Two coding-agent tasks start from commit A. Task X edits authentication. Task Y edits logging. While both run, a human pushes commit B.

If the patches do not identify their base, “apply both” is unsafe. Parallel agent sessions are a consistency problem, not only a speed feature.

Here is a black-box experiment for MonkeyCode SaaS, not a claim about its concurrency implementation.

Define four invariants

Every result is associated with immutable base A.