What is security-pass?

A security-review skill for MCP servers, which connect AI agents to tools and data. It checks the server's exposed actions, permissions, inputs, authentication, and possible data leaks.

Use it before release, after changing handlers, or during a security audit of an MCP server.

It helps find ways an agent, user input, or network request could cause unintended access or harmful actions.

security-pass — Skill for Claude Code by cyanheads

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 cyanheads/met-museum-mcp-server --skill security-pass

Clone the repo

git clone --depth 1 https://github.com/cyanheads/met-museum-mcp-server

Made for: Claude Code.

Or install met-museum-mcp-server, the plugin that ships this one along with the rest of its 33 skills, 1 MCP server.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/cyanheads/met-museum-mcp-server/security-pass/github.svg)](https://agentmods.dev/skills/cyanheads/met-museum-mcp-server/security-pass)

Your own site

<a href="https://agentmods.dev/skills/cyanheads/met-museum-mcp-server/security-pass"><img src="https://agentmods.dev/badge/skills/cyanheads/met-museum-mcp-server/security-pass/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/cyanheads/met-museum-mcp-server/security-pass"><img src="https://agentmods.dev/badge/skills/cyanheads/met-museum-mcp-server/security-pass.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 118 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 6,315 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 2 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 100% copy Near-identical to another mod 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.

Model	Per session	Once invoked
Fable 5.1	$0.00118	$0.06315
Opus 5.5	$0.00047	$0.02526
Sonnet 5.5	$0.00024	$0.01263
Haiku 4.5	$0.00012	$0.00632

Measured 12d ago against content hash 4cde0960b972, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

security-pass scanned grade A with 2 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 12d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

**Smell:** `return { body: await fetch(url).then(r => r.text()) }` rendered directly in `format()`. Or: `description: \`Look up ${tenant.customLabel}\`` where `customLabel` is tenant-supplied.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

grep -rnE "\b(exec|spawn|execSync|spawnSync)\b" src/

Origin

This is a copy

100% identical to security-pass — 44 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

framework-skills/security-pass/SKILL.md · 356 lines

How it starts

The opening of the file, as written. The whole thing — 356 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Context

An MCP server is a new attack surface with unique properties — tool output feeds back into the LLM's context, scopes gate what the model can do on the user's behalf, and per-request state must stay tenant-scoped. This skill walks a server through eight axes shaped around what the server builder actually controls. Framework-level concerns (transport, JSON-RPC parsing, auto-correlation, error classification) are out of scope — mcp-ts-core handles those.

Read the code. Don't trust patterns from memory.

When to Use

Before a release
After adding or modifying a batch of handlers or services
Periodically (quarterly-ish)
User asks for a "security review", "audit", "hardening pass", or similar

Inputs

Gather before starting. Ask if unclear:

Scope — whole server, specific module, or recent diff?
Known concerns — anything the user already suspects?
Deployment context — multi-tenant? public network? auth mode? (stdio / local-http / public-http behave differently)
Severity floor — report all findings, or skip medium/low?

Steps

1. Build the map

Surface what you're auditing before diving in. Paths below assume the mcp-ts-core layout — adjust to your repo.

find src/mcp-server/tools/definitions -name "*.tool.ts" | sort
find src/mcp-server/resources/definitions -name "*.resource.ts" 2>/dev/null | sort
find src/mcp-server/prompts/definitions -name "*.prompt.ts" 2>/dev/null | sort
find src/services -maxdepth 1 -mindepth 1 -type d | sort

Note: tool / resource / prompt counts, auth mode, storage provider, upstream APIs, which tools have destructiveHint, which handlers request a consent round via ctx.requestInput, which services hold module-scope state, whether the server reads roots.

If transport is streamable HTTP or SSE, also capture:

Bind address (127.0.0.1 for local, or 0.0.0.0 / public interface?)
Origin allowlist (DNS rebinding mitigation) — configured, or wildcard / missing?
Session ID source (framework CSPRNG, or builder-supplied?) and binding to auth identity
Any unauthenticated routes (/healthz, /sse, metadata endpoints) — do they leak tool lists or tenant hints?
MCP Authorization spec: if implemented, PKCE enforced, token audience (aud) checked, resource indicators used

Read the full file on GitHub · 356 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.

12d ago Changed 4cde0960b972
26d ago Changed · +9 lines 676faff2eac2
1mo ago Changed 359052dfdcef
1mo ago First seen · 347 lines · 118 tokens per session scan A bdcf2da08d1c

Subscribe to this mod's changes

security-pass is a skill published in the GitHub repository cyanheads/met-museum-mcp-server (4 stars, last pushed 10d ago), licensed Apache-2.0. It adds 118 tokens to every session and 6,315 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 2 findings (makes network calls, runs shell commands). It is 100% identical to security-pass, differing in 44 lines, and is treated as a copy.

Security ai-agents art bun cultural-heritage mcp mcp-server

search

Hybrid search across Captain Memo's local memory + skills + observations. Use when the user types /captain-memo:search to retrieve top hits without the model having to decide whether to call searchall on its own.

kalinbogatzevski/captain-memo · 49 tokens

doctor

Health probe across the worker, embedder, summarizer, queue, vector index, schema, cross-AI wiring and plugin install (cache and live versions). Use when the user types /captain-memo:doctor or when something seems wrong.

kalinbogatzevski/captain-memo · 52 tokens

openstreetmap-guide

Use openstreetmap tools for OSM feature surveys, boundary-scoped searches, tag-based discovery, or Overpass QL. Resolve object references and check scope, coverage, and pagination before drawing absence or completeness conclusions.

cyanheads/openstreetmap-mcp-server · 50 tokens

wtf-happened

Retrieve a distilled timeline of the current troubleshooting incident and generate a runbook skeleton. Returns a concise summary by default, or the full untruncated timeline on request.

Wave-Engineering/mcp-server-wtf · 0 tokens

wtf

Launch the WTF flight recorder for a new troubleshooting incident. Archives any prior incident, prompts for an optional title, then puts Claude into flight recorder mode where significant observations, theories, and corrective actions are journaled automatically.