Authors and runs FlaUI-based Windows UI tests - the .NET-native wrapper around Microsoft UI Automation (UIA2 + UIA3). Covers the `FlaUI.Core` / `FlaUI.UIA2` / `FlaUI.UIA3` NuGet packages, `Application.Launch` / `Application.Attach` lifecycles, `ConditionFactory` + `FindFirstDescendant` locator patterns, `Retry` waits, and xUnit / NUnit / MSTest harness integration. Use when the test stack is C# / .NET-first and the team wants idiomatic in-process UIA calls rather than the HTTP/JSON wire protocol of `winappdriver` (direct or Appium-wrapped).

Reference catalog of desktop GUI test strategies across Windows, macOS, and Linux. Defines the three accessibility-tree backends (Microsoft UI Automation on Windows, Apple Accessibility / XCTest on macOS, AT-SPI on Linux), the wrapper-tools that drive each backend, the cross-toolkit Electron + Qt paths, the project-marker detection table plus one-driver-per-app decision table (FlaUI / WinAppDriver / electron-playwright / QtTest / XCUITest / AT-SPI), an accessibility-first locator strategy, and a desktop test-review hazard checklist (screen-object encapsulation, locator stability, explicit waits, STA / foreground-lock / elevation). Deep operational detail (per-OS async-wait hierarchies, parallel-test policy, UAC / TCC / AT-SPI elevation hazards, the high-DPI matrix) lives in references/. Use when choosing how to test or automate a desktop GUI application on Windows, macOS, or Linux, or when reviewing an existing desktop UI test suite - the strategic reference ahead of the per-tool implementation skills.

Reference catalog of HIPAA Security Rule-aligned test patterns - administrative safeguards (45 CFR §164.308: workforce training, access management, contingency planning), physical safeguards (§164.310: facility access, workstation security, device disposal), technical safeguards (§164.312: access control, audit logs, integrity, transmission security); PHI handling assertions in fixtures; minimum-necessary tests per §164.502(b); BAA-scope boundary verification. Use when authoring HIPAA-readiness tests for any product handling Protected Health Information.

Wraps Redis cache testing: EXPIRE / PEXPIRE / TTL verification (Redis 7+ NX/XX/GT/LT flags), cache-aside write-then-invalidate (write source → DEL key → assert fresh read), eviction under memory pressure (maxmemory + allkeys-lru), pub/sub invalidation across nodes, and tenant key-namespacing. Use when Redis is the app's primary cache. For the CDN/browser HTTP tier use cdn-cache-purge-tests; a runnable test, not the cache-coherence-patterns-reference catalog (which owns the stampede + stale-while-revalidate references).

Author the Playwright fixture layer every Chromium extension test depends on - `chromium.launchPersistentContext` with `--disable-extensions-except=$DIR` + `--load-extension=$DIR`, the `channel: 'chromium'` selection that unlocks headless extension support, the `context.serviceWorkers()` + `waitForEvent('serviceworker')` race-handling pattern, and the `extensionId = serviceWorker.url().split('/')[2]` extraction recipe - plus, in references/, the extension load / reload matrix (which edit re-evaluates which surface), the `chrome.storage` test suite (area selection, quota-exceeded, `storage.onChanged`, managed read-only), and the per-surface assertion recipes (popup, content script, background messaging, MV3 auto-suspend survival). Use when authoring or debugging the fixture a Chromium extension test imports, when an edit appears to have no effect and you need the reload matrix, or when authoring popup / content-script / storage tests.

Pure-reference catalog of the Manifest V3 test surface for Firefox + Chromium browser extensions. Maps each manifest field that changed from MV2 (manifest_version, background.service_worker vs background.scripts, action vs browser_action / page_action, host_permissions split, web_accessible_resources object-form, content_security_policy object-form), the runtime restrictions service workers impose (no DOM, no XMLHttpRequest, no localStorage, ephemeral lifecycle, synchronous listener registration, alarms instead of setTimeout), and the Firefox-vs-Chrome key matrix (browser_specific_settings.gecko, externally_connectable / offline_enabled gaps, MV2-only user_scripts manifest key); references/ carry Mozilla's web-ext CLI (lint via addons-linter, run on firefox-desktop / firefox-android / chromium targets, deterministic build, AMO sign). Use as the manifest-surface reference when authoring extension tests across both browsers, or when driving Firefox runs / AMO signing with web-ext.

