os-mcp

os-mcp is a skill for Claude Code from naveedharri/benai-skills. It costs 115 tokens per session (1,716 once invoked), scanned A, original, MIT.

A deployment tool that runs an MCP server on your Railway account and connects Claude to an Obsidian vault through Relay.md. MCP is a way for an AI client to access tools and data from another service.

In plain words
What is it for?
Use it to deploy the Relay server, then let Claude clients read and update notes and folders in an Obsidian vault.
Why use it?
It provides a hosted connection for reading and writing vault content without requiring a separate server repository. After signing in, the server discovers the user’s Relay vault and folders.

Skill for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable. Also seen: mentions Claude Code.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the agentic-os plugin — 4 skills shipped together

Good fit Use it to deploy the Relay server, then let Claude clients read and update notes and folders in an Obsidian vault.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add naveedharri/benai-skills
Claude Code
/plugin install agentic-os

Made for: Claude Code.

Or install agentic-os, the plugin that ships this one along with the rest of its 4 skills.

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 os-mcp

README.md
[![agentmods](https://agentmods.dev/badge/skills/naveedharri/benai-skills/os-mcp/github.svg)](https://agentmods.dev/skills/naveedharri/benai-skills/os-mcp)
Your own site
<a href="https://agentmods.dev/skills/naveedharri/benai-skills/os-mcp"><img src="https://agentmods.dev/badge/skills/naveedharri/benai-skills/os-mcp/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 os-mcp

Your own site · 80×15
<a href="https://agentmods.dev/skills/naveedharri/benai-skills/os-mcp"><img src="https://agentmods.dev/badge/skills/naveedharri/benai-skills/os-mcp.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 115 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,716 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00115 $0.01716
Opus 5 $0.00057 $0.00858
Sonnet 5 $0.00023 $0.00343
Haiku 4.5 $0.00012 $0.00172

Measured 12d ago against content hash 4fbbc5fb0a35, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

os-mcp scanned grade A with 1 finding 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.

The scan reads SKILL.md. This mod also ships 12 executable files (reference/relay-mcp-server/src/auth/clients.ts, reference/relay-mcp-server/src/auth/codes.ts, reference/relay-mcp-server/src/auth/jsonfile.ts, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

curl https://<the-domain>/health
plugins/agentic-os/skills/os-mcp/SKILL.md · 177 lines

How it starts

The opening of the file, as written. The whole thing — 177 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OS MCP — Railway Deploy

This skill deploys the Relay MCP v2 server to the user's own Railway account. The MCP source is bundled at ${CLAUDE_PLUGIN_ROOT}/skills/os-mcp/reference/relay-mcp-server/ — copy from there, do not fetch from anywhere else. The deployed server lets Claude clients (Claude Code or claude.ai) read/write the user's Obsidian vault by talking to the Relay.md sync protocol.

What the user provides

One thing: a Railway account token — created at https://railway.com/account/tokens.

That's it. After deploy, the user signs in with their Relay.md credentials via OAuth; the MCP then auto-discovers their relay vault and the folders inside it via PocketBase. No vault GUIDs, no folder maps.

Values set automatically by the skill

Var Source Value
RELAY_API_URL preset https://api.system3.md
PB_AUTH_URL preset https://auth.system3.md
PB_COLLECTION preset users
DATA_DIR preset /data
PORT preset 3000
JWT_SECRET auto-generated openssl rand -hex 32
STATIC_MCP_BEARER auto-generated openssl rand -hex 24
ALLOWED_EMAILS preset blank (any authenticated Relay.md user)
RELAY_AUTH_TOKEN preset blank (OAuth-only; no static fallback)
RELAY_ID not set auto-discovered at runtime per user
PUBLIC_URL derived from railway domain after first deploy

Save the generated STATIC_MCP_BEARER in the chat for the user — they'd use it for any CLI/script access bypassing OAuth.

If the user has multiple Relay vaults, the MCP auto-picks the first one. They can call the vault_relays tool after connecting to see which is active and pin a different one by setting RELAY_ID in railway variables.


Workflow

Execute in order. Confirm each step before moving on.

Step 1 — Verify Railway CLI

railway --version

If missing:

  • macOS: brew install railway
  • Anywhere: npm i -g @railway/cli

Read the full file on GitHub · 177 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. 12d ago First seen · 177 lines · 115 tokens per session scan A 4fbbc5fb0a35

Subscribe to this mod's changes

os-mcp is a skill published in the GitHub repository naveedharri/benai-skills (61 stars, last pushed today), licensed MIT. It adds 115 tokens to every session and 1,716 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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