What is an agent harness?

An agent harness is everything that wraps a model call to turn it into a working agent: rendering the prompt, executing tool calls, handling retries and timeouts, and recording what happened.

Open source

How AgentOven does it

The AgentOven Executor runs managed agents. It renders the prompt template, calls the Model Router, executes tool calls through the MCP Gateway and emits an OpenTelemetry span for each step. Agents already built in LangGraph, LangChain or CrewAI run in framework-native runtimes (local, Docker or Kubernetes), and external agents are proxied over A2A.

ExecutorFramework-native runtimesA2A proxy