feat(mcp-exa): Add Exa MCP Server Setup Instructions

[divideby0]

Overview

Add comprehensive instructions for obtaining and configuring the Exa API key required by the exa-mcp-server.

Current State

• Exa MCP server is supported in the registry
• .mcp.json includes EXA_API_KEY in env vars
• No guidance provided on how to obtain the API key

Requirements

Account Registration

1. Free Tier Available: Exa offers a free tier for API access
2. Registration URL: Users can sign up at https://dashboard.exa.ai
3. Authentication Options:
   • Google OAuth
   • SSO login (for team members)

API Key Retrieval

1. Navigate to https://dashboard.exa.ai/api-keys
2. Click "Create API Key" button
3. Copy the generated key

[TODO: USER INPUT NEEDED - Please verify the exact steps for creating an API key in the Exa dashboard, including any naming/permissions options]

Pricing Information

• Free Tier: Available (exact limits need confirmation)
• Starter Plan: $49/month - 8,000 credits/month
• Pro Plan: $449/month - 100,000 credits/month
• Enterprise: Custom pricing

[TODO: USER INPUT NEEDED - Please confirm free tier limits and whether API key creation requires payment method]

Implementation

Documentation Updates

registry/mcp-servers/exa/claude.md:

## Exa MCP Server Setup

### Prerequisites

You'll need an Exa API key to use this server.

### Getting Your API Key

1. **Sign up for Exa** (if you don't have an account):
   - Go to https://dashboard.exa.ai
   - Click "Continue with Google" or use SSO
   - Free tier available

2. **Create an API Key**:
   - Navigate to https://dashboard.exa.ai/api-keys
   - Click "Create API Key"
   - [TODO: Add specific steps - name the key? set permissions?]
   - Copy the generated key and store it securely

3. **Configure the key**:
   - The key will be stored in `.env.mcp.secrets` as `EXA_API_KEY`
   - Never commit this file to version control

### Pricing

- **Free Tier**: [TODO: Confirm limits]
- **Paid Plans**: Start at $49/month for increased usage
- See https://exa.ai/exa-api for current pricing

### Usage in CLAUDE.md

The Exa MCP server provides:
- Semantic web search powered by embeddings
- Web crawling and content extraction
- Company research capabilities
- Deep research with AI synthesis

Example searches:
- "latest developments in ML research papers"
- "YC-backed startups in AI infrastructure"
- "technical blog posts about Rust performance"

Interactive Configuration

Update registry/mcp-servers/exa/index.ts configure() method:

async configure(ctx: ConfigContext): Promise<ServerConfig> {
  const apiKey = await Input.prompt({
    message: "Enter your Exa API key:",
    hint: "Get one at https://dashboard.exa.ai/api-keys",
    validate: (value) => {
      if (!value || value.trim().length === 0) {
        return "API key is required";
      }
      // Exa keys typically start with a specific prefix
      // [TODO: Confirm key format/validation pattern]
      return true;
    }
  });

  return {
    command: "npx",
    args: ["-y", `exa-mcp-server@${this.version}`],
    env: {
      EXA_API_KEY: apiKey
    }
  };
}

Help Text

Add to init command when Exa is selected:

ℹ️  Exa API Key Required
   
   To use the Exa MCP server, you'll need an API key:
   
   1. Sign up at https://dashboard.exa.ai (free tier available)
   2. Go to https://dashboard.exa.ai/api-keys
   3. Create a new API key
   4. Enter it when prompted
   
   Your key will be stored securely in .env.mcp.secrets

Testing

• Verify registration flow at dashboard.exa.ai
• Confirm API key creation steps
• Test key validation (if possible)
• Verify free tier availability
• Document any payment requirements

Related Issues

• Depends on version pinning (feat(init): pin MCP server versions in .mcp.json configuration #6) for exa-mcp-server@x.y.z format
• Related to .env.mcp.secrets management

References

• Exa Dashboard: https://dashboard.exa.ai
• API Keys: https://dashboard.exa.ai/api-keys
• Documentation: https://docs.exa.ai/reference/getting-started
• Pricing: https://exa.ai/exa-api
• MCP Server: https://github.com/exa-labs/exa-mcp-server