spec-drift-check

spec-drift-check is a skill for Claude Code from QBall-Inc/the-bulwark. It costs 54 tokens per session (4,234 once invoked), scanned A, original, MIT.

A document-checking skill that compares a Work Package brief—a written coding task plan—with the current code. It checks whether the brief’s file paths, names, dependencies, and described behavior are still accurate.

In plain words
What is it for?
Use it before starting work from a brief or specification. It checks factual claims, flags missing or changed details, adjusts the plan, and gives a proceed-or-stop decision.
Why use it?
Coding briefs can become outdated as a project changes. This finds those mismatches before the brief is treated as the source of truth and says whether work can proceed.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions subagents; names the AskUserQuestion tool.

Part of the the-bulwark plugin — 30 skills, 17 agents, 6 hooks shipped together

Good fit Use it before starting work from a brief or specification. It checks factual claims, flags missing or changed details, adjusts the plan, and gives a proceed-or-stop decision.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/qball-inc/the-bulwark/spec-drift-check
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add QBall-Inc/the-bulwark --skill spec-drift-check
Clone the repo
git clone --depth 1 https://github.com/QBall-Inc/the-bulwark

Made for: Claude Code.

Or install the-bulwark, the plugin that ships this one along with the rest of its 30 skills, 17 agents, 6 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for spec-drift-check

README.md
[![agentmods](https://agentmods.dev/badge/skills/qball-inc/the-bulwark/spec-drift-check/github.svg)](https://agentmods.dev/skills/qball-inc/the-bulwark/spec-drift-check)
Your own site
<a href="https://agentmods.dev/skills/qball-inc/the-bulwark/spec-drift-check"><img src="https://agentmods.dev/badge/skills/qball-inc/the-bulwark/spec-drift-check/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for spec-drift-check

Your own site · 80×15
<a href="https://agentmods.dev/skills/qball-inc/the-bulwark/spec-drift-check"><img src="https://agentmods.dev/badge/skills/qball-inc/the-bulwark/spec-drift-check.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,234 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00054 $0.04234
Opus 5 $0.00027 $0.02117
Sonnet 5 $0.00011 $0.00847
Haiku 4.5 $0.00005 $0.00423

Measured 11d ago against content hash 7ccf0b854520, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

spec-drift-check scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/spec-drift-check/SKILL.md · 291 lines

How it starts

The opening of the file, as written. The whole thing — 291 lines — stays where its author put it; the contents beside it link to each section on GitHub.

spec-drift-check

Audits a Work Package brief (or any spec document) for drift against the current code state. The skill extracts every verifiable factual claim from the subject spec — file paths, line refs, function and type names, constants, sequence-of-events claims, dependency claims, state claims — verifies each against current code via Grep / Read / Bash, categorizes findings (CONFIRMED, drift variants, AC re-interpretation, GAP) at LOW / MEDIUM / HIGH severity, rewrites the implementation plan based on findings, and emits a structured verdict (PROCEED, PROCEED_ADJUSTED, STOP_USER_APPROVAL). The verified plan supersedes the original spec for the rest of the work package.


When to Use This Skill

Load this skill when the user request matches ANY of these patterns:

Trigger Pattern Example User Request
Pre-WP verification "Run spec drift check on the P10.16 brief", "Verify this brief before I start the WP"
Drift audit "Check for drift between the spec and current state", "Audit this brief for stale claims"
Claim verification "Extract claims from this brief and verify them", "Are the file refs in this doc still valid?"

DO NOT use for:

  • Implementing a brief (use the relevant implementer skill / agent — this skill is verification only)
  • General code review or PR review (use code-review)
  • Test audit (use test-audit)
  • Debugging issues (use issue-debugging)

This skill is READ-ONLY with respect to the subject spec. It does NOT modify the input brief or any code referenced by it. The skill DOES write its own outputs — verification log under $PROJECT_DIR/logs/spec-verify-*.md and diagnostic YAML under $PROJECT_DIR/logs/diagnostics/ — those are not "modifications" of the subject. To FIX issues found in the subject spec, the user invokes a separate skill (manual edits, fix-bug, or an implementer agent). The skill's value is the audit + adjusted plan, not the fix. The frontmatter lists Edit under disallowed-tools, which removes it from the available tool pool while the skill runs, preventing accidental subject-spec modification at the permission layer.

Read the full file on GitHub · 291 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 291 lines · 54 tokens per session scan A 7ccf0b854520

Subscribe to this mod's changes

spec-drift-check is a skill published in the GitHub repository QBall-Inc/the-bulwark (8 stars, last pushed today), licensed MIT. It adds 54 tokens to every session and 4,234 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Related

Other skills, from other repositories

github-pr-review

Handles PR review comments and feedback resolution. Use when user wants to resolve PR comments, handle review feedback, fix review comments, address PR review, check review status, respond to reviewer, verify PR readiness, review PR comments, analyze review feedback, evaluate PR comments, assess review suggestions, or…

fvadicamo/dev-agent-skills · 95 tokens

github-pr-creation

Creates GitHub Pull Requests with automated validation and task tracking. Use when user wants to create PR, open pull request, submit for review, or check if ready for PR. Analyzes commits, validates task completion, generates Conventional Commits title and description, suggests labels. NOTE - for merging existing…

fvadicamo/dev-agent-skills · 75 tokens

adversarial-reviewer

Use when you want a genuinely critical review of recent changes — before merging a PR, after a sprint, or when you suspect the review is being too agreeable. Forces perspective shifts through three hostile reviewer personas that catch blind spots the author's mental model shares with the reviewer. Triggers on…

tmj-90/gaffer · 93 tokens

card-review

Internal skill for onboard's semantic review gate. After the deterministic validation gate (which catches invented symbols / hash drift / secrets), this skill drives a sampled claude -p pass that checks whether the TLDR and role are DIRECTIONALLY ACCURATE given the file's structure and head snippet. The deterministic…

tmj-90/gaffer · 125 tokens

triage-report

Drain the .review/ report queue. Resolves un-triaged scan/audit reports (producer-agnostic — check-docs-consistency and any other scanner), dispatches the triage-report subagent (Sonnet) one report at a time for per-finding dispositions (promote / patch / dup / needs-investigation / dismiss), then the gateway absorbs…

RockyHong/super-bootstrap · 151 tokens

review-ticket

Use as a reviewer agent to review another agent's inreview ticket — never your own. Judge whether each acceptance criterion is genuinely met and the change is sound, then record an ADVISORY verdict (per-AC evidence + an overall RECOMMEND APPROVE / RECOMMEND CHANGES line) via the scoped Dispatch MCP, leaving the ticket…

tmj-90/gaffer · 129 tokens