diff --git a/packages/server/src/server/hub/hub-session.test.ts b/packages/server/src/server/hub/hub-session.test.ts
index 3518d2505a..6a0981f09b 100644
--- a/packages/server/src/server/hub/hub-session.test.ts
+++ b/packages/server/src/server/hub/hub-session.test.ts
@@ -16,8 +16,10 @@ import { HubSession } from "./hub-session.js";
 class InMemoryHubExecutions implements HubExecutions {
   private readonly listeners = new Set<(event: OwnedAgentEvent) => void>();
   private reconcileError: Error | null = null;
+  private creates = 0;
 
   async create(_input: HubAgentCreateInput): Promise<OwnedAgentSnapshot> {
+    this.creates++;
     return { executionId: "execution-1", agent: createAgentSnapshot() };
   }
 
@@ -31,6 +33,8 @@ class InMemoryHubExecutions implements HubExecutions {
     return () => this.listeners.delete(listener);
   }
 
+  async invalidateAuthority(): Promise<void> {}
+
   publishCurrentState(): void {
     for (const listener of this.listeners) {
       listener({ type: "update", executionId: "execution-1", agent: createAgentSnapshot() });
@@ -40,6 +44,10 @@ class InMemoryHubExecutions implements HubExecutions {
   failReconcile(error: Error): void {
     this.reconcileError = error;
   }
+
+  createCount(): number {
+    return this.creates;
+  }
 }
 
 class HubSessionBoundary {
@@ -67,6 +75,21 @@ class HubSessionBoundary {
     });
   }
 
+  async createWith(input: { prompt: string; cwd: string }): Promise<void> {
+    await this.session.handleMessage({
+      type: "hub.agent.create.request",
+      requestId: "create-1",
+      executionId: "execution-1",
+      provider: "codex",
+      workspaceId: "workspace-1",
+      ...input,
+    });
+  }
+
+  createCount(): number {
+    return this.executions.createCount();
+  }
+
   deliveredMessages(): SessionOutboundMessage[] {
     return this.messages.slice();
   }
@@ -104,6 +127,30 @@ test("reconcile storage failures receive a terminal empty response", async () =>
   ]);
 });
 
+test.each([
+  { field: "prompt", prompt: "  ", cwd: "/workspace" },
+  { field: "cwd", prompt: "Do the work", cwd: "\t" },
+])("blank Hub $field values reject the create before execution", async ({ field, prompt, cwd }) => {
+  const hub = new HubSessionBoundary();
+
+  await hub.createWith({ prompt, cwd });
+
+  expect(hub.createCount()).toBe(0);
+  expect(hub.deliveredMessages()).toEqual([
+    {
+      type: "hub.agent.create.response",
+      payload: {
+        requestId: "create-1",
+        executionId: "execution-1",
+        agentId: null,
+        agent: null,
+        success: false,
+        error: `Hub agent ${field} cannot be blank`,
+      },
+    },
+  ]);
+});
+
 function createAgentSnapshot(): AgentSnapshotPayload {
   return AgentSnapshotPayloadSchema.parse({
     id: "agent-1",
diff --git a/packages/server/src/server/hub/hub-session.ts b/packages/server/src/server/hub/hub-session.ts
index 6e80bdc8de..e9b6b3c633 100644
--- a/packages/server/src/server/hub/hub-session.ts
+++ b/packages/server/src/server/hub/hub-session.ts
@@ -49,6 +49,8 @@ export class HubSession {
 
   private async createAgent(message: HubAgentCreateRequest): Promise<void> {
     try {
+      requireNonBlankHubAgentField("prompt", message.prompt);
+      requireNonBlankHubAgentField("cwd", message.cwd);
       const result = await this.executions.create({
         executionId: message.executionId,
         provider: message.provider,
@@ -131,6 +133,12 @@ export class HubSession {
   }
 }
 
