--- title: How to test agent skills without hitting real APIs description: When evaluating AI agent skills that call external APIs, every test run risks incurring costs or mutating production data. The post explains why most teams... canonical: https://daily.dev/posts/how-to-test-agent-skills-without-hitting-real-apis-oz8x5b0z1 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How to test agent skills without hitting real APIs | daily.dev og:description: When evaluating AI agent skills that call external APIs, every test run risks incurring costs or mutating production data. The post explains why most teams... og:url: https://daily.dev/posts/how-to-test-agent-skills-without-hitting-real-apis-oz8x5b0z1 og:image: https://api.daily.dev/og/posts/OZ8x5B0z1.png og:image:alt: How to test agent skills without hitting real APIs 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. # How to test agent skills without hitting real APIs **[DevBlogs](https://daily.dev/sources/devblogs)** · 5 min read · 0 upvotes · 0 comments ## Summary When evaluating AI agent skills that call external APIs, every test run risks incurring costs or mutating production data. The post explains why most teams skip evaluation entirely and why naive mock server approaches introduce variables that compromise test validity. A lighter alternative uses Dev Proxy to intercept HTTP traffic and respond with local seed data, keeping the real API URLs intact so the skill under test is identical to what ships. The data resets on every run, eliminating cost, state contamination, and non-determinism from external writes. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Agentic development hinges on verification. 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