Module session 

Session state for the MCP daemon.

Each connected client (one external CLI process) creates a session via POST /session, receives a { session_id, token } pair, and attaches both headers on every JSON-RPC call. Sessions hold their own cwd and some future-proof scaffolding (allowed-tools filter, created-at stamp). Storage is a tokio::sync::RwLock<HashMap<...>> — Send+Sync, no deps.

Session-wide progress broadcast (M4)

In addition to the per-request SSE stream that /mcp tools/call uses to ship progress events back to the caller, we also publish each event onto a per-session tokio::sync::broadcast channel. Any subscriber holding the session token can tap that stream via GET /session/<id>/events to observe every Construct tool’s progress for that session in real time — which is how the V2 Code tab surfaces “what Construct is doing right now” while an external CLI is mid tools/call.

Broadcast capacity is small (64). Slow consumers simply miss frames (broadcast::Receiver returns Lagged); progress events are advisory, never load-bearing for correctness.

Structs

ProgressEvent

Session-wide progress event published to any subscriber of /session/<id>/events. Mirrors the per-request notifications/progress payload with additional tool + timestamp fields so subscribers can render “Notion — 4/10 at 10:20:33” without having to correlate tokens back to the originating request.

SessionState

SessionStore

Type Aliases

SharedSessionStore