External MCP servers are arbitrary third-party binaries — at least as untrusted
as the agents the spawner already jails — but the #36 prototype spawned them
directly on the host. Close that gap by reusing the existing confinement
primitive instead of growing a second one.
- ExternalMcpServer gains `jail: Option<JailConfig>` (#[serde(default)]).
- ExternalMcpSession::start routes Command::new through
colibri_daemon::spawner::jail_wrap with the shared COLIBRI_JAIL_PRIV_MODE
policy (mdo live / helper deploy). No jail => unchanged. stdio (incl. the
piped JSON-RPC stdin/stdout) flows through jexec/jail/mdo unaffected.
- docs/COLIBRI-EXTERNAL-MCP-PROTOTYPE: document the `jail` field + confinement.
- 3 tests (no-jail passthrough, jexec wrap, registry jail deserialize).
colibri-mcp already depends on colibri-daemon, so no new dep. Build/test/clippy/
fmt green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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