Authors Maestro YAML flow files (`.maestro/*.yaml`) for mobile + web UI automation: declarative `tapOn`, `inputText`, `assertVisible`, `swipe`, supported targets (iOS, Android, Flutter, React Native, web), nested flow imports, JavaScript hooks for complex conditions. Use when the team has already chosen Maestro, is coming from an existing `.maestro/` directory, or explicitly wants YAML-declarative tests readable by non-engineers without a compile step. For framework selection or authoring tests in XCUITest / Espresso / Detox / Appium / Flutter, use a mobile driver-selection or per-flow mobile test-authoring step instead.

Build-an-X workflow that verifies locale-specific format rendering - dates (US `5/4/2026` vs ISO `2026-05-04` vs DE `04.05.2026` vs JP `2026/05/04`), numbers (US `1,234.56` vs DE `1.234,56` vs FR `1 234,56`), currencies (US `$1,234.56` vs JP `¥1,235` vs DE `1.234,56 €`), times, durations. Use when the product displays locale-sensitive data and the team needs assurance the formatting matches per-locale conventions.

Wraps Pothos GraphQL schema-builder testing patterns: testing the SchemaBuilder output (lexicographicSortSchema + printSchema for snapshot tests), testing resolvers via the standard `graphql()` function from graphql-js (no server needed), integration with Apollo Server / GraphQL Yoga (Pothos emits standard graphql-js schemas), and code-first builder unit tests. Covers the SchemaBuilder API surface (queryType, mutationType, objectType, t.field, t.arg). Use when testing a Pothos-built schema before or alongside the server-runtime tests.

Workflow-driven skill that builds the runbook for safely removing a feature flag from the codebase + the flag platform. Walks through: pre-removal verification (flag fully rolled out, no usage variance in evaluations, dependent code paths identified), the code-removal steps (delete the if-branches, simplify, restore types), the platform-side removal (archive in LaunchDarkly / Unleash / Flagsmith / GrowthBook), the verification post-removal, and the rollback plan. Use when removing a flag that has finished its mission (rollout-complete, experiment-shipped, kill-switch retired).

Wraps Split.io (Harness FME) SDK testing patterns: hermetic localhost/offline mode with an in-memory features map (JavaScript/browser) or a YAML fixture file (Node.js server-side), getTreatment and getTreatmentWithConfig evaluation, the SDK_READY event and whenReady() promise, impression listener verification, sync.impressionsMode configuration, and CI setup. Use when writing tests for application code instrumented with the Split.io or Harness Feature Management & Experimentation SDK.

Reference catalog of data-quality conventions - when to choose dbt-tests vs Great Expectations vs Soda, column-level vs table-level coverage, severity tiering, SLA and freshness conventions, and common anti-patterns to avoid. Use when designing coverage for a new data product or auditing an existing one.

Diffs two GraphQL schemas with `graphql-inspector diff`, classifies each change as BREAKING / DANGEROUS / NON_BREAKING, and applies opt-in rules (suppress-removal-of-deprecated-field, consider-usage, ignore-description-changes) to gate CI on schema regressions. Use when reviewing GraphQL schema changes in a PR or evaluating Federation supergraph drift.

Reference catalog of CCPA + CPRA-aligned test patterns - do-not-sell-or-share opt-out via Global Privacy Control (GPC) signal; data-disclosure category tests per Cal. Civ. Code §1798.110; sensitive personal information (SPI) handling per CPRA §1798.121; deletion-request workflows per §1798.105; CPRA's right to correct (§1798.106) + limit-use (§1798.121). Use when authoring CCPA/CPRA-readiness tests for any product processing California consumer data.

Snapshot testing for terminal UI apps (TUIs) - captures rendered terminal frames as deterministic SVG / text snapshots, diffs them on every run, surfaces a reviewable HTML report on failure, and supports `--snapshot-update` to accept changes intentionally. Wraps `pytest-textual-snapshot` for Python Textual apps; provides equivalent recipes for Ratatui (Rust) `insta` snapshots, Charm Bracelet (Go) `teatest` golden files, and Ink (Node) `ink-testing-library`. Use for any TUI where layout regressions otherwise reach users via `screenshot looks wrong in terminal`.

Build-an-X workflow for a chaos experiment per the Principles of Chaos Engineering - defines steady-state hypothesis, picks the variables (real-world events: network latency, node failure, region outage), sets the blast radius (which percentage / namespace / user cohort), automates execution, and emits the verdict (steady-state held / didn't hold). Includes the five-check pre-flight validation of the steady-state hypothesis (measurable, baselined, SLI-backed tolerance, defined measurement window, metric moves under the fault) with hard-reject rules, and routes the tool choice: Chaos Mesh has its own standalone skill, while LitmusChaos and Gremlin setup live in this skill's references. Use to scope and pre-flight-validate a chaos experiment before running it via Chaos Mesh / Litmus / Gremlin / Toxiproxy.

Authors Tavern API tests as YAML files (`test_*.tavern.yaml`) with `test_name` + `stages` + `request` + `response` blocks, runs them through the Tavern pytest plugin (auto-discovered), and gates CI on the resulting JUnit XML. Covers RESTful, MQTT, and gRPC variants. Use when the project runs on pytest and prefers YAML over a Python- or Java-DSL; on the JVM use karate-testing or restassured-testing instead, and for schema-driven property-based fuzzing on the same pytest stack use schemathesis-fuzzing.

Builds a per-component WCAG 2.2 accessibility checklist from a component spec - covers focus management, color contrast, ARIA roles & states, keyboard interaction, error handling, and live-region announcements - emitting a markdown checklist or YAML test plan that pairs with screen-reader-test-author for manual verification and the violation gate for automated scans. Use during component-spec review or pre-implementation acceptance.

Authors WebdriverIO E2E tests - `npm init wdio@latest` scaffolding, services architecture (sauce, browserstack, appium, devtools), reporters (spec, allure, junit), built-in Mocha/Jasmine/Cucumber framework integrations. WebdriverIO sits between Selenium (W3C protocol) and Playwright (modern API) - Selenium-protocol-compatible with rich plugin ecosystem. Use when the team needs WebDriver protocol + service-based device-farm integration.