+function requireNonBlankHubAgentField(field: "prompt" | "cwd", value: string): void {
+  if (value.trim().length === 0) {
+    throw new Error(`Hub agent ${field} cannot be blank`);
+  }
+}
+
 function requestIdForMessage(message: SessionInboundMessage): string | undefined {
   if ("requestId" in message && typeof message.requestId === "string") {
     return message.requestId;
diff --git a/packages/server/src/server/hub/index.ts b/packages/server/src/server/hub/index.ts
deleted file mode 100644
index 2deb939266..0000000000
--- a/packages/server/src/server/hub/index.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-export { HubSession } from "./hub-session.js";
-export { RelationshipOwnedExecutions } from "./relationship-owned-executions.js";
-export type {
-  HubAgentCreateInput,
-  HubExecutions,
-  OwnedAgentEvent,
-  OwnedAgentSnapshot,
-} from "./relationship-owned-executions.js";
diff --git a/packages/server/src/server/hub/relationship-controller.test.ts b/packages/server/src/server/hub/relationship-controller.test.ts
index 48ff6b1797..d8a8d9e13b 100644
--- a/packages/server/src/server/hub/relationship-controller.test.ts
+++ b/packages/server/src/server/hub/relationship-controller.test.ts
@@ -282,6 +282,35 @@ describe("Hub relationship", () => {
     expect(relationship.socketAttempts()).toBe(0);
   });
 
+  test("a persisted WebSocket transport with a fragment is quarantined before startup", async () => {
+    relationship = await HubRelationshipHarness.start();
+    await relationship.corruptRelationshipFile(
+      JSON.stringify({
+        version: 1,
+        state: "active",
+        relationship: {
+          id: "relationship-1",
+          idempotencyKey: "ceremony-1",
+          hubOrigin: "https://hub.test",
+          createdAt: "2026-07-13T00:00:00.000Z",
+          scopes: ["hub.*"],
+        },
+        credential: { secret: "credential" },
+        transport: {
+          kind: "direct_websocket",
+          webSocketUrl: "wss://hub.test/daemon#fragment",
+        },
+      }),
+    );
+
+    await relationship.startStoppedDaemon();
+
+    expect(await relationship.status()).toMatchObject({ state: "not_connected" });
+    expect(relationship.relationshipFile()).toBeNull();
+    expect(await relationship.quarantinedRelationshipFiles()).toHaveLength(1);
+    expect(relationship.socketAttempts()).toBe(0);
+  });
+
   test("disconnect revokes an ambiguous pending enrollment before removing local authority", async () => {
     relationship = await HubRelationshipHarness.start();
     relationship.holdEnrollment();
@@ -549,6 +578,49 @@ describe("Hub relationship", () => {
     expect(durableAgentIds).toHaveLength(1);
   });
 
+  test("reconcile waits for a pending create across socket generations", async () => {
+    relationship = await HubRelationshipHarness.start();
+    await relationship.beginConnect().result;
+    relationship.connectLatestSocket();
+    relationship.holdAgentCreation();
+    relationship.beginOwnedCreate("pending-create", "pending-execution");
+    await relationship.agentCreationAttempts(1);
+
+    relationship.closeLatestSocket(1006);
+    await relationship.retry();
+    relationship.connectLatestSocket();
+    const reconciliation = relationship.reconcileOwned("pending-execution");
+    relationship.finishAgentCreation();
+
+    await expect(reconciliation).resolves.toMatchObject({
+      executionId: "pending-execution",
+      agentId: expect.any(String),
+      agent: { id: expect.any(String) },
+    });
+    expect(relationship.providerCreations()).toBe(1);
+    expect(await relationship.durableOwnedAgentIds()).toHaveLength(1);
+  });
+
+  test("force disconnect fences a pending create before removing authority", async () => {
+    relationship = await HubRelationshipHarness.start();
+    await relationship.beginConnect().result;
+    relationship.connectLatestSocket();
+    relationship.holdAgentCreation();
+    relationship.beginOwnedCreate("cancelled-create", "cancelled-execution", {
+      worktree: { mode: "branch-off", newBranch: "cancelled-hub-create" },
+    });
+    await relationship.agentCreationAttempts(1);
+
+    const disconnecting = relationship.beginDisconnect(true);
+    await relationship.relationshipStateBecomes(null);
+    relationship.finishAgentCreation();
+    await disconnecting.result;
+
+    expect(relationship.activeOwnedAgentIds()).toEqual([]);
+    expect(await relationship.durableOwnedAgentIds()).toEqual([]);
+    expect(await relationship.listedWorktrees()).toHaveLength(1);
+  });
+
   test.each([
     [4403, "Hub revoked this relationship"],
     [401, "Hub rejected socket authentication (401)"],
@@ -610,6 +682,18 @@ describe("Hub relationship", () => {
     expect(relationship.relationshipFile()).toBeNull();
   });
 
