Duck Tidy

Stale comment and doc cleanup 🦆🧹. Audit-first, evidence-backed staleness detection.

Purpose

Identify stale/outdated comments and non-CONTEXT docs so they stop polluting future sessions and confusing agents and developers. Audit-first; edits hand off to duck-patch.

Philosophy Guardrails (skill-local)

Inherit shared guardrails from references/GUARDRAILS.md.

• ask 1-3 targeted clarifying questions when context is incomplete
• state assumptions explicitly when evidence is missing

Skill-specific delta:

• Staleness evidence-backed: comment contradicts current code, describes behavior no longer existing, or documents worktree-only add/remove never merged to main.
• TODO/FIXME/HACK/XXX markers out of scope (duck-debt owns the ledger).
• ADR/design notes historic by design: if info is superseded, flag it; do not edit.

Activation

Audit-only (default): scan, report, no edits. Signals: "duck-tidy", "stale comments audit", "outdated docs audit".

Audit-and-edit: audit, then hand agreed findings to duck-patch. Signals: "tidy and fix comments", "clean up stale comments".

Method

1. Scan scope

Scope: explicit paths/globs from user, else worktree files (tracked + untracked, git-ignored excluded) minus CONTEXT.md, .duck-tape/, and common generated dirs (build/, dist/, node_modules/, coverage/, target/).

If the repo's generated dirs differ, ask one question before scanning.

If scope unclear, ask one question: single file / directory / worktree diff vs default branch.

Collect code comments, doc comments, non-CONTEXT markdown in scope.

2. Gather staleness evidence

Stale iff any rule holds:

• Contradiction: text contradicts current code (outdated invariants, wrong parameter semantics, old return type or signature).
• Removed behavior: describes functionality no longer present (referenced symbol/function/feature deleted).
• Worktree-only add/remove: documents behavior added then removed in the current worktree, never merged to the default branch. Verify via git diff <default-branch>: behavior exists only in unmerged worktree changes. Resolve default branch with git symbolic-ref refs/remotes/origin/HEAD, fall back to main. For untracked files, confirm worktree-only status via git status --porcelain.

Cross-reference each suspect: symbol resolves? tests exercise it? Cite the contradiction (file:line, symbol, diff hunk). No vibes-based staleness.

3. Classify findings

• stale-comment: actionable (contradiction / removed behavior / worktree-only). Editable.
• superseded-doc: ADR/design note now outdated. If outdated, flag only; do not edit.
• skip: TODO markers (duck-debt), accurate or historic comments, CONTEXT.md/.duck-tape content (duck-tape).

4. Produce audit report

Ledger per finding: location (file:line), class, evidence (one cited line), proposed action (delete / reword / flag).

ADR findings grouped separately as flags: "outdated — do not cite as current", with supersession evidence.

Audit-only mode stops here. Report only; no edits.

5. Patch handoff

Audit-and-edit only:

1. Present audit ledger.
2. User selects findings to fix.
3. Hand selected edits to duck-patch as bounded scope.
4. Walk execution approval before edits.

Workspace-changing actions (require approval based on change type):

Semantic changes (require full execution approval):

• Code/logic changes
• Documentation/planning changes (README, markdown docs, ADRs, CONTEXT.md, runbooks, design notes), except typo-only fixes in non-code text files
• Config/schema changes (settings, env vars, build config)
• Dependency changes (package.json, requirements.txt, etc.)
• File operations (create, delete, move)
• Mutating commands (git commit, install, build, deploy)
• Task delegation for implementation/patching

Cosmetic changes (require lightweight confirmation):

• Formatting/whitespace-only changes
• Typo fixes in non-code text files
• Confirmation phrase: "Confirm to proceed with [formatting change/typo fix]?"

Edge cases:

• JSDoc/docstring changes in code files are semantic (affects generated docs, code contracts)
• Comments explaining logic in code are semantic (affects maintainability understanding)
• Config comments are semantic (affects interpretation)
• Document updates (ADRs, CONTEXT.md) are semantic
• Examples in README that are code snippets are semantic (users copy-paste)

Approval workflow: Before any semantic change, require execution approval:

