From 662b805ffb35c1d94a00cc7542a545a6950c678b Mon Sep 17 00:00:00 2001
From: phucnguyen1707 <phucnguyen17072001@gmail.com>
Date: Tue, 16 Jun 2026 11:31:31 +0700
Subject: [PATCH] Reject unknown task assignees

---
 packages/agentstack/src/index.test.ts | 33 +++++++++++++++++++--------
 packages/agentstack/src/index.ts      | 17 ++++++++------
 2 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/packages/agentstack/src/index.test.ts b/packages/agentstack/src/index.test.ts
index 1e7cd45..8ad492c 100644
--- a/packages/agentstack/src/index.test.ts
+++ b/packages/agentstack/src/index.test.ts
@@ -109,16 +109,29 @@ describe("AgentStack coordinator", () => {
     expect(listener).toHaveBeenCalledWith(expect.objectContaining({ type: "delegation.granted" }));
   });
 
-  it("rejects unknown agents and invalid DIDs", () => {
-    const stack = new AgentStack();
-    expect(() => stack.createTask({ ownerDid: "nope", sourceApp: "x", title: "t" })).toThrow();
-    const task = stack.createTask({ ownerDid: owner, sourceApp: "x", title: "t" });
-    expect(() => stack.assignTask(task.id, agentDid("ghost"))).toThrow(/Unknown agent/);
-  });
-
-  it("filters tasks in snapshots", () => {
-    const stack = new AgentStack();
-    stack.createTask({ ownerDid: owner, sourceApp: "x", title: "a" });
+  it("rejects unknown agents and invalid DIDs", () => {
+    const stack = new AgentStack();
+    expect(() => stack.createTask({ ownerDid: "nope", sourceApp: "x", title: "t" })).toThrow();
+    const task = stack.createTask({ ownerDid: owner, sourceApp: "x", title: "t" });
+    expect(() => stack.assignTask(task.id, agentDid("ghost"))).toThrow(/Unknown agent/);
+  });
+
+  it("rejects tasks preassigned to unknown agents", () => {
+    const stack = new AgentStack();
+    expect(() =>
+      stack.createTask({
+        ownerDid: owner,
+        sourceApp: "ugig.net",
+        title: "Ghost assignment",
+        assigneeDid: agentDid("ghost")
+      })
+    ).toThrow(/Unknown agent/);
+    expect(stack.listTasks({ assigneeDid: agentDid("ghost") })).toHaveLength(0);
+  });
+
+  it("filters tasks in snapshots", () => {
+    const stack = new AgentStack();
+    stack.createTask({ ownerDid: owner, sourceApp: "x", title: "a" });
     stack.createTask({ ownerDid: userDid("999"), sourceApp: "x", title: "b" });
     expect(stack.listTasks({ ownerDid: owner })).toHaveLength(1);
     expect(stack.snapshot().tasks).toHaveLength(2);
diff --git a/packages/agentstack/src/index.ts b/packages/agentstack/src/index.ts
index 92f84ef..52e0ce4 100644
--- a/packages/agentstack/src/index.ts
+++ b/packages/agentstack/src/index.ts
@@ -83,13 +83,16 @@ export class AgentStack {
     return this.agents.get(did);
   }
 
-  createTask(input: CreateTaskInput): DidTask {
-    if (!parseDid(input.ownerDid)) {
-      throw new Error(`Invalid owner DID: ${input.ownerDid}`);
-    }
-    const ts = this.now();
-    const task: DidTask = {
-      id: this.nextId("task"),
+  createTask(input: CreateTaskInput): DidTask {
+    if (!parseDid(input.ownerDid)) {
+      throw new Error(`Invalid owner DID: ${input.ownerDid}`);
+    }
+    if (input.assigneeDid && !this.agents.has(input.assigneeDid)) {
+      throw new Error(`Unknown agent: ${input.assigneeDid}`);
+    }
+    const ts = this.now();
+    const task: DidTask = {
+      id: this.nextId("task"),
       ownerDid: input.ownerDid,
       assigneeDid: input.assigneeDid,
       sourceApp: input.sourceApp,