> ## Documentation Index
> Fetch the complete documentation index at: https://docs.adenhq.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Worker Agent

> Runtime model for sessions, iterations, headless execution, and resilience

## What a Worker Agent Is

A worker agent is a specialized runtime agent generated for a defined business process.

The coding agent creates it; the worker agent executes it.

## Sessions

A session is one execution against one input.

* Isolated shared memory and state per session
* Supports long pauses/resumes (for HITL)
* Captures complete execution history for debugging

## Iterations

Within a session, `event_loop` nodes iterate:

1. reason
2. call tools
3. evaluate output
4. retry or continue

Iteration limits prevent runaway loops.

## Headless Execution

Worker agents are designed for unattended operation:

* Continuous background execution
* Human intervention only at explicit checkpoints
* Suitable for production process automation

## Runtime Responsibilities

The runtime coordinates:

* Graph execution lifecycle
* LLM/tool access
* Shared memory and credentials
* Cost tracking and budget enforcement
* Event streaming and observability
* Crash recovery and checkpoint resume

## Practical Model

This mirrors team operations:

* define role (goal)
* provide context and tools
* set quality constraints
* automate routine actions
* escalate exceptions to humans
* evolve based on outcomes

## Related Concepts

* [Agent Graph](/building-agent/concepts/agent-graph)
* [Evolution](/building-agent/concepts/evolution)
* [Human-in-the-Loop](/building/human-in-the-loop)