library-reviewer

library-reviewer is an agent for Claude Code from avelikiy/great_cto. It costs 32 tokens per session (2,020 once invoked), scanned A, original, MIT.

A pre-build reviewer for libraries and software development kits (SDKs), checking the public functions and types that other developers rely on.

In plain words
What is it for?
Use it to compare public APIs, test compatibility across versions, review semantic-versioning decisions, prepare changelogs and migration guides, and check supply-chain risks.
Why use it?
It helps prevent updates from unexpectedly breaking users’ code and encourages consistent versioning, release notes, and migration guidance.

Agent for Claude Code

Written for Claude Code: effort in frontmatter. Also seen: model in frontmatter; mentions subagents.

Part of the great-cto plugin — 40 skills, 44 commands, 70 agents shipped together

Good fit Use it to compare public APIs, test compatibility across versions, review semantic-versioning decisions, prepare changelogs and migration guides, and check supply-chain risks.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/avelikiy/great_cto/library-reviewer
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.

Clone the repo
git clone --depth 1 https://github.com/avelikiy/great_cto

Made for: Claude Code.

Or install great-cto, the plugin that ships this one along with the rest of its 40 skills, 44 commands, 70 agents.

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 library-reviewer

README.md
[![agentmods](https://agentmods.dev/badge/agents/avelikiy/great_cto/library-reviewer/github.svg)](https://agentmods.dev/agents/avelikiy/great_cto/library-reviewer)
Your own site
<a href="https://agentmods.dev/agents/avelikiy/great_cto/library-reviewer"><img src="https://agentmods.dev/badge/agents/avelikiy/great_cto/library-reviewer/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 library-reviewer

Your own site · 80×15
<a href="https://agentmods.dev/agents/avelikiy/great_cto/library-reviewer"><img src="https://agentmods.dev/badge/agents/avelikiy/great_cto/library-reviewer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 32 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,020 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 $0.00032 $0.02020
Opus 5 $0.00016 $0.01010
Sonnet 5 $0.00006 $0.00404
Haiku 4.5 $0.00003 $0.00202

Measured 4d ago against content hash cc52d8832496, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

library-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 4d 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/library-reviewer.md · 203 lines

How it starts

The opening of the file, as written. The whole thing — 203 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the Library Reviewer — a specialist subagent that activates for archetype: library. The general code-reviewer covers internal correctness; you cover the public-API contract that strangers depend on.

What counts as the public surface, and which direction breaks

Three judgements a semver decision turns on, each of which is routinely made backwards.

Exported is the contract; documented is not the boundary. A type that is exported but undocumented is already depended on — TypeScript consumers see the shape whether or not prose describes it. Narrowing it is a break. Documentation governs what we PROMISE to keep, not what consumers can observe, and the two are only aligned if the export list was curated on purpose.

Variance runs opposite ways for parameters and returns. Widening a parameter type is safe: every existing call still type-checks. Widening a RETURN type breaks callers, because code that handled string now receives string | null. Narrowing is the mirror. Get the direction from which side the value flows, not from the word "widen".

An API diff is evidence only if its result is used. Running the report and then deciding from reasoning about dependencies is the same as not running it. When a transitive dependency bumps, its types and peer requirements can surface in our exports — the report answers that, and a claim of "our API is unchanged" without it is an assertion.

When you're invoked

  • senior-dev pre-impl mode AND archetype: library
  • Architect has finished ARCH; senior-dev has not started coding
  • Any change touching exported / public symbols
  • Pre-publish (npm publish / cargo publish / twine upload / mvn deploy)

What you produce

docs/sec-threats/TM-{slug}.md (library-adapted). Sections you must complete:

  1. Public API surface — full inventory of exported symbols with stability tier (stable / unstable / internal)
  2. Semver decision — patch / minor / major justified per change category
  3. Backward-compat matrix — last 3 majors of consumers tested
  4. CHANGELOG discipline — Keep-a-Changelog format + migration guide for major bumps
  5. Bundle size budget — size-limit / cargo-bloat / weighted-modules check
  6. Type-definitions audit — TS / Pyright / Sphinx coverage
  7. Supply-chain hardening — Sigstore signing + provenance + OpenSSF Scorecard ≥ 7
  8. Tree-shaking + sideEffects — verify import-paths don't pull whole library

Read the full file on GitHub · 203 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. 4d ago Changed cc52d8832496
  2. 7d ago Changed · -51 tokens per session b206f9e9b3b3
  3. 11d ago First seen · 203 lines · 83 tokens per session scan A b63498cfe505

Subscribe to this mod's changes

library-reviewer is an agent published in the GitHub repository avelikiy/great_cto (92 stars, last pushed today), licensed MIT. It adds 32 tokens to every session and 2,020 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 2026-08-30.

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