diff --git a/tests/unit/social-draft.test.ts b/tests/unit/social-draft.test.ts
new file mode 100644
index 00000000..2b93b2b1
--- /dev/null
+++ b/tests/unit/social-draft.test.ts
@@ -0,0 +1,194 @@
+import { describe, expect, it } from "vitest";
+import { z } from "zod";
+import { approvalInputSchema } from "../../src/shared/contracts";
+
+/**
+ * Schema for social draft API input. Mirrors the one that will be defined
+ * in api-server.ts -- duplicated here for independent validation testing.
+ */
+const socialDraftSchema = z.object({
+  socialAccountId: z.string().uuid(),
+  platform: z.string(),
+  content: z.string().min(1).max(10000),
+  mediaUrls: z.array(z.string()).default([]),
+  scheduledAt: z.string().datetime().optional(),
+});
+
+describe("social draft pipeline", () => {
+  describe("socialDraftSchema validation", () => {
+    it("accepts a valid social draft with all fields", () => {
+      const input = {
+        socialAccountId: "00000000-0000-0000-0000-000000000001",
+        platform: "twitter",
+        content: "Hello world! This is a social media post.",
+        mediaUrls: ["https://example.com/image.png"],
+        scheduledAt: "2026-04-01T12:00:00Z",
+      };
+      const parsed = socialDraftSchema.parse(input);
+      expect(parsed.socialAccountId).toBe(input.socialAccountId);
+      expect(parsed.platform).toBe("twitter");
+      expect(parsed.content).toBe(input.content);
+      expect(parsed.mediaUrls).toEqual(["https://example.com/image.png"]);
+      expect(parsed.scheduledAt).toBe("2026-04-01T12:00:00Z");
+    });
+
+    it("accepts a draft without optional mediaUrls and scheduledAt", () => {
+      const input = {
+        socialAccountId: "00000000-0000-0000-0000-000000000002",
+        platform: "linkedin",
+        content: "Professional update.",
+      };
+      const parsed = socialDraftSchema.parse(input);
+      expect(parsed.mediaUrls).toEqual([]);
+      expect(parsed.scheduledAt).toBeUndefined();
+    });
+
+    it("rejects empty content", () => {
+      expect(() =>
+        socialDraftSchema.parse({
+          socialAccountId: "00000000-0000-0000-0000-000000000003",
+          platform: "twitter",
+          content: "",
+        }),
+      ).toThrow();
+    });
+
+    it("rejects invalid socialAccountId (non-uuid)", () => {
+      expect(() =>
+        socialDraftSchema.parse({
+          socialAccountId: "not-a-uuid",
+          platform: "twitter",
+          content: "Some content",
+        }),
+      ).toThrow();
+    });
+
+    it("rejects content exceeding 10000 characters", () => {
+      expect(() =>
+        socialDraftSchema.parse({
+          socialAccountId: "00000000-0000-0000-0000-000000000004",
+          platform: "reddit",
+          content: "x".repeat(10001),
+        }),
+      ).toThrow();
+    });
+  });
+
+  describe("social_post is a valid ApprovalType", () => {
+    it("approvalInputSchema accepts type social_post", () => {
+      const input = {
+        companyId: "00000000-0000-0000-0000-000000000010",
+        type: "social_post",
+        payloadSummary: "Post to Twitter via @companyhandle",
+        impactSummary: "Public social media post on company account",
+      };
+      const parsed = approvalInputSchema.parse(input);
+      expect(parsed.type).toBe("social_post");
+    });
+  });
+
+  describe("payloadSummary truncation", () => {
+    it("truncates content to 120 chars with ellipsis for payloadSummary", () => {
+      const longContent = "A".repeat(200);
+      const contentPreview = longContent.slice(0, 120) + (longContent.length > 120 ? "..." : "");
+      expect(contentPreview.length).toBe(123); // 120 + "..."
