build-mcp-server

build-mcp-server is a skill for Claude Code from thevibeworks/claude-code-docs. It costs 111 tokens per session (2,791 once invoked), scanned A, a copy of build-mcp-server, MIT.

A development guide for building an MCP server, which lets an AI assistant use tools and connect to services or data sources.

In plain words
What is it for?
Use it to design and build integrations for cloud APIs, local processes, filesystems, desktop apps, hardware, or operating-system services.
Why use it?
It helps choose the right server type and plan the connection before implementation, reducing the risk of building the wrong integration.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions Claude Code.

Part of the mcp-server-dev plugin — 3 skills shipped together

Good fit Use it to design and build integrations for cloud APIs, local processes, filesystems, desktop apps, hardware, or operating-system services.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/thevibeworks/claude-code-docs/build-mcp-server
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 thevibeworks/claude-code-docs --skill build-mcp-server
Clone the repo
git clone --depth 1 https://github.com/thevibeworks/claude-code-docs

Made for: Claude Code.

Or install mcp-server-dev, the plugin that ships this one along with the rest of its 3 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 build-mcp-server

README.md
[![agentmods](https://agentmods.dev/badge/skills/thevibeworks/claude-code-docs/build-mcp-server.svg)](https://agentmods.dev/skills/thevibeworks/claude-code-docs/build-mcp-server)
Your own site
<a href="https://agentmods.dev/skills/thevibeworks/claude-code-docs/build-mcp-server"><img src="https://agentmods.dev/badge/skills/thevibeworks/claude-code-docs/build-mcp-server.svg" alt="Measured on agentmods" height="20"></a>
Per session 111 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,791 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00111 $0.02791
Opus 5 $0.00056 $0.01396
Sonnet 5 $0.00022 $0.00558
Haiku 4.5 $0.00011 $0.00279

Measured 4d ago against content hash 088cd04be7f0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

build-mcp-server 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 4d 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.

Origin

This is a copy

100% identical to build-mcp-server — 0 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.

content/github/claude-plugins-official/plugins/mcp-server-dev/skills/build-mcp-server/SKILL.md · 222 lines

How it starts

The opening of the file, as written. The whole thing — 222 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Build an MCP Server

You are guiding a developer through designing and building an MCP server that works seamlessly with Claude. MCP servers come in many forms — picking the wrong shape early causes painful rewrites later. Your first job is discovery, not code.

Load Claude-specific context first. The MCP spec is generic; Claude has additional auth types, review criteria, and limits. Before answering questions or scaffolding, fetch https://claude.com/docs/llms-full.txt (the full export of the Claude connector docs) so your guidance reflects Claude's actual constraints.

Do not start scaffolding until you have answers to the questions in Phase 1. If the user's opening message already answers them, acknowledge that and skip straight to the recommendation.


Phase 1 — Interrogate the use case

Ask these questions conversationally (batch them into one message, don't interrogate one-at-a-time). Adapt wording to what the user has already told you.

1. What does it connect to?

If it connects to… Likely direction
A cloud API (SaaS, REST, GraphQL) Remote HTTP server
A local process, filesystem, or desktop app MCPB or local stdio
Hardware, OS-level APIs, or user-specific state MCPB
Nothing external — pure logic / computation Either — default to remote

2. Who will use it?

  • Just me / my team, on our machines → Local stdio is acceptable (easiest to prototype)
  • Anyone who installs it → Remote HTTP (strongly preferred) or MCPB (if it must be local)
  • Users of Claude desktop who want UI widgets → MCP app (remote or MCPB)

3. How many distinct actions does it expose?

This determines the tool-design pattern — see Phase 3.

  • Under ~15 actions → one tool per action
  • Dozens to hundreds of actions (e.g. wrapping a large API surface) → search + execute pattern

4. Does a tool need mid-call user input or rich display?

  • Simple structured input (pick from list, enter a value, confirm) → Elicitation — spec-native, zero UI code. Host support is rolling out (Claude Code ≥2.1.76) — always pair with a capability check and fallback. See references/elicitation.md.
  • Rich/visual UI (charts, custom pickers with search, live dashboards) → MCP app widgets — iframe-based, needs @modelcontextprotocol/ext-apps. See build-mcp-app skill.
  • Neither → plain tool returning text/JSON.

Read the full file on GitHub · 222 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. 4d ago First seen · 222 lines · 111 tokens per session scan A 088cd04be7f0

Subscribe to this mod's changes

build-mcp-server is a skill published in the GitHub repository thevibeworks/claude-code-docs (39 stars, last pushed yesterday), licensed MIT. It adds 111 tokens to every session and 2,791 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to build-mcp-server, differing in 0 lines, and is treated as a copy.