primer

Use when authoring, modifying, reviewing, or debugging Primer React component and hook tests in Vitest browser mode. Do not use for Node/SSR tests, standalone Playwright visual or accessibility tests, or component implementation without test changes.

Use when: adding changesets to pull requests, determining semver bump types, versioning packages, or preparing releases. Covers changeset file format, semver guidance, when changesets are required, and the release pipeline.

Use when planning an ADR-driven migration from adoption tooling through stacked batch implementation and cleanup.

Use when: deprecating Primer React components or hooks. Covers source annotations, docs metadata, changesets, docs page updates, and validation for deprecations.

Use when: implementing, creating, testing, or debugging feature flags in Primer React. Covers useFeatureFlag hook, FeatureFlags provider, DefaultFeatureFlags, FeatureFlagScope, Storybook integration, and the feature flag lifecycle at GitHub.

Use when: determining which Primer React API type (config, presentational, base, or utility) should own a specific accessibility responsibility, or documenting that ownership for a new component. Covers a responsibility matrix mapping ARIA requirements to API…

Use when: building or evaluating unstyled Primer React primitives, especially accessibility primitives or low-level behavior that other components should build on. Covers when to create a base component instead of baking behavior into a styled component, the…

Use when: building or evaluating a props-based, "all-in-one" Primer React component for an established, stable pattern. Covers when config components are appropriate, opinionated defaults, the props-driven customization surface, escape hatches to…

Use when installing or using @primer/agent-eval, designing agent evaluations, creating benchmarks, experiments, scenarios, checks, judges, or treatments, and running, planning, sharding, or interpreting evaluations with the agent-eval CLI.

Use when adding, updating, or reviewing tests in agent-eval, choosing test coverage, organizing Vitest tests, or isolating filesystem, Docker, and other external dependencies.

Turborepo monorepo build system guidance. Triggers on: turbo.json, task pipelines, dependsOn, caching, remote cache, the "turbo" CLI, --filter, --affected, CI optimization, environment variables, internal packages, monorepo structure/best practices, and…

Determine whether agent-eval changes need a changeset and write consumer-focused changesets for public API changes.

Use when triaging a new Octicons icon request, recommending an existing icon, facilitating an icon design review, or reviewing a pull request that adds, updates, or renames an icon.

Use when a pull request changes a package's public API. Covers affected packages, semantic version impact, file format, and user-focused release notes.

Use when creating or updating agent skills (.agents/skills)