Writes MySQL 8.4 stored procedures and the sequelize-cli migration that creates them, for Node backends on Sequelize 6 and mysql2. Covers a .sql script that also runs with the mysql client through DELIMITER, a migration that sends DROP and only the CREATE PROCEDURE block in separate queries, a JSON parameter read with JSON_TABLE for header-plus-lines data such as a sale and its items, an EXIT HANDLER with ROLLBACK and RESIGNAL, SIGNAL SQLSTATE 45000 for business rules, totals computed in SQL as DECIMAL(10,2), and exactly one final SELECT. Use when asked to create or change a stored procedure, to save a sale with its items (or any header with lines) in one call, when a migration fails with ER_PARSE_ERROR 1064 near DELIMITER, when deciding between docker-entrypoint-initdb.d and migrations, or when a procedure must validate input and roll back.

Calls MySQL stored procedures from Node with Sequelize 6 and mysql2 and turns their errors into HTTP responses in Express. Covers CALL with named replacements and JSON.stringify for lists, reading rows[0], why QueryTypes.SELECT, OUT parameters and sequelize.transaction() break a CALL, errno mapping (1644, 1452, 3140, 1062) to 422, 404, 400 and 409, money kept as DECIMAL strings, and safe name or barcode search with Op symbols. Use when writing a service or route that runs CALL, when a CALL returns nested arrays, objects with numeric keys or undefined, when adding status codes for procedure errors, when someone wants to wrap a procedure call in a transaction, or when searching products by name or barcode.

Use when a learner wants to start, work through, or be guided or tutored through the Your first code review lesson, the opening lesson of the Code Review Loops course. Walks them one step at a time through scaffolding a small service with a deliberately flawed branch, running a Tessl Code Review over it three different ways, and reading the outcome, the severities and the JSON result, checking what they got after each step before moving on. Triggers on asks like guide me through your first code review, start the code review course, how do I run tessl code review, or review my branch with Tessl.

Use when a learner wants to start, work through, or be guided or tutored through the Writing a review lens lesson from the Code Review Loops course. Walks them one step at a time through authoring a review lens that encodes one of their own team's conventions, running it beside pinned default lenses, and testing it in both directions so it fires on the bad case and stays quiet on the good one. Triggers on asks like guide me through writing a review lens, how do I write a custom code review lens, make Tessl check my team's conventions, or create a lens for tessl code review.

Use when a learner wants to start, work through, or be guided or tutored through the Routing lenses by path lesson from the Code Review Loops course. Walks them one step at a time through writing a repository YAML review profile, scoping each lens to the paths its rule governs with globs and exclusions, proving the routing in both directions, and understanding why a skipped review must never be read as an approval. Triggers on asks like guide me through routing lenses by path, how do I write a tessl-code-review.yml, scope a review lens to certain files, or what does no-matching-lenses mean.

Generates bUnit component tests for Blazor components (.razor): renders the page, fills and submits its forms, asserts the rendered markup and the validation and error messages the use case states, and replaces the handlers and services it injects with test doubles, one test per scenario and business rule tagged with [UseCase]. Use when the user asks to "write bUnit tests", "test a Blazor component", "test the Razor page of UC-001", "create UI tests for Blazor", or mentions bUnit or xUnit rendering tests. Backend tests are /dotnet-test, browser tests /playwright-test.

Generates C# backend unit and integration tests for EF Core DbContext repositories, domain services, and vertical slice handlers using xUnit or NUnit against SQLite in-memory or Testcontainers databases, one test per scenario and business rule, each tagged with [UseCase]. Use when the user asks to "write backend tests for C#", "write .NET tests for this handler", "test ef core context", "write integration tests for dotnet", or mentions xUnit or NUnit handler tests. Blazor component tests are /bunit-test, browser tests /playwright-test.

Builds the data layer of a C# / .NET project from docs/entity_model.md with Entity Framework Core: generates the entity classes, writes IEntityTypeConfiguration Fluent API mappings (table names, decimal precision, enum conversions, foreign keys, unique indexes, binary columns), registers them in the DbContext, and adds a native C# migration with dotnet ef migrations add. Use when the user asks to "create an EF Core migration", "add ef migration", "update the schema with ef core", "map the entities in the DbContext", "generate a db migration for .net", or mentions EF Core, DbContext, Fluent API, or dotnet ef in a Blazor .NET project.