fix(hub): fail creates when prompts cannot start

packages/server/src/server/hub/relationship-owned-executions.test.ts

@@ -53,3 +53,17 @@ test("a failed Hub create removes its auto-created worktree", async () => {
   expect(await hub.listedWorktrees()).toHaveLength(1);
   expect(await hub.durableOwnedAgentIds()).toEqual([]);
 });
+
+test("a Hub create fails when its initial prompt cannot start", async () => {
+  const hub = await launchRelationship();
+  hub.failNextProviderPromptStart();
+  hub.beginOwnedCreate("failed-prompt-create", "failed-prompt-execution");
+
+  const response = await hub.ownedCreateResult("failed-prompt-create");
+
+  expect(response).toMatchObject({
+    type: "hub.agent.create.response",
+    payload: { success: false, executionId: "failed-prompt-execution" },
+  });
+  expect(await hub.durableOwnedAgentIds()).toEqual([]);
+});

packages/server/src/server/hub/relationship-owned-executions.ts

@@ -137,6 +137,7 @@ export class RelationshipOwnedExecutions implements HubExecutions {
         provider: input.model ? `${input.provider}/${input.model}` : input.provider,
         title: input.prompt,
         initialPrompt: input.prompt,
+        promptFailure: "throw",
         cwd: input.cwd,
         workspaceId: input.workspaceId,
         mode: input.modeId,
@@ -156,7 +157,11 @@ export class RelationshipOwnedExecutions implements HubExecutions {
         },
       });
     } catch (error) {
-      await this.cleanupFailedCreate({ createdWorktree, createdAgentId });
+      if (createdAgentId) {
+        await this.agentManager.closeAgent(createdAgentId);
+        await this.agentStorage.remove(createdAgentId);
+      }
+      await this.cleanupFailedCreate({ createdWorktree, createdAgentId: null });
       throw error;
     }
 

packages/server/src/server/hub/test-utils/relationship-harness.ts

@@ -424,12 +424,19 @@ export class HubRelationshipHarness {
   private host = "";
   private readonly logs: string[] = [];
   private readonly providerPrompts: AgentPromptInput[] = [];
+  private failNextPromptStart = false;
   private observedEnrollments = 0;
   private observedSockets = 0;
   private reconcileRequests = 0;
   private readonly codex = new ControlledAgentClient(
     createTestAgentClients({
-      onStartTurn: (prompt) => this.providerPrompts.push(prompt),
+      onStartTurn: (prompt) => {
+        if (this.failNextPromptStart) {
+          this.failNextPromptStart = false;
+          throw new Error("Requested provider prompt startup failure");
+        }
+        this.providerPrompts.push(prompt);
+      },
     }).codex,
   );
 
@@ -534,6 +541,10 @@ export class HubRelationshipHarness {
     this.remote.failRevocations(count);
   }
 
+  failNextProviderPromptStart(): void {
+    this.failNextPromptStart = true;
+  }
+
   async socketDialed(): Promise<void> {
     await this.remote.socketAt(this.observedSockets++);
   }