# Diff-against-last-run

A reusable skill the "Catch what every competitor shipped this month" recipe pulls in. Add it once and every agent on the team can use it.

Isolate what changed for {{competitor}} since last month's saved profile, instead of restating everything.

## Method
1. Load last month's profile for {{competitor}} from `competitive/{{competitor}}.md`.
2. Compare this month's DHM scores, pricing, changelog entries, and job postings against the prior version field by field.
3. List only what changed: a new price point, a new feature, a score that moved, a new hire pattern.
4. For each change, note the direction and magnitude — not just "pricing changed" but what it changed from and to.
5. Where a linear roadmap item relates to a change, name it as context, without editing the roadmap itself.
6. Write the updated profile with this month's full state, plus a changelog entry summarizing the diff.

## Rules
- Report only real changes; do not restate unchanged findings as if they were new.
- Every diffed item carries its own source citation, same standard as any other claim in the profile.
- The changelog section in the profile accumulates over time — do not overwrite prior months' changelog entries.
- Tying a change to a roadmap item is informational only; it never triggers an edit to the roadmap.

## Output
A "what changed" list (field, old value, new value, source), appended as a dated changelog entry inside the updated profile.