Plan Audit

Plan Audit

What this skill is — and isn't

| Skill | Question it answers | Output | |---|---|---| | vd:plan | "Given the chosen approach, what are the steps?" | Phased plan files | | vd:plan --deep Phase 6 (red-team) | "What does THIS author's plan assume that isn't true?" | Three hostile questions, same context | | vd:plan-audit | "Independently — does this plan hold up against the real codebase and the stated goal?" | Severity-tagged audit report (clean-context subagent) | | vd:research | "What do external sources say about X?" | Comparison report with citations |

The --deep red-team round (in vd:plan) lives inside the same conversation that wrote the plan — it shares the author's blind spots. Plan-audit escapes that by spawning a subagent with only the plan files + audit checklist as input. No conversation history, no author bias.

It's a second pair of eyes, not a redesign tool. Findings are advisory — the author still owns the plan.

Hard rules

1. Never edit source code. This skill only edits plan files (and only with --fix, only HIGH/CRITICAL findings, with per-finding confirmation by default — or single up-front confirmation when --apply-all is set). Never touches the actual codebase.
2. Always use a clean-context subagent. Inline reasoning shares the same blind spots as the author. The point of audit is independence — a clean-context subagent (Agent tool in Claude Code; see Phase 3 for the Codex fallback), fresh context, plan files as the only input. Hand the subagent the plan and the goal, not the author's argument for why the plan is sound — withholding the claim is what keeps the second look honest. "Confirm this is right" invites agreement; "does this hold up?" invites scrutiny.
3. Findings are advisory, not blocking. Audit prints a report and exits. It never blocks vd:plan completion or vd:cook execution. The author decides.
4. Only HIGH/CRITICAL are eligible for --fix. MEDIUM/LOW are observational — surfacing them is the value, fixing them auto would be over-reach.
5. Respect decisions.md. If the plan dir contains decisions.md, listed non-goals are intentional exclusions — drop those findings entirely. "Trade-offs" entries: drop the unchosen-side findings. "Constraints accepted" entries: a finding that contradicts the constraint may surface as MEDIUM with note "constraint may need revisiting" — never CRITICAL/HIGH.
6. Audit one plan at a time. Multi-plan batch audit is out of scope — different plans, different contexts.

Modes

| Mode | When | Behavior | |---|---|---| | default | Standard audit — read, spawn subagent, write report | No file edits beyond writing the report | | --fix | Author wants to apply HIGH/CRITICAL findings inline | After report, walk findings interactively; per-finding y/n; edit phase file in place. Interactive-only — never auto-invoked by other skills. | | --fix --apply-all | Author trusts the audit + wants one keypress instead of N | Print a unified preview of every HIGH/CRITICAL edit (file/line/old→new); single y/n at the top; apply the whole batch atomically on y. Still HIGH/CRITICAL only. Interactive-only. |

Detect mode from the explicit flags. --apply-all without --fix is a usage error — error out and print the help line. Announce mode in your first reply.

Phase 1 — Resolve plan dir

• If a plan-dir path is provided as an argument → use it. Verify it exists and contains plan.md. If missing, error and stop.
• If no argument → check the injected Plans path for entries matching {YYYYMMDD-HHMM}-* or {YYMMDD-HHMM}-*; sort by date prefix descending, pick the most recent that contains plan.md. Print "Auditing most-recent plan: {path}" so the user can confirm.
• If no plan dir is found → error: "No plan dir argument and no recent plan found under the injected Plans path. Pass a path explicitly."

Phase 2 — Read inputs

Read into the controller context (so the subagent prompt can paste them verbatim):

• {plan-dir}/plan.md — required
• {plan-dir}/phase-*.md — all phase files
• {plan-dir}/decisions.md — optional. If present, pass to subagent as the "non-goals / out-of-scope" block.
• {plan-dir}/research/*.md — optional. If present, summarize paths only (not full content) for the subagent's awareness.
• {plan-dir}/reports/*.md — optional. Same — paths only.

If decisions.md is absent, treat as "no exclusions stated."

Phase 3 — Spawn audit subagent

Use the Agent tool with subagent_type: general-purpose. Single subagent, full plan context. Do not spawn N parallel agents — plans are small (5-10 phase files, ~5K tokens) and an independent voice across the whole plan is the goal.

When this auditor runs inside a Workflow harness (e.g. auto-fired from vd:plan --deep), keep its output schema minimal — mark only summary and findings as required, avoid additionalProperties: false, and keep the one-line JSON example below in the prompt so the first attempt conforms (strict schemas fail ~74% of first attempts and burn retries).

Portability: the Agent tool with subagent_type is Claude Code-only. In another runtime, spawn the independent auditor with that runtime's subagent mechanism (or a fresh codex exec process); only if none exists, fall back to a documented degraded inline pass with fresh eyes and say so — weaker isolation, but better than dead-ending.

Subagent prompt template

You are an independent plan auditor. You have NO access to the prior conversation.
Your only inputs are the plan files below + the audit checklist + (if present) decisions.md.
Treat the plan as the only source of truth about intent.