+  test("successful disconnect clears a transient revocation error", async () => {
+    relationship = await HubRelationshipHarness.start();
+    await relationship.beginConnect().result;
+    relationship.failRevocations(1);
+
+    const disconnecting = await relationship.disconnect();
+    await relationship.retry();
+
+    expect(disconnecting).toMatchObject({ state: "disconnecting", error: expect.any(String) });
+    expect(await relationship.status()).toMatchObject({ state: "not_connected", error: null });
+  });
+
   test("force disconnect removes local authority and reports the remote warning", async () => {
     relationship = await HubRelationshipHarness.start();
     await relationship.beginConnect().result;
diff --git a/packages/server/src/server/hub/relationship-controller.ts b/packages/server/src/server/hub/relationship-controller.ts
index 55b90932a8..23a8916f64 100644
--- a/packages/server/src/server/hub/relationship-controller.ts
+++ b/packages/server/src/server/hub/relationship-controller.ts
@@ -31,7 +31,8 @@ const TransportSchema = z.object({
   webSocketUrl: z
     .string()
     .url()
-    .refine((value) => ["ws:", "wss:"].includes(new URL(value).protocol)),
+    .refine((value) => ["ws:", "wss:"].includes(new URL(value).protocol))
+    .refine((value) => new URL(value).hash === ""),
 });
 const PendingSchema = z.object({
   version: z.literal(1),
@@ -262,15 +263,18 @@ export class HubRelationshipController implements HubRelationshipManagement {
     force: boolean;
   }): Promise<{ status: HubRelationshipStatus; warning?: string }> {
     const waitForEnrollment = this.record?.state === "pending";
+    const pendingCreateCleanup = this.executions?.value.invalidateAuthority() ?? Promise.resolve();
     this.cancelLifecycle();
     this.socket?.close();
     this.socket = null;
     if (!this.record || this.record.state === "revoked") {
       this.remove();
+      await pendingCreateCleanup;
       return { status: this.status() };
     }
     if (input.force) {
       this.remove();
+      await pendingCreateCleanup;
       return {
         status: this.status(),
         warning: "Local Hub credential removed; remote revocation may remain pending.",
@@ -290,6 +294,7 @@ export class HubRelationshipController implements HubRelationshipManagement {
       await Promise.all(this.inFlightEnrollments);
     }
     await this.tryRevocation(disconnecting);
+    await pendingCreateCleanup;
     return { status: this.status() };
   }
 
@@ -453,6 +458,7 @@ export class HubRelationshipController implements HubRelationshipManagement {
   }
 
   private revoke(reason: string): void {
+    void this.executions?.value.invalidateAuthority();
     this.cancelLifecycle();
     if (!this.record) return;
     const revoked: RevokedRecord = {
@@ -492,11 +498,13 @@ export class HubRelationshipController implements HubRelationshipManagement {
   }
 
   private remove(): void {
+    void this.executions?.value.invalidateAuthority();
     this.cancelLifecycle();
     rmSync(this.filePath, { force: true });
     this.record = null;
     this.state = "not_connected";
     this.connectedAt = null;
+    this.lastError = null;
   }
 
   private load(): HubRelationshipRecord | null {
diff --git a/packages/server/src/server/hub/relationship-owned-executions.ts b/packages/server/src/server/hub/relationship-owned-executions.ts
index e27c905eb9..f8f206fd5c 100644
--- a/packages/server/src/server/hub/relationship-owned-executions.ts
+++ b/packages/server/src/server/hub/relationship-owned-executions.ts
@@ -61,6 +61,7 @@ export interface HubExecutions {
   create(input: HubAgentCreateInput): Promise<OwnedAgentSnapshot>;
   reconcile(executionId: string): Promise<OwnedAgentSnapshot | null>;
   subscribe(listener: (event: OwnedAgentEvent) => void): () => void;
+  invalidateAuthority(): Promise<void>;
 }
 
