fix(studio): Experiment Session, expand scores into unique columns

[nakolean]

Screen.Recording.2026-06-12.at.9.41.47.AM.mov

Summary by CodeRabbit

• Improvements
  • Evaluator scores in experiment sessions now display as individual columns per evaluator with percentage formatting, replacing the previous combined view. Missing scores are clearly indicated, providing better visibility of individual evaluator performance at a glance.

[coderabbitai]

📝 Walkthrough

Walkthrough

ExperimentSessionsDataView replaces its single aggregated evaluator-scores column with per-evaluator columns. The change imports a case converter, introduces a percentage formatter, derives evaluator names from experiment metadata and page data, and renders one score column per evaluator.

Changes

Dynamic Evaluator Score Columns

Layer / File(s)	Summary
Formatting utilities for evaluators web/packages/studio/src/components/dataViews/ExperimentSessionsDataView/index.tsx	Imports snakeCaseToTitleCase for header formatting and replaces prior formatEvaluatorScores with new formatScore function that converts numeric scores to percentage strings.
Dynamic evaluator column generation web/packages/studio/src/components/dataViews/ExperimentSessionsDataView/index.tsx	Computes evaluatorNames by unioning experiment.evaluator_names with score keys present on current page, then generates one accessor/column per evaluator with formatted headers and - for missing scores.

Suggested reviewers

• walston

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	Title accurately describes the main change: dynamically building individual evaluator score columns instead of a single aggregated column.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch nkolean/expand-group-score-columns

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In
`@web/packages/studio/src/components/dataViews/ExperimentSessionsDataView/index.tsx`:
- Line 29: The formatter assumes evaluator_scores are in the 0–1 range but the
DTO doesn't guarantee it; update code to clamp the incoming value to [0,1]
before formatting in formatScore and add a clarifying comment or JSDoc on
ExperimentSessionResponse.evaluator_scores (and reference
EvaluatorResultInput.value) that the field represents a mean in the 0–1 range;
specifically, modify formatScore to clamp its numeric input (e.g., Math.min(1,
Math.max(0, value))) then multiply/format, and add a brief comment on
ExperimentSessionResponse.evaluator_scores documenting the 0–1 contract so
callers and the OpenAPI/DTO are explicit.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: e3524fb5-89fc-48ac-9262-9649d65cbe08

📥 Commits

Reviewing files that changed from the base of the PR and between 5a973b1 and 4fd4e18.

📒 Files selected for processing (1)

• web/packages/studio/src/components/dataViews/ExperimentSessionsDataView/index.tsx

[github-actions]

Suite	Lines Covered	Line Rate	Branch Rate
Unit Tests	19029/25222	75.4%	61.4%
Integration Tests	11024/23994	45.9%	20.4%

[shanaiabuggy]

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