--- title: Tool use (function calling) | daily.dev description: Claude is capable of interacting with external client-side tools and functions, allowing you to equip Claude with your own custom tools to perform a wider... canonical: https://daily.dev/posts/tool-use-function-calling--avrstlwxs twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Tool use (function calling) | daily.dev og:description: Claude is capable of interacting with external client-side tools and functions, allowing you to equip Claude with your own custom tools to perform a wider... og:url: https://daily.dev/posts/tool-use-function-calling--avrstlwxs og:image: https://api.daily.dev/og/posts/AvrsTLWXs.png og:image:alt: Tool use (function calling) og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Tool use (function calling) **[Hacker News](https://daily.dev/sources/hn)** · 13 min read · 0 upvotes · 0 comments ## Summary Claude is capable of interacting with external client-side tools and functions, allowing you to equip Claude with your own custom tools to perform a wider variety of tasks. This post explains how tool use works, provides best practices for tool definitions, and discusses the limitations of tool use. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Don’t just attend KubeCon \+ CloudNativeCon, Merge Forward your experience\!](https://daily.dev/posts/don-t-just-attend-kubecon-cloudnativecon-merge-forward-your-experience--l0rpp73x8) · CNCF · 1 upvotes · 0 comments - [Announcing H2 2026 KCDs](https://daily.dev/posts/announcing-h2-2026-kcds-m96goajm1) · CNCF · 1 upvotes · 0 comments - [Two months of Open Community Groups](https://daily.dev/posts/two-months-of-open-community-groups-asf52zhbs) · CNCF · 0 upvotes · 0 comments - [CNCF Unveils Schedule for KubeCon \+ CloudNativeCon Europe 2026](https://daily.dev/posts/cncf-unveils-schedule-for-kubecon-cloudnativecon-europe-2026-ikhcoa5cb) · CNCF · 2 upvotes · 0 comments - [CNCF Debuts KubeCon \+ CloudNativeCon Japan 2026 Schedule](https://daily.dev/posts/cncf-debuts-kubecon-cloudnativecon-japan-2026-schedule-xp5pyudub) · CNCF · 1 upvotes · 0 comments --- [View this post on daily.dev](https://daily.dev/posts/tool-use-function-calling--avrstlwxs) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Tool use (function calling)","url":"https://daily.dev/posts/tool-use-function-calling--avrstlwxs","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/tool-use-function-calling--avrstlwxs"},"datePublished":"2024-04-05T09:35:51.679Z","dateModified":"2024-05-09T09:21:59.549Z","description":"Claude is capable of interacting with external client-side tools and functions, allowing you to equip Claude with your own custom tools to perform a wider...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/688a34a94534a8999fbf4dee62b3b60e?_a=AQAEufR","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/688a34a94534a8999fbf4dee62b3b60e?_a=AQAEufR","isAccessibleForFree":true,"articleSection":"Hacker News","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Hacker News","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/hn","url":"https://daily.dev/sources/hn"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/tool-use-function-calling--avrstlwxs","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"","timeRequired":"PT13M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Hacker News","item":"https://daily.dev/sources/hn"},{"@type":"ListItem","position":3,"name":"Tool use (function calling)"}]} ```