Brings up real backing services (databases, message brokers, browsers, anything dockerizable) as throwaway containers from inside a test process - Java, Node.js, Python, Go, .NET, Ruby and ten other languages - using the Testcontainers library family. Wires the per-test container lifecycle, exposed-port → host-port mapping, wait strategies (port / log / HTTP / SQL), Ryuk-based cleanup, container-to-container networks, and the (experimental) `withReuse` shortcut for local dev. Use when integration tests need a real Postgres / Redis / Kafka / Selenium / etc. and the team wants per-test isolation without hand-rolled docker-compose teardown.

Scaffold and author a custom Tessl reviewer plugin, by forking the default rubric or building one from scratch. Fetches the published default Tessl review rubric (tessl/default-skill-review) so you can read and tweak it, scaffolds the plugin directory, writes rubric files and config.json, and validates with tessl review run. Use when the user wants to create or customise a review plugin, fork or tweak the default reviewer rubric, change scoring weights, add custom judges, or build a domain-specific rubric for tessl review.

Derive custom review-plugin judges, rubrics, and scoring criteria from evidence — existing skills, PR review feedback, and accumulated agent logs — by finding where agents needed correction or skills failed to activate, then translating those patterns into scoring dimensions and anchors. Hands the rubric design to create-review-plugin for scaffolding. Use when the user wants a custom skill reviewer or scoring rubric grounded in how their agents actually behave — to grade skills consistently, or build review criteria from past PR feedback and agent logs.

Use when an AI agent needs to programmatically drive, test, or record a terminal (TUI) application. Launches programs via pseudo-TTY, captures screen output, sends keystrokes and control sequences, and records sessions to asciicast format. Trigger on: launching interactive terminal programs, automating CLI workflows, testing TUI apps, recording terminal sessions, sending keystrokes to running programs, waiting for terminal output, or any task that requires controlling a terminal application non-interactively.

Creates Vaadin Browserless server-side unit tests for Vaadin views covering navigation, component interactions, form validation, grid operations, and notifications. Use when the user asks to "write Browserless tests", "write Vaadin UI unit tests", "unit test a Vaadin view without a browser", "create view tests with the official Vaadin testing framework", or mentions Browserless testing, SpringBrowserlessTest, browserless-test-junit6, UI Unit Testing, or server-side Vaadin testing.

Audits an already-written use case (UC-XXX) or test case (TC-XXX) against its specification and reports a coverage matrix: which main success scenario steps, alternative flows, business rules, preconditions, and postconditions have code and tests behind them, which are still open, and which code or tests have drifted away from the specification. Use when the user asks to "check coverage", "run a coverage check", "is UC-001 fully implemented", "is UC-001 completely tested", "audit the use case", "show me the coverage matrix", "do a traceability check", "what is still missing for UC-001", or "can I set the status to Tested". This is specification coverage, not line coverage from a coverage report. It reports only — it writes no code, no tests, and no files. When the user wants the gaps closed rather than listed, use /implement, /implement-hilla, /browserless-test, /hilla-test, /karibu-test, or /playwright-test instead.

Creates versioned Flyway database migration scripts (V*.sql) with sequences, tables, constraints, and foreign keys from the entity model. Use when the user asks to "create a migration", "generate SQL scripts", "set up database tables", "write a Flyway migration", or mentions schema migration, DB migration, database versioning, or SQL migration files.

Use once there is a confirmed composition plan, to create it. Scaffolds the plugin, authors or restructures the skills, and adds the rules, hooks, MCP servers, or commands the plan called for. Uses the CLI to scaffold the plugin, then authors the planned composition.

Use when someone wants to turn a problem, a messy or sprawling skill, or some existing work into well-shaped reusable context for their agent. Triggers include "help me make a skill for X", "my skill is a mess, sort it out", "I want to get more out of Tessl with this skill", or "package this so my team can use it". Runs the arc - understand the problem, gather the artifacts, plan the right composition, build it - then points to eval as a separate next step.

Use during build when a skill or a problem is too big for one skill - a sprawling SKILL.md doing several jobs, or a large problem the user wants a single skill for. Splits it into focused, independently-verifiable skills, with a plugin as the superstructure that holds them together.