mcp-guide

mcp-guide is a skill for Claude Code, Codex from pbc-os/smb-starter-kit. It costs 54 tokens per session (2,696 once invoked), scanned A, original, MIT.

An educational guide to MCP, or Model Context Protocol, an open standard that lets AI agents discover and use external services through a consistent interface. An MCP server is a service that exposes those tools to the agent.

In plain words
What is it for?
Understanding MCP, comparing it with command-line tools, deciding whether to build an MCP server, and learning how agents connect to external services.
Why use it?
It helps you decide whether an MCP server is needed or whether a simpler command-line tool and skill are enough. It explains how integrations differ with and without a shared standard.

Skill for Claude CodeCodex

Which agent this was written for is unclear — built for cline. Also seen: mentions Claude Code; built for cline.

Good fit Understanding MCP, comparing it with command-line tools, deciding whether to build an MCP server, and learning how agents connect to external services.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pbc-os/smb-starter-kit/mcp-guide
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 pbc-os/smb-starter-kit --skill mcp-guide
Clone the repo
git clone --depth 1 https://github.com/pbc-os/smb-starter-kit

Made for: Claude Code, Codex.

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-guide

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/pbc-os/smb-starter-kit/mcp-guide"><img src="https://agentmods.dev/badge/skills/pbc-os/smb-starter-kit/mcp-guide.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,696 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 $0.00054 $0.02696
Opus 5 $0.00027 $0.01348
Sonnet 5 $0.00011 $0.00539
Haiku 4.5 $0.00005 $0.00270

Measured 9d ago against content hash 06ec3fd8d6ec, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

mcp-guide 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 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.

| You're doing simple CRUD operations | **Direct API calls** via curl/scripts in a skill |
skills/tier-1-foundation/mcp-guide/SKILL.md · 255 lines

How it starts

The opening of the file, as written. The whole thing — 255 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MCP Guide

Understand MCP so you can decide if you need one — and build one if you do.

This is an educational skill. It doesn't install anything. It teaches agents and humans what MCP (Model Context Protocol) is, when it's the right tool, and when simpler alternatives (CLIs + skills) are better.

Triggers

  • "what is MCP"
  • "should I build an MCP server"
  • "MCP vs CLI"
  • "how do MCPs work"
  • "build an MCP"
  • "connect [service] to my agent"
  • When an agent is trying to figure out how to integrate an external service

What Is MCP?

MCP (Model Context Protocol) is an open standard that lets AI agents talk to external services through a structured interface. Think of it as a universal adapter between your AI agent and the tools it uses.

The Restaurant Metaphor

Without MCP With MCP
You walk into every restaurant and shout your order in English, hoping someone understands Every restaurant has the same ordering kiosk with the same interface — you always know how to order

Without MCP, every integration is custom. With MCP, there's a standard way for agents to discover tools, understand their inputs/outputs, and call them.

How It Works

Your Agent (Claude Code, etc.)
    ↕ MCP Protocol (JSON-RPC)
MCP Server (runs locally or remotely)
    ↕ API calls
External Service (Gmail, Slack, Square, etc.)

An MCP server:

  1. Advertises tools — "I can send emails, read inbox, create filters"
  2. Describes each tool — "send_email takes: to, subject, body. Returns: message_id"
  3. Executes tool calls — Agent says "call send_email with these params" → server makes the API call → returns the result
  4. Handles auth — Server manages API keys, OAuth tokens, etc.

The agent never touches the raw API. It just calls structured tools.

When Do You Need an MCP?

You probably DON'T need an MCP if:

Situation Better Alternative
There's already a good CLI for the service CLI + skill (like gws + our Google Workspace skills)
You're doing simple CRUD operations Direct API calls via curl/scripts in a skill
Your agent only needs read access CLI + skill with read-only commands
You're the only user Scripts + skill — less infra to maintain
The service has a well-designed REST API Skill with curl patterns — teach the agent to call it directly

Read the full file on GitHub · 255 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 255 lines · 54 tokens per session scan A 06ec3fd8d6ec

Subscribe to this mod's changes

mcp-guide is a skill published in the GitHub repository pbc-os/smb-starter-kit (10 stars, last pushed 3mo ago), licensed MIT. It adds 54 tokens to every session and 2,696 once invoked, about $0.0003 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 2026-08-31.

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