Verifies Bearer tokens from Google Chat using google-auth-library.
Checks issuer (chat@system.gserviceaccount.com) and audience
(CHAT_PROJECT_NUMBER). Verification is skipped when project number
is not configured, allowing local testing without tokens.
Implements a Google Chat HTTP webhook bridge that connects Google Chat
to the A2A server. Each Chat thread maps to an A2A contextId/taskId
pair. The bridge converts A2UI tool approval surfaces to Google Chat
Cards V2 with Approve/Always Allow/Reject buttons, and handles
CARD_CLICKED events to forward tool confirmations back to the A2A server.
Components:
- chat-bridge/types.ts: Google Chat event/response types
- chat-bridge/session-store.ts: Thread -> A2A session mapping
- chat-bridge/a2a-bridge-client.ts: A2A SDK client wrapper
- chat-bridge/response-renderer.ts: A2UI -> Google Chat Cards V2
- chat-bridge/handler.ts: Event handler (MESSAGE, CARD_CLICKED)
- chat-bridge/routes.ts: Express routes mounted at /chat/webhook
Adam Weidman