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Custom Tools

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Calling your own APIs

• API Endpoints mode — define each endpoint (or import an OpenAPI spec) as a named, typed function the agent calls directly. This is the recommended path.
• Free-form Request mode — let the agent compose its own requests under a base URL.
• Webhook mode — fire-and-forget POSTs to Zapier / Make / n8n / custom URLs.

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MCP (Model Context Protocol) Integration

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What is MCP?

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Connecting an MCP Server

1. Go to your agent’s Tools section.
2. Click Add Tool and select MCP Server.
3. Enter the MCP server URL:

# Example MCP server endpoints
MCP_SERVER_URL=https://your-mcp-server.com/mcp
MCP_SERVER_URL=http://localhost:3001/mcp

4. Configure authentication if required (API key or bearer token).
5. Click Discover Tools — thinnestAI will fetch the list of available tools from the server.
6. Select which tools to enable for your agent.
7. Save.

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Running Your Own MCP Server

# Install an MCP server framework
npm install @modelcontextprotocol/server

# Or use Python
pip install mcp

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MCP Use Cases

• Internal APIs — Expose company-specific tools without building custom integrations for each one.
• Shared tool servers — One MCP server can serve tools to multiple agents.
• Third-party MCP servers — Connect to the growing ecosystem of public MCP servers.

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Best Practices

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Tool Naming

• Use snake_case names: check_inventory, create_order, get_user_info.
• Make names action-oriented: the agent should understand what the tool does.

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Descriptions

• Describe inputs and outputs clearly.
• Mention edge cases: “Returns null if the user is not found.”
• Include example values when helpful.

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Error Handling

• Your API should return meaningful error messages.
• The agent will read error responses and can explain them to the user or retry.
• Use standard HTTP status codes (400 for bad input, 404 for not found, etc.).

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Security

• Use HTTPS for all production endpoints.
• Rotate API keys regularly.
• Limit tool permissions to only what the agent needs (read-only if possible).
• Consider rate limiting on your API to prevent excessive calls.

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Example: Order Status Checker

User:    "Where's my order ORD-78901?"
Agent:   [calls check_order_status with order_id="ORD-78901"]
Agent:   "Your order ORD-78901 is currently in transit. It's expected to
          arrive by March 8th. Your tracking number is 1Z999AA10123456784."

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Next Steps

• CRM & Webhooks — Connect to CRMs and send data to external systems.
• Built-in Tools — Browse all pre-built tools available.