api-contract

api-contract is an agent for Claude Code from ncoevoet/claude-review-all. It costs 31 tokens per session (669 once invoked), scanned A, original, MIT.

A code-review agent that checks whether changes break public interfaces, such as exported code, API routes, data schemas, or database migrations.

In plain words
What is it for?
Use it when reviewing library APIs, REST or GraphQL endpoints, shared message types, package exports, or database changes.
Why use it?
It helps find changes that could stop other applications, services, or packages from working and identifies where coordination may be needed.

Agent for Claude Code

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

Part of the review-all plugin — 1 skill, 12 agents shipped together

Good fit Use it when reviewing library APIs, REST or GraphQL endpoints, shared message types, package exports, or database changes.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/ncoevoet/claude-review-all/09-api-contract
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/ncoevoet/claude-review-all

Made for: Claude Code.

Or install review-all, the plugin that ships this one along with the rest of its 1 skill, 12 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 api-contract

README.md
[![agentmods](https://agentmods.dev/badge/agents/ncoevoet/claude-review-all/09-api-contract.svg)](https://agentmods.dev/agents/ncoevoet/claude-review-all/09-api-contract)
Your own site
<a href="https://agentmods.dev/agents/ncoevoet/claude-review-all/09-api-contract"><img src="https://agentmods.dev/badge/agents/ncoevoet/claude-review-all/09-api-contract.svg" alt="Measured on agentmods" height="20"></a>
Per session 31 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 669 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 $0.00031 $0.00669
Opus 5 $0.00015 $0.00334
Sonnet 5 $0.00006 $0.00134
Haiku 4.5 $0.00003 $0.00067

Measured 4d ago against content hash 05b6ff8866b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

api-contract 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.

skills/review-all/agents/09-api-contract.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent 9: API & Contract

Detect breaking changes to public surfaces and external contracts.

Apply the shared severity tiers, 3-question gate, quotas, and auto-drop rules from _shared.md.

Inputs you receive: full diff, changed file list, Project Profile, CLAUDE.md rules, Phase 1 gate results.

Skip if

  • No changes to: exported symbols, public methods, schemas/DTOs, REST routes, GraphQL schema, DB migrations, IPC/message types, library package.json exports.
  • Return empty list if diff is purely internal.

Public API changes (libraries / exported modules)

For each changed exported symbol:

  • Removed export — anyone importing it breaks. 🔴 Critical unless dead-code-verified.
  • Renamed export — same as removed for old name.
  • Signature change: parameter added (without default), parameter removed, parameter type narrowed, return type widened, generic constraint tightened — all break callers.
  • Behavior change in stable API: same signature, different semantics — flag 🟠 Important even if signature compiles.

Use ${codegraphTools.callers} (if orchestrator resolved it; see _shared.md) or grep for importers to assess blast radius.

REST / RPC / GraphQL routes

  • Removed route → breaking
  • Changed required request fields (added required, removed, type narrowed) → breaking
  • Changed response shape (removed field, type narrowed) → breaking for consumers
  • Status code changes (e.g. 200 → 204) → breaking
  • Auth requirement added → breaking for unauthenticated callers

Schema / DTO changes

  • Field removed from published schema (Zod, JSON Schema, OpenAPI, protobuf) → breaking
  • Field type narrowed → breaking
  • Required-ness flipped (optional → required) → breaking
  • New required field without default → breaking deserializer

For schema validators (Zod, Yup, Joi, Pydantic, etc.): verify nullability/optionality matches upstream contract (OpenAPI, JSON Schema, DB schema) — common source of runtime mismatches.

DB migrations

  • Column dropped → check not referenced in any code path
  • Column renamed → ensure all code uses new name
  • NOT NULL added → ensure backfill exists
  • Foreign key added → ensure no orphans

Read the full file on GitHub · 66 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 · +1 lines 05b6ff8866b9
  2. 8d ago First seen · 65 lines · 31 tokens per session scan A 882f2296f711

Subscribe to this mod's changes

api-contract is an agent published in the GitHub repository ncoevoet/claude-review-all (25 stars, last pushed 6d ago), licensed MIT. It adds 31 tokens to every session and 669 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.

Related

Other agents, from other repositories

enterprise-saas-reviewer

B2B / enterprise-SaaS pre-implementation reviewer. Outputs threat model TM-{slug}.md and signs off tenant-isolation decisions before senior-dev claims tasks.

avelikiy/great_cto · 40 tokens

integrations-engineer

Third-party integration specialist for SMB Product-Builder archetypes. Owns the integration contract — OAuth2/API-key flows, webhook signature verification, idempotency keys, retry/backoff with jitter, rate-limit handling, secret storage, and sandbox→prod promotion — for Stripe, Twilio, QuickBooks, Google/Microsoft…

avelikiy/great_cto · 106 tokens

migration-import-engineer

Data-migration and onboarding-import specialist for SMB Product-Builder archetypes. Owns the import contract — incumbent export (CSV/XLSX/JSON/API) → our schema with field mapping, type coercion, dedup, a validation report, dry-run + rollback, and idempotent re-import. Source playbooks for ServiceTitan, Toast…

avelikiy/great_cto · 109 tokens

api-platform-reviewer

API platform / dev-API pre-implementation reviewer. Outputs threat model TM-{slug}.md.

avelikiy/great_cto · 25 tokens

inspector-contract-consistency

Pre-delivery inspector for API contract consistency and architectural consistency. Derives the codebase's own conventions and flags deviations. Produces findings only; never edits code.

mumerfarooq-con/asdlc-tools · 39 tokens

api-contract-validator

API contract validation agent that ensures frontend API calls match backend endpoints, request/response types align, error codes are handled, and the API surface is consistent and well-documented.

ShaheerKhawaja/ProductionOS · 39 tokens