mastra

How to build Mastra frontend interfaces with the @mastra/playground-ui design system. This skill should be used when creating or modifying any application UI — pages, components, styling, or tokens — in this repo or in an external consumer of the design system. The docs site has its own styling and is out of scope.

Documentation guidelines for Mastra. This skill should be used when writing or editing documentation for Mastra. Triggers on tasks involving documentation creation or updates.

REQUIRED when modifying any file in packages/playground-ui or packages/playground. Triggers on: React component creation/modification/refactoring, UI changes, new playground features, bug fixes affecting studio UI. Generates Playwright E2E tests that validate PRODUCT BEHAVIOR, not just UI states.

Interactive documentation quality review for Mastra docs. Use when auditing, reviewing, or critiquing Mastra documentation; checking docs against source code; validating code examples, API accuracy, or property completeness; checking whether docs follow the styleguide and deterministic linters; or evaluating whether a beginner or agent can follow a doc to complete a job. This skill keeps humans in the loop with ask_user and submit_plan, then always runs an agent-build eval after approved fixes.

Use early when debugging a medium or hard bug, especially when tests alone may not reveal the real runtime failure. Trigger this before extended TDD iteration when a bug involves runtime state, ordering, persistence, streaming, concurrency, UI/manual reproduction, external services, or when a red or newly passing test may not model the real issue. Skip only when the root cause is already directly proven by a stack trace or deterministic test that exercises the real runtime path.

Smoke test the Agent Builder feature branch end-to-end against a hermetic project scaffolded by the skill (linked to the current worktree). Covers workspace reconciliation, stored agents/skills CRUD, ownership, visibility, stars, registry/library Copy flow, picker allowlists, model policy, RBAC role gating, role impersonation UI, builder defaults, infrastructure diagnostics, channels, and Studio + Agent Builder UI. Trigger when validating the agent-builder feature branch, PRs that touch packages/server, packages/playground, packages/playground-ui agent-builder routes, or builder EE code paths.