Tool calls
Also written: Function calling
AI models can use external tools like search engines or calculators to get information or complete tasks.
Some AI models can go beyond their own knowledge to get things done. They do this by using 'tool calls,' which means they can access and use other software or services.
For example, if you ask an AI about the current weather, it might use a tool call to access a weather website or app to get the most up-to-date information before telling you. This lets the AI perform tasks that require real-time data or specific calculations.
Tool calls enable large language models (LLMs) to interact with external APIs and functions. This allows the model to retrieve real-time information, perform complex calculations, or execute actions in other systems, extending its capabilities beyond its training data. The process typically involves the LLM identifying a need for an external tool, formatting a request for that tool (e.g., specifying a function name and arguments), receiving the tool's output, and then using that output to formulate its final response.
This capability is crucial for building more sophisticated AI agents that can interact with the real world. Tradeoffs include increased latency due to external calls and the complexity of managing tool execution and error handling.
Tool calls are appearing in recent news as companies integrate them into their AI models to enhance capabilities. For example, Anthropic is allowing users to customize Claude Code's actions with custom functions, and Google is using AI safety nets for enterprise agents, suggesting a trend towards more interactive and functional AI systems.
- Mods in Claude Code: change how Claude Code worksAnthropic · Claude on YouTube ·
- Claude Sonnet 5.5 in GitHub CopilotMicrosoft · GitHub Changelog: Copilot ·
- Agent Anomaly Detection, now in Private Preview on the Gemini Enterprise Agent PlatformGoogle · Google Developers Blog ·
- When should I use web search, extended thinking, and research?Anthropic · Claude Help Center ·
- Koray Kavukcuoglu: “This Is How We Are Going to Build AGI”Google · Google AI: Release Notes ·
- Anthropic Claude
- Anthropic's Claude Code can be customized with user-written functions, enabling tool calls for specific actions.
- Google Gemini
- Google Gemini's Enterprise Agent Platform is incorporating AI safety nets that likely involve tool calls to catch risks.
- Microsoft Copilot
- Microsoft Copilot is integrating Anthropic's models, which support tool calls, to provide enhanced coding assistance.
- Function calling
- This is often used interchangeably with tool calls, referring
- Plugins
- These are often pre-built tools or extensions that an LLM can access, s
- Agents
- Tool calls are a fundamental component that enables AI agents to interac
The concept of LLMs using external tools has evolved from early research into function calling and API integration, becoming a core feature for advanced AI assistants.
Ask an AI assistant like ChatGPT, Claude, or Gemini to tell you the current time or the weather in a specific city. If the AI uses a tool call, it will likely access an external service to get that real-time information before providing its answer.
The Playbook: reusable how-tos, prompts, configs and tips pulled out of the news.
- HeuristicThe loop: declare, decide, execute, return for AI agentsUnderstand the core cycle of how AI agents with tool calling operate. · 5 min
- Code snippetAgent Development Kit tool calling structure and callbackDemonstrates how to define tools and implement a callback to intercept tool calls before execution in Gemini agents. · 15 min
- Setting tipDiscover and add local Ollama models in GitHub Copilot CLIUse the /model command to find and add local Ollama models to GitHub Copilot CLI without leaving your workflow. · 5 min
- Setting tipEnable function calling in GPT-6 Luna Chat CompletionsUse Chat Completions with `reasoning_effort` set to 'none' for function calling. · 1 min
- RuleKeep every tool instant and put policy in one callbackCentralize policy checks in a single callback for AI agent tool execution. · 10 min
Questions people ask
- Can all AI models make tool calls?
- No, only specific AI models are designed with the capability to make tool calls. This feature needs to be explicitly built into the model's architecture and training.
- What kind of tools can an AI use?
- An AI can potentially use any tool that has a well-defined interface (API), such as search engines, calculators, databases, calendars, or even custom software.
First seen on Subvolts Sep 3, 2026. Updated Oct 12, 2026. Written by an AI model from the items above and reviewed against them weekly; report an error.