# Plan dir
{plan-dir-path}

# plan.md
{verbatim contents}

# Phase files
{verbatim contents of each phase-XX-*.md}

# decisions.md (if present)
{verbatim contents}
If a "Non-goals" item appears here, it is an intentional exclusion. Do NOT
report it as a gap. If a "Trade-offs" item lists chosen vs unchosen, do NOT
flag the unchosen alternative.

NEGATIVE EXAMPLE: if decisions.md says "no auth — internal tool only", do
NOT add a CRITICAL finding "missing auth phase". The author already decided.

# Audit checklist
{paste contents of references/audit-checklist.md}

# Codebase root
{repo-root-path}

You may use Read/Glob/Grep tools to:
- Re-Read each phase file directly so `line_range` numbers are real, not fabricated.
  (The verbatim contents above are for context; cite line numbers from your own Read calls.)
- Spot-check codebase reality (does file X exist? does the naming convention match?).
Do not read more than ~20 files total — this is a survey, not deep analysis.

# Your task
1. Walk the audit checklist (6 categories) against the plan.
2. For each finding, classify severity: CRITICAL / HIGH / MEDIUM / LOW (defs
   in checklist).
3. For each finding, name: phase number, line range (best-effort), one-line
   summary, suggested fix.
4. Skip findings that decisions.md already covers as non-goals.
5. Recommended action: block | revise-before-cook | proceed-with-caveats | proceed
6. Return ONLY a single JSON object with keys `summary` and `findings`. Shape:

{
  "summary": {
    "counts": {"critical": N, "high": N, "medium": N, "low": N},
    "recommended_action": "block | revise-before-cook | proceed-with-caveats | proceed",
    "verdict_one_liner": "..."
  },
  "findings": [
    {
      "severity": "CRITICAL|HIGH|MEDIUM|LOW",
      "category": "consistency|codebase-drift|missing-scaffolding|unrealistic-criteria|deps-sequencing|scope-shape",
      "phase": "plan|N",
      "line_range": "L42-L48 (best effort, omit if unknown)",
      "summary": "one-line gist",
      "detail": "1-3 sentences explaining the gap",
      "suggested_fix": "concrete edit the author can apply"
    }
  ]
}

If you find NO issues, return the same wrapper with empty findings array and
verdict "proceed". Do not pad. Do not invent gaps to look thorough.

Phase 4 — Apply findings

• Parse subagent JSON output. Validate shape; if malformed, ask the subagent to retry once.
• Render report — write into the audited plan's own folder so every artifact for this feature stays grouped: {plan-dir}/reports/. Filename: audit-{YYMMDD-HHMM}-{plan-slug}.md. Date format matches the session-hook ## Naming block (6-digit YY). plan-slug = the date-stripped slug of the plan dir (e.g. 260510-0938-vd-plan-audit-skill → vd-plan-audit-skill). If the plan dir doesn't follow {date}-{slug} pattern, fall back to the dir name itself as the slug.
• If --fix mode (per-finding):
• Walk findings filtered to severity in {CRITICAL, HIGH}.
• For each, print finding + suggested fix, ask user Apply? (y/n/skip-rest).
• On y: open the named phase file, apply the suggested edit (Edit tool, with the user's confirmation of the exact diff if it's non-trivial). Mark finding as "applied" in the report.
• On n or skip-rest: leave finding unfixed, note as "deferred" in the report.

• If --fix --apply-all mode (batch):
• Filter findings to severity in {CRITICAL, HIGH}. If the filtered list is empty, print "No HIGH/CRITICAL findings to apply" and exit without prompting.
• Compute the concrete edit for each finding (the exact old_string/new_string pair that the Edit tool will use). If any edit cannot be made concrete from the suggested_fix (ambiguous instruction, target line missing) → mark that finding unactionable and exclude it from the batch.
• Print a single unified preview: for each actionable finding, show phase-NN.md @ Lstart-Lend + a 3-line context diff (old → new). Group by file. Cap at 60 lines total — if longer, write the full preview alongside the audit report in {plan-dir}/reports/, filename audit-{date}-{slug}.preview.diff, and print only the file/line summary inline.
• Ask one prompt: Apply N HIGH/CRITICAL edits across M files? (y/n). Default is n. No skip-rest — it's all-or-nothing.
• On y: apply each edit in order. If any edit fails (file changed since audit read, old_string not unique, etc.) → stop, mark already-applied as applied, the failing one as failed, remaining as deferred. Surface the failure inline and in the report so the author can re-audit. Do not roll back applied edits — they're plan-file edits, not code, and partial progress is recoverable via git.
• On n: leave all findings unfixed, note them as deferred. Skill exits with a one-line summary.
• unactionable findings always appear in the report regardless of choice — surfacing them is the value.

