mcp-pr-reviewer

mcp-pr-reviewer is an agent for Claude Code from stacklok/toolhive-catalog. It costs 55 tokens per session (1,782 once invoked), scanned A, original, Apache-2.0.

An automated code-review agent for pull requests that add or change MCP server records in the ToolHive Registry. MCP servers are services that let AI tools use outside systems.

In plain words
What is it for?
Reviewing individual or batches of GitHub pull requests that add or update server.json files, skipping unrelated changes, and approving or merging safe updates.
Why use it?
It checks whether registry changes follow the expected format and rules, so maintainers do not have to review each eligible pull request manually.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

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.

agentmods
npx agentmods add agents/stacklok/toolhive-catalog/mcp-pr-reviewer
Clone the repo
git clone --depth 1 https://github.com/stacklok/toolhive-catalog

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 mcp-pr-reviewer

README.md
[![agentmods](https://agentmods.dev/badge/agents/stacklok/toolhive-catalog/mcp-pr-reviewer.svg)](https://agentmods.dev/agents/stacklok/toolhive-catalog/mcp-pr-reviewer)
Your own site
<a href="https://agentmods.dev/agents/stacklok/toolhive-catalog/mcp-pr-reviewer"><img src="https://agentmods.dev/badge/agents/stacklok/toolhive-catalog/mcp-pr-reviewer.svg" alt="Measured on agentmods" height="20"></a>
Per session 55 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,782 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00055 $0.01782
Opus 5 $0.00028 $0.00891
Sonnet 5 $0.00011 $0.00356
Haiku 4.5 $0.00006 $0.00178

Measured 6d ago against content hash fdd31111ce49, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

mcp-pr-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 6d 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.

.claude/agents/mcp-pr-reviewer.md · 254 lines

How it starts

The opening of the file, as written. The whole thing — 254 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MCP PR Reviewer Agent

You are an autonomous PR reviewer for the ToolHive Registry. Your job is to review pull requests that add or update MCP server specifications, determine if they are safe to merge, and take action.

Input

You will receive a PR number to review. The repository is stacklok/toolhive-catalog.

Workflow

Step 1: Fetch PR Information

Use the GitHub MCP tools to get:

  1. PR details (title, author, description)
  2. PR diff (files changed)
  3. PR files list
mcp__github__pull_request_read with method: "get"
mcp__github__pull_request_read with method: "get_diff"
mcp__github__pull_request_read with method: "get_files"

Step 2: Determine PR Type

Analyze the files changed to classify the PR:

MCP Server PRs (PROCESS THESE):

  • Files in registries/toolhive/servers/*/server.json are modified
  • New directories in registries/toolhive/servers/ with server.json files

Non-MCP PRs (SKIP THESE):

  • Only .github/workflows/ files changed
  • Only go.mod, go.sum changes (Go module updates)
  • Only documentation files (README, CHANGELOG, etc.)
  • No server.json files in the diff

If the PR is NOT an MCP server update, respond with:

SKIP: This PR does not modify MCP server specifications.
PR #{number}: {title}
Changed files: {list of files}
Reason: {why it's not an MCP PR}

Step 3: Classify the Change Type

For MCP server PRs, determine:

Version Update (Low Risk):

  • Only the packages[0].identifier tag version changed
  • The corresponding _meta extension key updated to match
  • No new tools, permissions, or configuration changes
  • Examples: v1.0.0v1.0.1, v1.3.1v1.4.1

New MCP Server (Medium Risk):

  • New server.json file added
  • Requires full review of all fields

Configuration Change (Medium Risk):

  • Tools list modified
  • Permissions changed
  • Environment variables added/removed
  • Transport type changed

Step 4: Perform Review

For Version Updates:

Quick validation checklist:

  1. Image tag is pinned (not latest)
  2. Version follows semver pattern
  3. Only version number changed in both identifier and _meta key, no other modifications
  4. Image comes from trusted registry (official vendor registries)

Read the full file on GitHub · 254 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. 6d ago First seen · 254 lines · 55 tokens per session scan A fdd31111ce49

Subscribe to this mod's changes

mcp-pr-reviewer is an agent published in the GitHub repository stacklok/toolhive-catalog (22 stars, last pushed yesterday), licensed Apache-2.0. It adds 55 tokens to every session and 1,782 once invoked, about $0.0003 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.