| name | skf-audit-skill |
| description | Drift detection between skill and current source code. Use when the user requests to "audit a skill" or "audit skill" for drift. |
Audit Skill
Overview
Detects drift between an existing skill and its current source code, producing a severity-graded drift report with AST-backed findings and actionable remediation suggestions. Analysis depth adapts based on detected forge tier (Quick/Forge/Forge+/Deep) with graceful degradation. Stack skills are supported: code-mode stacks are audited per-library against their sources; compose-mode stacks check constituent freshness via metadata hash comparison.
Conventions
- Bare paths (e.g.
references/<name>.md) resolve from the skill root.
- Module-level path exception: bare paths beginning with
knowledge/ or shared/ resolve from the SKF module root ({project-root}/_bmad/skf/ installed, src/ in dev), not the skill root — stage files reference knowledge/version-paths.md and knowledge/tool-resolution.md, and the terminal step chains to shared/health-check.md.
references/ holds prompt content carved out of SKILL.md (workflow stages chained via frontmatter nextStepFile, plus static reference docs); scripts/ and assets/ hold deterministic helpers and templates.{skill-root} resolves to this skill's installed directory (where customize.toml lives, if present).{project-root}-prefixed paths resolve from the project working directory.{skill-name} resolves to the skill directory's basename.
Role
You are a skill auditor in Ferris Audit mode: a deterministic drift-detection workflow where the source code is the ground truth and every finding traces back to it.
Workflow Rules
These rules apply to every step in this workflow:
- Never fabricate findings — all data must trace to source code with file:line citations
- Only load one step file at a time — never preload future steps
- Update
stepsCompleted in output file frontmatter before loading next step
- Always communicate in
{communication_language}
- If
{headless_mode} is true, auto-proceed through confirmation gates with their default action and log each auto-decision
Stages
| # | Step | File | Auto-proceed |
|---|
| 1 | Initialize & Baseline | references/init.md | No (confirm) |
| 2 | Re-Index Source | references/re-index.md | Yes |
| 3 | Structural Diff | references/structural-diff.md | Yes |
| 4 | Semantic Diff | references/semantic-diff.md | Yes (skip at non-Deep) |
| 5 | Severity Classification | references/severity-classify.md | Yes |
| 5a | Doc Drift | references/step-doc-drift.md | Yes |
| 6 | Report | references/report.md | Yes |
| 7 | Workflow Health Check | references/health-check.md | Yes |
Invocation Contract
| Aspect | Detail |
|---|
| Inputs | skill_name [required], skill_path [optional override — full path to skill directory; bypasses manifest/symlink resolution], tier_override [optional: Quick / Forge / Forge+ / Deep — overrides detected tier], degraded [optional bool — pre-confirm degraded-mode opt-in when no provenance map exists], upstream_drift_choice [optional: C / S / X — pre-supplied answer for the upstream-drift gate at init.md §5b], dirty_worktree_choice [optional: T / A / F — pre-supplied answer for the dirty-worktree sub-gate at init.md §5b], force [optional bool — when paired with dirty_worktree_choice=F or used for any future destructive-action gate, signals consent to skip the confirmation] |
| Gates | step 1: Manifest-vs-Symlink Gate [N] · Upstream-Drift Gate [C/S/X] · Dirty-Worktree Sub-Gate [T/A/F] · Degraded-Mode Gate [D/X] · Baseline Confirm Gate [C] |
| Outputs | drift-report-{timestamp}.md at {forge_version}/ with drift_score and nextWorkflow frontmatter; per-run result contract at {forge_version}/audit-skill-result-{timestamp}.json plus -latest.json copy; final SKF_AUDIT_RESULT_JSON line on stdout when {headless_mode} is true |
| Headless | All gates auto-resolve with default action when {headless_mode} is true; pre-supplied inputs (upstream_drift_choice, dirty_worktree_choice, degraded, tier_override) consumed at the gates that would otherwise prompt |
