Agentic AI Systems: Autonomous Agents with Reasoning, Planning, and Tool Use
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Agentic AI Systems: Autonomous Agents with Reasoning, Planning, and Tool Use

Michael Brenndoerfer•November 2, 2025•14 min read•3,244 words•Interactive

A comprehensive guide covering agentic AI systems introduced in 2024. Learn how AI systems evolved from reactive tools to autonomous agents capable of planning, executing multi-step workflows, using external tools, and adapting behavior. Understand the architecture, applications, limitations, and legacy of this paradigm-shifting development in artificial intelligence.

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Reference

BIBTEXAcademic
@misc{agenticaisystemsautonomousagentswithreasoningplanningandtooluse, author = {Michael Brenndoerfer}, title = {Agentic AI Systems: Autonomous Agents with Reasoning, Planning, and Tool Use}, year = {2025}, url = {https://mbrenndoerfer.com/writing/agentic-ai-systems-autonomous-agents-reasoning-planning-tool-use}, organization = {mbrenndoerfer.com}, note = {Accessed: 2025-11-02} }
APAAcademic
Michael Brenndoerfer (2025). Agentic AI Systems: Autonomous Agents with Reasoning, Planning, and Tool Use. Retrieved from https://mbrenndoerfer.com/writing/agentic-ai-systems-autonomous-agents-reasoning-planning-tool-use
MLAAcademic
Michael Brenndoerfer. "Agentic AI Systems: Autonomous Agents with Reasoning, Planning, and Tool Use." 2025. Web. 11/2/2025. <https://mbrenndoerfer.com/writing/agentic-ai-systems-autonomous-agents-reasoning-planning-tool-use>.
CHICAGOAcademic
Michael Brenndoerfer. "Agentic AI Systems: Autonomous Agents with Reasoning, Planning, and Tool Use." Accessed 11/2/2025. https://mbrenndoerfer.com/writing/agentic-ai-systems-autonomous-agents-reasoning-planning-tool-use.
HARVARDAcademic
Michael Brenndoerfer (2025) 'Agentic AI Systems: Autonomous Agents with Reasoning, Planning, and Tool Use'. Available at: https://mbrenndoerfer.com/writing/agentic-ai-systems-autonomous-agents-reasoning-planning-tool-use (Accessed: 11/2/2025).
SimpleBasic
Michael Brenndoerfer (2025). Agentic AI Systems: Autonomous Agents with Reasoning, Planning, and Tool Use. https://mbrenndoerfer.com/writing/agentic-ai-systems-autonomous-agents-reasoning-planning-tool-use
Michael Brenndoerfer

About the author: Michael Brenndoerfer

All opinions expressed here are my own and do not reflect the views of my employer.

Michael currently works as an Associate Director of Data Science at EQT Partners in Singapore, where he drives AI and data initiatives across private capital investments.

With over a decade of experience spanning private equity, management consulting, and software engineering, he specializes in building and scaling analytics capabilities from the ground up. He has published research in leading AI conferences and holds expertise in machine learning, natural language processing, and value creation through data.

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