diff --git a/src/lib/social-cards.ts b/src/lib/social-cards.ts
new file mode 100644
index 0000000..38f05e4
--- /dev/null
+++ b/src/lib/social-cards.ts
@@ -0,0 +1,103 @@
+import type { BeadIssue } from './types';
+
+export type SocialCardStatus = 'ready' | 'in_progress' | 'blocked' | 'closed';
+
+export type AgentStatus = 'active' | 'stale' | 'stuck' | 'dead';
+
+export interface AgentInfo {
+  name: string;
+  status: AgentStatus;
+}
+
+export type SocialCardPriority = 'P0' | 'P1' | 'P2' | 'P3' | 'P4';
+
+export interface SocialCard {
+  id: string;
+  title: string;
+  status: SocialCardStatus;
+  unlocks: string[];
+  blocks: string[];
+  agents: AgentInfo[];
+  lastActivity: Date;
+  priority: SocialCardPriority;
+}
+
+function mapStatus(status: BeadIssue['status']): SocialCardStatus {
+  switch (status) {
+    case 'open':
+      return 'ready';
+    case 'in_progress':
+      return 'in_progress';
+    case 'blocked':
+      return 'blocked';
+    case 'closed':
+    case 'tombstone':
+      return 'closed';
+    case 'deferred':
+    case 'pinned':
+    case 'hooked':
+      return 'ready';
+    default:
+      return 'ready';
+  }
+}
+
+function mapPriority(priority: number): SocialCardPriority {
+  if (priority <= 0) return 'P0';
+  if (priority === 1) return 'P1';
+  if (priority === 2) return 'P2';
+  if (priority === 3) return 'P3';
+  return 'P4';
+}
+
+function extractAgents(bead: BeadIssue): AgentInfo[] {
+  const agents: AgentInfo[] = [];
+  if (bead.assignee) {
+    const agentStatus: AgentStatus = 
+      typeof bead.metadata?.agentStatus === 'string' 
+        ? (bead.metadata.agentStatus as AgentStatus) 
+        : 'active';
+    agents.push({ name: bead.assignee, status: agentStatus });
+  }
+  return agents;
+}
+
+export function buildSocialCards(beads: BeadIssue[]): SocialCard[] {
+  const beadMap = new Map<string, BeadIssue>();
+  for (const bead of beads) {
+    beadMap.set(bead.id, bead);
+  }
+
+  const blocksIncoming = new Map<string, string[]>();
+  const blocksOutgoing = new Map<string, string[]>();
+
+  for (const bead of beads) {
+    blocksIncoming.set(bead.id, []);
+    blocksOutgoing.set(bead.id, []);
+  }
+
+  for (const bead of beads) {
+    for (const dep of bead.dependencies) {
+      if (dep.type === 'blocks' && beadMap.has(dep.target)) {
+        const outgoing = blocksOutgoing.get(bead.id) ?? [];
+        outgoing.push(dep.target);
+        blocksOutgoing.set(bead.id, outgoing);
+
+        const incoming = blocksIncoming.get(dep.target) ?? [];
+        incoming.push(bead.id);
+        blocksIncoming.set(dep.target, incoming);
+      }
+    }
+  }
+
+  return beads.map((bead) => ({
+    id: bead.id,
+    title: bead.title,
+    status: mapStatus(bead.status),
+    unlocks: blocksOutgoing.get(bead.id) ?? [],
+    blocks: blocksIncoming.get(bead.id) ?? [],
+    agents: extractAgents(bead),
+    lastActivity: new Date(bead.updated_at),
+    priority: mapPriority(bead.priority),
+  }));
+}
diff --git a/tests/lib/social-cards.test.ts b/tests/lib/social-cards.test.ts
new file mode 100644
index 0000000..e48bfb4
--- /dev/null
+++ b/tests/lib/social-cards.test.ts
