Definition
What is an agent runtime?
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Definition
An agent runtime is the execution environment that runs an AI agent — handling state persistence, tool dispatch, retries, observability, and the LLM API client — so the agent's logic doesn't have to.
Just as web frameworks abstract HTTP plumbing from request handlers, agent runtimes abstract LLM plumbing from agent logic. Common runtimes include LangGraph, CrewAI, AutoGen, and custom state machines. The runtime provides primitives for tools, memory, branching, parallel execution, and HITL interrupts. Without a runtime, every agent reinvents these primitives — usually badly.
What runtimes provide
- State persistence across LLM calls and process restarts
- Tool dispatch with schema validation and error handling
- Retries with backoff for transient failures
- Observability — every node’s input, output, and timing
- HITL interrupts to pause for human approval
A “production agent” without a runtime usually means an agent that can’t handle one of those five concerns — and you find out which one in production.