FetchSandbox: Testing Agents Against Real Vendor Behavior

Developers open-sourced FetchSandbox after finding that agents passing all mock tests still failed on real webhooks, since mocks are stateless while real vendors have rate limits and auth quirks. The tool enables end-to-end testing against realistic vendor behavior.

2026-09-01 ~ 2026-09-02 · 2 related posts

• Agents pass every test, then fail the first live webhook: why mocks lie — Common_Dream9420 · 2026-09-01
• FetchSandbox MCP lets agents test against recorded real provider behavior, not mocks — Common_Dream9420 · 2026-09-02