spec-anchored-agentic-development: Skill for Claude Code

.agents/skills/prep/SKILL.md

prep is a skill for Claude Code, Codex from w00fx/spec-anchored-agentic-development. It costs 90 tokens per session (2,547 once invoked), scanned A, original, MIT.

A repository setup skill that prepares commands, tests, reference-value checks, mutation or fuzz checks when needed, and basic continuous integration. It changes verification setup only, not application code.

In plain words
What is it for?
Use it to inspect an existing repository and add or extend its test harness, verification commands, coverage-related gates, and CI workflows.
Why use it?
It gives a repository a consistent way to run full checks, capability-specific checks, and reference tests before implementation and review work.

Skill for Claude CodeCodex

Written for Claude Code and Codex: disable-model-invocation in frontmatter, but also agents/openai.yaml present. Also seen: mentions CLAUDE.md; installed under .agents/ (shared by several agents); mentions AGENTS.md.

This is w00fx/spec-anchored-agentic-development's own configuration. It tells Claude Code and Codex how to work on spec-anchored-agentic-development itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything spec-anchored-agentic-development configures →

Reuse

Borrowing it

Nothing to install: this file belongs to w00fx/spec-anchored-agentic-development. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/w00fx/spec-anchored-agentic-development/main/.agents/skills/prep/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/w00fx/spec-anchored-agentic-development

Made for: Claude Code, Codex.

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 prep

README.md
[![agentmods](https://agentmods.dev/badge/skills/w00fx/spec-anchored-agentic-development/prep.svg)](https://agentmods.dev/skills/w00fx/spec-anchored-agentic-development/prep)
Your own site
<a href="https://agentmods.dev/skills/w00fx/spec-anchored-agentic-development/prep"><img src="https://agentmods.dev/badge/skills/w00fx/spec-anchored-agentic-development/prep.svg" alt="Measured on agentmods" height="20"></a>
Per session 90 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,547 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.
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 $0.00090 $0.02547
Opus 5 $0.00045 $0.01273
Sonnet 5 $0.00018 $0.00509
Haiku 4.5 $0.00009 $0.00255

Measured 2d ago against content hash faf3664aad5b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

prep 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 2d 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.

.agents/skills/prep/SKILL.md · 188 lines

How it starts

The opening of the file, as written. The whole thing — 188 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prepare this repository so the implementation Owner, General Code Reviewer, Mutation Hardener, external review pipeline, and CI have the verification infrastructure they expect. Additive and brownfield-safe: read before writing, extend instead of replacing, flag anything you had to work around. No application code changes.

Phase 0 — Detect

Identify: stacks present (TypeScript? Go? both?), layout (monorepo? capability folders?), existing test runners and configs, existing Makefile / package scripts / justfile, existing CI workflows, current coverage if measurable. Report the findings in one short block before changing anything.

Phase 1 — The commands interface (the contract)

The harness learns how to verify from a three-command core plus two conditional hardening command families. The tool is free (Make, just, npm scripts — follow repo convention); the interface is fixed:

  • check — lint + typecheck + tests, whole repo.
  • check-<capability> — the same, scoped to one capability folder (the chunk loop's command; a pattern — one target per capability).
  • golden — the reference-value tests only, reading specs/<capability>/tables/.
  • mutation-<capability> — pinned, differential mutation for one eligible capability/target, with structured coverage and survivor output.
  • fuzz-<capability> — property/fuzz targets for applicable parsers, validators, untrusted-input, serialization, protocol, and state-machine surfaces; the command may explicitly report N/A when no target applies.

Create or extend them. Then declare them in the root AGENTS.md under ## Commands. If a runtime needs an adapter such as CLAUDE.md, configure it separately; never create a competing operational authority.

Also preserve the shared Spec Anchored routing in AGENTS.md and ensure .agent-runs/ is present in .gitignore. Runtime logs, approvals, evidence, hardening handoffs, Owner dispositions, and results never live under .claude/, .codex/, or .cursor/.

Read the full file on GitHub · 188 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 2d ago First seen · 188 lines · 90 tokens per session scan A faf3664aad5b

Subscribe to this mod's changes

prep is a skill published in the GitHub repository w00fx/spec-anchored-agentic-development (5 stars, last pushed 4d ago), licensed MIT. It adds 90 tokens to every session and 2,547 once invoked, about $0.0005 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 2026-09-05.

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