ai-evals-course/evals-skills

write-code-eval

Write code evaluators for known failure modes with objective rules.

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How to use

  1. Copy the installation command and review the source package before installing it in your own agent environment.
  2. Check the source document for required tools, credentials and supported hosts.
  3. Describe your input and desired deliverable; review the output against the source material.
npx skills add https://github.com/ai-evals-course/evals-skills --skill write-code-eval

Before you start

  • Installation does not include a model subscription, API allowance or permission to access your files.
  • Repository stars and installation counts describe activity, not an independent quality or security test.
Original skill document

Rendered from the source repository. Headings, examples, code, tables, links, and referenced images are preserved.

Write a code evaluator

Start with a failure mode found through error analysis. Write one check for that failure mode, much like a unit test that asserts what should hold for each trace.

  1. State the rule and identify the trace fields or reference data the check needs. If the rule requires interpretation, use write-judge-prompt.
  2. Implement the check in the project's language and eval framework. Return a result and a reason in the format that framework expects.
  3. Test known passes and failures, including borderline cases. Run the check on available traces and inspect mistakes. If the rule uses a proxy for human judgment, compare its results with human labels.

Examples

Failure modePossible check
Invalid output structureParse the output and check required fields
Missing or forbidden textMatch a string or pattern
Citation not in retrieved documentsCompare cited IDs with retrieved IDs
Bad tool callCheck arguments against the tool schema or run the call in a safe test environment
Wrong valueCompare the output with a reference value

Choose the check from the failure rule. For a failure with both objective and interpretive parts, check the objective part with code and use a judge for the rest.

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