diff --git a/tests/lib/agent-registry-bd.test.ts b/tests/lib/agent-registry-bd.test.ts
new file mode 100644
index 0000000..d9769b1
--- /dev/null
+++ b/tests/lib/agent-registry-bd.test.ts
@@ -0,0 +1,128 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import fs from 'node:fs/promises';
+import os from 'node:os';
+import path from 'node:path';
+import { execSync } from 'node:child_process';
+
+import {
+  extendActivityLease,
+  listAgents,
+  registerAgent,
+  showAgent,
+  setAgentState,
+} from '../../src/lib/agent-registry';
+
+async function withTempProject(run: (projectRoot: string) => Promise<void>): Promise<void> {
+  const tempDir = await fs.mkdtemp(path.join(os.tmpdir(), 'beadboard-agent-bd-test-'));
+  
+  // Initialize bd rig
+  execSync('bd init --prefix bb --force', { cwd: tempDir, stdio: 'ignore' });
+
+  try {
+    await run(tempDir);
+  } finally {
+    await fs.rm(tempDir, { recursive: true, force: true });
+  }
+}
+
+test('BD REGISTRY: registerAgent creates a bd agent bead', async () => {
+  await withTempProject(async (projectRoot) => {
+    const result = await registerAgent(
+      {
+        name: 'test-agent',
+        display: 'Test Agent Display',
+        role: 'infra',
+      },
+      { projectRoot }
+    );
+
+    assert.equal(result.ok, true, `Register failed: ${result.error?.message}`);
+    assert.equal(result.data?.agent_id, 'test-agent');
+    assert.equal(result.data?.display_name, 'Test Agent Display');
+    assert.equal(result.data?.role, 'infra');
+    assert.equal(result.data?.status, 'idle');
+
+    // Verify via direct bd call
+    const showRaw = execSync('bd agent show bb-test-agent --json', { cwd: projectRoot, encoding: 'utf8' });
+    const show = JSON.parse(showRaw);
+    assert.equal(show.id, 'bb-test-agent');
+    assert.equal(show.title, 'Agent: Test Agent Display');
+  });
+});
+
+test('BD REGISTRY: showAgent returns agent data', async () => {
+  await withTempProject(async (projectRoot) => {
+    await registerAgent({ name: 'show-agent', role: 'ui' }, { projectRoot });
+
+    // Note: showAgent doesn't take projectRoot currently, it uses process.cwd()
+    const originalCwd = process.cwd();
+    process.chdir(projectRoot);
+    try {
+      const result = await showAgent({ agent: 'show-agent' });
+      assert.equal(result.ok, true);
+      assert.equal(result.data?.agent_id, 'show-agent');
+    } finally {
+      process.chdir(originalCwd);
+    }
+  });
+});
+
+test('BD REGISTRY: listAgents returns all agents', async () => {
+  await withTempProject(async (projectRoot) => {
+    await registerAgent({ name: 'agent-a', role: 'ui' }, { projectRoot });
+    await registerAgent({ name: 'agent-b', role: 'backend' }, { projectRoot });
+
+    const originalCwd = process.cwd();
+    process.chdir(projectRoot);
+    try {
+      const result = await listAgents({});
+      assert.equal(result.ok, true);
+      assert.equal(result.data?.length, 2);
+      assert.equal(result.data?.[0].agent_id, 'agent-a');
+      assert.equal(result.data?.[1].agent_id, 'agent-b');
+    } finally {
+      process.chdir(originalCwd);
+    }
+  });
+});
+
+test('BD REGISTRY: extendActivityLease emits wisp and preserves issue state', async () => {
+  await withTempProject(async (projectRoot) => {
+    const agentId = 'telemetry-agent';
+    await registerAgent({ name: agentId, role: 'infra' }, { projectRoot });
+    
+    const issuesPath = path.join(projectRoot, '.beads', 'issues.jsonl');
+    const beforeState = await fs.readFile(issuesPath, 'utf8');
+
+    const result = await extendActivityLease({ agent: agentId }, { projectRoot });
+    if (!result.ok) console.error('Extend Lease Failed:', result.error);
+    assert.equal(result.ok, true);
+
+    const afterState = await fs.readFile(issuesPath, 'utf8');
+    assert.equal(beforeState, afterState, 'Durable issues.jsonl should NOT change during lease extension');
+
+    // Verify wisp exists via direct bd list
+    const listRaw = execSync('bd list --wisp-type heartbeat --json', { cwd: projectRoot, encoding: 'utf8' });
+    const wisps = JSON.parse(listRaw);
+    assert.ok(wisps.length > 0, 'Heartbeat wisp should be present in the stream');
+    assert.ok(wisps[0].title.startsWith('pulse:'), 'Wisp title should match pulse prefix');
+  });
+});
+
+test('BD REGISTRY: setAgentState updates ZFC state', async () => {
+  await withTempProject(async (projectRoot) => {
+    const agentId = 'state-agent';
+    await registerAgent({ name: agentId, role: 'infra' }, { projectRoot });
+
+    // Transition to working
+    const result = await setAgentState({ agent: agentId, state: 'working' }, { projectRoot });
+    assert.equal(result.ok, true);
+    assert.equal(result.data?.status, 'working');
+
+    // Transition to stuck
+    const failResult = await setAgentState({ agent: agentId, state: 'stuck' }, { projectRoot });
+    assert.equal(failResult.ok, true);
+    assert.equal(failResult.data?.status, 'stuck');
+  });
+});