diff --git a/backend/__tests__/service/tasks.source-provenance.test.js b/backend/__tests__/service/tasks.source-provenance.test.js
new file mode 100644
index 00000000..d671b575
--- /dev/null
+++ b/backend/__tests__/service/tasks.source-provenance.test.js
@@ -0,0 +1,99 @@
+process.env.PG_HOST = '';
+process.env.JWT_SECRET = 'tasks-source-provenance-test-secret';
+
+const express = require('express');
+const request = require('supertest');
+const Pod = require('../../models/Pod');
+const Task = require('../../models/Task');
+const User = require('../../models/User');
+const tasksApiRoutes = require('../../routes/tasksApi');
+const { hash } = require('../../utils/secret');
+const {
+  setupMongoDb,
+  closeMongoDb,
+  clearMongoDb,
+  generateTestToken,
+} = require('../utils/testUtils');
+
+const AGENT_TOKEN = 'cm_agent_task_source_provenance';
+
+describe('POST /api/v1/tasks/:podId source provenance', () => {
+  let app;
+  let human;
+  let agent;
+  let pod;
+
+  beforeAll(async () => {
+    await setupMongoDb();
+    app = express();
+    app.use(express.json());
+    app.use('/api/v1/tasks', tasksApiRoutes);
+  });
+
+  beforeEach(async () => {
+    await clearMongoDb();
+    human = await User.create({
+      username: `task-human-${Date.now()}`,
+      email: `task-human-${Date.now()}@test.com`,
+      password: 'Password123!',
+      verified: true,
+    });
+    agent = await User.create({
+      username: `task-agent-${Date.now()}`,
+      email: `task-agent-${Date.now()}@agents.commonly.local`,
+      password: 'Password123!',
+      verified: true,
+      isBot: true,
+      botType: 'agent',
+      botMetadata: {
+        agentName: 'task-agent',
+        instanceId: 'default',
+      },
+      agentRuntimeTokens: [{
+        tokenHash: hash(AGENT_TOKEN),
+        label: 'task-source-provenance',
+        createdAt: new Date(),
+      }],
+    });
+    pod = await Pod.create({
+      name: 'Task provenance pod',
+      type: 'team',
+      createdBy: human._id,
+      members: [human._id, agent._id],
+    });
+  });
+
+  afterAll(async () => {
+    await clearMongoDb();
+    await closeMongoDb();
+  });
+
+  it('stamps agent-authenticated creates as agent even when the body claims human', async () => {
+    const response = await request(app)
+      .post(`/api/v1/tasks/${pod._id}`)
+      .set('Authorization', `Bearer ${AGENT_TOKEN}`)
+      .send({
+        title: 'Agent-authored task',
+        source: 'human',
+      })
+      .expect(201);
+
+    expect(response.body.task.source).toBe('agent');
+    const stored = await Task.findById(response.body.task._id).lean();
+    expect(stored.source).toBe('agent');
+  });
+
+  it('preserves the existing source override for human-authenticated imports', async () => {
+    const response = await request(app)
+      .post(`/api/v1/tasks/${pod._id}`)
+      .set('Authorization', `Bearer ${generateTestToken(human._id)}`)
+      .send({
+        title: 'Imported task',
+        source: 'github',
+        sourceRef: 'GH#999',
+      })
+      .expect(201);
+
+    expect(response.body.task.source).toBe('github');
+  });
+});
diff --git a/backend/routes/tasksApi.ts b/backend/routes/tasksApi.ts
index c4cfa487..ebc367a1 100644
--- a/backend/routes/tasksApi.ts
+++ b/backend/routes/tasksApi.ts
@@ -218,9 +218,16 @@ router.post('/:podId', rateLimit({
     if (sourceRef) initUpdate.text = `Created by ${author} from ${sourceRef}${assignee ? ` · assigned to ${assignee}` : ''}`;
     if (ghNumber) initUpdate.text += ` · GH#${ghNumber}`;
     if (parentTask) initUpdate.text += ` · sub-task of ${parentTask}`;
+    // `source` is provenance for task creation, so an agent-authenticated
+    // caller may not self-identify as human (or any other source) through
+    // the request body. Human callers retain the existing source override
+    // for GitHub/import workflows.
+    const taskSource = req.agentUser?._id
+      ? 'agent'
+      : source || (ghNumber ? 'github' : 'human');
     let task;
     try {
-      task = await Task.create({ podId, taskNum, taskId, title, assignee: assignee || null, dep: dep || null, depMockOk: !!depMockOk, parentTask: parentTask || null, source: source || (ghNumber ? 'github' : 'human'), sourceRef: sourceRef || (ghNumber ? `GH#${ghNumber}` : undefined), githubIssueNumber: ghNumber, githubIssueUrl: ghUrl, updates: [initUpdate] });
+      task = await Task.create({ podId, taskNum, taskId, title, assignee: assignee || null, dep: dep || null, depMockOk: !!depMockOk, parentTask: parentTask || null, source: taskSource, sourceRef: sourceRef || (ghNumber ? `GH#${ghNumber}` : undefined), githubIssueNumber: ghNumber, githubIssueUrl: ghUrl, updates: [initUpdate] });
     } catch (createErr) {
       const duplicate = createErr as {
         code?: number;