Files
codex/codex-rs/codex-mcp
Charlie Marsh 8fdf647295 Add per-chat leases for shared MCP connections (#57978)
## What changed

Negotiate the `codex/connection-lease` extension for pooled stdio connections. For servers that advertise it, open a unique lease per chat and attach its host-owned ID to tool calls and resource reads via `codex/connectionLease`, overriding caller-supplied lease metadata.

When a chat releases its lease, write cancellations for pending requests before sending `codex/connection/release`. Preserve open-before-release ordering across startup timeouts, bound unload waits, and remove connections from the pool when lease cleanup fails or times out. Servers without the extension retain existing behavior.

## Testing

Add coverage for cancellation-before-release ordering, late open acknowledgements, and lease drops outside the runtime. Extend app-server sharing tests to verify distinct chat leases, metadata replacement, release on unload, and continued use by another chat.

GitOrigin-RevId: f4c8b606cb98b5697acab1c515e992ff80ec8425
2026-10-29 03:47:52 +00:00
..

Codex MCP runtime

This crate manages Codex's MCP connections, tool calls, and their captured authority.

Sandbox request metadata

An MCP server advertises the experimental codex/sandbox-state capability to receive sandbox metadata on tool calls. The deprecated capability name codex/sandbox-state-meta opts into the same contract during migration.

Codex supplies these entries in the request's _meta object:

Key Value
codex/sandbox-state Opaque policy to pass to codex sandbox --sandbox-state-json.
codex/sandbox-state-meta An identical copy of that policy under the deprecated name.
codex/sandbox-launcher When available, an object with an absolute codexExecutable path to a verified full Codex CLI on the MCP server's host.

Use the launcher path to invoke sandbox --sandbox-state-json with the entire state value serialized as one argument, followed by -- and the command to run. The state contains neither launcher discovery data nor deprecation messages. Preserve unknown policy fields by forwarding the original value rather than deserializing and reconstructing it. The two state names are aliases, not separate policies; new consumers should prefer codex/sandbox-state.

Launcher metadata is currently available only for local stdio servers. An HTTP endpoint, including loopback, or a remote executor does not establish a shared filesystem with the harness. Codex omits the launcher when its path is unknown, not representable as UTF-8, or fails the cached capability probe. Absence does not authorize a PATH search or unsandboxed fallback. Servers that require a launcher must fail closed or require an explicit operator opt-out.

The state and launcher describe the issuing call. Retain both when starting a long-lived subprocess or caching policy-bound results; reject changed authority before reusing them. Tool arguments supplied by the model are not authority. See sandbox_metadata.rs for the wire types and binding.rs for execution-environment selection.