mlsanityData to 7 Oct 2026

How are AI agents used? Evidence from 177,000 MCP tools

arXiv 2603.23802 ↗First posted 25 Mar 2026cs.CYcited by 7

On the map: LLM agents and tool use → Tool learning and function calling

Abstract (arXiv)

Today's AI agents are built on large language models (LLMs) equipped with tools to access and modify external environments, such as corporate file systems, API-accessible platforms and websites. AI agents offer the promise of automating computer-based tasks across the economy. However, developers, researchers and governments lack an understanding of how AI agents are currently being used, and for what kinds of (consequential) tasks. To address this gap, we evaluated 177,436 agent tools created from 11/2024 to 02/2026 by monitoring public Model Context Protocol (MCP) server repositories, the current predominant standard for agent tools. We categorise tools according to their direct impact: perception tools to access and read data, reasoning tools to analyse data or concepts, and action tools to directly modify external environments, like file editing, sending emails or steering drones in the physical world. We use O*NET mapping to identify each tool's task domain and consequentiality. Software development accounts for 67% of all agent tools, and 90% of MCP server downloads. Notably, the share of 'action' tools rose from 27% to 65% of total usage over the 16-month period sampled. While most action tools support medium-stakes tasks like editing files, there are action tools for higher-stakes tasks like financial transactions. Using agentic financial transactions as an example, we demonstrate how governments and regulators can use this monitoring method to extend oversight beyond model outputs to the tool layer to monitor risks of agent deployment.

Key facts. Cited by 7 papers in the map (data through 7 Oct 2026). Placed in Tool learning and function calling, one of 16 directions in LLM agents and tool use. Builds on 25 of its 70 references that are in the map. First posted on arXiv 25 Mar 2026.

Builds on

25 of 70 references.

References · 25

  1. 2021On the Opportunities and Risks of Foundation Modelscited by 3,961
  2. 2024The AI Scientist: Towards Fully Automated Open-Ended Scientific Discoverycited by 1,002
  3. 2022BERTopic: Neural topic modeling with a class-based TF-IDF procedurecited by 779
  4. 2025Darwin Godel Machine: Open-Ended Evolution of Self-Improving Agentscited by 294
  5. 2025Multi-Agent Risks from Advanced AIcited by 150
  6. 2025Agentic Misalignment: How LLMs Could Be Insider Threatscited by 136
  7. 2023Harms from Increasingly Agentic Algorithmic Systemscited by 134
  8. 2024Secret Collusion among AI Agents: Multi-Agent Deception via Steganographycited by 107
  9. 2025Which Economic Tasks are Performed with AI? Evidence from Millions of Claude Conversationscited by 88
  10. 2025Superintelligent Agents Pose Catastrophic Risks: Can Scientist AI Offer a Safer Path?cited by 70
  11. 2024Navigating the Risks: A Survey of Security, Privacy, and Ethics Threats in LLM-Based Agentscited by 63
  12. 2025Fully Autonomous AI Agents Should Not be Developedcited by 43
13 more
  1. 2025Future of Work with AI Agents: Auditing Automation and Augmentation Potential across the U.S. Workforcecited by 33
  2. 2025Characterizing AI Agents for Alignment and Governancecited by 30
  3. 2025EchoLeak: The First Real-World Zero-Click Prompt Injection Exploit in a Production LLM Systemcited by 26
  4. 2024AI-AI Bias: large language models favor communications generated by large language modelscited by 25
  5. 2025HedgeAgents: A Balanced-aware Multi-agent Financial Trading Systemcited by 24
  6. 2025Attractive Metadata Attack: Inducing LLM Agents to Invoke Malicious Toolscited by 23
  7. 2023Market Concentration Implications of Foundation Modelscited by 15
  8. 2026State of AI: An Empirical 100 Trillion Token Study with OpenRoutercited by 15
  9. 2025The Adoption and Usage of AI Agents: Early Evidence from Perplexitycited by 12
  10. 2025Measuring and mitigating overreliance to build human-compatible AIcited by 9
  11. 2024The Role of Governments in Increasing Interconnected Post-Deployment Monitoring of AIcited by 6
  12. 2016A Model of Pathways to Artificial Superintelligence Catastrophe for Risk and Decision Analysiscited by 4
  13. 2024Can Large Language Models Invent Algorithms to Improve Themselves?: Algorithm Discovery for Recursive Self-Improvement through Reinforcement Learningcited by 4

Built on by

Cited by year (2026 to 7 Oct)

Citing papers per year: 2026: 7.

7 papers.

Similar, not cited

Close in wording, no citation either way

  1. 2026Model Context Protocol (MCP) Tool Descriptions Are Smelly! Towards Improving AI Agent Efficiency with Augmented MCP Tool Descriptions
  2. 2025MCP-AgentBench: Evaluating Real-World Language Agent Performance with MCP-Mediated Tools
  3. 2025MCPZoo: A Large-Scale Dataset of Runnable Model Context Protocol Servers for AI Agent
  4. 2025MCPAgentBench: A Real-world Task Benchmark for Evaluating LLM Agent MCP Tool Use
  5. 2026Evaluating Tool Cloning in Agentic-AI Ecosystems
  6. 2026MCP-Atlas: A Large-Scale Benchmark for Tool-Use Competency with Real MCP Servers
  7. 2026Don't believe everything you read: Understanding and Measuring MCP Behavior under Misleading Tool Descriptions
  8. 2025OSWorld-MCP: Benchmarking MCP Tool Invocation In Computer-Use Agents