## 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
CCA can select a capability root that lives in an executor environment,
but
Codex only had a host-filesystem plugin loader. Before selected executor
plugins can contribute MCP servers, we need a small package boundary
that can
answer:
> Does this selected root contain a plugin, and if so, what does its
manifest
> declare?
The answer must come from the selected environment's filesystem. A
failed
executor lookup must never fall back to the orchestrator filesystem.
## What this changes
This PR introduces:
```rust
PluginProvider::resolve(root)
-> Result<Option<ResolvedPlugin>, Error>
```
`ExecutorPluginProvider` resolves one `SelectedCapabilityRoot` through
its
exact `environment_id`. It checks the recognized manifest locations,
reads the
manifest through that environment's `ExecutorFileSystem`, and returns an
inert
`ResolvedPlugin` containing:
- the opaque selected-root ID;
- the environment-bound plugin root;
- the authority-bound manifest resource;
- parsed metadata and authority-bound component locators.
Descriptor construction rejects manifest or component paths outside the
selected package root, so consumers cannot accidentally lose the package
boundary when they receive a resolved plugin.
If the root has no plugin manifest, resolution returns `None`, allowing
the
caller to treat it as a standalone capability such as a skill.
```text
selected root: repo -> env-1:/workspace/repo
|
| env-1 filesystem only
v
.codex-plugin/plugin.json
|
v
ResolvedPlugin { authority, root, manifest }
```
The existing host loader and the new executor provider now share the
same
manifest parser. Existing `codex-core-plugins::manifest` type paths
remain
available through re-exports, so host behavior and callers are
unchanged.
## Scope
This is intentionally a non-user-visible package-resolution PR. It does
not:
- parse or register plugin MCP server configurations;
- activate skills, connectors, hooks, or MCP servers;
- change app-server wiring;
- introduce host fallback, caching, or lifecycle behavior.
#27670 has merged, and this PR is now based directly on `main`. Together
with
the resolved MCP catalog from #27634, it establishes the inputs needed
for the
executor stdio MCP vertical without changing the existing MCP runtime.
## Follow-up
The next PR will consume `ResolvedPlugin`, read its declared/default MCP
config
through the same executor filesystem, bind supported stdio servers to
that
environment, and feed those registrations into the resolved MCP catalog.
An
app-server E2E will prove that selecting an executor plugin exposes and
invokes
its tool on the owning executor.
Resume/fork semantics, dynamic environment replacement, and non-stdio
placement remain separate lifecycle decisions.
## Validation
- `just fmt`
- `cargo check --tests -p codex-plugin -p codex-core-plugins`
- `just bazel-lock-check`
- `git diff --check`
Test targets were compiled but not executed locally; CI will run the
test and
Clippy suites.
jif