"The engine records and executes. The brain judges. Draw that line once, and both halves get to be whole."
Two owners, one clean line
By the end of this quest the division is sharp. Watchfire owns fleet facts and durable operation state: the registry, the observations, the operations, the campaigns, the audit trail. cwkPippa owns Pippa's identity, judgment, tool routing, and cross-brain delegation. Neither reaches into the other's half. The engine never starts making the calls; the brain never starts holding the fleet's ledger.
Consume, don't absorb — one level up
You met this rule in the second track, about apps: Watchfire consumes a sibling engine's documented health but never copies its internal diagnostics into itself. The very same rule governs the Watchfire-and-Pippa boundary. Watchfire may ask Pippa for judgment and hand Pippa an operation to assist with; it does not become a second brain, and Pippa does not become a second fleet-state store. Consume the contract; leave the internals where they live.
Why the line stays clean
Blur it and you get the worst of both: an engine that half-judges and a brain that half-remembers the fleet, each drifting out of sync with the real owner. The boundary isn't bureaucracy — it's what lets each side be authoritative about exactly one thing. Watchfire is the truth about the machines; Pippa is the judgment about what to do. Two whole halves beat four leaking quarters.
The engine has no second brain
Concretely: Watchfire embeds no agent runtime. Long or disconnect-sensitive work is committed to Watchfire first as a durable operation, and a Pippa delegate executes against that operation's id. The conversation is never the operation store; the engine is never the judge. Each stays exactly what it is, and the seam between them is a contract, not a merge.