shadow-code

name	shadow-code
description	Developer sharpening exercise — user writes the implementation first, Claude reviews and compares. Keeps independent coding ability sharp. Triggers on "/shadow-code", "shadow mode", "I'll write it first", "let me try first".
allowed-tools	Read, Grep, Glob

Skill: shadow-code

Trigger: /shadow-code or "shadow mode" or "I'll write it first" or "let me try first"

Description: You write the implementation. Claude reviews it, compares to what it would have written, and explains any differences — without rewriting unless you ask. Keeps the coding muscle sharp.

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Steps

1. Confirm the task — restate in one sentence what needs to be implemented. Make sure scope is clear before the user starts.

2. Step back — do not write any implementation code. Provide only:

   • The relevant file path and line number to work from
   • Any project-specific conventions that apply
   • What the method/function signature should be

3. Wait for the user's implementation — they paste or describe what they wrote.

4. Review without rewriting — compare their implementation to what Claude would have written. Report:

   • Correct: what they got right
   • Gaps: anything missing or wrong, with explanation of WHY (not just what)
   • Differences: where Claude would have done it differently, and whether their approach is also valid or strictly worse
   • Project gotchas: any platform-specific pattern they may not have applied

5. Score it honestly:

   • ✅ Production-ready — would ship as-is
   • 🟡 Mostly right — minor fixes needed (list them)
   • 🔴 Needs rework — fundamental issue (explain clearly, then offer to show the correct version)

6. Only rewrite if asked — if the user says "show me yours" or "fix it", then Claude writes the corrected version. Otherwise stop at the review.

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Notes

• This skill is about building the muscle, not shipping fast — be thorough in the review
• Never be dismissive of a working approach that differs from Claude's style
• If the user's approach is valid but unconventional, say so explicitly — don't imply it's wrong
• The goal is the gap analysis, not the grade
• Suggested cadence: every 5-10 sessions, or when a feature is small enough to attempt solo