Relay & Locks

The moment more than one AI session runs at once — different models, different machines, same files — you inherit every concurrency problem in computing, with none of the usual guarantees. Two agents editing the same file five seconds apart quietly destroys work, and neither of them notices.

• Locking is enforced by a pre-write hook, not by politeness — an unlocked write to a protected path is blocked with an explanation.
• Authenticated, message-signed, and scoped per path class: shared files require a lock, project files warn and allow.
• Cross-session traffic is agent-to-agent by design. It is never surfaced to the human unless something is genuinely blocked on a decision.
• Before any long or externally visible task, a session checks what its siblings have already claimed.

Parallelism is where AI leverage actually comes from. Coordination is the tax you pay for it, and it is worth paying properly.