implement-spec

implement-spec is a skill for Claude Code from SteveVitali/agent-skills. It costs 43 tokens per session (6,041 once invoked), scanned A, original, MIT.

An end-to-end workflow for turning an authoritative written specification into a reviewed and verified pull request, a proposed code change submitted for review.

In plain words
What is it for?
Use it to plan from a specification, write tests alongside the code, implement the changes, review them, find gaps, run downstream checks, and produce evidence of completion.
Why use it?
It checks the implementation against the full specification and looks for missing requirements, so passing a build alone is not treated as proof that the work is complete.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions CLAUDE.md; mentions subagents; mentions AGENTS.md.

Part of the agent-skills plugin — 8 skills shipped together

Good fit Use it to plan from a specification, write tests alongside the code, implement the changes, review them, find gaps, run downstream checks, and produce evidence of completion.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/stevevitali/agent-skills/implement-spec
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 SteveVitali/agent-skills --skill implement-spec
Clone the repo
git clone --depth 1 https://github.com/SteveVitali/agent-skills

Made for: Claude Code.

Or install agent-skills, the plugin that ships this one along with the rest of its 8 skills.

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 implement-spec

README.md
[![agentmods](https://agentmods.dev/badge/skills/stevevitali/agent-skills/implement-spec.svg)](https://agentmods.dev/skills/stevevitali/agent-skills/implement-spec)
Your own site
<a href="https://agentmods.dev/skills/stevevitali/agent-skills/implement-spec"><img src="https://agentmods.dev/badge/skills/stevevitali/agent-skills/implement-spec.svg" alt="Measured on agentmods" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,041 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 $0.00043 $0.06041
Opus 5 $0.00022 $0.03021
Sonnet 5 $0.00009 $0.01208
Haiku 4.5 $0.00004 $0.00604

Measured 7d ago against content hash 5adae1e1780e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

implement-spec 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 7d 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/implement-spec/SKILL.md · 419 lines

How it starts

The opening of the file, as written. The whole thing — 419 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Implement Spec

Turn an authoritative spec into a reviewable, spec-complete, rigorously-verified PR — autonomously.

This extends a conventional implement-and-PR workflow (context-loading, implementation discipline, self-review-before-commit, clean PR) with the two phases a spec-driven autonomous run needs: gap analysis vs the spec (Phase 4) and rigorous downstream verification (Phase 5). The output is a PR plus an evidence report that proves completeness/correctness against the spec — not just "it builds."

When to use this skill: when there is an authoritative written spec, when the run must be fully autonomous to completion, and when "done" means provably matches the spec (not just "compiles + self-reviewed"). For a rough idea that just needs a quick clean PR, use a lighter ticket workflow instead.

Configuration

Every rigor phase can be disabled independently (all default on). Opting out trades assurance for speed — the table states what you lose. No toggle disables the Phase 6.0 green gate: existing builds and affected test suites must pass regardless.

Input Disables You lose
ledger=false Phase 0.4 run ledger (keep that state in-context instead) Crash/compaction resumability; durable gap-table evidence
self_review=false Phase 3 Design critique + mechanical checklist pass before the spec diff
gap_analysis=false Phase 4 The explicit spec-completeness proof; ACs checked only via Phase 5
tests=false 1.4 test matrix, new tests in Phase 2, 5.1–5.2 new-test runs Regression protection for the new logic
live_verification=false Phase 5.3 End-to-end proof on the running system
evidence_report=false Phase 6.4 + the PR AC/evidence table The per-AC evidence trail; PR gets a standard summary

Sensible presets: full (all on — the default); fast-follow (gap_analysis=false live_verification=false) for small mechanical changes against a precise spec; prototype (tests=false evidence_report=false) for explicitly throwaway spikes. When in doubt, leave everything on.

Read the full file on GitHub · 419 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. 7d ago First seen · 419 lines · 43 tokens per session scan A 5adae1e1780e

Subscribe to this mod's changes

implement-spec is a skill published in the GitHub repository SteveVitali/agent-skills (9 stars, last pushed 5d ago), licensed MIT. It adds 43 tokens to every session and 6,041 once invoked, about $0.0002 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