Agent as MCP Server: Exposing Agent Capabilities as MCP Tools
An AI agent exposes its own capabilities as MCP tools — allowing other agents, orchestrators, or clients to invoke it through the MCP protocol.
What Is Agent as MCP Server?
In the Agent as MCP Server pattern, an AI agent exposes its own capabilities as MCP tools — allowing other agents, orchestrators, or clients to invoke it through the MCP protocol. The agent becomes a callable component in a larger agentic system, not just a consumer of tools.
This pattern enables multi-agent architectures where a specialist agent (one that handles HR processes, or one that handles financial analysis) is called by an orchestrating agent as needed. The orchestrator doesn't need to know how the specialist agent works — it calls the MCP tool, the specialist agent executes, and the result comes back through the protocol.
When to Use This Pattern
- You have specialized agent capabilities that multiple orchestrators need to use
- You want to compose complex workflows from discrete, reusable agents
- You need to govern the interface between agents the same way you govern agent-to-system interfaces
- A specialist agent needs to be callable by external MCP clients (Microsoft Copilot, Claude, etc.)
Designing the Agent's MCP Interface
Apply the same design principles to agent-exposed tools as to system-exposed tools. The tool names should describe capabilities, not implementation. analyze_contract_risk is a good agent-exposed tool. run_contract_analysis_v2 is not.
Define what the tool accepts (input schema), what it returns (output schema), and what can go wrong (error schema). The calling agent or orchestrator relies on this contract — breaking it breaks every system built on top of it.
Governance Implications
Agent-to-agent MCP calls carry the same governance requirements as agent-to-system calls. The called agent may take actions with real enterprise consequences. Workato's Control Plane logs inter-agent tool calls — every agent-to-agent interaction is visible in the audit trail alongside agent-to-system interactions.
Example: Multi-Agent HR System
An HR orchestrating agent calls three specialist agents via MCP: an HRIS agent (handles Workday interactions), an IT provisioning agent (handles Active Directory and system access), and a communication agent (handles Slack and email notifications). Each specialist exposes its capabilities as MCP tools. The orchestrator calls them in the right order without needing to know their implementation details.