name: trace description: TRACE (Type/Readability/Atomic/Cognitive/Essential) lens for explaining code and proposing improvements (no edits applied).

Trace

Intent

Explain code by tracing what it does and scoring friction through TRACE.

Deliver actionable suggestions (file/line targets + minimal patch sketches) but do not modify files.

When to use

• “trace it” / “what is this doing?”
• Explain confusing control flow or hidden side effects.
• Readability/cognitive-load feedback when you want analysis-only.
• Refactor planning (“what would you change?”) without implementation.

Workflow

1. Choose the slice: entrypoint, inputs, outputs, and state.
2. Build a cognitive heat map (hotspots + surprises).
3. Trace behavior: happy path + key failure paths; call out mutations/IO.
4. Apply the TRACE checklist (below) to each hotspot.
5. Propose suggested edits:
   • 1–3 smallest improvements per hotspot.
   • Include file:line targets.
   • Use short pseudo-diffs or code sketches.
6. Stop before editing; if changes are desired, escalate to $fix.

Guardrails

• No file edits, no commits.
• No running commands unless explicitly requested.
• If expected behavior is unclear/product-sensitive, stop and ask.
• If you suspect crash/corruption risk, recommend $fix.

TRACE checklist

• Type: make invalid states unrepresentable; eliminate “maybe” states where possible.
• Readability: understandable in 30 seconds; names match behavior.
• Atomic: one responsibility per unit; explicit side effects.
• Cognitive: minimize branching, hidden dependencies, and cross-file hops.
• Essential: keep only domain-required complexity; delete incidental ceremony.

Activation cues

• "trace" / "walk me through" / "explain"
• "what is this doing" / "why is this complex"
• "readability" / "cognitive load" (analysis-only)
• "suggest improvements" / "refactor plan"