1. Preflight (required for every approval ask; if a field is missing, ask one clarifying question):
   • target phase:
     • Phase 1: stubs/skeleton/interfaces
     • Phase 2: wiring/integration
     • Phase 3: concrete implementation
   • phase-fit statement (why this diff matches phase constraints)
   • target files (bounded for selected phase)
   • expected behavior change
   • smallest verification check
2. Present list of changes broken down by file as formatted diff
   • File exists: unified diff (---/+++/@@ hunks, -/+ prefixes)
   • File does not exist: full content in fenced code block, file path as header
   • One file per diff block
   • Inline an annotation above the diff hunks explaining each change
   • If any file violates phase constraints, split and re-propose before approval ask
3. Approval ask: Approve this scope? (examples: approve/ok/confirm)
4. Wait for approval: do not proceed with edits/commands/task delegation until user replies with explicit approval intent

Rules:

• No workspace-changing action without user approval/confirmation Approval intent tokens:

• Accept as approval intent: "approve", "approved", "ok", "go ahead", "confirm", "yes"

• Also accept option-referencing approval sentences: "Proceed with option B in files X and Y.", "Approved. Run verification plan as proposed."

• Examples are non-exhaustive. Any clear approval intent is accepted.

• Do not treat non-approval continuation signals as approval: bare "continue", bare option letters ("B"), "next". No approval verb, no scope reference — not approval.

Scope rules:

• Phase caps (default):

  • Phase 1 (stubs/skeleton/interfaces): up to 6 files
  • Phase 2 (wiring/integration): up to 4 files
  • Phase 3 (concrete implementation): up to 2 files

• Phase content constraints (hard gate):

  • Phase 1 (stubs/skeleton/interfaces) must contain only:
    • file/module skeleton shape (folders, exports, section layout)
    • type/interface declarations
    • function/class signatures
    • placeholder returns/errors/TODO markers
    • minimal no-op wiring with no business logic
  • Phase 1 must not contain:
    • full feature/business logic
    • side-effectful flows (DB/network/auth/file writes)
    • complete UI behavior beyond placeholders
  • Phase 2 (wiring/integration) can contain:
    • route registration, DI/container wiring, module composition, event hookups
    • adaptation glue between existing components
  • Phase 2 must not contain:
    • substantial new business logic blocks
  • Phase 3 (concrete implementation) contains:
    • business logic, algorithms, side effects, full behavior completion

• New-file bootstrap rule:

  • If scope introduces new feature files, first approval pass must be Phase 1 stubs/skeleton/interfaces only.
  • Implement bodies in later Phase 2/3 approvals.
  • If a new file exceeds stub/skeleton intent, split that file into stub-first then implementation follow-up.

• If a phase exceeds its cap, split into smaller bounded approvals before executing.

• Review-fatigue triggers (objective):

  • Phase 1 (stubs/skeleton/interfaces):
    • If proposed diff in one approval exceeds 180 changed lines (additions + deletions) total, reduce current phase cap by at least 1 file (minimum cap is 1 file).
    • If any single file exceeds 90 changed lines (additions + deletions), split that file into a separate approval or smaller sequential edits.
  • Phase 2 (wiring/integration):
    • If proposed diff in one approval exceeds 120 changed lines (additions + deletions) total, reduce current phase cap by at least 1 file (minimum cap is 1 file).
    • If any single file exceeds 60 changed lines (additions + deletions), split that file into a separate approval or smaller sequential edits.
  • Phase 3 (concrete implementation):
    • If proposed diff in one approval exceeds 80 changed lines (additions + deletions) total, reduce current phase cap by at least 1 file (minimum cap is 1 file).
    • If any single file exceeds 40 changed lines (additions + deletions), split that file into a separate approval or smaller sequential edits.
  • If reviewer requests clarification on more than 2 files in same batch, reduce next batch by at least 1 file.

• If complexity or review fatigue increases, reduce cap further and continue in smaller batches.

• Reopen execution approval between phases, even when objective stays same.

• If scope changes after approval, reopen scope confirmation before continuing.

• Phase examples (application):

  • Phase 1 example: 5 files, 170 changed lines (additions + deletions) total, max single file 80 changed lines (additions + deletions). This is within cap and thresholds, so one approval can proceed.
  • Phase 2 example: 4 files, 130 changed lines (additions + deletions) total. This exceeds phase total threshold, so split into 2 approvals before execution.
  • Phase 3 example: 2 files, one file at 45 changed lines (additions + deletions). This exceeds single-file threshold, so split into smaller sequential edits.

Verify with smallest runnable check (build/test, or re-audit of changed hunks).

Boundaries

• No auto-edits without approval.
• If a target is a TODO/FIXME/HACK/XXX marker, leave it — duck-debt owns those.
• If a target is an ADR/design note, flag only; do not edit.
• If a target is CONTEXT.md or .duck-tape state, leave it — duck-tape owns those.
• Every deletion carries cited evidence.