diff --git a/buildengine/engine.go b/buildengine/engine.go
index 3446a0f20..36390e304 100644
--- a/buildengine/engine.go
+++ b/buildengine/engine.go
@@ -32,21 +32,34 @@ type Engine struct {
 // Completely offline builds are possible if the full dependency graph is
 // locally available. If the FTL controller is available, it will be used to
 // pull in missing schemas.
-func New(ctx context.Context, client ftlv1connect.ControllerServiceClient) (*Engine, error) {
+//
+// "dirs" are directories to scan for local modules.
+func New(ctx context.Context, client ftlv1connect.ControllerServiceClient, dirs ...string) (*Engine, error) {
 	ctx = rpc.ContextWithClient(ctx, client)
-	engine := &Engine{
+	e := &Engine{
 		modules:          map[string]Module{},
 		controllerSchema: xsync.NewMapOf[*schema.Module](),
 	}
-	engine.controllerSchema.Store("builtin", schema.Builtins())
+	e.controllerSchema.Store("builtin", schema.Builtins())
 	ctx, cancel := context.WithCancel(ctx)
-	engine.cancel = cancel
+	e.cancel = cancel
+	configs, err := DiscoverModules(ctx, dirs...)
+	if err != nil {
+		return nil, err
+	}
+	modules, err := UpdateAllDependencies(ctx, configs...)
+	if err != nil {
+		return nil, err
+	}
+	for _, module := range modules {
+		e.modules[module.Module] = module
+	}
 	if client == nil {
-		return engine, nil
+		return e, nil
 	}
-	schemaSync := engine.startSchemaSync(ctx, client)
+	schemaSync := e.startSchemaSync(ctx, client)
 	go rpc.RetryStreamingServerStream(ctx, backoff.Backoff{Max: time.Second}, &ftlv1.PullSchemaRequest{}, client.PullSchema, schemaSync)
-	return engine, nil
+	return e, nil
 }
 
 // Sync module schema changes from the FTL controller, as well as from manual
@@ -128,25 +141,6 @@ func (e *Engine) buildGraph(name string, out map[string][]string) error {
 	return nil
 }
 
-// Add a directory of local modules to the engine.
-//
-// Existing modules will be replaced. A local module will take precedence over
-// any schema from the FTL cluster, building as required.
-func (e *Engine) Add(ctx context.Context, dir string) error {
-	configs, err := DiscoverModules(ctx, dir)
-	if err != nil {
-		return err
-	}
-	modules, err := UpdateAllDependencies(ctx, configs...)
-	if err != nil {
-		return err
-	}
-	for _, module := range modules {
-		e.modules[module.Module] = module
-	}
-	return nil
-}
-
 // Import manually imports a schema for a module as if it were retrieved from
 // the FTL controller.
 func (e *Engine) Import(ctx context.Context, schema *schema.Module) {
diff --git a/buildengine/engine_test.go b/buildengine/engine_test.go
index 787f8ff1a..770bdea42 100644
--- a/buildengine/engine_test.go
+++ b/buildengine/engine_test.go
@@ -13,17 +13,11 @@ import (
 
 func TestEngine(t *testing.T) {
 	ctx := log.ContextWithNewDefaultLogger(context.Background())
-	engine, err := buildengine.New(ctx, nil)
+	engine, err := buildengine.New(ctx, nil, "testdata/modules/alpha", "testdata/modules/another")
 	assert.NoError(t, err)
 
 	defer engine.Close()
 
-	// Explicitly add only two of the modules.
-	err = engine.Add(ctx, "testdata/modules/alpha")
-	assert.NoError(t, err)
-	err = engine.Add(ctx, "testdata/modules/another")
-	assert.NoError(t, err)
-
 	// Import the schema from the third module, simulating a remote schema.
 	otherSchema := &schema.Module{
 		Name: "other",
diff --git a/cmd/ftl/cmd_build.go b/cmd/ftl/cmd_build.go
index e2447818a..4b10d5737 100644
--- a/cmd/ftl/cmd_build.go
+++ b/cmd/ftl/cmd_build.go
@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"fmt"
 
 	"github.com/TBD54566975/ftl/backend/protos/xyz/block/ftl/v1/ftlv1connect"
 	"github.com/TBD54566975/ftl/buildengine"
@@ -15,15 +14,9 @@ type buildCmd struct {
 
 func (b *buildCmd) Run(ctx context.Context) error {
 	client := rpc.ClientFromContext[ftlv1connect.ControllerServiceClient](ctx)
-	engine, err := buildengine.New(ctx, client)
+	engine, err := buildengine.New(ctx, client, b.Dirs...)
 	if err != nil {
 		return err
 	}
-	for _, dir := range b.Dirs {
-		err = engine.Add(ctx, dir)
-		if err != nil {
-			return fmt.Errorf("%s: %w", dir, err)
-		}
-	}
 	return engine.Build(ctx)
 }