Report template

---
title: "Plan Audit — {plan-title}"
date: {YYYY-MM-DD}
auditor: plan-audit-subagent
plan: ../{plan-dir-name}/
verdict: {recommended_action} — {verdict_one_liner}
---

# Plan Audit: {plan-title}

## Summary
- {N} findings: {C} critical · {H} high · {M} medium · {L} low
- Recommended action: **{block | revise-before-cook | proceed-with-caveats | proceed}**
- {one-line verdict}

## Findings (severity-sorted)

### CRITICAL
- **{summary}** — phase {N}, {line range} — {detail}
  → fix: {suggested fix}
  → status: {advisory | applied | deferred}

### HIGH
- ...

### MEDIUM
- ...

### LOW
- ...

## Decisions respected
- {non-goal from decisions.md that the audit honored, if any}

## Files inspected
- {list of plan files read}
- {list of codebase files spot-checked, if any}

Phase 5 — Hand off

After writing the report:

1. Print report path — use an openable location such as Audit report: [audit-report.md](/absolute/path/to/audit-report.md) and include file:///absolute/path/to/audit-report.md when helpful. Do not print only the basename.
2. Print top-3 findings inline — sorted by severity. Just summary + phase ref. Full detail in the file.
3. Recommend next step based on verdict:

• block → "Critical findings — revise plan before vd:cook."
• revise-before-cook → "Address HIGH findings before execution."
• proceed-with-caveats → "Plan is workable; review MEDIUM findings."
• proceed → "No blocking issues. Cook when ready."

1. If --fix ran, summarize: {N} fixes applied, {M} deferred, {U} unactionable, {F} failed. (omit zero-count buckets).
2. Recommend re-run after fixes: "Re-run vd:plan-audit after edits to verify."

Anti-rationalization

| Excuse | Reality | |---|---| | "I'll do the audit inline — it's faster" | Inline = same context = same blind spots. Use the subagent. (Phase 3's degraded inline fallback is only for runtimes with no subagent tool — not a speed shortcut.) | | "The plan is small — skip decisions.md check" | Small plans have non-goals too. Read it if it exists. | | "Audit found 0 issues — must be wrong" | Or the plan is good. Don't pad findings to look thorough. | | "I'll fix MEDIUM findings too while I'm in --fix" | Out of scope. Surface, don't fix. The author decides. | | "I'll extend --apply-all to MEDIUM/LOW for tidy output" | No. The trust boundary is HIGH/CRITICAL — anything below is observational. | | "Just have another skill invoke --apply-all automatically" | --apply-all is interactive — one human keypress at the preview gate. It is NOT for auto-invocation by vd:plan --deep or vd:cook --auto. | | "Just block on CRITICAL by default" | Audit is advisory. The author owns the call. | | "I'll re-read the plan in main context to double-check" | That defeats the point. Trust the subagent's report. |

Quality bar

• Independent. Audit subagent has no parent conversation context. No author bias.
• Severity-honest. A CRITICAL is "plan will fail at cook." A HIGH is "plan succeeds but produces a flawed result." Don't inflate.
• Concrete. Every finding names a phase, ideally a line range, and a suggested fix. "Plan is vague" is not a finding. "Phase 3 step 4 says 'add validation' without naming the validator" is.
• Decisions-aware. Listed non-goals don't show up as gaps. The audit respects what was already decided.
• Re-runnable. Author can fix → re-run → see fewer findings. The skill is composable, not one-shot.

Specials

• Migration plans — audit specifically checks: rollback path tested? consumers updated after migration? feature flag for staged rollout? If any missing → HIGH.
• API breaking changes — audit checks the "add new → migrate callers → remove old" sequence is explicit (not collapsed). If collapsed → HIGH.
• Performance plans — audit checks for baseline numbers in phase 1 + comparison evidence in success criteria. Missing → HIGH.
• Library upgrades — audit checks each phase ends with smoke test of an affected feature. Missing → MEDIUM.
• Bug fixes — audit checks for a failing-test-first step. Missing → MEDIUM.
• Plans with no decisions.md — audit emits a LOW advisory: "Consider adding decisions.md to record explicit non-goals — reduces false positives on re-audit."

Output rules

1. Announce mode (default / --fix / --fix --apply-all) and resolved plan-dir in the first reply.
2. Phase 1 (resolve) and Phase 2 (read) happen visibly — print plan dir + file count before spawning the subagent.
3. Subagent dispatch is one Agent tool call. Print "Spawning audit subagent..." so the user sees the boundary.
4. After subagent returns, print the report path and top-3 findings inline. Don't paste the whole report.
5. --fix (per-finding) walks findings interactively — one prompt per HIGH/CRITICAL.
6. --fix --apply-all (batch) shows one unified preview, asks one y/n, applies the batch atomically. Default-no on the prompt.
7. End with the recommended next step. Don't leave the author wondering whether to cook.

References

• references/audit-checklist.md — six audit categories + severity definitions (subagent paste-target)

Workflow position

Typically follows: vd:plan (manual run after planning), vd:plan --deep (auto-invoked as Phase 7) Typically precedes: vd:cook (with HIGH/CRITICAL addressed)

…

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: vanducng
• Source: vanducng/skills
• License: MIT
• Homepage: https://skills.vanducng.dev

Install and usage instructions live in the source repository linked above.