Mcp builder

Skill Anoxxx/skillcache/examples/mcp-builder

MRU attention protocol for skills that learn from every use — zero compute

Install

npx -y skills add Anoxxx/skillcache --skill mcp-builder

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

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What its author says it does

Copied from the file, not written here

Guide for creating high-quality MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools. Use when building MCP servers to integrate external APIs or services, whether in Python (FastMCP) or Node/TypeScript (MCP SDK).

The file declares its own license as Original by Anthropic (Apache 2.0). Adapted here as an adaptive skills example.. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.

SKILL.md

2.8 KB, as published. Nobody here has run it

MCP Server Development Guide

Overview

Create MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools. The quality of an MCP server is measured by how well it enables LLMs to accomplish real-world tasks.

High-Level Workflow

Phase 1: Deep Research and Planning

API Coverage vs. Workflow Tools: Balance comprehensive API endpoint coverage with specialized workflow tools. When uncertain, prioritize comprehensive API coverage.

Tool Naming and Discoverability: Clear, descriptive tool names help agents find the right tools quickly. Use consistent prefixes (e.g., github_create_issue, github_list_repos) and action-oriented naming.

Context Management: Agents benefit from concise tool descriptions and the ability to filter/paginate results. Design tools that return focused, relevant data.

Actionable Error Messages: Error messages should guide agents toward solutions with specific suggestions and next steps.

Phase 2: Implementation

Recommended stack:

Language: TypeScript (high-quality SDK support, good compatibility across execution environments)
Transport: Streamable HTTP for remote servers (stateless JSON). stdio for local servers.

For each tool, define:

Input Schema (Zod for TypeScript, Pydantic for Python)
Output Schema (structured content where possible)
Tool Description (concise summary + parameter descriptions)
Annotations (readOnlyHint, destructiveHint, idempotentHint, openWorldHint)

Phase 3: Review and Test

No duplicated code (DRY principle)
Consistent error handling
Full type coverage
Test with MCP Inspector: npx @modelcontextprotocol/inspector

Phase 4: Create Evaluations

Create 10 evaluation questions that are independent, read-only, complex, realistic, verifiable, and stable.

Adaptive Heuristics

This skill maintains a HEURISTICS.md alongside this file. Load it at skill activation. After completing the task:

Did anything unexpected happen? (failure, workaround, surprise, user correction) → Append a one-line lesson to the TOP of HEURISTICS.md.
Did you rely on an existing heuristic? → Move it to the TOP (MRU promotion).
Does a heuristic contradict this SKILL.md? → SKILL.md wins. Note the conflict in the heuristic entry.

Keep heuristics ≤ 20 entries. When full, the bottom entry is the eviction candidate.