 export class RelationshipOwnedExecutions implements HubExecutions {
@@ -69,6 +70,8 @@ export class RelationshipOwnedExecutions implements HubExecutions {
   private readonly agentStorage: AgentStorage;
   private readonly createAgentCommand: BoundCreateAgentCommand;
   private readonly pendingCreates = new Map<string, Promise<OwnedAgentSnapshot>>();
+  private authorityGeneration = 0;
+  private authorityActive = true;
   private readonly registerAutoArchive: (input: {
     agentId: string;
     createdWorktree: CreatePaseoWorktreeWorkflowResult | null;
@@ -88,6 +91,9 @@ export class RelationshipOwnedExecutions implements HubExecutions {
   }
 
   create(input: HubAgentCreateInput): Promise<OwnedAgentSnapshot> {
+    if (!this.authorityActive) {
+      return Promise.reject(new Error("Hub relationship authority is no longer active"));
+    }
     const owner = this.owner(input.executionId);
     const key = hubExecutionKey(owner);
     const pending = this.pendingCreates.get(key);
@@ -95,7 +101,8 @@ export class RelationshipOwnedExecutions implements HubExecutions {
       return pending;
     }
 
-    const create = this.createOrResolve(owner, input).finally(() => {
+    const authorityGeneration = this.authorityGeneration;
+    const create = this.createOrResolve(owner, input, authorityGeneration).finally(() => {
       if (this.pendingCreates.get(key) === create) {
         this.pendingCreates.delete(key);
       }
@@ -105,10 +112,19 @@ export class RelationshipOwnedExecutions implements HubExecutions {
   }
 
   async reconcile(executionId: string): Promise<OwnedAgentSnapshot | null> {
-    const record = await this.agentStorage.findByHubExecution(this.owner(executionId));
+    const owner = this.owner(executionId);
+    const pending = this.pendingCreates.get(hubExecutionKey(owner));
+    if (pending) return pending;
+    const record = await this.agentStorage.findByHubExecution(owner);
     return record ? this.resolveRecord(record) : null;
   }
 
+  async invalidateAuthority(): Promise<void> {
+    this.authorityActive = false;
+    this.authorityGeneration++;
+    await Promise.allSettled(this.pendingCreates.values());
+  }
+
   subscribe(listener: (event: OwnedAgentEvent) => void): () => void {
     return this.agentManager.subscribe(
       (event) => {
@@ -124,11 +140,14 @@ export class RelationshipOwnedExecutions implements HubExecutions {
   private async createOrResolve(
     owner: HubAgentOwner,
     input: HubAgentCreateInput,
+    authorityGeneration: number,
   ): Promise<OwnedAgentSnapshot> {
     const existing = await this.agentStorage.findByHubExecution(owner);
     if (existing) {
+      this.requireAuthority(authorityGeneration);
       return this.resolveRecord(existing);
     }
+    this.requireAuthority(authorityGeneration);
 
     let createdWorktree: CreatePaseoWorktreeWorkflowResult | null = null;
     let createdAgentId: string | null = null;
@@ -164,6 +183,7 @@ export class RelationshipOwnedExecutions implements HubExecutions {
           }
         },
       });
+      this.requireAuthority(authorityGeneration);
     } catch (error) {
       try {
         await autoArchiveRegistration.cancel();
@@ -195,6 +215,12 @@ export class RelationshipOwnedExecutions implements HubExecutions {
     return this.projectRecord(record);
   }
 
+  private requireAuthority(authorityGeneration: number): void {
+    if (!this.authorityActive || authorityGeneration !== this.authorityGeneration) {
+      throw new Error("Hub relationship authority ended during agent creation");
+    }
+  }
+
   private projectRecord(record: StoredAgentRecord): OwnedAgentSnapshot {
     const owner = this.requireOwner(record);
     const live = this.agentManager.getAgent(record.id);
diff --git a/packages/server/src/server/hub/relationship-remote.test.ts b/packages/server/src/server/hub/relationship-remote.test.ts
index 280f6a7841..af1c03639e 100644
--- a/packages/server/src/server/hub/relationship-remote.test.ts
+++ b/packages/server/src/server/hub/relationship-remote.test.ts
@@ -91,6 +91,24 @@ test("enrollment rejects a transport URL that cannot open a WebSocket", async ()
   ).rejects.toThrow("Hub WebSocket URL must use ws or wss");
 });
 
