An agentic system wraps a large language model (LLM) inside a control loop that lets it reason, take actions in the external world through tools, observe the outcome, and decide the next step. Unlike a one-turn assistant, an agent maintains a working memory of its trajectory and pursues a goal across many steps — booking travel, refactoring a codebase, or running a multi-stage data analysis without a human in the loop for every action.
Working principle
Most production agents implement a variant of the ReAct pattern (Reason + Act). The model emits an interleaved stream of thoughts and actions; each action is a structured tool call whose result (the observation) is fed back into the context window for the next reasoning step. A planner may first break the goal into sub-tasks, while a critic or verifier checks intermediate output and triggers self-correction when a step fails.
Architecture of an autonomous workflow
Real deployments separate concerns into layers: an orchestrator that manages the loop and state, a tool / function-calling layer that exposes APIs, databases and code execution, a memory subsystem (short-term scratchpad plus long-term vector store), and guardrails that constrain what the agent may do.
| Property | Chat completion | Agentic workflow |
|---|---|---|
| Horizon | One turn | Many steps until goal met |
| External actions | None | Tool calls, code, API writes |
| State | Stateless / context only | Persistent memory + scratchpad |
| Failure handling | User retries | Self-reflection & retry |
| Main risk | Hallucination | Compounding errors, unsafe actions |
Applications
- Autonomous software engineering — issue triage, code generation, test-and-fix loops
- Operations copilots that resolve tickets by querying systems and executing fixes
- Research and data-analysis agents that gather, clean and synthesise sources
- Customer-workflow automation: claims, onboarding, procurement
Challenges
Key insightThe dominant failure mode is error compounding: a small mistake early in a long trajectory cascades. Robust agents therefore add verification at every step, cap tool budgets, and keep a human approval gate on irreversible actions.
- Reliability over long horizons and cost of repeated LLM calls
- Tool-use safety and prompt-injection from retrieved content
- Evaluation — measuring task success, not just token-level accuracy
References & further reading
- Yao et al., “ReAct: Synergizing Reasoning and Acting in Language Models,” ICLR 2023.
- Shinn et al., “Reflexion: Language Agents with Verbal Reinforcement Learning,” NeurIPS 2023.
- Wang et al., “A Survey on Large Language Model Based Autonomous Agents,” 2024.