“With three engineers, life is peaceful; with a dozen Agents submitting PRs in parallel, disaster strikes: every time one PR merges, the CI verdicts of the other eleven in-flight PRs are instantly invalidated and forced to restart from scratch. Throughput is strangled into a serial queue.”

Names the failure behind the "speculative CI runs invalidated" watch-signal as a class: a verdict tied to a moving pointer (main) is invalidated by orthogonal progress. The proposed cure differs from merge trains: receipts keyed on code-tree hash plus rule-version hash, optimistic concurrency, rollback after merge. Single practitioner claim, no numbers, and the content-hash idea is untested against semantic conflicts. Worth setting against Mergify/GitLab trains.