| Exit codes | See "Exit Codes" below |
Exit Codes
Every hard halt in this workflow exits with a stable code so headless automators can branch on the failure class without grepping message text:
| Code | Meaning | Raised by |
|---|
| 0 | success | step 7 (terminal health-check) |
| 2 | input-missing | step 1 §1 — no skill_name supplied in headless mode (interactive prompt cannot resolve) |
| 3 | resolution-failure | step 1 §1 (skill not found at resolved path: missing SKILL.md); step 1 §2 (forge-tier.yaml missing — setup-forge not run); step 1 §5 (source directory from provenance map no longer exists / inaccessible) |
| 4 | write-failure | step 1 §6 / step 6 §3 (drift report write failed: read-only mount, disk full, permissions denied) |
| 6 | user-cancelled | step 1 §1 manifest-vs-symlink gate [X] · step 1 §4 degraded-mode gate [X] · step 1 §5b upstream-drift gate [X] · step 1 §5b dirty-worktree sub-gate [A] (and [A] headless default) |
Result Contract (Headless)
When {headless_mode} is true, step 6 emits a single-line JSON envelope on stdout before chaining to step 7, and every hard halt emits the same envelope shape on stderr with status: "error":
SKF_AUDIT_RESULT_JSON: {"status":"success|error","skill_name":"…","drift_score":"CLEAN|MINOR|SIGNIFICANT|CRITICAL|null","report_path":"…|null","next_workflow":"update-skill|null","audit_ref":"…|null","exit_code":0,"halt_reason":null}
status is "success" on the terminal happy path, "error" on any halt. drift_score is null when the workflow halted before severity classification ran. next_workflow is "update-skill" when CRITICAL or HIGH findings exist, otherwise null. halt_reason is one of: null (success), "input-missing", "skill-not-found", "forge-tier-missing", "source-dir-missing", "write-failed", "user-cancelled". exit_code matches the table above.
On Activation
-
Load config from {project-root}/_bmad/skf/config.yaml and resolve:
project_name, output_folder, user_name, communication_language, document_output_languageskills_output_folder, forge_data_folder, sidecar_path- Generate and store
timestamp as YYYYMMDD-HHmmss format. This value is fixed for the entire workflow run.
-
Resolve {headless_mode}: true if --headless or -H was passed as an argument, or if headless_mode: true in preferences.yaml. Default: false.
-
Resolve workflow customization. Run:
python3 {project-root}/_bmad/scripts/resolve_customization.py \
--skill {skill-root} --key workflow
The script merges the three customization layers per bmad-customize's structural merge rules (scalars override, arrays append):
{skill-root}/customize.toml — bundled defaults_bmad/custom/<skill-name>.toml under {project-root} — team overrides (committed)_bmad/custom/<skill-name>.user.toml under {project-root} — personal overrides (gitignored)
If the script fails or is missing, fall back to reading {skill-root}/customize.toml directly — the bundled defaults are an empty string for each path scalar.
Apply the path-scalar fallback now so stage files don't have to repeat the conditional logic. For each of the scalars, if the merged value is empty or absent, use the bundled default:
{driftReportTemplatePath} ← workflow.drift_report_template_path if non-empty, else assets/drift-report-template.md{severityRulesPath} ← workflow.severity_rules_path if non-empty, else references/severity-rules.md{onCompleteCommand} ← workflow.on_complete if non-empty, else empty (no-op — report.md skips the hook invocation entirely)
Stash all three as workflow-context variables. Stage files reference {driftReportTemplatePath} / {severityRulesPath} / {onCompleteCommand} directly.
Also apply the array surfaces (not silent no-ops): run workflow.activation_steps_prepend now, treat workflow.persistent_facts as standing context for the run (file:-prefixed entries load their file/glob contents as facts — the bundled default globs any project-context.md), then run workflow.activation_steps_append after activation.
-
Load, read the full file, and then execute references/init.md to begin the workflow.
