# Install globally
bun install -g @hasna/evals
# Register MCP server with your agent runtime
evals mcp register --claude # Claude Code
evals mcp register --codex # Codex CLI
evals mcp register --gemini # Gemini CLI
evals mcp register --all # all three at once
# Restart your agent — evals_* tools will be available| Tool | When to use |
|---|---|
evals_run_single |
Self-check your own response before returning it to a user |
evals_run |
Run a full test suite against an app |
evals_judge |
One-shot judge call without a dataset |
evals_list_datasets |
Discover available eval datasets |
evals_get_results |
Look up a past run by ID |
evals_compare |
Check for regressions between two runs |
evals_create_case |
Add a new test case to a dataset |
evals_generate_cases |
Auto-generate cases from a description |
evals_run_single(
input: <user's question>,
output: <your drafted response>,
rubric: "Should be accurate, helpful, and under 200 words."
)
If verdict is FAIL or UNKNOWN, revise your response before returning it.
evals_run(
dataset: "datasets/smoke.jsonl",
adapter: { type: "http", url: "http://localhost:3000/api/chat" },
save: true
)
evals_compare(before: "main", after: "<latest-run-id>")
❌ Don't pass numeric scores in rubrics — write pass/fail criteria instead
❌ Don't skip the judge on important cases — UNKNOWN means human review needed
❌ Don't run evals without saving — save: true enables history and baseline comparison
❌ Don't use evals_run_single for bulk testing — use evals_run with a dataset file