# How to test agent skills without hitting real APIs

DevFeed: [How to test agent skills without hitting real APIs](<https://devfeed.tech/articles/how-to-test-agent-skills-without-hitting-real-apis-23831.md>)

Original publisher: [Read original article](<https://devblogs.microsoft.com/blog/how-to-test-agent-skills-without-hitting-real-apis/>)

Author: Waldek Mastykarz

Published: 2026-07-17T09:27:50Z

Content type: tutorial

Language: en

Sources: [Developer Blogs](<https://devfeed.tech/sources/developer-blogs.md>)

Topics: [Agent Skills](<https://devfeed.tech/topics/agent-skills.md>), [API](<https://devfeed.tech/topics/api.md>), [Testing](<https://devfeed.tech/topics/testing.md>)

Tags: [agent-experience](<https://devfeed.tech/tags/agent-experience.md>), [agent-skills](<https://devfeed.tech/tags/agent-skills.md>), [ai](<https://devfeed.tech/tags/ai.md>), [apis](<https://devfeed.tech/tags/apis.md>), [ax](<https://devfeed.tech/tags/ax.md>), [evals](<https://devfeed.tech/tags/evals.md>), [how-to](<https://devfeed.tech/tags/how-to.md>), [microsoft](<https://devfeed.tech/tags/microsoft.md>), [testing](<https://devfeed.tech/tags/testing.md>)

## AI overview

This tutorial explains how to evaluate agent skills that call APIs without incurring external API costs or mutating live data. It introduces transparent API mocking to support isolated, repeatable evaluation runs without changing the skill or contacting real endpoints.

## Source excerpt

Your agent skill calls an API. The moment you start evaluating it, every run either costs money or mutates production data. Learn how to mock APIs transparently so you can run evals without changing your skill or hitting real endpoints. The post How to test agent skills without hitting real APIs appeared first on Microsoft for Developers.