security-pass

security-pass is a skill for Claude Code from cyanheads/obsidian-mcp-server. It costs 118 tokens per session (5,026 once invoked), scanned A, original, Apache-2.0.

A security review for an MCP server, which is a program that gives an AI tools, data sources, or reusable prompts. It examines how the server could be misused and how much damage a compromised request could cause.

In plain words
What is it for?
Use it before release, after changing handlers or services, or during periodic audits. It reviews tool and prompt injection, destructive actions, authentication, URLs, file paths, shell commands, regular-expression risks, tenant isolation, and error leakage.
Why use it?
MCP servers add risks because tool results go back into the AI's context and the AI may act on a user's behalf. The review helps find unsafe inputs, excessive permissions, data leaks, and missing separation between customers.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the obsidian-mcp-server plugin — 32 skills, 1 MCP server shipped together

Good fit Use it before release, after changing handlers or services, or during periodic audits. It reviews tool and prompt injection, destructive actions, authentication, URLs, file paths, shell commands, regular-expression risks, tenant isolation, and error leakage.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cyanheads/obsidian-mcp-server/security-pass
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/obsidian-mcp-server --skill security-pass
Clone the repo
git clone --depth 1 https://github.com/cyanheads/obsidian-mcp-server

Made for: Claude Code.

Or install obsidian-mcp-server, the plugin that ships this one along with the rest of its 32 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.

agentmods badge for security-pass

README.md
[![agentmods](https://agentmods.dev/badge/skills/cyanheads/obsidian-mcp-server/security-pass/github.svg)](https://agentmods.dev/skills/cyanheads/obsidian-mcp-server/security-pass)
Your own site
<a href="https://agentmods.dev/skills/cyanheads/obsidian-mcp-server/security-pass"><img src="https://agentmods.dev/badge/skills/cyanheads/obsidian-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.

agentmods 80×15 button for security-pass

Your own site · 80×15
<a href="https://agentmods.dev/skills/cyanheads/obsidian-mcp-server/security-pass"><img src="https://agentmods.dev/badge/skills/cyanheads/obsidian-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 5,026 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 4
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
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 $0.00118 $0.05026
Opus 5 $0.00059 $0.02513
Sonnet 5 $0.00024 $0.01005
Haiku 4.5 $0.00012 $0.00503

Measured 9d ago against content hash bdcf2da08d1c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, 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 9d 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

Copies of this mod

8 near-identical copies found in the catalogue:

skills/security-pass/SKILL.md · 347 lines

How it starts

The opening of the file, as written. The whole thing — 347 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:

  1. Scope — whole server, specific module, or recent diff?
  2. Known concerns — anything the user already suspects?
  3. Deployment context — multi-tenant? public network? auth mode? (stdio / local-http / public-http behave differently)
  4. 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 · 347 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. 9d 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/obsidian-mcp-server (674 stars, last pushed 4d ago), licensed Apache-2.0. It adds 118 tokens to every session and 5,026 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 2 findings (makes network calls, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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