What is Agent Runtime?
Agent Runtime is the execution environment that manages an AI agent session, including state, tool calls, memory access, policies, events, cancellation, retries, and failure handling.
How It Works
An Agent Runtime is where an agent actually runs. It coordinates the loop between model reasoning, tool execution, observation, memory access, and final response. A runtime may be embedded inside an application framework or deployed as a separate service. Its responsibilities are operational: track session state, enforce limits, schedule steps, cancel unsafe or stalled work, isolate tenants, and emit events that make the run observable.
Key Characteristics
- Session execution: owns the lifecycle of one or more agent runs
- State management: tracks messages, plans, intermediate observations, memory references, and outputs
- Tool mediation: invokes tools through controlled interfaces instead of exposing arbitrary execution
- Runtime policies: enforces timeouts, step limits, budgets, approvals, and cancellation
- Event emission: produces traces and lifecycle events for monitoring, debugging, and evaluation
Common Use Cases
- Running a multi-step customer support agent with bounded retries
- Coordinating tool calls and memory updates in a coding assistant
- Canceling an agent run when it exceeds step, time, or cost limits
- Separating tenant-specific state in an enterprise agent platform
- Streaming runtime events to an observability or evaluation pipeline
Example
Loading code...Frequently Asked Questions
How is Agent Runtime different from Agent Harness?
Runtime is the execution environment that runs sessions and steps. Harness is the broader control layer around the agent, often including runtime, policies, observability, evaluation, and governance.
What should an Agent Runtime isolate?
It should isolate users, tenants, credentials, tool permissions, memory scopes, and run state so one session cannot accidentally affect another.
Why does cancellation matter?
Agents can enter long loops, wait on slow tools, or attempt risky actions. Runtime cancellation lets systems stop work when limits are exceeded or when a user revokes intent.
Can an Agent Runtime be stateless?
A thin runtime can delegate state to external stores, but the agent run still needs durable state somewhere if it supports long tasks, recovery, or audit.