Add a Claude Code skill (`.claude/skills/mcp-docs/`) that provides live
MCP documentation and specification context
## Motivation and Context
The modelcontextprotocol.io site provides both an [MCP
server](https://modelcontextprotocol.io/mcp) and an
[llms.txt](https://modelcontextprotocol.io/llms.txt) index for
machine-readable access to the documentation. This skill leverages both
to give Claude live access to the current spec during development.
## How Has This Been Tested?
The skill was evaluated on 3 realistic scenarios (implementation, code
review, spec question) comparing with-skill vs without-skill baseline:
- **Pass rate**: 100% vs 67% — skill consistently cites spec sources and
uses RFC 2119 language
- **Token efficiency**: 41% fewer tokens on average (44k vs 75k) — goes
directly to spec instead of reverse-engineering from codebase
- **Accuracy**: with-skill discovered URL mode elicitation (new in spec
2025-11-25) that baseline missed entirely
- **Description triggering**: optimized through 5 iterations of
automated trigger evaluation against 20 test prompts
## Breaking Changes
None
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [x] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
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