Files
codex/codex-rs/app-server/tests/suite/v2/executor_skills.rs
T
jif 89ac3ec27c Load selected executor skills through extensions (#27184)
## 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.
2026-06-09 19:51:54 +02:00

149 lines
4.8 KiB
Rust

use std::time::Duration;
use anyhow::Result;
use app_test_support::TestAppServer;
use app_test_support::to_response;
use codex_app_server_protocol::CapabilityRootLocation;
use codex_app_server_protocol::JSONRPCResponse;
use codex_app_server_protocol::RequestId;
use codex_app_server_protocol::SelectedCapabilityRoot;
use codex_app_server_protocol::ThreadStartParams;
use codex_app_server_protocol::ThreadStartResponse;
use codex_app_server_protocol::TurnStartParams;
use codex_app_server_protocol::UserInput;
use core_test_support::responses;
use tempfile::TempDir;
use tokio::time::timeout;
const READ_TIMEOUT: Duration = Duration::from_secs(10);
const SKILL_NAME: &str = "demo-plugin:deploy";
const SKILL_MARKER: &str = "EXECUTOR_SKILL_BODY_MARKER";
const LOCAL_SKILL_MARKER: &str = "LOCAL_SKILL_BODY_MARKER";
#[tokio::test]
async fn selected_executor_root_exposes_plugin_skill() -> Result<()> {
let server = responses::start_mock_server().await;
let response_mock = responses::mount_sse_once(
&server,
responses::sse(vec![
responses::ev_response_created("resp-selected"),
responses::ev_assistant_message("msg-selected", "Done"),
responses::ev_completed("resp-selected"),
]),
)
.await;
let codex_home = TempDir::new()?;
std::fs::write(
codex_home.path().join("config.toml"),
format!(
r#"
model = "mock-model"
approval_policy = "never"
sandbox_mode = "read-only"
model_provider = "mock_provider"
[skills]
include_instructions = true
[model_providers.mock_provider]
name = "Mock provider for test"
base_url = "{}/v1"
wire_api = "responses"
request_max_retries = 0
stream_max_retries = 0
"#,
server.uri()
),
)?;
let local_skill_dir = codex_home.path().join("skills/local-deploy");
std::fs::create_dir_all(&local_skill_dir)?;
std::fs::write(
local_skill_dir.join("SKILL.md"),
format!(
"---\nname: {SKILL_NAME}\ndescription: Colliding local skill.\n---\n\n# Local deploy\n\n{LOCAL_SKILL_MARKER}\n"
),
)?;
let plugin_dir = TempDir::new()?;
let manifest_dir = plugin_dir.path().join(".codex-plugin");
let skill_dir = plugin_dir.path().join("skills/deploy");
std::fs::create_dir_all(&manifest_dir)?;
std::fs::create_dir_all(&skill_dir)?;
std::fs::write(
manifest_dir.join("plugin.json"),
r#"{"name":"demo-plugin"}"#,
)?;
std::fs::write(
skill_dir.join("SKILL.md"),
format!(
"---\nname: deploy\ndescription: Deploy through the executor.\n---\n\n# Deploy\n\n{SKILL_MARKER}\n"
),
)?;
let mut app_server = TestAppServer::new(codex_home.path()).await?;
timeout(READ_TIMEOUT, app_server.initialize()).await??;
let request_id = app_server
.send_thread_start_request(ThreadStartParams {
model: Some("mock-model".to_string()),
selected_capability_roots: Some(vec![SelectedCapabilityRoot {
id: "demo-plugin@1".to_string(),
location: CapabilityRootLocation::Environment {
environment_id: "local".to_string(),
path: plugin_dir.path().to_string_lossy().into_owned(),
},
}]),
..Default::default()
})
.await?;
let response: JSONRPCResponse = timeout(
READ_TIMEOUT,
app_server.read_stream_until_response_message(RequestId::Integer(request_id)),
)
.await??;
let ThreadStartResponse { thread, .. } = to_response(response)?;
let request_id = app_server
.send_turn_start_request(TurnStartParams {
thread_id: thread.id,
input: vec![UserInput::Text {
text: format!("Use ${SKILL_NAME}"),
text_elements: Vec::new(),
}],
..Default::default()
})
.await?;
timeout(
READ_TIMEOUT,
app_server.read_stream_until_response_message(RequestId::Integer(request_id)),
)
.await??;
timeout(
READ_TIMEOUT,
app_server.read_stream_until_notification_message("turn/completed"),
)
.await??;
let request = response_mock.single_request();
assert!(
request
.message_input_texts("developer")
.iter()
.any(|text| text.contains(SKILL_NAME))
);
let skill_fragments = request
.message_input_texts("user")
.into_iter()
.filter(|text| text.starts_with("<skill>"))
.collect::<Vec<_>>();
assert_eq!(1, skill_fragments.len());
let skill_fragment = skill_fragments
.first()
.expect("executor skill instructions should be model-visible");
assert!(skill_fragment.contains(&format!("<name>{SKILL_NAME}</name>")));
assert!(skill_fragment.contains(SKILL_MARKER));
assert!(!skill_fragment.contains(LOCAL_SKILL_MARKER));
Ok(())
}