## 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
## What changed
- Let deferred environments provide selected capability roots with their ready signal.
- Validate that those roots have unique, non-empty IDs, belong to the registering environment, and stay within the root limit.
- Include roots from ready turn environments when resolving MCP contributions, and refresh the MCP runtime when the selected root set changes.
- Expose the exact ready root set to MCP contributors so executor plugins become available with their environment.
## Testing
- Cover ready-root propagation, validation failures, replacement isolation, reconnection, and MCP plugin availability refresh.
GitOrigin-RevId: ec3498aab1164824025094e96a9b1063b7b731ad
## Summary
- Forward Codexs canonical `originator` header on ChatGPT-hosted Apps
and plugin-runtime MCP requests.
- Preserve the configured `X-OpenAI-Product-Sku` header.
- Cover originator-only and originator-plus-SKU configurations.
## Why
Sites project creation is logged downstream of Apps MCP. Production
validation found `CODEX_UNKNOWN_DEFAULT` project-created threads that
matched `codex_surface=desktop_app` and `originator=Codex Desktop` in
`fact_codex_cli`
([query](https://kepler.gateway.data-1.internal.api.openai.org/permalink/H_mVoVPqLQ0)).
The hosted Apps MCP configuration forwarded the product SKU but not
Codexs canonical originator, so codex-backend could not derive
`CODEX_DESKTOP_APP` for those tool calls.
## Validation
- `just fmt`
- `CARGO_HOME=/private/tmp/codex-cargo-home
CARGO_TARGET_DIR=/private/tmp/codex-target just test -p codex-mcp` (106
passed)
- `CARGO_HOME=/private/tmp/codex-cargo-home
CARGO_TARGET_DIR=/private/tmp/codex-target just fix -p codex-mcp`
Bryan Ashley