Borrowing it
Nothing to install: this file belongs to timothywarner-org/context-engineering. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/timothywarner-org/context-engineering/main/.claude/skills/mcp-server-builder/SKILL.mdgit clone --depth 1 https://github.com/timothywarner-org/context-engineeringWrote 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.
[](https://agentmods.dev/skills/timothywarner-org/context-engineering/mcp-server-builder)<a href="https://agentmods.dev/skills/timothywarner-org/context-engineering/mcp-server-builder"><img src="https://agentmods.dev/badge/skills/timothywarner-org/context-engineering/mcp-server-builder/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.
<a href="https://agentmods.dev/skills/timothywarner-org/context-engineering/mcp-server-builder"><img src="https://agentmods.dev/badge/skills/timothywarner-org/context-engineering/mcp-server-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00071 | $0.01366 |
| Opus 5.5 | $0.00028 | $0.00546 |
| Sonnet 5.5 | $0.00014 | $0.00273 |
| Haiku 4.5 | $0.00007 | $0.00137 |
Grade A, and why
mcp-server-builder 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 2mo 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.
How it starts
The opening of the file, as written. The whole thing — 217 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MCP Server Builder
Build production-ready MCP servers with proper tool schemas, resources, and transport configuration.
Quick Start
Python (FastMCP)
from mcp.server.fastmcp import FastMCP
mcp = FastMCP("my-server")
@mcp.tool()
async def greet(name: str) -> str:
"""Greet someone by name."""
return f"Hello, {name}!"
if __name__ == "__main__":
mcp.run()
JavaScript
import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
const server = new Server({ name: "my-server", version: "1.0.0" }, { capabilities: { tools: {} } });
server.setRequestHandler(ListToolsRequestSchema, async () => ({
tools: [{ name: "greet", description: "Greet someone", inputSchema: { type: "object", properties: { name: { type: "string" } }, required: ["name"] } }]
}));
server.setRequestHandler(CallToolRequestSchema, async (request) => {
if (request.params.name === "greet") {
return { content: [{ type: "text", text: `Hello, ${request.params.arguments.name}!` }] };
}
});
const transport = new StdioServerTransport();
await server.connect(transport);
Language Selection
| Criterion | Python (FastMCP) | JavaScript/TypeScript |
|---|---|---|
| Rapid prototyping | Best | Good |
| Type safety | Via Pydantic | Native (TS) |
| Async I/O | Native | Native |
| Package ecosystem | pip/uv | npm |
| Production deploy | Container Apps | Container Apps |
Project Structure
Python
my-mcp/
├── pyproject.toml
├── src/
│ └── my_mcp/
│ ├── __init__.py
│ ├── server.py # FastMCP instance
│ └── tools/ # Tool implementations
├── data/ # Persistent storage
└── .env.example
JavaScript/TypeScript
my-mcp/
├── package.json
├── src/
│ ├── index.js # Server entry
│ └── tools/ # Tool handlers
├── data/ # Persistent storage
└── .env.example
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.
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.
- 2mo ago First seen · 217 lines · 71 tokens per session scan A 8ce7ecb1ee64
mcp-server-builder is a skill published in the GitHub repository timothywarner-org/context-engineering (27 stars, last pushed 1mo ago), licensed MIT. It adds 71 tokens to every session and 1,366 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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