[cdfox]

What does this PR do? What is the motivation?

Adds a Code Evaluators page for Agent Observability. Code evaluators run a JavaScript function on spans, traces, or sessions instead of calling an LLM judge, which suits checks with a definite answer like empty tool results or keyword matches.

The new page covers:

• Creating a code evaluator from the Code Evaluations templates or from Scratch with the Type selector
• The __evalDeterministic(data) function: input shape per scope, and how return values map to Boolean, score, categorical, and JSON results
• Example functions for each scope
• Testing in the editor, querying results, and creating code evaluators through the custom evaluator API

It also adds the page to the Evaluations nav, the Evaluations overview, and a pointer from the Custom LLM-as-a-Judge page.

Merge readiness

• Ready for merge

AI assistance

Drafted with Claude Code from the feature's implementation, then reviewed by the author.

For Datadog employees:

• ⚠️ Your branch name MUST follow the <name>/<description> convention and include the forward slash (/). If you've already created your PR with an incorrect branch name, please rename your branch and open a fresh PR.
• 🤖 New: Comment with /review to run an automated check that catches common issues before a Documentation team member reviews your PR.

Additional notes

🤖 Generated with Claude Code

[github-actions]

Preview links (active after the build_preview check completes)

New or renamed files

• https://docs-staging.datadoghq.com/christopher.fox/code-evaluations-docs/llm_observability/investigate/evaluations/code_evaluations

Modified Files

• https://docs-staging.datadoghq.com/christopher.fox/code-evaluations-docs/llm_observability/investigate/evaluations/
• https://docs-staging.datadoghq.com/christopher.fox/code-evaluations-docs/llm_observability/investigate/evaluations/llm_as_a_judge_evaluations/

[cdfox]

/review

[github-actions]

🤖 Automated review by Claude. AI-generated; verify before acting.

Nice, well-structured addition. Frontmatter, menu entry, cross-links, and reference-style links all look good. A couple of minor clarity and style nits inline — nothing blocking.

_{Reviewed 6afdf5191c4f260fabe708b9b346f566083ed9c9 — workflow run}