Agent skill · operations · google-gemini
behavioral-evals
Guidance for creating, running, fixing, and promoting behavioral evaluations. Use when verifying agent decision logic, debugging failures, debugging prompt steering, or adding workspace regression tests.
Why this skill is useful
Provides detailed procedural guides and specific testing workflows for validating agent decision-making that the AI wouldn't reliably generate on its own.
What it needs
About 1k tokens when loaded. Last updated 2026-08-07. 106,400 stars on the source repository.
What this skill does
Behavioral Evals Overview Behavioral evaluations (evals) are tests that validate the agent's decision-making (e.g., tool choice) rather than pure functionality. They are critical for verifying prompt changes, debugging steerability, and preventing regressions. [!NOTE] Single Source of Truth: For core concepts, policies, running tests, and general best practices, always refer to evals/README.md. --- 🔄 Workflow Decision Tree 1. Does a prompt/tool change need validation? No -> Normal integration tests. Yes -> Continue below. 2. Is it UI/Interaction heavy? Yes -> Use appEvalTest (AppRig). See creating.md. No -> Use evalTest (TestRig). See creating.md. 3. Is it a new test? Yes -> Set policy to USUALLYPASSES. No -> ALWAYSPASSES (locks in regression). 4. Are you fixing a failure or promoting a test? Fixing -> See fixing.md. Promoting -> See promoting.md. --- 📋 Quick Checklist 1. Setup Workspace Seed the workspace with necessary files using the files object to simulate a realistic scenario (e.g., NodeJS project with package.json). Details in creating.md 2. Write Assertions Audit agent decisions using rig.setBreakpoint() (AppRig only) or index verification on rig.readToolLogs(). Details in creating.md 3. Verify Run single tests locally with Vitest. Confirm stability locally before relying on CI workflows. See evals/README.md for running commands. --- 📦 Bundled Resources Detailed procedural guides: creating.md: Assertion strategies, Rig selection, Mock MCPs. fixing.md: Step-by-step automated investigation, architecture diagnosis guidelines. promoting.md: Candidate identification criteria and threshold guidelines.
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills google-gemini/behavioral-evals