feat: add CREATE/DROP MODEL for agent-editor Model documents

Implements write support for the agent-editor Model document type,
the first CustomBlobDocument writer in the codebase.

New commands:
- CREATE MODEL Module.Name (Provider: MxCloudGenAI, Key: Module.Const)
- DROP MODEL Module.Name

Infrastructure built for reuse by other agent-editor doc types:
- sdk/mpr/writer_customblob.go — generic CustomBlobDocument BSON
  wrapper writer (sets $Type, $ID, Metadata with CreatedByExtension
  and ReadableTypeName, Contents JSON, ExportLevel, Excluded)
- sdk/mpr/writer_agenteditor_model.go — Model-specific Contents
  JSON encoder matching Studio Pro's exact output shape
- Executor.resolveConstantRef() — resolves a qualified constant name
  to {documentId, qualifiedName} for the providerFields.key reference

Validation:
- Rejects duplicate model names in the same project
- Rejects missing Key constant references with actionable error
- Defaults Provider to MxCloudGenAI when omitted

Byte-for-byte verified: Contents JSON produced by CREATE MODEL
matches the Studio-Pro-created Agents.MyFirstModel exactly (same
field names, order, nesting, and values including the resolved
constant documentId UUID).

Grammar: createModelStatement rule with modelProperty alternatives
(identifierOrKeyword for Provider, qualifiedName for Key,
STRING_LITERAL for Portal-populated metadata). DROP MODEL added
to dropStatement rule.

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

Author: ako

mdl/ast/ast_agenteditor.go

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package ast
+
+// CreateModelStmt represents:
+//
+//	CREATE MODEL Module.Name (
+//	  Provider: MxCloudGenAI,
+//	  Key: Module.SomeConstant
+//	  -- optional Portal-populated fields:
+//	  [, DisplayName: '...']
+//	  [, KeyName: '...']
+//	  [, KeyId: '...']
+//	  [, Environment: '...']
+//	  [, ResourceName: '...']
+//	  [, DeepLinkURL: '...']
+//	);
+type CreateModelStmt struct {
+	Name             QualifiedName
+	Documentation    string
+	Provider         string         // "MxCloudGenAI" by default
+	Key              *QualifiedName // qualified name of the String constant holding the Portal key
+	DisplayName      string         // optional Portal-populated metadata
+	KeyName          string         // optional Portal-populated metadata
+	KeyID            string         // optional Portal-populated metadata
+	Environment      string         // optional Portal-populated metadata
+	ResourceName     string         // optional Portal-populated metadata
+	DeepLinkURL      string         // optional Portal-populated metadata
+}
+
+func (s *CreateModelStmt) isStatement() {}
+
+// DropModelStmt represents: DROP MODEL Module.Name
+type DropModelStmt struct {
+	Name QualifiedName
+}
+
+func (s *DropModelStmt) isStatement() {}

mdl/backend/infrastructure.go

@@ -50,4 +50,6 @@ type AgentEditorBackend interface {
 	ListAgentEditorKnowledgeBases() ([]*agenteditor.KnowledgeBase, error)
 	ListAgentEditorConsumedMCPServices() ([]*agenteditor.ConsumedMCPService, error)
 	ListAgentEditorAgents() ([]*agenteditor.Agent, error)
+	CreateAgentEditorModel(m *agenteditor.Model) error
+	DeleteAgentEditorModel(id string) error
 }

mdl/backend/mock/mock_infrastructure.go

@@ -187,3 +187,6 @@ func (m *MockBackend) ListAgentEditorAgents() ([]*agenteditor.Agent, error) {
 	}
 	return nil, nil
 }
+
+func (m *MockBackend) CreateAgentEditorModel(_ *agenteditor.Model) error { return nil }
+func (m *MockBackend) DeleteAgentEditorModel(_ string) error             { return nil }

mdl/backend/mpr/backend.go

@@ -700,3 +700,9 @@ func (b *MprBackend) ListAgentEditorConsumedMCPServices() ([]*agenteditor.Consum
 func (b *MprBackend) ListAgentEditorAgents() ([]*agenteditor.Agent, error) {
 	return b.reader.ListAgentEditorAgents()
 }
+func (b *MprBackend) CreateAgentEditorModel(m *agenteditor.Model) error {
+	return b.writer.CreateAgentEditorModel(m)
+}
+func (b *MprBackend) DeleteAgentEditorModel(id string) error {
+	return b.writer.DeleteAgentEditorModel(id)
+}

mdl/executor/cmd_agenteditor_models.go

@@ -130,6 +130,99 @@ func describeAgentEditorModel(ctx *ExecContext, name ast.QualifiedName) error {
 	return nil
 }
 
