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What is MCP?

The Model Context Protocol (MCP) is an open protocol created and maintained by Anthropic - MCP github organization

MCP defines how AI agents (like Dexto agents) can discover, connect to, and interact with external tools, services, and APIs in a standardized way.

Comprehensive Documentation

For complete MCP server configuration documentation including detailed field references, environment variables, tool aggregation, troubleshooting, and best practices, see the MCP Configuration Guide.

Why MCP Matters​

  • Interoperability: MCP provides a common language for agents and tools, making it easy to connect new services without custom integration code for each one.
  • Extensibility: Anyone can build and share MCP-compatible tools, expanding what agents can do.
  • Modularity: Tools are decoupled from the agent's core logic, so you can add, remove, or swap tools as needed.

How Dexto Agents Use MCP​

Dexto agents use MCP to:

  • Discover available tools: MCP servers advertise what actions they support (e.g., read a file, send an email, browse the web).
  • Connect to tools: Dexto agents communicate with MCP servers using a standard protocol (often over stdio, HTTP, or sockets).
  • Invoke tool actions: When you give a command, Dexto selects the right tool(s) via MCP and orchestrates their use to fulfill your request.
  • Read server resources: Dexto agents can read resources from the server, like files, databases, etc., and use that to reason about what to do next.
  • Request structured input: Servers can use elicitation to request specific data from users during workflows.

Quick Configuration Reference​

Add MCP servers under mcpServers in your agent.yml. Dexto supports three server types: stdio, sse, and http.

stdio Server Type​

For local MCP servers running as child processes:

mcpServers:
  filesystem:
    type: stdio
    command: npx
    args:
      - "@modelcontextprotocol/server-filesystem"
    env:
      ROOT: ./
    timeout: 30000
    connectionMode: lenient

Fields:

  • type (required): Must be stdio
  • command (required): Command to execute (e.g., npx, python, node)
  • args (optional): Array of command arguments. Default: []
  • env (optional): Environment variables for the server process. Default: {}
  • timeout (optional): Connection timeout in milliseconds. Default: 30000
  • connectionMode (optional): lenient or strict. Default: lenient

sse Server Type​

For Server-Sent Events (SSE) based MCP servers:

mcpServers:
  remote-sse:
    type: sse
    url: https://api.example.com/mcp/events
    headers:
      Authorization: Bearer ${MCP_API_KEY}
    timeout: 30000
    connectionMode: lenient

Fields:

  • type (required): Must be sse
  • url (required): SSE endpoint URL. Supports environment variable expansion (e.g., ${VAR})
  • headers (optional): HTTP headers to send with requests. Default: {}
  • timeout (optional): Connection timeout in milliseconds. Default: 30000
  • connectionMode (optional): lenient or strict. Default: lenient

http Server Type​

For HTTP-based MCP servers:

mcpServers:
  remote-http:
    type: http
    url: https://api.example.com/mcp
    headers:
      Authorization: Bearer ${MCP_API_KEY}
    timeout: 30000
    connectionMode: strict

Fields:

  • type (required): Must be http
  • url (required): HTTP server URL. Supports environment variable expansion (e.g., ${VAR})
  • headers (optional): HTTP headers to send with requests. Default: {}
  • timeout (optional): Connection timeout in milliseconds. Default: 30000
  • connectionMode (optional): lenient or strict. Default: lenient

Connection Modes​

The connectionMode field controls how Dexto handles connection failures:

  • lenient (default): If the server fails to connect, Dexto logs a warning but continues initialization. The server can be retried later. Use this for optional servers or when you want graceful degradation.

  • strict: If the server fails to connect, Dexto throws an error and stops initialization. Use this for critical servers that must be available for your agent to function properly.

Runtime Changes​

  • Add/update/remove servers dynamically via the SDK or REST APIs
  • Events: mcp:server-added, mcp:server-updated, mcp:server-removed

See: MCP Manager

Learn More​

MCP is a key part of what makes Dexto flexible, extensible, and able to automate across a wide range of tools and services.

Next Steps​