Glossary · Definition
Tool calling
Tool calling (function calling) lets a language model request that your code run a defined function — such as “look up order” — with structured arguments.
By Nythrex EngineeringUpdated 1 min read
In plain words
You describe available tools to the model with names, descriptions and argument types. When useful, the model responds with a request to call one; your code validates the arguments, runs the function and returns the result. The model never touches your systems directly.
When it matters to you
- Connecting AI to live data or actions
- Building agents
- Getting structured, validated outputs
Common pitfalls
- Not validating arguments server-side
- Tools that are too generic
- Trusting tool results that contain untrusted content
Keep reading
GlossaryAI agentAn AI agent is a system where a language model plans and takes actions through tools — searching, updating records, sending messages — to complete a task.GlossaryMCP (Model Context Protocol)MCP is an open protocol that standardises how AI applications connect to tools and data sources, so a system exposed once can be used by many AI apps.GuideMCP explainedThe Model Context Protocol in plain language: hosts, clients and servers, when to build an MCP server for your systems, and how to secure it.
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