@@ -0,0 +1,183 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+
+import type { BeadDependency, BeadIssue } from '../../src/lib/types';
+import { buildSocialCards } from '../../src/lib/social-cards';
+
+function issue(overrides: Partial<BeadIssue>): BeadIssue {
+  return {
+    id: overrides.id ?? 'bb-x',
+    title: overrides.title ?? 'Issue',
+    description: overrides.description ?? null,
+    status: overrides.status ?? 'open',
+    priority: overrides.priority ?? 2,
+    issue_type: overrides.issue_type ?? 'task',
+    assignee: overrides.assignee ?? null,
+    owner: overrides.owner ?? null,
+    labels: overrides.labels ?? [],
+    dependencies: overrides.dependencies ?? [],
+    created_at: overrides.created_at ?? '2026-02-12T00:00:00Z',
+    updated_at: overrides.updated_at ?? '2026-02-12T00:00:00Z',
+    closed_at: overrides.closed_at ?? null,
+    close_reason: overrides.close_reason ?? null,
+    closed_by_session: overrides.closed_by_session ?? null,
+    created_by: overrides.created_by ?? null,
+    due_at: overrides.due_at ?? null,
+    estimated_minutes: overrides.estimated_minutes ?? null,
+    external_ref: overrides.external_ref ?? null,
+    metadata: overrides.metadata ?? {},
+  };
+}
+
+function dep(type: BeadDependency['type'], target: string): BeadDependency {
+  return { type, target };
+}
+
+test('buildSocialCards transforms basic bead properties', () => {
+  const beads = [
+    issue({ id: 'bb-1', title: 'Test Task', status: 'in_progress', priority: 1 }),
+    issue({ id: 'bb-2', title: 'Bug Fix', status: 'blocked', priority: 0 }),
+    issue({ id: 'bb-3', title: 'Done', status: 'closed', priority: 3 }),
+  ];
+
+  const cards = buildSocialCards(beads);
+
+  assert.equal(cards.length, 3);
+  assert.equal(cards[0].id, 'bb-1');
+  assert.equal(cards[0].title, 'Test Task');
+  assert.equal(cards[0].status, 'in_progress');
+  assert.equal(cards[0].priority, 'P1');
+  assert.equal(cards[1].status, 'blocked');
+  assert.equal(cards[1].priority, 'P0');
+  assert.equal(cards[2].status, 'closed');
+  assert.equal(cards[2].priority, 'P3');
+});
+
+test('buildSocialCards maps priority correctly', () => {
+  const beads = [
+    issue({ id: 'bb-1', priority: -1 }),
+    issue({ id: 'bb-2', priority: 0 }),
+    issue({ id: 'bb-3', priority: 1 }),
+    issue({ id: 'bb-4', priority: 2 }),
+    issue({ id: 'bb-5', priority: 3 }),
+    issue({ id: 'bb-6', priority: 4 }),
+    issue({ id: 'bb-7', priority: 10 }),
+  ];
+
+  const cards = buildSocialCards(beads);
+
+  assert.equal(cards[0].priority, 'P0');
+  assert.equal(cards[1].priority, 'P0');
+  assert.equal(cards[2].priority, 'P1');
+  assert.equal(cards[3].priority, 'P2');
+  assert.equal(cards[4].priority, 'P3');
+  assert.equal(cards[5].priority, 'P4');
+  assert.equal(cards[6].priority, 'P4');
+});
+
+test('buildSocialCards computes unlocks (outgoing blocks)', () => {
+  const beads = [
+    issue({ id: 'bb-1', dependencies: [dep('blocks', 'bb-2'), dep('blocks', 'bb-3')] }),
+    issue({ id: 'bb-2' }),
+    issue({ id: 'bb-3' }),
+  ];
+
+  const cards = buildSocialCards(beads);
+  const card1 = cards.find((c) => c.id === 'bb-1')!;
+
