design-mcp-server

design-mcp-server is a skill for Claude Code from wallieinformal201/pentest-mcp-server. It costs 62 tokens per session (13,567 once invoked), scanned A, a copy of design-mcp-server, Apache-2.0.

A planning guide for designing a new MCP server, which lets an AI assistant use tools and data from another system. It produces a design document before implementation.

In plain words
What is it for?
Use it to plan a server that exposes an API, database, file system, or internal capability to AI assistants, or to plan a major new area in an existing server.
Why use it?
It helps clarify the server’s users, data sources, permissions, and scope before code is written.

Skill for Claude Code

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

Part of the @cyanheads/pentest-mcp-server plugin — 31 skills shipped together

Good fit Use it to plan a server that exposes an API, database, file system, or internal capability to AI assistants, or to plan a major new area in an existing server.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/wallieinformal201/pentest-mcp-server/design-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 wallieinformal201/pentest-mcp-server --skill design-mcp-server
Clone the repo
git clone --depth 1 https://github.com/wallieinformal201/pentest-mcp-server

Made for: Claude Code.

Or install @cyanheads/pentest-mcp-server, the plugin that ships this one along with the rest of its 31 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 design-mcp-server

README.md
[![agentmods](https://agentmods.dev/badge/skills/wallieinformal201/pentest-mcp-server/design-mcp-server/github.svg)](https://agentmods.dev/skills/wallieinformal201/pentest-mcp-server/design-mcp-server)
Your own site
<a href="https://agentmods.dev/skills/wallieinformal201/pentest-mcp-server/design-mcp-server"><img src="https://agentmods.dev/badge/skills/wallieinformal201/pentest-mcp-server/design-mcp-server/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 design-mcp-server

Your own site · 80×15
<a href="https://agentmods.dev/skills/wallieinformal201/pentest-mcp-server/design-mcp-server"><img src="https://agentmods.dev/badge/skills/wallieinformal201/pentest-mcp-server/design-mcp-server.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 13,567 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 91% 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 $0.00062 $0.13567
Opus 5 $0.00031 $0.06783
Sonnet 5 $0.00012 $0.02713
Haiku 4.5 $0.00006 $0.01357

Measured 11d ago against content hash bd81ccb7d365, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

design-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 11d 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

91% identical to design-mcp-server — 123 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.

skills/design-mcp-server/SKILL.md · 660 lines

How it starts

The opening of the file, as written. The whole thing — 660 lines — stays where its author put it; the contents beside it link to each section on GitHub.

When to Use

  • User says "I want to build a ___ MCP server"
  • User has an API, database, or system they want to expose to LLMs
  • User wants to plan tools before scaffolding
  • Existing server needs a new capability area (design the addition, not just a single tool)

Do NOT use for single-tool additions — use add-tool directly.

Inputs

Gather before designing. Ask the user if not obvious from context:

  1. Domain — what system, API, or capability is this server wrapping? Or is the server providing internal capability with no external dependency (computation, text/code utilities, in-memory state)?
  2. Data sources / source of truth — APIs, databases, file systems, external services? Or is the server itself the source (in-memory state, pure computation, local-only utility, embedded model)?
  3. Target users — what will the LLM (and its human) be trying to accomplish?
  4. Scope constraints — read-only? write access? admin operations? what's off-limits?

If the domain has a public API, read its docs before designing. For internal-only servers, skip API research and go straight to user goals. Don't design from vibes either way.

Server scope and audience

Before committing to a server boundary, answer: what workflow does this server serve, and who is the audience?

The unit of a server is a user workflow, not an API. A single rich API can earn its own server when the audience is large and the API surface supports a full workflow (PubMed for literature research, SEC EDGAR for financial analysis, Shodan for internet-wide device intelligence). Multiple APIs should collapse into one server when they serve the same workflow from different angles — a "threat intelligence" server that aggregates VirusTotal, AbuseIPDB, and GreyNoise is more useful than three separate servers because the user's goal is "assess this indicator," not "query VirusTotal."

Don't default to one-API-one-server. That's the right call when the API is deep enough and the audience is large enough, but it's not the starting point. The starting point is the workflow:

Read the full file on GitHub · 660 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. 11d ago First seen · 660 lines · 62 tokens per session scan A bd81ccb7d365

Subscribe to this mod's changes

design-mcp-server is a skill published in the GitHub repository wallieinformal201/pentest-mcp-server (2 stars, last pushed 2d ago), licensed Apache-2.0. It adds 62 tokens to every session and 13,567 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to design-mcp-server, differing in 123 lines, and is treated as a copy.