Vitest: Fix agent detection breaking runs

[JReinhold]

Co-authored-by: Copilot copilot@github.com

Closes #

What I did

It is never valid to call context.vitest.provide() from within configureVitest, so I moved the computation of agent context to the config hook and used the provide config instead of providing dynamically using the function call.

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

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  MIGRATION.MD

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  • bug: Internal changes that fixes incorrect behavior.
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🦋 Canary release

This pull request has been released as version 0.0.0-pr-34681-sha-1d5ea958. Try it out in a new sandbox by running npx storybook@0.0.0-pr-34681-sha-1d5ea958 sandbox or in an existing project with npx storybook@0.0.0-pr-34681-sha-1d5ea958 upgrade.

More information

Published version	0.0.0-pr-34681-sha-1d5ea958
Triggered by	@yannbf
Repository	storybookjs/storybook
Branch	jeppe/fix-vitest-provide-agent
Commit	1d5ea958
Datetime	Fri May 1 11:00:10 UTC 2026 (1777633210)
Workflow run	25211981040

To request a new release of this pull request, mention the @storybookjs/core team.

core team members can create a new canary release here or locally with gh workflow run --repo storybookjs/storybook publish.yml --field pr=34681

Summary by CodeRabbit

• Refactor
  • Optimized Vitest plugin initialization by relocating telemetry detection and session management to an earlier configuration stage for improved efficiency.
  • Expanded conditions for test analysis feature activation to cover broader scenarios beyond component test paths.

[github-actions]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 5491707 and 1d5ea95.

📒 Files selected for processing (1)

• code/addons/vitest/src/vitest-plugin/index.ts

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📝 Walkthrough

Walkthrough

The Vitest plugin refactors telemetry and agent detection, moving this logic from the configureVitest hook to an earlier config hook. The reporter injection condition is updated to activate based on previously computed values, and render analysis activation is broadened to include agents within ai-setup sessions.

Changes

Cohort / File(s)	Summary
Vitest Plugin Telemetry Refactoring code/addons/vitest/src/vitest-plugin/index.ts	Relocated agent and session detection from configureVitest to config hook; gated reporter injection on previously computed detection state; expanded test.provide activation condition to include ai-setup session agents.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

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