Claude Code MCP Expert

Claude Code MCP Expert

Connect Claude Code to external tools, databases, and services using Model Context Protocol (MCP).

When to Use

• User wants to connect external services (GitHub, Jira, Sentry)
• User needs database access (PostgreSQL, MongoDB)
• User asks about MCP configuration or .mcp.json
• User has MCP connection or authentication issues

What is MCP?

Model Context Protocol (MCP) is an open standard that connects AI agents to:

• External APIs (GitHub, Jira, Notion, Slack)
• Databases (PostgreSQL, MongoDB, MySQL)
• File systems (local, Google Drive)
• Custom integrations

Quick Start

# Add an HTTP server
claude mcp add --transport http sentry https://mcp.sentry.dev/​mcp

# Add an SSE server
claude mcp add --transport sse atlassian https://mcp.atlassian.com/​v1/​sse

# Add a stdio server (npm package)
claude mcp add --transport stdio github -- npx -y @modelcontextprotocol/​server-github

# Manage servers interactively
/​mcp

Transport Types

HTTP (Most Common)

For cloud services with REST-like endpoints.

claude mcp add --transport http sentry https://mcp.sentry.dev/​mcp
claude mcp add --transport http github https://api.github.com/​mcp
claude mcp add --transport http notion https://mcp.notion.com/​mcp

SSE (Server-Sent Events)

For streaming services.

claude mcp add --transport sse atlassian https://mcp.atlassian.com/​v1/​sse
claude mcp add --transport sse asana https://mcp.asana.com/​sse

stdio (Local/​NPM Packages)

For local tools or npm packages.

claude mcp add --transport stdio postgres \
  --env POSTGRES_CONNECTION_STRING="postgresql://user:pass@localhost:5432/​db" \
  -- npx -y @modelcontextprotocol/​server-postgres

claude mcp add --transport stdio filesystem \
  --env ALLOWED_DIRECTORIES="/​path/​to/​dir" \
  -- npx -y @modelcontextprotocol/​server-filesystem

Popular Integrations

Development Tools

Project Management

Databases

# PostgreSQL
claude mcp add --transport stdio postgres \
  --env POSTGRES_CONNECTION_STRING="postgresql://localhost:5432/​mydb" \
  -- npx -y @modelcontextprotocol/​server-postgres

# MongoDB
claude mcp add --transport stdio mongodb \
  --env MONGODB_URI="mongodb://localhost:27017/​mydb" \
  -- npx -y @modelcontextprotocol/​server-mongodb

Communication

# Slack
claude mcp add --transport stdio slack \
  --env SLACK_BOT_TOKEN=xoxb-your-token \
  --env SLACK_TEAM_ID=T1234567 \
  -- npx -y @modelcontextprotocol/​server-slack

# Gmail
claude mcp add --transport stdio gmail \
  -- npx -y @modelcontextprotocol/​server-gmail

Configuration Files

.mcp.json Structure

{
  "mcpServers": {
    "server-name": {
      "transport": "http",
      "url": "https://mcp.service.com/​mcp"
    },
    "database": {
      "transport": "stdio",
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/​server-postgres"],
      "env": {
        "POSTGRES_CONNECTION_STRING": "postgresql://localhost/​db"
      }
    }
  }
}

Configuration Scopes

Add with Scope

claude mcp add --transport http sentry https://mcp.sentry.dev/​mcp --user     # Global
claude mcp add --transport http linear https://mcp.linear.app/​mcp --project  # Team
claude mcp add --transport http notion https://mcp.notion.com/​mcp --local    # Personal override

Authentication

OAuth (Recommended)

# Install server
claude mcp add --transport http github https://api.github.com/​mcp

# Authenticate via /​mcp command
/​mcp
# Select: Authenticate with server
# Browser opens → authorize → done

API Keys (Environment Variables)

claude mcp add --transport stdio server-name \
  --env API_KEY=your_api_key \
  -- npx -y package-name

Via settings.json

{
  "env": {
    "GITHUB_TOKEN": "ghp_xxxxx",
    "SENTRY_AUTH_TOKEN": "sntrys_xxxxx"
  }
}

Using MCP Features

MCP Tools

Once connected, use naturally:

"Check Sentry for errors in the last 24 hours"
"Create a PR for this feature on GitHub"
"List my assigned Jira tickets"
"Query the users table for active accounts"

MCP Resources

Reference MCP-provided files:

Review @mcp://github/​README.md and suggest improvements

MCP Prompts as Commands

MCP prompts become slash commands:

/​mcp__github__create_issue "Bug in login" high
/​mcp__jira__update_status PROJ-123 "In Progress"

Managing Servers

Interactive Management

/​mcp
# Options:
# - View all servers
# - Add new server
# - Remove server
# - Authenticate
# - View tools/​prompts/​resources

Command Line

claude mcp list                    # List servers
claude mcp add ...                 # Add server
claude mcp remove server-name      # Remove server

Troubleshooting

Server Not Connecting

1. Verify URL/​command - check for typos
2. Check auth - run /​mcp → Authenticate
3. Test network - can you reach the URL?
4. Debug mode - run claude --debug

Authentication Failing

1. Re-authenticate: /​mcp → Clear auth → Re-authenticate
2. Check API key validity
3. Verify OAuth tokens not expired
4. Check permissions/​scopes

stdio Server Errors

# Test command manually
npx -y @modelcontextprotocol/​server-postgres

# Check environment variables are set
echo $POSTGRES_CONNECTION_STRING

# Verify npm package exists
npm info @modelcontextprotocol/​server-postgres

Tools Not Available

1. Confirm server is connected: /​mcp
2. Check authentication completed
3. Restart Claude Code
4. Verify server provides expected tools

Security Best Practices

DO:

• Use OAuth when available
• Store secrets in settings.json, not .mcp.json
• Use project scope for team configs
• Review server permissions regularly

DON'T:

• Commit API keys to git
• Install untrusted servers
• Share OAuth tokens
• Use broad permissions unnecessarily

Example Workflows

Issue to PR

# Setup
claude mcp add --transport http github https://api.github.com/​mcp
claude mcp add --transport sse atlassian https://mcp.atlassian.com/​v1/​sse

# Usage
"Read JIRA ticket ENG-123, implement the feature, and create a PR on GitHub"

Error Investigation

# Setup
claude mcp add --transport http sentry https://mcp.sentry.dev/​mcp

# Usage
"Check Sentry for errors in the last hour and fix them"

Database Query to Report

# Setup
claude mcp add --transport stdio postgres \
  --env POSTGRES_CONNECTION_STRING="postgresql://localhost/​analytics" \
  -- npx -y @modelcontextprotocol/​server-postgres

# Usage
"Find users who signed up this month and summarize their activity"

Resources

• MCP Website: https://modelcontextprotocol.io/
• MCP Servers List: https://github.com/modelcontextprotocol/servers
• Claude Code MCP Docs: https://docs.anthropic.com/en/docs/claude-code/mcp