diff --git a/kiloclaw/src/durable-objects/kiloclaw-instance.test.ts b/kiloclaw/src/durable-objects/kiloclaw-instance.test.ts
index d93c7911e..335b4eddd 100644
--- a/kiloclaw/src/durable-objects/kiloclaw-instance.test.ts
+++ b/kiloclaw/src/durable-objects/kiloclaw-instance.test.ts
@@ -322,6 +322,20 @@ afterEach(() => {
 });
 
 describe('two-phase destroy', () => {
+  it('throws with status 404 when instance was never provisioned', async () => {
+    const { instance } = createInstance();
+
+    const err: Error & { status?: number } = await instance.destroy().then(
+      () => {
+        throw new Error('expected rejection');
+      },
+      (e: Error & { status?: number }) => e
+    );
+
+    expect(err.message).toBe('Instance not provisioned');
+    expect(err.status).toBe(404);
+  });
+
   it('clears all state when both Fly deletes succeed', async () => {
     const { instance, storage } = createInstance();
     await seedRunning(storage);
@@ -1246,6 +1260,22 @@ describe('alarm runs for all live statuses', () => {
   });
 });
 
+describe('start: not provisioned', () => {
+  it('throws with status 404 when instance was never provisioned', async () => {
+    const { instance } = createInstance();
+
+    const err: Error & { status?: number } = await instance.start('user-1').then(
+      () => {
+        throw new Error('expected rejection');
+      },
+      (e: Error & { status?: number }) => e
+    );
+
+    expect(err.message).toBe('Instance not provisioned');
+    expect(err.status).toBe(404);
+  });
+});
+
 describe('startExistingMachine: transient vs 404 errors', () => {
   it('does NOT recreate machine on transient 500 error', async () => {
     const { instance, storage } = createInstance();
@@ -2888,6 +2918,20 @@ describe('stop: error propagation', () => {
     expect(storage._store.get('status')).toBe('stopped');
     expect(storage._store.get('lastStoppedAt')).toBeDefined();
   });
+
+  it('throws with status 404 when instance was never provisioned', async () => {
+    const { instance } = createInstance();
+
+    const err: Error & { status?: number } = await instance.stop().then(
+      () => {
+        throw new Error('expected rejection');
+      },
+      (e: Error & { status?: number }) => e
+    );
+
+    expect(err.message).toBe('Instance not provisioned');
+    expect(err.status).toBe(404);
+  });
 });
 
 // ============================================================================
diff --git a/kiloclaw/src/durable-objects/kiloclaw-instance/index.ts b/kiloclaw/src/durable-objects/kiloclaw-instance/index.ts
index 18350fec7..e631d0f18 100644
--- a/kiloclaw/src/durable-objects/kiloclaw-instance/index.ts
+++ b/kiloclaw/src/durable-objects/kiloclaw-instance/index.ts
@@ -690,7 +690,7 @@ export class KiloClawInstance extends DurableObject<KiloClawEnv> {
     }
 
     if (!this.s.userId || !this.s.sandboxId) {
-      throw new Error('Instance not provisioned');
+      throw Object.assign(new Error('Instance not provisioned'), { status: 404 });
     }
 
     const flyConfig = getFlyConfig(this.env, this.s);
@@ -944,7 +944,7 @@ export class KiloClawInstance extends DurableObject<KiloClawEnv> {
     await this.loadState();
 
     if (!this.s.userId || !this.s.sandboxId) {
-      throw new Error('Instance not provisioned');
+      throw Object.assign(new Error('Instance not provisioned'), { status: 404 });
     }
     if (
       this.s.status === 'stopped' ||
@@ -990,8 +990,8 @@ export class KiloClawInstance extends DurableObject<KiloClawEnv> {
   async destroy(): Promise<DestroyResult> {
     await this.loadState();
 
-    if (!this.s.userId) {
-      throw new Error('Instance not provisioned');
+    if (!this.s.userId || !this.s.sandboxId) {
+      throw Object.assign(new Error('Instance not provisioned'), { status: 404 });
     }
 
     const machineUptimeMs = this.s.lastStartedAt ? Date.now() - this.s.lastStartedAt : 0;