jif
9cd11e9e62
## Stack - Base: #27191 - This PR is the third vertical and should be reviewed against `jif/external-plugins-2`, not `main`. ## Why #27191 moves the host-owned Apps MCP registration behind an extension contributor, but deliberately preserves the existing endpoint-selection feature while that contribution contract lands. App-server can therefore resolve the server through extensions, yet the hosted plugin endpoint is still selected through temporary `apps_mcp_path_override` plumbing. That is not the long-term plugin model. A plugin can bundle skills, connectors, MCP servers, and hooks, and those components do not all need the same source or execution environment. In particular, an authenticated HTTP MCP server can expose plugin capabilities directly from a backend without an executor or an orchestrator filesystem. This PR completes that hosted vertical. App-server's MCP extension now owns the aggregate hosted plugin runtime at `/ps/mcp`. Connector actions continue to arrive as MCP tools, while backend-provided skills arrive as MCP resources and use Codex's existing resource list/read paths. No second backend client, skill filesystem, or generic plugin activation framework is introduced. The backend route remains the hosted implementation. This change replaces Codex's temporary endpoint-selection mechanism, not the service behind the endpoint. ## What changed ### Hosted plugin runtime The MCP extension now contributes `codex_apps` as the hosted plugin runtime rather than as a configurable Apps endpoint: - `https://chatgpt.com` resolves to `https://chatgpt.com/backend-api/ps/mcp`; - a bare custom ChatGPT base resolves to `/api/codex/ps/mcp`; - the existing product-SKU header and ChatGPT authentication behavior are preserved; - executor availability is never consulted for this streamable HTTP transport. The same MCP connection carries both component shapes supported by the hosted endpoint: - connector actions are discovered and invoked as MCP tools; - hosted skills are enumerated and read as MCP resources through the existing `list_mcp_resources` and `read_mcp_resource` paths. This keeps component access in the subsystem that already owns the protocol instead of downloading backend skills into an orchestrator filesystem or inventing a parallel hosted-skill client. ### Explicit runtime ordering `McpManager` now resolves the reserved `codex_apps` entry in three ordered phases: 1. install the legacy Apps fallback for compatibility; 2. apply ordered extension `Set` or `Remove` overlays; 3. apply the final ChatGPT-auth gate without synthesizing the server again. This ordering is important: - an ordinary configured or plugin MCP server cannot claim the auth-bearing `codex_apps` name; - an extension-contributed hosted runtime wins over the fallback; - an extension `Remove` remains authoritative; - a host without the MCP extension retains the legacy Apps endpoint and current local-only behavior. The temporary `legacy_apps_mcp_loader_enabled` coordination flag is no longer needed. ### Remove the path override The `apps_mcp_path_override` feature and its runtime plumbing are removed, including: - the feature registry entry and structured feature config; - `Config` and `McpConfig` fields; - config schema output; - config-lock materialization; - URL override handling in `codex-mcp`. Existing boolean and structured forms still deserialize as ignored compatibility input. They are omitted from new serialized config, and config-lock comparison normalizes the removed input so older locks remain replayable. ### App-server coverage App-server MCP fixtures now serve the hosted route at `/api/codex/ps/mcp`. Existing resource-read and tool/elicitation flows therefore exercise the extension-owned endpoint rather than succeeding through the legacy fallback. The stack also adds the missing `codex_chatgpt::connectors` re-export for the manager-backed connector helper introduced in #27191. ## Compatibility - App-server installs the extension and uses `/ps/mcp` for the hosted runtime. - CLI and other hosts that do not install the extension retain the legacy Apps endpoint. - Apps disabled or non-ChatGPT authentication removes `codex_apps` from the effective runtime view. - Existing local plugins, local skills, executor-selected skills, configured MCP servers, and MCP OAuth behavior are otherwise unchanged. - Backend plugin enablement remains account/workspace state owned by the hosted endpoint; this PR does not add thread-local backend plugin selection. ## Architectural fit The stack now proves two independent runtime shapes: 1. #27184 resolves filesystem-backed skills through the executor that owns a selected root. 2. #27191 and this PR resolve a backend-hosted HTTP MCP through an extension with no executor. Together they preserve the intended separation: - selection identifies a plugin/root when explicit selection is needed; - each component's owning extension resolves its concrete access mechanism; - execution stays with the runtime required by that component; - existing skills, MCP, connector, and hook subsystems remain the downstream consumers. ## Planned follow-ups 1. **Executor stdio MCP:** selecting an executor plugin registers a manifest-declared stdio MCP server and executes it in the environment that owns the plugin. 2. **Optional backend selection:** only if CCA needs thread-local selection distinct from backend account/workspace enablement, add a concrete backend-owned capability location and surface those selected skills through the skills catalog. 3. **Connector metadata and hooks:** activate those plugin components through their existing owning subsystems, with executor hooks remaining environment-bound. 4. **Propagation and persistence:** define explicit resume, fork, subagent, refresh, and environment-removal semantics once selected roots have multiple real consumers. 5. **Local convergence:** migrate legacy local skill, MCP, connector, and hook paths behind their owning extensions one vertical at a time, then remove duplicate core managers and compatibility plumbing after parity. ## Verification Coverage in this change exercises: - extension-owned `/backend-api/ps/mcp` registration without an executor; - preservation of the legacy endpoint in hosts without the extension; - extension `Set` and `Remove` precedence over the legacy fallback; - ChatGPT-auth gating for the reserved server; - hosted MCP resource reads with and without an active thread; - connector tool invocation and MCP elicitation through the hosted route; - ignored boolean and structured forms of the removed path override; - config-lock replay compatibility for the removed feature. `cargo check -p codex-features -p codex-mcp-extension -p codex-app-server` passes. Tests and Clippy were not run locally under the current development instruction; CI provides the full validation pass.
