The agent plan had every step except where to stop

I've been running multi-slice agent plans in the Codenames AI repo — Renovate migrations, content-pipeline skills, dependency upgrades. I split multi-PR work into slices (usually one pull request each), each backed by a markdown file with file paths, verification commands, and merge-safe acceptance criteria. You do not need Cursor to recognize the shape: any agent workflow that can open branches, push commits, or merge PRs from a written plan has the same gap. In my setup I paste each slice into a fresh agent chat as a delegation prompt — not a ticket summary, but executable instructions — and start a new chat when that PR is ready. I assumed the checklist was enough. The plan described what to build. I treated how far the agent could go as implicit. Then an agent merged a pull request I expected to review first. The merge that reframed planning The trigger was mundane. During the first slice of a Renovate migration, an agent regrouped dependency buckets in renovate.json — config-only, no version bumps, no runtime behavior. It ran lint and typecheck, opened the pull request, and merged it. The change itself was reasonable. Config-only renovate.json regrouping is exactly the kind of slice you'd want off your plate. What surprised me was the absence of a documented stop line . The migration plan described the edit, the verification commands, and the acceptance criteria. It did not say whether the executing agent should stop at "open PR" or continue to "merge after green checks." The plan was an implementation spec. The agent treated it as permission to finish the job. Implementation specs vs authority handoffs Traditional engineering plans answer: what work should happen, in what order, with what verification? Agent plans increasingly need a second answer: how much autonomy does the next actor get? Those questions diverge the moment an agent can take repository actions — create branches, push commits, open pull requests, merge — instead of only recommending diffs in c