+      expect(contentPreview.endsWith("...")).toBe(true);
+    });
+
+    it("does not add ellipsis for content <= 120 chars", () => {
+      const shortContent = "Short post";
+      const contentPreview = shortContent.slice(0, 120) + (shortContent.length > 120 ? "..." : "");
+      expect(contentPreview).toBe("Short post");
+      expect(contentPreview.endsWith("...")).toBe(false);
+    });
+
+    it("truncates exactly at 120 char boundary", () => {
+      const exactContent = "B".repeat(120);
+      const contentPreview = exactContent.slice(0, 120) + (exactContent.length > 120 ? "..." : "");
+      expect(contentPreview).toBe(exactContent);
+      expect(contentPreview.length).toBe(120);
+    });
+  });
+
+  describe("approval resolution logic", () => {
+    it("approved social_post with no scheduledAt dispatches immediately", () => {
+      const approval = {
+        type: "social_post" as const,
+        payloadJson: JSON.stringify({
+          socialAccountId: "00000000-0000-0000-0000-000000000020",
+          platform: "twitter",
+          content: "Hello from the AI company!",
+          mediaUrls: [],
+          scheduledAt: null,
+        }),
+        state: "approved" as const,
+      };
+
+      const draft = JSON.parse(approval.payloadJson) as {
+        socialAccountId: string;
+        platform: string;
+        content: string;
+        mediaUrls: string[];
+        scheduledAt: string | null;
+      };
+
+      // Verify payloadJson contains scheduledAt key (cross-plan contract with 03-03)
+      expect(draft).toHaveProperty("scheduledAt");
+      expect(draft.scheduledAt).toBeNull();
+
+      // Should dispatch immediately since scheduledAt is null
+      const shouldDefer = draft.scheduledAt ? new Date(draft.scheduledAt).getTime() - Date.now() > 0 : false;
+      expect(shouldDefer).toBe(false);
+    });
+
+    it("approved social_post with future scheduledAt defers dispatch", () => {
+      const futureDate = new Date(Date.now() + 60 * 60 * 1000).toISOString(); // 1 hour from now
+      const approval = {
+        type: "social_post" as const,
+        payloadJson: JSON.stringify({
+          socialAccountId: "00000000-0000-0000-0000-000000000021",
+          platform: "linkedin",
+          content: "Scheduled professional update",
+          mediaUrls: [],
+          scheduledAt: futureDate,
+        }),
+      };
+
+      const draft = JSON.parse(approval.payloadJson) as {
+        scheduledAt: string | null;
+      };
+
+      expect(draft.scheduledAt).toBe(futureDate);
+      const delay = new Date(draft.scheduledAt!).getTime() - Date.now();
+      expect(delay).toBeGreaterThan(0);
+    });
+
+    it("rejected social_post creates no browser action", () => {
+      // When decision is "rejected", the social_post handler should NOT run saveBrowserAction.
+      // This validates the condition: approval.type === "social_post" && decision === "approved"
+      const decision = "rejected";
+      const shouldCreateAction = decision === "approved";
+      expect(shouldCreateAction).toBe(false);
+    });
+
+    it("browser action payloadJson includes scheduledAt for startup recovery", () => {
+      // Cross-plan contract with 03-03: browser action payloadJson MUST include scheduledAt
+      const draft = {
+        content: "Recovery test post",
+        mediaUrls: ["https://img.example.com/photo.jpg"],
+        scheduledAt: "2026-04-01T09:00:00Z",
+      };
+      const actionPayload = JSON.stringify({
+        content: draft.content,
+        mediaUrls: draft.mediaUrls,
+        scheduledAt: draft.scheduledAt,
+      });
+
+      const parsed = JSON.parse(actionPayload) as Record<string, unknown>;
+      expect(parsed).toHaveProperty("scheduledAt");
+      expect(parsed.scheduledAt).toBe("2026-04-01T09:00:00Z");
+      expect(parsed).toHaveProperty("content");
+      expect(parsed).toHaveProperty("mediaUrls");
+    });
+  });
+});