Foundry agents now search for tools on demand. Your description decides who gets found.
By Lior AharonovFounder, 7IT Solutions ·
Microsoft's September 2026 Foundry roundup, posted on 15 October, confirms Tool Search is generally available, as announced on 24 September. Instead of sending every tool definition with each model request, a Toolbox exposes discovery and invocation through tool_search and call_tool. Toolboxes for prompt agents entered public preview.
An agent that loads tools on demand only reads the definitions its search returns. A vague name or description can mean your tool never gets loaded at all. Microsoft adds that its demo proves discovery and does not measure token savings.
Rewrite each tool description so its first line names the task and the object it acts on, then test whether a plain-language search finds it.
Tool search turns every description into a search listing. Write it for the query, not for the README.
Lior Aharonov · my takeSources
- Microsoft Foundry Blog: What's new in Microsoft Foundry, September 2026 devblogs.microsoft.com
Researched with AI tools; every fact is checked against the linked sources.