+test("enrollment rejects a WebSocket URL with a fragment", async () => {
+  const hubOrigin = await startEnrollmentHub("ws://hub.test/daemon#fragment");
+  const remote = new DirectHubRelationshipRemote();
+
+  await expect(
+    remote.enroll({
+      relationshipId: "relationship-1",
+      idempotencyKey: "ceremony-1",
+      hubOrigin,
+      token: "token",
+      serverId: "server-1",
+      daemonPublicKey: "public-key",
+      credentialVerifier: "verifier",
+      scopes: ["hub.*"],
+    }),
+  ).rejects.toThrow("Hub WebSocket URL cannot include a fragment");
+});
+
 test("enrollment rejects a WebSocket outside the enrolled Hub authority", async () => {
   const hubOrigin = await startEnrollmentHub("ws://other-hub.test/daemon");
   const remote = new DirectHubRelationshipRemote();
@@ -467,6 +485,7 @@ const unusedExecutions: HubExecutions = {
   },
   reconcile: async () => null,
   subscribe: () => () => undefined,
+  invalidateAuthority: async () => undefined,
 };
 
 async function connectController(
diff --git a/packages/server/src/server/hub/relationship-remote.ts b/packages/server/src/server/hub/relationship-remote.ts
index 37e1fbb95e..fcc22f6266 100644
--- a/packages/server/src/server/hub/relationship-remote.ts
+++ b/packages/server/src/server/hub/relationship-remote.ts
@@ -63,6 +63,9 @@ const EnrollmentResultSchema = z.object({
     .url()
     .refine((value) => ["ws:", "wss:"].includes(new URL(value).protocol), {
       message: "Hub WebSocket URL must use ws or wss",
+    })
+    .refine((value) => new URL(value).hash === "", {
+      message: "Hub WebSocket URL cannot include a fragment",
     }),
 });
 
diff --git a/packages/server/src/server/hub/test-utils/relationship-harness.ts b/packages/server/src/server/hub/test-utils/relationship-harness.ts
index 2d98cde428..b7d3b3f8d1 100644
--- a/packages/server/src/server/hub/test-utils/relationship-harness.ts
+++ b/packages/server/src/server/hub/test-utils/relationship-harness.ts
@@ -499,12 +499,12 @@ export class HubRelationshipHarness {
     return { result: this.runCli(["hub", "disconnect", ...(force ? ["--force"] : [])]) };
   }
 
-  async relationshipStateBecomes(expected: string): Promise<void> {
+  async relationshipStateBecomes(expected: string | null): Promise<void> {
     const observed = deferred<void>();
     const watcher = watch(this.paseoHome, () => {
-      if (this.relationshipFile()?.state === expected) observed.resolve();
+      if ((this.relationshipFile()?.state ?? null) === expected) observed.resolve();
     });
-    if (this.relationshipFile()?.state === expected) observed.resolve();
+    if ((this.relationshipFile()?.state ?? null) === expected) observed.resolve();
     try {
       await observed.promise;
     } finally {
diff --git a/packages/server/src/server/websocket-server.ts b/packages/server/src/server/websocket-server.ts
index dee65a001a..5bcceb22a8 100644
--- a/packages/server/src/server/websocket-server.ts
+++ b/packages/server/src/server/websocket-server.ts
@@ -36,8 +36,9 @@ import {
   type SessionPeer,
   type SessionRuntimeMetrics,
 } from "./session.js";
-import { HubSession, type HubExecutions } from "./hub/index.js";
+import { HubSession } from "./hub/hub-session.js";
 import type { HubRelationshipManagement } from "./hub/relationship-controller.js";
+import type { HubExecutions } from "./hub/relationship-owned-executions.js";
 import type { AgentProvider } from "./agent/agent-sdk-types.js";
 import { ProviderSnapshotManager } from "./agent/provider-snapshot-manager.js";
 import type { WorkspaceGitRuntimeSnapshot, WorkspaceGitService } from "./workspace-git-service.js";