systeminit · stack72 · Mar 17, 2026 · Mar 17, 2026 · Mar 17, 2026
diff --git a/src/domain/models/method_execution_service.ts b/src/domain/models/method_execution_service.ts
@@ -545,9 +545,6 @@ export class DefaultMethodExecutionService implements MethodExecutionService {
             ]),
           )
           : undefined,
-        bundle: modelDef.bundleSource
-          ? new TextEncoder().encode(modelDef.bundleSource)
-          : undefined,
       };
 
     let currentHandles: DataHandle[];
@@ -581,6 +578,13 @@ export class DefaultMethodExecutionService implements MethodExecutionService {
       // Use the driver's context with writers for follow-up actions
       executionContext = driver.contextWithWriters ?? context;
     } else {
+      // Populate bundle only for out-of-process drivers (raw driver doesn't use it)
+      if (modelDef.bundleSourceFactory) {
+        executionRequest.bundle = new TextEncoder().encode(
+          await modelDef.bundleSourceFactory(),
+        );
+      }
+
       // Look up a registered driver type
       const driverInfo = driverTypeRegistry.get(driverType);
       if (!driverInfo) {

diff --git a/src/domain/models/model.ts b/src/domain/models/model.ts
@@ -599,11 +599,11 @@ export interface ModelDefinition<
   upgrades?: VersionUpgrade[];
 
   /**
-   * Pre-compiled self-contained bundle source (JS) for out-of-process execution.
-   * Set by UserModelLoader at load time. Includes all dependencies inlined
-   * (including zod) so it can run without network access inside containers.
+   * Lazily builds the self-contained bundle for out-of-process execution (e.g. Docker).
+   * Called by the execution service when a non-raw driver is used. Memoizes its
+   * result so multiple executions of the same model in one process only bundle once.
    */
-  bundleSource?: string;
+  bundleSourceFactory?: () => Promise<string>;
 }
 
 /**

diff --git a/src/domain/models/user_model_loader.ts b/src/domain/models/user_model_loader.ts
@@ -350,19 +350,23 @@ export class UserModelLoader {
 
         const modelDef = this.convertToModelDefinition(userModel);
 
-        // Create self-contained bundle for out-of-process drivers (e.g., Docker).
-        // This inlines all deps including zod so the bundle runs without network.
-        try {
-          modelDef.bundleSource = await bundleExtension(
+        // Defer self-contained bundling to first out-of-process execution (e.g. Docker).
+        // Memoized so multiple executions in one process only bundle once.
+        // Uses promise-based memoization to avoid duplicate work under concurrent calls.
+        let bundlePromise: Promise<string> | undefined;
+        modelDef.bundleSourceFactory = () => {
+          bundlePromise ??= bundleExtension(
             absolutePath,
             denoPath,
             { selfContained: true },
-          );
-        } catch (error) {
-          logger
-            .warn`Failed to create self-contained bundle for ${file}: ${error}`;
-          // Non-fatal — model still works with raw driver
-        }
+          ).catch((error) => {
+            bundlePromise = undefined;
+            logger
+              .warn`Failed to create self-contained bundle for ${file}: ${error}`;
+            throw error;
+          });
+          return bundlePromise;
+        };
 
         if (!modelRegistry.has(modelDef.type)) {
           modelRegistry.register(modelDef);