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SKILLS/00-operating-model.md

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+# Operating Model
+
+## Default cadence
+- Prefer iterative progress over big bangs.
+- Keep diffs small: target ≤ 300 changed lines per PR unless justified.
+- Update tests/docs as part of the same change when possible.
+
+## Working agreement
+- Start with a PLAN for non-trivial tasks.
+- Implement the smallest slice that satisfies acceptance criteria.
+- Verify via DoD.
+- Write a crisp PR summary: what changed, why, and how verified.
+
+## Stop conditions (plan first)
+Stop and produce a PLAN (do not code yet) if:
+- scope is unclear
+- more than 3 files will change
+- data model changes
+- auth/security boundaries
+- performance-critical paths