jif
4ec3b8eeea
## Stack - Base: #27184 - This PR is the second vertical and should be reviewed against `jif/external-plugins-1`, not `main`. ## Why CCA is moving toward a split runtime where the orchestrator may have no filesystem or executor, but it still needs to activate remotely hosted plugin components. HTTP MCP servers are the simplest complete example: they need configuration and host authentication, but they do not need an executor process. The Apps MCP endpoint is currently synthesized by a special-purpose loader inside the MCP runtime. That works locally, but it leaves hosted MCP activation outside the extension model being established in #27184. It also makes the Apps path a poor foundation for plugins whose skills, MCP servers, connectors, and hooks may come from different sources or execute in different places. This PR moves that one behavior behind an extension-owned contribution while preserving the existing local fallback. It deliberately does not introduce a generic plugin activation framework. ## What changed ### MCP extension contribution `codex-extension-api` gains an ordered `McpServerContributor` contract. A contributor returns typed `Set` or `Remove` overlays for MCP server configuration; later contributors win for the names they own. The contract stays at the existing MCP configuration boundary. Extensions do not create a second connection manager or transport abstraction. ### Hosted Apps MCP extension A new `codex-mcp-extension` contributes the reserved `codex_apps` server from the existing Apps feature, ChatGPT base URL, path override, and product SKU configuration. When `apps_mcp_path_override` is enabled for `https://chatgpt.com`, the resulting streamable HTTP endpoint is `https://chatgpt.com/backend-api/ps/mcp`. The existing ChatGPT-auth gate remains authoritative, so this server can run in an orchestrator-only process without being exposed for API-key sessions. ### One resolved runtime view `McpManager` now distinguishes three views: - **configured:** config- and plugin-backed servers before extension overlays; - **runtime:** configured servers plus host-installed extension contributions; - **effective:** runtime servers after auth gating and compatibility built-ins. App-server installs the hosted MCP extension and uses the runtime view for thread startup, refresh, status, threadless resource reads, connector discovery, and MCP OAuth lookup. This keeps `mcpServer/oauth/login` consistent with the servers exposed by the other MCP APIs. The hosted Apps server itself continues to use existing ChatGPT host authentication rather than MCP OAuth. ## Compatibility Hosts that do not install the MCP extension retain the existing Apps MCP synthesis path. This preserves current local-only, CLI, and standalone-host behavior while app-server exercises the extension path. Disabling Apps removes the reserved `codex_apps` entry, and losing ChatGPT auth removes it from the effective runtime view. Executor availability is not consulted for this HTTP transport. ## Follow-ups The next vertical will resolve a manifest-declared stdio MCP server from an executor-selected plugin root and execute it in the environment that owns that root. Later verticals can add backend-owned skills, connector metadata, hooks, durable selection semantics, and incremental local convergence without changing the component-specific runtime boundaries introduced here. ## Verification Focused coverage was added for: - contributing the hosted Apps MCP at `/backend-api/ps/mcp` without an executor; - requiring ChatGPT auth in the effective runtime view; - removing a reserved configured Apps server when the Apps feature is disabled. `cargo check -p codex-app-server -p codex-mcp-extension -p codex-extension-api -p codex-mcp` passed. 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.