+  assert.deepEqual(card1.unlocks.sort(), ['bb-2', 'bb-3']);
+  assert.deepEqual(card1.blocks, []);
+});
+
+test('buildSocialCards computes blocks (incoming blocks)', () => {
+  const beads = [
+    issue({ id: 'bb-1' }),
+    issue({ id: 'bb-2', dependencies: [dep('blocks', 'bb-1')] }),
+    issue({ id: 'bb-3', dependencies: [dep('blocks', 'bb-1')] }),
+  ];
+
+  const cards = buildSocialCards(beads);
+  const card1 = cards.find((c) => c.id === 'bb-1')!;
+
+  assert.deepEqual(card1.blocks.sort(), ['bb-2', 'bb-3']);
+  assert.deepEqual(card1.unlocks, []);
+});
+
+test('buildSocialCards ignores missing targets for blocks', () => {
+  const beads = [
+    issue({ id: 'bb-1', dependencies: [dep('blocks', 'bb-missing')] }),
+  ];
+
+  const cards = buildSocialCards(beads);
+
+  assert.equal(cards.length, 1);
+  assert.deepEqual(cards[0].unlocks, []);
+  assert.deepEqual(cards[0].blocks, []);
+});
+
+test('buildSocialCards extracts agents from assignee', () => {
+  const beads = [
+    issue({ id: 'bb-1', assignee: 'agent-alpha' }),
+    issue({ id: 'bb-2', assignee: 'agent-beta', metadata: { agentStatus: 'stale' } }),
+    issue({ id: 'bb-3', assignee: null }),
+  ];
+
+  const cards = buildSocialCards(beads);
+
+  assert.deepEqual(cards[0].agents, [{ name: 'agent-alpha', status: 'active' }]);
+  assert.deepEqual(cards[1].agents, [{ name: 'agent-beta', status: 'stale' }]);
+  assert.deepEqual(cards[2].agents, []);
+});
+
+test('buildSocialCards maps status correctly', () => {
+  const beads = [
+    issue({ id: 'bb-1', status: 'open' }),
+    issue({ id: 'bb-2', status: 'in_progress' }),
+    issue({ id: 'bb-3', status: 'blocked' }),
+    issue({ id: 'bb-4', status: 'closed' }),
+    issue({ id: 'bb-5', status: 'tombstone' }),
+    issue({ id: 'bb-6', status: 'deferred' }),
+    issue({ id: 'bb-7', status: 'pinned' }),
+    issue({ id: 'bb-8', status: 'hooked' }),
+  ];
+
+  const cards = buildSocialCards(beads);
+
+  assert.equal(cards[0].status, 'ready');
+  assert.equal(cards[1].status, 'in_progress');
+  assert.equal(cards[2].status, 'blocked');
+  assert.equal(cards[3].status, 'closed');
+  assert.equal(cards[4].status, 'closed');
+  assert.equal(cards[5].status, 'ready');
+  assert.equal(cards[6].status, 'ready');
+  assert.equal(cards[7].status, 'ready');
+});
+
+test('buildSocialCards converts updated_at to lastActivity Date', () => {
+  const beads = [
+    issue({ id: 'bb-1', updated_at: '2026-02-15T12:30:00Z' }),
+  ];
+
+  const cards = buildSocialCards(beads);
+
+  assert.ok(cards[0].lastActivity instanceof Date);
+  assert.equal(cards[0].lastActivity.toISOString(), '2026-02-15T12:30:00.000Z');
+});
+
+test('buildSocialCards returns empty array for empty input', () => {
+  const cards = buildSocialCards([]);
+  assert.deepEqual(cards, []);
+});
+
+test('buildSocialCards ignores non-blocks dependencies', () => {
+  const beads = [
+    issue({ id: 'bb-1', dependencies: [dep('parent', 'bb-2'), dep('relates_to', 'bb-3')] }),
+    issue({ id: 'bb-2' }),
+    issue({ id: 'bb-3' }),
+  ];
+
+  const cards = buildSocialCards(beads);
+
+  assert.deepEqual(cards[0].unlocks, []);
+  assert.deepEqual(cards[0].blocks, []);
+});