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.
npx agentmods add skills/chris-debug-0225/learn-claude-code-java/mcp-buildernpx skills add Chris-debug-0225/learn-claude-code-java --skill mcp-buildergit clone --depth 1 https://github.com/Chris-debug-0225/learn-claude-code-javaWhat 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 | $0.00038 | $0.00308 |
| Opus 5 | $0.00019 | $0.00154 |
| Sonnet 5 | $0.00008 | $0.00062 |
| Haiku 4.5 | $0.00004 | $0.00031 |
Grade A, and why
mcp-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 2d 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.
What it actually says
MCP Server Building Skill
You now have expertise in building MCP (Model Context Protocol) servers. MCP enables Claude to interact with external services through a standardized protocol.
What is MCP?
MCP servers expose:
- Tools: Functions Claude can call
- Resources: Data Claude can read
- Prompts: Pre-built prompt templates
Quick Start: Python MCP Server
from mcp.server import Server
from mcp.server.stdio import stdio_server
server = Server("my-server")
@server.tool()
async def hello(name: str) -> str:
return f"Hello, {name}!"
TypeScript MCP Server
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" });
const transport = new StdioServerTransport();
server.connect(transport);
Best Practices
- Clear tool descriptions
- Input validation
- Meaningful error handling
- Async for I/O
- Security first
- Idempotent tools when possible
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.
- 2d ago First seen · 49 lines · 38 tokens per session scan A bffd183c7805
mcp-builder is a skill published in the GitHub repository Chris-debug-0225/learn-claude-code-java (100 stars, last pushed 5mo ago), licensed MIT. It adds 38 tokens to every session and 308 once invoked, about $0.0002 per session on Opus 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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