Strengthens and speeds up JVM API test suites - assertions so loose that an empty `200 OK` passed for three days, a 220-test suite spending fourteen minutes mostly waiting on sequential HTTP calls, or endpoints exercised through a hand-rolled JDK HTTP client with JSON parsed by hand. Authors REST Assured (Java) tests in the given().when().then() BDD-style DSL: status code and JSON / XML path assertions, authentication (Basic, OAuth2, API key), Maven / Gradle dependencies, JUnit 5 execution, and Surefire / JaCoCo reports for CI gating. Use when the project is on the JVM and its API tests miss real assertions, run too slowly, or are written by hand.

Build-an-X workflow that uses an LLM to map existing tests to spec sections - given a spec doc + the test suite, the LLM identifies which tests cover which sections, surfaces uncovered sections (gap), and recommends specific tests to add. Output is a coverage matrix per spec ID. Scope is mapping tests that already exist and naming the gaps, not authoring tests for new acceptance criteria. Use when a spec doc and a test suite both exist but nobody can say which requirements are actually covered - before a release sign-off, an audit, or a decision about where to spend the next round of test effort.

Reference catalog for WCAG 2.2 keyboard-navigation conformance - covers SC 2.1.1 (Keyboard), 2.1.2 (No Keyboard Trap), 2.1.4 (Character Key Shortcuts), 2.4.3 (Focus Order), 2.4.7 (Focus Visible), 2.4.11/2.4.12 (Focus Not Obscured) - with conformance levels (A/AA), test scripts, and per-criterion failure patterns, plus the modal focus-trap / focus-management pattern (focus-on-open, Tab-cycle, inert, Escape-closes, restore-to-trigger, native `<dialog>`) in references/. Use when authoring or reviewing keyboard-only interaction support, or a modal / drawer / popover's focus management.

Evidence-first mailbox triage, drafting, send verification, and sent-mail-safe follow-up workflow for ECC. Use when the user wants to organize email, draft or send through the real mail surface, or prove what landed in Sent.

Write articles, guides, blog posts, tutorials, newsletter issues, and other long-form content in a distinctive voice derived from supplied examples or brand guidance. Use when the user wants polished written content longer than a paragraph, especially when voice consistency, structure, and credibility matter.

Clean up merged branches locally and on remote, keeping only main, dev, and gh-pages.

Design multi-stage CI/CD pipelines with approval gates, security checks, and deployment orchestration. Use when architecting deployment workflows, setting up continuous delivery, or implementing GitOps practices.

MANDATORY first step before writing any code that uses a framework, library, or technology. Searches the Tessl registry for best-practice tiles and installs them before implementation begins. MUST be invoked before: building a new app or feature, writing tests, configuring CI, setting up auth, designing APIs, database work, Docker setup, linting config, or any task involving React, Express, Next.js, TypeScript patterns, Playwright, SQLite, or other technologies. Use when the user says "build", "create", "implement", "set up", "configure", "write tests", or starts any greenfield project. Do NOT use for trivial edits or renaming variables. Requires Tessl MCP tools: search and install.

Apply this skill when designing, building, or reviewing API routes, Server Actions, or data fetching patterns in a Next.js + TypeScript + Drizzle application. Triggers on requests like "create an API endpoint", "add a server action", "design the API", "add pagination", "handle this request", "validate query params", or any time you are building the boundary between client and server. Use proactively — all API design decisions should follow these patterns.

Apply this skill when writing, reviewing, or planning tests for a Next.js + TypeScript + Drizzle application using Vitest, React Testing Library, MSW, and Playwright. Triggers on requests like "write tests for", "add test coverage", "test this component", "test this hook", "test this API route", "add E2E tests", "is this testable", or any time you are building features that need verification. Use proactively — all new features should include tests.

Apply this skill when writing, reviewing, or refactoring any code in a React + TypeScript + Tailwind + shadcn + Drizzle project. Triggers on requests like "review this code", "refactor this component", "is this good practice", "write a hook for", "clean this up", "add types to", "write a form", or any time you are producing code that should meet production standards. Use proactively — all generated code should conform to these standards without being asked.

Apply this skill when building, optimising, or reviewing components, data fetching, or database queries in a Next.js App Router + TypeScript + Tailwind + shadcn + Drizzle application where performance matters. Triggers on requests like "optimise this", "this is slow", "reduce re-renders", "improve load time", "this list is laggy", "bundle is too large", "slow query", or any time you are building features that involve large lists, frequent updates, heavy computations, or significant data volumes. Use proactively for anything rendering more than ~50 items or running on every keystroke.