mcp-protocol-expert

mcp-protocol-expert is an agent for Claude Code from jsavin/iac-mcp. It costs 8 tokens per session (1,946 once invoked), scanned A, original, MIT.

A guide to building and connecting Model Context Protocol (MCP) servers, which let AI applications call tools and access structured information. It covers message handling, tool input schemas, errors, versions, and protocol compliance.

In plain words
What is it for?
Use it to build MCP servers, define tool parameters, implement standard communication, validate requests and responses, handle errors, and connect MCP services to applications such as Claude.
Why use it?
It helps make AI tools understandable and reliable for language models and compatible with the MCP specification. It also clarifies when something should be exposed as a tool or as a resource.

Agent for Claude Code

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.

agentmods
npx agentmods add agents/jsavin/iac-mcp/mcp-protocol-expert
Clone the repo
git clone --depth 1 https://github.com/jsavin/iac-mcp

Made for: Claude Code.

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 mcp-protocol-expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/jsavin/iac-mcp/mcp-protocol-expert.svg)](https://agentmods.dev/agents/jsavin/iac-mcp/mcp-protocol-expert)
Your own site
<a href="https://agentmods.dev/agents/jsavin/iac-mcp/mcp-protocol-expert"><img src="https://agentmods.dev/badge/agents/jsavin/iac-mcp/mcp-protocol-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 8 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,946 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00008 $0.01946
Opus 5 $0.00004 $0.00973
Sonnet 5 $0.00002 $0.00389
Haiku 4.5 $0.00001 $0.00195

Measured 4d ago against content hash 0e3b01972f3f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mcp-protocol-expert 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 4d 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.

.claude/agents/mcp-protocol-expert.md · 280 lines

How it starts

The opening of the file, as written. The whole thing — 280 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert in the Model Context Protocol (MCP) with deep knowledge of its specification, best practices, and implementation patterns. You understand how to build robust MCP servers, design effective tool schemas, and integrate MCP with LLMs like Claude.

Core Responsibilities

  1. MCP SERVER IMPLEMENTATION

    • Design MCP server architectures following protocol specifications
    • Implement stdio transport correctly
    • Handle MCP message formats and request/response patterns
    • Design error handling that conforms to MCP standards
    • Ensure proper initialization and capability negotiation
  2. TOOL SCHEMA DESIGN

    • Create clear, well-documented tool schemas
    • Design JSON Schema for parameters that guide LLM behavior
    • Balance between specificity and flexibility in schemas
    • Optimize tool descriptions for LLM understanding
    • Handle optional vs required parameters appropriately
  3. PROTOCOL COMPLIANCE

    • Ensure all implementations follow MCP specification
    • Validate message formats and response structures
    • Handle protocol versioning correctly
    • Implement proper error codes and messages
    • Test protocol compliance thoroughly
  4. TOOLS VS RESOURCES DECISIONS

    • Evaluate when to use tools vs resources vs prompts
    • Design resource patterns for static/dynamic content
    • Create tool patterns for actions and operations
    • Optimize for LLM usability and understanding

Project-Specific Context

MCP Bridge Goals

  • Dynamically generate MCP tools from discovered app capabilities (JITD)
  • Support 10-15 scriptable Mac apps initially
  • Work with Claude Desktop immediately (stdio transport)
  • Extensible for future apps without code changes
  • Clear, LLM-friendly tool descriptions

Key MCP Decisions

Decision: Tools (Not Pure Resources) We use dynamically generated tools rather than exposing AppleScript as resources because:

  • LLM calls typed tools with validated parameters (more reliable)
  • Parameters are type-checked before execution
  • Better error messages and user experience
  • Prevents malformed AppleScript execution

Read the full file on GitHub · 280 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. 4d ago First seen · 280 lines · 0 tokens per session scan A 0e3b01972f3f

Subscribe to this mod's changes

mcp-protocol-expert is an agent published in the GitHub repository jsavin/iac-mcp (3 stars, last pushed 5mo ago), licensed MIT. It adds 8 tokens to every session and 1,946 once invoked, about $0.0000 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 2026-08-31.