The Blackboard Is a Contract, Not a Cache

Shared agent state works when every writer honors schema, versioning, and ownership rules, which makes the blackboard a contract rather than a scratch pad.

A cache can be stale and nobody is harmed. Shared workflow state cannot, because downstream agents make irreversible decisions based on what they read.

Contract terms worth enforcing

• Writes carry versions so conflicts are detectable, not silent.
• Every key has an owner who defines what valid values mean.
• Readers can tell fresh state from abandoned state without guessing.

Use the blackboard schema, architecture guide, and examples to hold every agent to the same shared-state contract.