docs: add event handler examples, skill, quick reference, and tests

Following the PR review checklist for entity event handlers:
- mdl-examples/doctype-tests/01-domain-model-examples.mdl: working
  CREATE MICROFLOW + ALTER ENTITY ADD/DROP EVENT HANDLER examples
- .claude/skills/mendix/generate-domain-model.md: new section with
  syntax, moments, events, and usage notes
- docs/01-project/MDL_QUICK_REFERENCE.md: ALTER ENTITY table rows
- docs-site/src/language/entities.md: dedicated Event Handlers section
  in the language reference, plus syntax block update
- roundtrip_entity_test.go: integration tests for CREATE ENTITY with
  event handler and ALTER ENTITY ADD/DROP EVENT HANDLER

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ako

.claude/skills/mendix/generate-domain-model.md

@@ -253,6 +253,33 @@ WHERE e.Status != 'CANCELLED'   -- Correct: uses enum value
 WHERE e.Status != 'Cancelled'   -- Wrong: this is the caption
 ```
 
+### Entity Event Handlers
+
+Microflows can run before/after entity Create, Commit, Delete, or Rollback. Use the optional `RAISE ERROR` clause to make a handler act as a validation microflow — if it returns false, the operation is aborted.
+
+```sql
+-- In CREATE ENTITY (handlers go after attributes/indexes)
+CREATE PERSISTENT ENTITY Sales.Order (
+  Total: Decimal,
+  Status: String(50)
+)
+ON BEFORE COMMIT CALL Sales.ACT_ValidateOrder RAISE ERROR
+ON AFTER CREATE CALL Sales.ACT_InitDefaults;
+
+-- Add via ALTER ENTITY
+ALTER ENTITY Sales.Order
+  ADD EVENT HANDLER ON BEFORE DELETE CALL Sales.ACT_CheckCanDelete RAISE ERROR;
+
+-- Drop via ALTER ENTITY
+ALTER ENTITY Sales.Order
+  DROP EVENT HANDLER ON BEFORE COMMIT;
+```
+
+**Moments**: `BEFORE`, `AFTER`
+**Events**: `CREATE`, `COMMIT`, `DELETE`, `ROLLBACK`
+
+Each (Moment, Event) combination can only have one handler per entity. The microflow must exist (the executor validates the reference). `RAISE ERROR` is optional — without it, the handler runs but its return value doesn't affect the operation.
+
 ### Associations
 
 **CRITICAL: Association Directionality**

cmd/mxcli/lsp_completions_gen.go

@@ -20,6 +20,7 @@ CREATE [OR MODIFY] <entity-type> ENTITY <Module>.<Name> (
   <attribute-definitions>
 )
 [INDEX (<column-list>)]
+[ON BEFORE|AFTER CREATE|COMMIT|DELETE|ROLLBACK CALL <Module>.<Microflow> [RAISE ERROR]]
 [;|/]
 ```
 
@@ -142,6 +143,36 @@ INDEX (Email);
 
 Attribute-level documentation appears in Studio Pro when hovering over the attribute in the domain model.
 
+## Entity Event Handlers
+
+Persistent entities can have microflow event handlers that run before or after Create, Commit, Delete, or Rollback operations. The optional `RAISE ERROR` clause makes the handler act as a validation microflow — if it returns false, the operation is aborted.
+
+```sql
+CREATE PERSISTENT ENTITY Sales.Order (
+  Total: Decimal,
+  Status: String(50)
+)
+ON BEFORE COMMIT CALL Sales.ACT_ValidateOrder RAISE ERROR
+ON AFTER CREATE CALL Sales.ACT_InitDefaults;
+```
+
+Event handlers can also be added or removed via `ALTER ENTITY`:
+
+```sql
+-- Add a handler to an existing entity
+ALTER ENTITY Sales.Order
+  ADD EVENT HANDLER ON BEFORE DELETE CALL Sales.ACT_CheckCanDelete RAISE ERROR;
+
+-- Remove a handler
+ALTER ENTITY Sales.Order
+  DROP EVENT HANDLER ON BEFORE COMMIT;
+```
+
+**Moments**: `BEFORE`, `AFTER`
+**Events**: `CREATE`, `COMMIT`, `DELETE`, `ROLLBACK`
+
+Each (Moment, Event) combination supports one handler per entity. The microflow must exist in the project (validated at execution time).
+
 ## DROP ENTITY
 
 Removes an entity from the domain model:

docs-site/src/language/entities.md

@@ -63,6 +63,8 @@ Modifies an existing entity without full replacement.
 | Rename attribute | `ALTER ENTITY Module.Name RENAME OldName TO NewName;` | |
 | Add index | `ALTER ENTITY Module.Name ADD INDEX (Col1 [ASC\|DESC], ...);` | |
 | Drop index | `ALTER ENTITY Module.Name DROP INDEX (Col1, ...);` | |
+| Add event handler | `ALTER ENTITY Module.Name ADD EVENT HANDLER ON BEFORE COMMIT CALL Mod.MF [RAISE ERROR];` | Moments: BEFORE/AFTER, Events: CREATE/COMMIT/DELETE/ROLLBACK |
+| Drop event handler | `ALTER ENTITY Module.Name DROP EVENT HANDLER ON BEFORE COMMIT;` | |
 | Set documentation | `ALTER ENTITY Module.Name SET DOCUMENTATION 'text';` | |
 | Set position | `ALTER ENTITY Module.Name SET POSITION (100, 200);` | Canvas position |
 

docs/01-project/MDL_QUICK_REFERENCE.md

@@ -1453,6 +1453,36 @@ ALTER ENTITY DmTest.VATRate
 ALTER ENTITY DmTest.VATRate
   SET POSITION (300, 400);
 
