spec-spine: Agent for Claude Code

.claude/agents/reviewer.md

reviewer is an agent for Claude Code from statecrafting/spec-spine. It costs 39 tokens per session (1,966 once invoked), scanned A, original, Apache-2.0.

A read-only coding agent that examines recent changes for bugs, correctness, performance, security, and compliance with project specifications.

In plain words
What is it for?
Use it to review diffs, audit changes, check implementations against specifications, and assess code quality.
Why use it?
It provides a separate check after implementation, helping find problems before code is committed or merged.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter; mentions CLAUDE.md; mentions AGENTS.md.

This is statecrafting/spec-spine's own configuration. It tells Claude Code how to work on spec-spine 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-spine configures →

Reuse

Borrowing it

Nothing to install: this file belongs to statecrafting/spec-spine. 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/statecrafting/spec-spine/main/.claude/agents/reviewer.md
Clone the repo
git clone --depth 1 https://github.com/statecrafting/spec-spine

Made for: Claude Code.

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 reviewer

README.md
[![agentmods](https://agentmods.dev/badge/agents/statecrafting/spec-spine/reviewer.svg)](https://agentmods.dev/agents/statecrafting/spec-spine/reviewer)
Your own site
<a href="https://agentmods.dev/agents/statecrafting/spec-spine/reviewer"><img src="https://agentmods.dev/badge/agents/statecrafting/spec-spine/reviewer.svg" alt="Measured on agentmods" height="20"></a>
Per session 39 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,966 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 $0.00039 $0.01966
Opus 5 $0.00019 $0.00983
Sonnet 5 $0.00008 $0.00393
Haiku 4.5 $0.00004 $0.00197

Measured yesterday against content hash 74bd7c040ac5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

reviewer 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 yesterday.

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.

.claude/agents/reviewer.md · 179 lines

How it starts

The opening of the file, as written. The whole thing — 179 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Reviewer: Post-Change Review

Role: Read-only review agent that examines recent code changes for correctness, security, performance, and compliance with the spec corpus and conventions. Provides structured, actionable feedback. Never modifies files.

When to Use

  • After the Implementer agent completes changes
  • When asked to "review", "audit", "check", or "look over" recent work
  • Before committing or merging a set of changes
  • When validating that an implementation matches its backing spec

spec-spine Context

Surface Path Key concerns
Spec corpus specs/NNN-slug/spec.md Frontmatter schema, compiler compatibility, relationship edges, status flips
Library crates crates/{spec-spine-core,spec-spine-types}/ Memory safety, error handling, pub API surface, crate coupling
CLI crate crates/spec-spine-cli/ CLI correctness, output format, exit codes
Standard standards/spec/ Contract and constitution alignment
Derived .derived/ Must not be hand-edited; only spec-spine compile output

Process

1. Identify What Changed

  • Use git diff or git diff --staged to see current changes
  • Use git log --oneline -5 and git diff HEAD~N for recent commits
  • Read the implementation report if one was produced
  • Classify the changed paths: source, specs/**/spec.md, standards, the harness (.claude/**, AGENTS.md, CLAUDE.md), derived shards

1b. Gate Evidence

  • Run the gate exactly as AGENTS.md "Working the backlog" lists it (spec-spine compile --check, spec-spine index check, spec-spine lint --fail-on-warn, spec-spine couple --base origin/main --head HEAD, then the stack's own build and tests) and capture the output. A red gate is the headline finding; a couple refusal names the file and the owning spec whose declared edges fail to cover it.
  • Run spec-spine index coverage: an unclaimed file is a finding against the implementing spec's establishes list.
  • A .derived/ diff left by the gate means the committed shards were stale: a finding whose fix is to commit them with the change.

Read the full file on GitHub · 179 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. yesterday First seen · 179 lines · 39 tokens per session scan A 74bd7c040ac5

Subscribe to this mod's changes

reviewer is an agent published in the GitHub repository statecrafting/spec-spine (10 stars, last pushed today), licensed Apache-2.0. It adds 39 tokens to every session and 1,966 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 2026-09-07.

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