codex-core
This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.
Dependencies
Note that codex-core makes some assumptions about certain helper utilities being available in the environment. Currently, this support matrix is:
macOS
Expects /usr/bin/sandbox-exec to be present.
When using the workspace-write sandbox policy, the Seatbelt profile allows
writes under the configured writable roots while keeping .git (directory or
pointer file), the resolved gitdir: target, and .codex read-only.
Network access and filesystem read/write roots are controlled by
SandboxPolicy. Seatbelt consumes the resolved policy and enforces it.
Seatbelt also keeps the legacy default preferences read access
(user-preference-read) needed for cfprefs-backed macOS behavior.
Linux
Expects the binary containing codex-core to run the equivalent of codex sandbox when arg0 is codex-linux-sandbox. See the codex-arg0 crate for details.
Legacy SandboxPolicy / sandbox_mode configs are still supported on Linux.
They can continue to use the legacy Landlock path when the split filesystem
policy is sandbox-equivalent to the legacy model after cwd resolution.
Split filesystem policies that need direct FileSystemSandboxPolicy
enforcement, such as read-only or denied carveouts under a broader writable
root, automatically route through bubblewrap. The legacy Landlock path is used
only when the split filesystem policy round-trips through the legacy
SandboxPolicy model without changing semantics. That includes overlapping
cases like /repo = write, /repo/a = none, /repo/a/b = write, where the
more specific writable child must reopen under a denied parent.
The Linux sandbox helper prefers the first bwrap found on PATH outside the
current working directory whenever it is available. If bwrap is present but
too old to support --argv0, the helper keeps using system bubblewrap and
switches to a no---argv0 compatibility path for the inner re-exec. If
bwrap is missing, it falls back to the bundled codex-resources/bwrap
binary shipped with Codex and Codex surfaces a startup warning through its
normal notification path instead of printing directly from the sandbox helper.
Codex also surfaces a startup warning when bubblewrap cannot create user
namespaces. WSL2 uses the normal Linux bubblewrap path. WSL1 is not supported
for bubblewrap sandboxing because it cannot create the required user
namespaces, so Codex rejects sandboxed shell commands that would enter the
bubblewrap path before invoking bwrap.
Windows
Legacy SandboxPolicy / sandbox_mode configs are still supported on
Windows. Legacy read-only and workspace-write policies imply full
filesystem read access; exact readable roots are represented by split
filesystem policies instead.
The elevated Windows sandbox also supports:
- legacy
ReadOnlyandWorkspaceWritebehavior - split filesystem policies that need exact readable roots, exact writable roots, or extra read-only carveouts under writable roots
- backend-managed system read roots required for basic execution, such as
C:\Windows,C:\Program Files,C:\Program Files (x86), andC:\ProgramData, when a split filesystem policy requests platform defaults
The unelevated restricted-token backend still supports the legacy full-read
Windows model for legacy ReadOnly and WorkspaceWrite behavior. It also
supports a narrow split-filesystem subset: full-read split policies whose
writable roots still match the legacy WorkspaceWrite root set, but add extra
read-only carveouts under those writable roots.
New [permissions] / split filesystem policies remain supported on Windows
only when they can be enforced directly by the selected Windows backend or
round-trip through the legacy SandboxPolicy model without changing semantics.
Policies that would require direct explicit unreadable carveouts (none) or
reopened writable descendants under read-only carveouts still fail closed
instead of running with weaker enforcement.
All Platforms
Expects the binary containing codex-core to simulate the virtual
apply_patch CLI when arg1 is --codex-run-as-apply-patch. See the
codex-arg0 crate for details.