+// execCreateAgentEditorModel handles CREATE MODEL Module.Name (...).
+func execCreateAgentEditorModel(ctx *ExecContext, s *ast.CreateModelStmt) error {
+	if !ctx.Connected() {
+		return mdlerrors.NewNotConnected()
+	}
+
+	module, err := findOrCreateModule(ctx, s.Name.Module)
+	if err != nil {
+		return err
+	}
+
+	if existing := findAgentEditorModel(ctx, s.Name.Module, s.Name.Name); existing != nil {
+		return mdlerrors.NewAlreadyExists("model", s.Name.String())
+	}
+
+	var keyRef *agenteditor.ConstantRef
+	if s.Key != nil {
+		keyRef, err = resolveConstantRef(ctx, *s.Key)
+		if err != nil {
+			return fmt.Errorf("CREATE MODEL %s: %w", s.Name, err)
+		}
+	}
+
+	provider := s.Provider
+	if provider == "" {
+		provider = "MxCloudGenAI"
+	}
+
+	m := &agenteditor.Model{
+		ContainerID:  module.ID,
+		Name:         s.Name.Name,
+		Documentation: s.Documentation,
+		Provider:     provider,
+		Key:          keyRef,
+		DisplayName:  s.DisplayName,
+		KeyName:      s.KeyName,
+		KeyID:        s.KeyID,
+		Environment:  s.Environment,
+		ResourceName: s.ResourceName,
+		DeepLinkURL:  s.DeepLinkURL,
+	}
+
+	if err := ctx.Backend.CreateAgentEditorModel(m); err != nil {
+		return mdlerrors.NewBackend("create model", err)
+	}
+	invalidateHierarchy(ctx)
+	fmt.Fprintf(ctx.Output, "Created model: %s\n", s.Name)
+	return nil
+}
+
+// execDropAgentEditorModel handles DROP MODEL Module.Name.
+func execDropAgentEditorModel(ctx *ExecContext, s *ast.DropModelStmt) error {
+	if !ctx.Connected() {
+		return mdlerrors.NewNotConnected()
+	}
+
+	m := findAgentEditorModel(ctx, s.Name.Module, s.Name.Name)
+	if m == nil {
+		return mdlerrors.NewNotFound("model", s.Name.String())
+	}
+
+	if err := ctx.Backend.DeleteAgentEditorModel(string(m.ID)); err != nil {
+		return mdlerrors.NewBackend("delete model", err)
+	}
+	fmt.Fprintf(ctx.Output, "Dropped model: %s\n", s.Name)
+	return nil
+}
+
+// resolveConstantRef looks up a String constant by qualified name and
+// returns a ConstantRef ready to embed in a Model/KnowledgeBase
+// document's providerFields.key field.
+func resolveConstantRef(ctx *ExecContext, name ast.QualifiedName) (*agenteditor.ConstantRef, error) {
+	consts, err := ctx.Backend.ListConstants()
+	if err != nil {
+		return nil, fmt.Errorf("failed to list constants: %w", err)
+	}
+	h, err := getHierarchy(ctx)
+	if err != nil {
+		return nil, err
+	}
+	for _, c := range consts {
+		modID := h.FindModuleID(c.ContainerID)
+		modName := h.GetModuleName(modID)
+		if c.Name == name.Name && modName == name.Module {
+			return &agenteditor.ConstantRef{
+				DocumentID:    string(c.ID),
+				QualifiedName: name.String(),
+			}, nil
+		}
+	}
+	return nil, fmt.Errorf("constant not found: %s", name)
+}
+
 // findAgentEditorModel looks up a model by module and name.
 func findAgentEditorModel(ctx *ExecContext, moduleName, modelName string) *agenteditor.Model {
 	models, err := ctx.Backend.ListAgentEditorModels()

mdl/executor/register_stubs.go

@@ -442,3 +442,12 @@ func registerImportHandlers(r *Registry) {
 		return execImport(ctx, stmt.(*ast.ImportStmt))
 	})
 }
+
+func registerAgentEditorHandlers(r *Registry) {
+	r.Register(&ast.CreateModelStmt{}, func(ctx *ExecContext, stmt ast.Statement) error {
+		return execCreateAgentEditorModel(ctx, stmt.(*ast.CreateModelStmt))
+	})
+	r.Register(&ast.DropModelStmt{}, func(ctx *ExecContext, stmt ast.Statement) error {
+		return execDropAgentEditorModel(ctx, stmt.(*ast.DropModelStmt))
+	})
+}

mdl/executor/registry.go

@@ -55,6 +55,7 @@ func NewRegistry() *Registry {
 	registerFragmentHandlers(r)
 	registerSQLHandlers(r)
 	registerImportHandlers(r)
+	registerAgentEditorHandlers(r)
 	return r
 }
 

mdl/grammar/MDLParser.g4

@@ -105,6 +105,7 @@ createStatement
       | createConfigurationStatement
       | createPublishedRestServiceStatement
       | createDataTransformerStatement
+      | createModelStatement
       )
     ;
 
@@ -287,6 +288,7 @@ dropStatement
     | DROP REST CLIENT qualifiedName
     | DROP PUBLISHED REST SERVICE qualifiedName
     | DROP DATA TRANSFORMER qualifiedName
+    | DROP MODEL qualifiedName                               // DROP MODEL Module.Name (agent-editor)
     | DROP CONFIGURATION STRING_LITERAL
     | DROP FOLDER STRING_LITERAL IN (qualifiedName | IDENTIFIER)
     ;
@@ -883,6 +885,25 @@ imageName
     | keyword
     ;
 
+// =============================================================================
+// AGENT-EDITOR MODEL CREATION
+// =============================================================================
+// CREATE MODEL Module.Name (
+//   Provider: MxCloudGenAI,
+//   Key: Module.SomeConstant
+//   [, DisplayName: '...', KeyName: '...', etc. — Portal-populated metadata]
+// );
+createModelStatement
+    : MODEL qualifiedName
+      LPAREN modelProperty (COMMA modelProperty)* RPAREN
+    ;
+
+modelProperty
+    : identifierOrKeyword COLON identifierOrKeyword       // Provider: MxCloudGenAI
+    | identifierOrKeyword COLON qualifiedName             // Key: Module.Constant
+    | identifierOrKeyword COLON STRING_LITERAL            // DisplayName: 'GPT-4 Turbo' etc.
+    ;
+
 // =============================================================================
 // JSON STRUCTURE CREATION
 // =============================================================================