation paths to the
service
This keeps the service limited to host discovery, caching, roots, and
invalidation. Catalog rendering and invocation remain extension
responsibilities for the next stacked change.
## Why
`PathUri::from_abs_path` can fail for absolute paths that do not have a
normal `file:` URI representation, forcing filesystem call sites to
handle a conversion error even though the original path can be preserved
losslessly.
## What
Make `from_abs_path` infallible and migrate its callers. Unrepresentable
paths use `file:///%00/bad/path/<base64>`, encoding Unix bytes or
Windows UTF-16LE; `to_abs_path` validates and decodes that fallback. The
leading encoded null reserves a namespace that cannot collide with a
real Unix or Windows path, and fallback URIs remain opaque to lexical
path operations.
## Validation
Added path-URI coverage for Unix null and non-UTF-8 paths, Windows
device/verbatim and non-Unicode paths, serialization, malformed
fallbacks, opaque lexical operations, invalid native payloads, and
literal `/bad/path` collision resistance.
## Why
We're moving exec-server to use PathUri for its internal path
representations.
## What
Move `ExecutorFileSystem` APIs to use `PathUri` instead of
`AbsolutePathBuf`. Future changes will convert higher-level parts of
exec-server.
We're switching to using a static encoding of the host path in
`PathUri`. We may need a type like this again but we can add it when
it's more compelling.
Stacked on #27454.
## Why
PR #27387 makes backend plugin skills discoverable and invocable without
an executor, but resources referenced by those skills still sit behind
the generic MCP resource surface. The model needs a skills-owned API
that preserves the provider authority and package boundary instead of
treating remote resources like local files.
This is stacked on #27387.
## What
- Adds one `skills` namespace with bounded `list` and `read` tools for
remote skill providers.
- Revalidates `authority + package` against the live remote catalog on
every read, then routes the opaque resource ID back through that
provider.
- Allows the backend provider to read canonical child `skill://`
resources while rejecting cross-package, non-canonical, query, fragment,
and traversal-shaped URIs.
- Caps each serialized tool result at 8 KB. Lists are paginated; reads
return an opaque continuation cursor.
- Marks the JSON output as external context so memory generation can
apply its normal suppression policy.
- Deliberately does not add `skills.search`; that waits for a bounded
plugin-service search contract.
## Tool contract
Pseudo-Python matching the wire shape:
```python
from typing import Literal, NotRequired, TypedDict
class RemoteSkillAuthority(TypedDict):
kind: Literal["remote"]
id: str # e.g. "codex_apps"
class RemoteSkill(TypedDict):
authority: RemoteSkillAuthority
package: str # opaque provider-owned package ID
name: str
description: str
main_resource: str # opaque provider-owned SKILL.md ID
class SkillsListParams(TypedDict):
cursor: NotRequired[str]
class SkillsListResult(TypedDict):
skills: list[RemoteSkill]
next_cursor: str | None
warnings: list[str]
truncated: bool
class SkillsReadParams(TypedDict):
authority: RemoteSkillAuthority # copied from skills.list
package: str # copied from skills.list
resource: str # provider-owned child resource ID
cursor: NotRequired[str] # copy next_cursor to continue
class SkillsReadResult(TypedDict):
resource: str
contents: str
next_cursor: str | None
truncated: bool
class Skills:
def list(self, params: SkillsListParams) -> SkillsListResult: ...
def read(self, params: SkillsReadParams) -> SkillsReadResult: ...
```
There is one namespace for all remote skills, not one tool or MCP server
per skill. No resource ID is converted into a filesystem path.
## Backend dependency
`/ps/mcp` must support direct reads of child resources such as
`skill://plugin_demo/deploy/references/deploy.md`. This PR implements
and tests the Codex side of that contract; production child reads remain
dependent on the corresponding plugin-service support. Search remains
out of scope until that service exposes a bounded search/resource API.
## Validation
- Added an app-server integration test covering `skills.list` followed
by `skills.read` with no executor.
- Ran `just fmt`.
- Ran `just bazel-lock-update` and `just bazel-lock-check`.
- Did not run Rust tests or Clippy 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
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.
## Why
The skills extension needs to become the path that exposes local host
skills without losing the behavior already owned by core skill loading.
Host skill discovery is not just `$CODEX_HOME/skills`: it also includes
config layers, bundled-skill settings, plugin roots, runtime extra
roots, and the filesystem for the selected primary environment.
Rather than making the extension reload host skills and risk drifting
from that authoritative load, this PR bridges the already-loaded
per-turn skills outcome into the extension. That lets the extension
advertise host skills and inject explicit `$skill` prompts while
preserving the same roots, disabled/hidden state, rendered paths, and
environment-backed file reads that the legacy path uses.
## What Changed
- Adds `HostLoadedSkills` in `core-skills` to wrap the turn's
`SkillLoadOutcome` and read `SKILL.md` through the filesystem that
loaded that skill.
- Stores `HostLoadedSkills` in turn extension data for normal turns and
review turns, so the skills extension can consume the loaded host
catalog without reloading it.
- Adds `HostSkillProvider` under `ext/skills/src/provider/host.rs`,
mapping host-loaded skill metadata into the skills-extension
catalog/read contract.
- Registers the host provider by default from
`codex_skills_extension::install()`.
- Preserves host skill metadata such as dependencies, disabled state,
hidden-from-prompt policy, and slash-normalized display paths.
- Passes host-loaded skills through `SkillListQuery` and
`SkillReadRequest` so explicit skill invocation reads only resources
from the loaded host catalog.
- Adds integration coverage for a real legacy
`$CODEX_HOME/skills/.../SKILL.md` skill being listed and injected
through the installed extension.
## Testing
- Added `installed_extension_loads_host_skills_from_legacy_roots` in
`ext/skills/tests/skills_extension.rs`.
- `just test -p codex-skills-extension`
rphilizaire-openai