AI / A CONCEPT NOTE
Agent Harness
the orchestration framework that turns an LLM into a reliable agent
Overview · mechanism
pitfall · examples
01 / THE SHORT VERSION
The idea in a few sentences.
An agent harness is the scaffolding code around an LLM that manages the planning-execution loop, tool dispatch, error recovery, and state persistence. Frameworks like LangGraph, CrewAI, and AutoGen provide this harness out of the box — they handle retries, conversation memory, multi-agent coordination, and human-in-the-loop checkpoints so you don't reinvent it.
02 / FOLLOW THE MECHANISM
How a harness orchestrates an agent
Task input
user submits a goal: 'Research competitors and write a report.'
Planner
the harness prompts the LLM to decompose the goal into subtasks: search, extract, summarize, format.
Executor
each subtask is dispatched to the appropriate tool or sub-agent. The harness tracks state, handles tool failures with retries, and enforces timeouts.
Checkpoint
after each step, state is persisted. If the agent crashes, it resumes from the last checkpoint rather than starting over.
Output
the final result is assembled from subtask outputs and returned to the user.
04 / COMMAND NOTES
Read the command, then the result.
Inspect the flags and arguments before trying an example. Snippets can need local setup, replacement values, or resources in your own environment.
build a LangGraph agent with state management
python -c "from langgraph.graph import StateGraph; graph = StateGraph(...); graph.add_node('agent', agent_fn); app = graph.compile()"The ellipsis omits required code or values. This sketch is not runnable as written.
run a multi-agent crew with CrewAI
python -c "from crewai import Agent, Task, Crew; crew = Crew(agents=[...], tasks=[...]); crew.kickoff()"The ellipsis omits required code or values. This sketch is not runnable as written.
05 / CHECK YOURSELF
Could you explain Agent Harness to a teammate?
Try it out loud in two sentences: what it is, and the one detail that changes the picture. If you stall, the gap is the part to reread.
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