Architecture note · AI agent architecture

Agent Tool Loop: Planning, Tool Use, Observation, and Memory

An architecture note describing a practical agent control loop without relying on futuristic metaphors.

By AbdullahPublished 24 Aug 2026Updated 24 Aug 2026
Answer in one sentence

An agent can be understood as a controlled loop around a model: choose an action, use a tool, inspect the result, update state, and decide whether to continue.

Decision point

The system chooses whether to reason, retrieve, call a tool, or finish. Available actions should match capabilities the application can actually enforce.

Tool contract

Every tool needs an input schema, output shape, timeout, and failure behavior. The agent is only as reliable as the interfaces it calls.

Observation and state

Tool outputs become observations; memory decides which information should remain in active context or persist across turns.

Stop conditions

Maximum steps, timeouts, invalid-action handling, and a finalization rule prevent open-ended loops from becoming incidents.

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About the author

AI Developer / ML Engineer building end-to-end AI systems from research to production, with a focus on multimodal AI, LLM applications, retrieval, MLOps, and systems engineering. He is based in Rawalpindi, Pakistan and is the founder of GROVE SYSTEMS.

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