## 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
Multi-environment turns can run against different filesystems, so a single
thread-wide workspace-root list cannot accurately describe every selected
environment.
## What changed
- Add optional `runtimeWorkspaceRoots` to each app-server environment selection.
Omitted roots default to that environment's `cwd`, while an empty list selects
no roots.
- Carry environment-native roots through turn selection, model-visible context,
permission materialization, and tool sandboxing.
- Keep the top-level `runtimeWorkspaceRoots` field as a compatibility input when
constructing default environment selections; explicit selections use their
own roots.
## Testing
- Cover thread and turn API defaults, overrides, empty roots, and schema
round-tripping.
- Verify foreign roots remain model-visible and remote execution applies the
target environment's roots before sandbox selection.
GitOrigin-RevId: c6e7a62883c45c676c153055f46a55ee15a323a4
## Why
We should be running as many integrations tests as possible against the
split cross-OS configuration.
## What
- migrate eligible thread starts and builders to auto env
- keep explicit custom/local-executor cases local with rationale
comments
- keep auto-env coverage where possible and add narrow `TODO(anp)` skips
for fixtures that are not target-native yet
## Why
Generic plugin guidance is currently emitted only with initial context
from host plugin state. An executor-selected plugin can become available
later in the same turn, making its skills and tools usable without ever
telling the model how plugin capabilities should be used.
## What
- project every ready selected plugin package, including skill-only
plugins
- carry plugin availability with the exact MCP runtime projection while
preserving MCP manager reuse when servers and connectors are unchanged
- move generic plugin guidance from the static initial-context path into
persisted World State
- recognize legacy and retained plugin fragments so resume and
compaction do not duplicate guidance
## Testing
- `just test -p codex-mcp-extension`
- `just test -p codex-core plugins_instructions`
- `just test -p codex-core
plugin_availability_change_reuses_the_mcp_manager`
- `just test -p codex-app-server --test all selected_capabilit`
## Why
The selected-capability integration test already covers initial
attachment and cold resume, but it resumes while the selected executor
is still reachable.
That leaves an important World State transition untested: a thread
remembers its selected capability root, resumes while that environment
is unavailable, and later sees the same stable environment return.
## What this tests
This extends the existing end-to-end scenario:
```text
selected executor available
↓
app-server stops and the executor goes away
↓
thread resumes with the executor unavailable
↓
skills, selected MCP tools, and connector attribution are absent
↓
the same environment ID is attached again
↓
skills, MCP tools, and connector attribution return
```
The test also checks that the unavailable snapshot explicitly tells the
model that no selected-environment skills are currently available. After
reattachment, it invokes the selected skill again and verifies that a
new executor-owned MCP process starts.
## Scope
This is test-only. It keeps the existing assumption that an environment
ID refers to stable capability contents. It does not add package-file
invalidation or live transport reconnect behavior.
## Why
This stack crosses World State, executor skills, selected plugin
metadata, MCP processes, connectors, dynamic environments, and resume.
This PR adds two end-to-end scenarios that validate those pieces
together.
Both tests enable `deferred_executor`, so they exercise the real
delayed-environment path.
## Scenario 1: availability across turns and resume
```text
1. Start a thread with one selected plugin root bound to E1.
2. E1 is unavailable.
- executor skill is absent
- selected MCP is absent
- connector has no selected-plugin attribution
3. Start E1 and register the same stable environment ID.
4. Start a new turn.
- the executor skill appears through World State
- its body beats a colliding host skill
- the selected MCP tool is advertised and executes inside E1
- the connector is attributed to the selected plugin
5. Start another turn without changing E1.
- the MCP PID stays the same, proving runtime reuse
6. Restart app-server and resume the thread.
- durable selected-root intent is restored
- skills, MCP, and connector attribution are restored
- a new MCP PID proves ephemeral process state was rebuilt
```
## Scenario 2: availability changes inside one turn
```text
1. Start a turn while E1 is unavailable.
2. The first model sample sees no executor skill, MCP, or selected connector.
3. The turn pauses on request_user_input.
4. Start E1 and register it while that same turn is still active.
5. Continue the turn.
6. The very next model sample sees:
- the executor skill catalog
- the selected MCP tool
- selected-plugin connector attribution
7. The model calls the MCP, and its output proves execution happened inside E1.
```
This second scenario specifically protects the aeon-style behavior:
capability state is captured again for every sampling step, not only at
the next user turn.
## Scope
These are integration tests only. They do not add a combinatorial matrix
for unsupported plugin-file mutation, environment generations, transport
disconnects, or delayed `required = true` executor MCPs.
