modify-feature

!../principles/SKILL_BODY.md

!../tool-gitnexus/SKILL_BODY.md

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Modify Existing Feature / Module Workflow

Disambiguating modify-feature vs fix-bug

Use this skill when: the code does X correctly — you want it to do Z instead (desired behavior is changing). Use fix-bug when: the code should do X but does Y — you want to restore correct behavior.

Quick test: "Is the current behavior broken, or just not what we want going forward?" → Broken / was never right → stop. Tell the user: "This looks like a bug rather than a behavior change — the fix-bug workflow is a better fit. You can say something like 'this is broken / it used to work' to trigger the right workflow, or tell me to proceed anyway and I'll apply baseline rules only." Do not proceed unless the user explicitly says to proceed. → Worked correctly, requirements evolved → modify-feature (continue here).

Edge case: Performance problems and security gaps feel like bugs but are almost always modify-feature — the code "works," it just doesn't meet a non-functional requirement. Continue with this skill.

Core Principle

Modification requests are riskier than additions — you're touching a running system; pulling one thread affects the whole. The core strategy is understand first, analyze, then refine, and only then act.

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Complete Execution Workflow

Progress tracking: Output the progress block twice per step:

1. Before starting the step — mark it → — in progress, then immediately do the work.
2. After completing the step — output the block again with that step marked ✓ — <one-line finding>.

Do NOT batch all updates into a single block at the end. Each step must print its own start and completion block.

Include only the steps that apply to the current task scale — omit inapplicable steps entirely:

• Lightweight: Step 5 only
• Medium: Steps 1, 5, 6 (Step 3 optional — include if you run it)
• Large: All steps (1 → 2 → 3 → 4 → 5 → 6)

Large-task example mid-execution (adapt by removing rows for smaller scales):

Modify Feature Progress
✓ Step 1: Read & Establish Context  — <one-line finding>
→ Step 2: Impact Analysis           — in progress
○ Step 3: Requirements Refinement
○ Step 4: Solution Design + Confirm
○ Step 5: Implement
○ Step 6: Compliance Audit