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you-might-not-need-a-comment

Analyze and fix redundant or self-explanatory inline comments — remove noise, promote genuine documentation to TSDoc

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SKILL.md
Quality
Evals
Security

You Might Not Need a Comment

Arguments:

  • scope: what to analyze (default: your current changes). Examples: "diff to main", "PR #123", "src/components/", "whole codebase"
  • fix: whether to apply fixes (default: true). Set to false to only propose changes.

User arguments: $ARGUMENTS

The one rule that matters

A comment must add information the code cannot express itself. Code says what and how; a comment earns its place only by explaining why — a non-obvious constraint, a workaround, a decision, a gotcha. If deleting the comment loses no information a competent reader wouldn't recover from the code in seconds, delete it.

This codebase's convention: TSDoc for documentation, no non-TSDoc comments, no ==== separators. Genuine documentation belongs in a /** ... */ block on the declaration; everything that survives as an inline // comment must be a real why, kept terse.

Anti-patterns to detect

  1. Restates the code: // increment counter above counter++, // return the result above return result, // loop over items. Delete.
  2. Narrates the obvious from names: the function is fetchUserById, the comment says // fetches a user by id. The identifier already said it. Delete.
  3. Section-divider / banner comments: // ==== Helpers ====, // --- state ---, // #region. Against convention. Delete (the code's structure is the structure).
  4. Commented-out code: dead code left as a comment. Delete — git is the history.
  5. Redundant type/param echo in prose comments: // takes a string and returns a number when the signature already says so. Delete.
  6. Changelog / attribution noise: // added by X, // TODO(2021): ... long-stale, // fix for bug. Delete unless it encodes a live, actionable constraint.
  7. Genuine documentation written as a loose // block on a declaration: a real explanation of what an exported function/type/const is for, but written as stacked // lines instead of TSDoc. Convert to a /** ... */ TSDoc block on the declaration.

Patterns that ARE correct — do not flag

  • A // comment that explains a non-obvious why: a workaround for an upstream bug, an ordering constraint, a perf reason, a spec/edge-case the code can't self-document (// first-match wins — matches the old find() semantics).
  • Existing TSDoc /** ... */ blocks on declarations — leave them (only tighten if verbose).
  • // boundary-raw-fetch:, // double-cast-allowed:, // boundary-raw-json:, // untyped-response:, // migration-safe: and other machine-read annotations — these are load-bearing, never touch them.
  • // biome-ignore, // eslint-disable, // @ts-expect-error and other tooling directives.
  • // TODO / // FIXME that point at real, still-open work.

Bias

Prefer deletion over rewriting, and no comment over a comment when the code is already clear. When a comment is genuine documentation, prefer promoting it to terse TSDoc over leaving a loose // block. Never add new comments in this pass — this is a reduction pass. When unsure whether a comment encodes a real why, keep it.

Steps

  1. Analyze the specified scope for the anti-patterns listed above
  2. If fix=true, apply the fixes. If fix=false, propose the fixes without applying.
Repository
simstudioai/sim
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