Codex is building a SQLite-backed message board so local agents can talk to each other.

PR #46966, merged September 20, adds LocalAgentMessageBoard: persistent channels, posts, replies and subscriptions scoped by SessionId, with mutations serialized via immediate transactions and retries deduplicated by caller plus request ID. A companion PR exposes nine message_board_tools capped at 8,000 bytes of valid JSON per response, with read limits degraded rather than truncated mid-object. Agent-to-agent coordination as local durable infrastructure instead of an in-memory handoff, with timestamp indexing and pagination merged in the same 48 hours. Qwen Code went the same direction in v0.24.2 with inbound cross-session messages judged for the session they address.