Lesson 14MCP

MCP Configuration

Setup and transport

Configuration Scopes

User~/.claude/settings.json

Available in all projects

Common servers (GitHub, Slack)

Project.claude/settings.json

Only in this project

Project-specific (DB, API)

Local.claude/settings.local.json

Local, not in git

Secrets and personal settings

💡 Configs are merged: user → project → local

Transport Types

Standard input/output (default)

Pros

• Simple setup
• Works locally
• Secure

Cons

• Only local servers

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path"]
    }
  }
}

Environment Variables

Use environment variables for secrets with $VAR_NAME syntax:

"env": {
  "GITHUB_TOKEN": "$GITHUB_TOKEN",
  "DATABASE_URL": "$DATABASE_URL"
}

Method 1: .env file

GITHUB_TOKEN=ghp_xxx
DATABASE_URL=postgresql://...

Method 2: Shell export

export GITHUB_TOKEN=ghp_xxx
export DATABASE_URL=postgresql://...

⚠️ Never commit secrets in settings.json! Use environment variables.

Full Configuration Example

{
  "mcpServers": {
    "github": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-github"],
      "env": {
        "GITHUB_TOKEN": "$GITHUB_TOKEN"
      }
    },
    "postgres": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-postgres"],
      "env": {
        "POSTGRES_URL": "$DATABASE_URL"
      }
    },
    "brave-search": {
      "command": "npx",
      "args": ["-y", "@anthropic-ai/mcp-server-brave-search"],
      "env": {
        "BRAVE_API_KEY": "$BRAVE_API_KEY"
      }
    }
  }
}

Configuration Best Practices

1.Secrets — in environment variables or settings.local.json
2.Common servers (GitHub) — in user config
3.Project-specific (DB) — in project config, but without secrets
4.Add .claude/settings.local.json to .gitignore

This lesson is part of a structured LLM course.

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