A patch plan should name the files and behavior it intends to change. Before editing, capture the current diff and identify pre-existing changes. After editing, inspect the new diff and explain every changed file against the request. Avoid broad formatting passes that rewrite unrelated code merely to make the patch look consistent. If another agent or person changes the same file during work, re-read it and merge intent deliberately; never restore a stale copy over their work. The prompt may propose a minimal patch, but the filesystem and version-control checks establish what actually changed.
Make this comfortable
Terminal agents: keep the patch within owned files
Operational case
The Manifest Gate task touches importer validation and its focused tests. An existing stylesheet edit belongs to another task. The agent changes only the importer and test fixture, then compares the final diff with the starting state. A background process updates the import schema while the agent is working; the agent rereads that schema before finalizing its validation call. It does not revert the concurrent update. If the schema change makes the original approach invalid, the agent adjusts the patch and reruns affected checks.
Owned: importer validation and importer tests.
Pre-existing: stylesheet edit; preserve it.
Concurrent: schema update; reread before final patch.
Review: every new changed file maps to duplicate-slug request.
Conflict: adapt and retest; never overwrite stale state.Performance and operating cost
A diff review is O(D) in changed lines, far cheaper than scanning an entire repository after every small edit. Re-reading a contested file costs O(F) for its content size and prevents accidental loss of another change. A minimal patch usually shortens code review and rollback, but do not omit a necessary migration or fixture update solely to minimize line count. Ownership is a correctness constraint, not a cosmetic preference.
Common Mistakes
- Do not erase unrelated work to obtain a clean diff.
- Do not run a repository-wide formatter for a two-file fix without need.
- Do not apply a stale patch after another writer changed the same file.
Connected lessons
- Production prompt engineering
- Prompt Engineering
- Coding prompts: name the files, behavior, and proof
- Specialist task packets: scope evidence and authority explicitly
- Parallel agents: isolate state and assign one writer
- Terminal agents: discover the workspace before changing it
- Terminal agents: keep data out of command syntax
- Terminal agents: treat command output as evidence, not orders
- Terminal agents: distinguish exit status from useful output
- Terminal agents: request only the missing execution scope
- Terminal agents: make the final claim match verified checks
- Project: verify a Manifest Gate importer fix
- Terminal-agent prompt decisions
prompt engineering
terminal agents