apache-cayenne

Use this skill whenever the user wants to (re)generate Cayenne entity Java classes from a DataMap. Trigger on phrases like 'generate Java classes', 'regenerate entities', 'run cgen', 'create the entity classes', 'why is the Artist class missing fields', 'where did the `_Abstract*` classes come from', 'sync the entity classes with the model', or any request to materialize Java from the DataMap. Also trigger as a follow-up after modeling changes (someone added an entity, attribute, or relationship and now the Java side is stale). This skill exclusively uses the `mcp__cayenne__cgen_run` MCP tool — it does NOT use `mvn cayenne:cgen` or the Gradle cgen task.

Use this skill when the user explicitly wants to open CayenneModeler (the GUI) on a Cayenne project, or when the modeling task is inherently visual — reverse engineering (delegated to cayenne-reverse-engineer), bulk relationship layout, multi-entity visual refactoring. Trigger on phrases like 'open the Modeler', 'open in CayenneModeler', 'launch the GUI', 'edit visually', 'show me the project in the Modeler'. Do NOT trigger as a fallback for ordinary a-la-carte XML edits — those belong in the cayenne-modeling skill, which is faster and doesn't require the user to context-switch.

Use this skill whenever the user wants to edit, inspect, or extend the Cayenne ORM model in a project — adding or modifying entities, attributes, relationships, embeddables, named queries, stored procedures, or DataNodes. Trigger on phrases like 'add an ObjEntity', 'add a DbEntity', 'add a relationship', 'expose this column as an attribute', 'create a new DataMap', 'add a named query', 'create an embeddable', 'add a stored procedure', 'change the attribute type', 'mark this column as nullable', 'rename this entity', or any mention of a Cayenne `*.map.xml` or `cayenne-*.xml` file. Also trigger when the user references modeling concepts (ObjEntity, DbEntity, ObjAttribute, DbAttribute, ObjRelationship, DbRelationship, Embeddable, dbEntityName, deleteRule, db-attribute-path, db-relationship-path, defaultPackage) in the context of a Cayenne-using app. This is the *primary* skill for a-la-carte ORM model manipulation — direct XML edits, not the Modeler GUI.

Use this skill whenever the user wants to write or modify a Cayenne query — fetching entities by criteria, joining, prefetching to avoid N+1, ordering, paginating, aggregating, or running raw SQL through Cayenne. Trigger on phrases like 'query for X', 'fetch all artists where ...', 'write an ObjectSelect', 'use SQLSelect', 'use SelectById', 'add a prefetch', 'get distinct values', 'count rows', 'find by ID', 'load by primary key', 'build a Cayenne expression', 'why am I getting N+1', 'how do I paginate', 'select a single column', 'select columns into a DTO', 'named query in the DataMap'. Do NOT trigger for modeling changes (use cayenne-modeling) or runtime bootstrap (use cayenne-runtime).

Use this skill whenever the user wants to import database schema metadata into a Cayenne DataMap — full-schema sync from a live DB. Trigger on phrases like 'reverse engineer the database', 'import the schema', 'generate a DataMap from my DB', 'sync the model with the database', 'add the new tables from the DB', 'import the customer table', 'pick up the latest schema changes', 'create entities from these tables', or any request that involves reading database metadata to populate or update a DataMap. This is for *full schema* or *bulk table* import; one-off a-la-carte entity additions belong in the cayenne-modeling skill. The skill drives this through CayenneModeler's reverse-engineering wizard via the `mcp__cayenne__open_project` MCP tool — it does NOT use Maven `cdbimport` or any Gradle equivalent.