+-- ============================================================================
+-- ENTITY EVENT HANDLERS
+-- ============================================================================
+-- Entity event handlers run microflows before/after Create, Commit, Delete,
+-- or Rollback. RAISE ERROR makes the handler act as a validation microflow:
+-- if it returns false, the operation is aborted.
+
+CREATE MICROFLOW DmTest.ACT_ValidateBankAccount ()
+BEGIN
+  LOG INFO 'Validating bank account';
+END;
+/
+
+CREATE MICROFLOW DmTest.ACT_InitBankAccountDefaults ()
+BEGIN
+  LOG INFO 'Initializing defaults';
+END;
+/
+
+-- Add event handlers via ALTER ENTITY
+ALTER ENTITY DmTest.BankAccount
+  ADD EVENT HANDLER ON BEFORE COMMIT CALL DmTest.ACT_ValidateBankAccount RAISE ERROR;
+
+ALTER ENTITY DmTest.BankAccount
+  ADD EVENT HANDLER ON AFTER CREATE CALL DmTest.ACT_InitBankAccountDefaults;
+
+-- Drop an event handler
+ALTER ENTITY DmTest.BankAccount
+  DROP EVENT HANDLER ON AFTER CREATE;
+
 -- @version: 10.18+
 -- ============================================================================
 -- PART 11: COMPLEX VIEW ENTITIES WITH SUBQUERIES — requires Mendix 10.18+

mdl-examples/doctype-tests/01-domain-model-examples.mdl

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/mendixlabs/mxcli/mdl/ast"
@@ -88,6 +89,94 @@ func TestRoundtripEntity_WithIndex(t *testing.T) {
 	})
 }
 
+func TestRoundtripEntity_WithEventHandler(t *testing.T) {
+	env := setupTestEnv(t)
+	defer env.teardown()
+
+	entityName := testModule + ".TestEntityEventHandler"
+	mfName := testModule + ".ACT_ValidateTestEntity"
+
+	// Create a microflow first (event handler references it)
+	if err := env.executeMDL(`CREATE OR MODIFY MICROFLOW ` + mfName + ` ()
+BEGIN
+  LOG INFO 'validating';
+END;`); err != nil {
+		t.Fatalf("failed to create microflow: %v", err)
+	}
+
+	// Create entity with event handler
+	createMDL := `CREATE OR MODIFY PERSISTENT ENTITY ` + entityName + ` (
+		Name: String(100)
+	)
+	ON BEFORE COMMIT CALL ` + mfName + ` RAISE ERROR;`
+
+	// Verify roundtrip preserves the event handler
+	env.assertContains(createMDL, []string{
+		"PERSISTENT ENTITY",
+		"Name:",
+		"String(100)",
+		"ON BEFORE COMMIT CALL",
+		mfName,
+		"RAISE ERROR",
+	})
+}
+
+func TestRoundtripEntity_AlterAddDropEventHandler(t *testing.T) {
+	env := setupTestEnv(t)
+	defer env.teardown()
+
+	entityName := testModule + ".TestAlterEventHandler"
+	mfName := testModule + ".ACT_AlterEventTest"
+
+	// Create microflow
+	if err := env.executeMDL(`CREATE OR MODIFY MICROFLOW ` + mfName + ` ()
+BEGIN
+  LOG INFO 'test';
+END;`); err != nil {
+		t.Fatalf("failed to create microflow: %v", err)
+	}
+
+	// Create entity without handlers
+	if err := env.executeMDL(`CREATE OR MODIFY PERSISTENT ENTITY ` + entityName + ` (
+		Code: String(50)
+	);`); err != nil {
+		t.Fatalf("failed to create entity: %v", err)
+	}
+
+	// Add event handler via ALTER
+	if err := env.executeMDL(`ALTER ENTITY ` + entityName + `
+		ADD EVENT HANDLER ON AFTER CREATE CALL ` + mfName + `;`); err != nil {
+		t.Fatalf("failed to add event handler: %v", err)
+	}
+
+	// Verify handler appears in DESCRIBE
+	out, err := env.describeMDL(`DESCRIBE ENTITY ` + entityName + `;`)
+	if err != nil {
+		t.Fatalf("describe failed: %v", err)
+	}
+	if !strings.Contains(out, "ON AFTER CREATE CALL") {
+		t.Errorf("expected ON AFTER CREATE CALL in DESCRIBE output, got:\n%s", out)
+	}
+	if !strings.Contains(out, mfName) {
+		t.Errorf("expected microflow name %q in DESCRIBE output, got:\n%s", mfName, out)
+	}
+
+	// Drop the event handler
+	if err := env.executeMDL(`ALTER ENTITY ` + entityName + `
+		DROP EVENT HANDLER ON AFTER CREATE;`); err != nil {
+		t.Fatalf("failed to drop event handler: %v", err)
+	}
+
+	// Verify handler is gone
+	out, err = env.describeMDL(`DESCRIBE ENTITY ` + entityName + `;`)
+	if err != nil {
+		t.Fatalf("describe after drop failed: %v", err)
+	}
+	if strings.Contains(out, "ON AFTER CREATE CALL") {
+		t.Errorf("event handler should be removed but still in DESCRIBE output:\n%s", out)
+	}
+}
+
 func TestRoundtripEnumeration(t *testing.T) {
 	env := setupTestEnv(t)
 	defer env.teardown()