diff --git a/packages/cli/src/utils/relay.ts b/packages/cli/src/utils/relay.ts
index 0c0b544..abe2c0b 100644
--- a/packages/cli/src/utils/relay.ts
+++ b/packages/cli/src/utils/relay.ts
@@ -74,6 +74,31 @@ function branchRoot(agentId: string): string {
   return resolveDeliveryPath(agentId);
 }
 
+/** True if `recipient` is a local branch agent or team member (has a branch-office presence). */
+function isBranchRecipient(recipient: string): boolean {
+  const branchDir = join(process.env.HOME || homedir(), ".tps", "branch-office");
+  if (!existsSync(branchDir)) return false;
+  if (existsSync(join(branchDir, recipient))) return true; // registered branch / team root
+  try {
+    for (const d of readdirSync(branchDir)) {
+      const sidecar = join(branchDir, d, "team.json");
+      if (!existsSync(sidecar)) continue;
+      const s = JSON.parse(readFileSync(sidecar, "utf-8"));
+      if (Array.isArray(s.members) && s.members.includes(recipient)) return true;
+    }
+  } catch {}
+  return false;
+}
+
+/**
+ * Delivery hook for FileSystemTransport (ops-16): a local branch/team recipient
+ * reads its workspace inbox, not the flat host mail path, so route relayed mail
+ * there. Returns null for host agents so they keep the host path unchanged.
+ */
+function resolveBranchRecipientDir(recipient: string): string | null {
+  return isBranchRecipient(recipient) ? resolveDeliveryPath(recipient) : null;
+}
+
 function assertAgent(agentId: string): void {
   const safe = sanitizeIdentifier(agentId);
   if (!agentId || safe !== agentId) {
@@ -92,7 +117,7 @@ function atomicWriteJson(targetPath: string, data: unknown): void {
 }
 
 const detectors = new Map<string, LoopDetector>();
-const transportRegistry = new TransportRegistry(new FileSystemTransport());
+const transportRegistry = new TransportRegistry(new FileSystemTransport(resolveBranchRecipientDir));
 
 function getDetector(agentId: string): LoopDetector {
   if (!detectors.has(agentId)) {
diff --git a/packages/cli/src/utils/transport.ts b/packages/cli/src/utils/transport.ts
index f4e4ae4..8380614 100644
--- a/packages/cli/src/utils/transport.ts
+++ b/packages/cli/src/utils/transport.ts
@@ -107,13 +107,25 @@ function hostMailRoot(): string {
 }
 
 export class FileSystemTransport implements DeliveryTransport {
+  /**
+   * @param resolveRecipientDir Optional hook: given a recipient id, return the mail
+   *   root to deliver into (its `<root>/new` is used), or null to use the flat host
+   *   mail path. relay.ts injects a branch-aware resolver so a message to a local
+   *   branch agent lands in that branch's workspace inbox (where it actually reads),
+   *   not the host path (ops-16). With no hook, host delivery is unchanged.
+   */
+  constructor(private readonly resolveRecipientDir?: (recipient: string) => string | null) {}
+
   name(): string {
     return "filesystem";
   }
 
   async deliver(envelope: MailEnvelope): Promise<DeliveryResult> {
     try {
-      const recipientNew = join(hostMailRoot(), envelope.to, "new");
+      const branchRoot = this.resolveRecipientDir?.(envelope.to) ?? null;
+      const recipientNew = branchRoot
+        ? join(branchRoot, "new")
+        : join(hostMailRoot(), envelope.to, "new");
       ensureDir(recipientNew);
 
       const payload = {
diff --git a/packages/cli/test/relay.test.ts b/packages/cli/test/relay.test.ts
index ef6ce30..a536e64 100644
--- a/packages/cli/test/relay.test.ts
+++ b/packages/cli/test/relay.test.ts
@@ -1,5 +1,5 @@
 import { beforeEach, afterEach, describe, expect, test } from "bun:test";
-import { mkdtempSync, rmSync, mkdirSync, writeFileSync, readdirSync, readFileSync } from "node:fs";
+import { mkdtempSync, rmSync, mkdirSync, writeFileSync, readdirSync, readFileSync, existsSync } from "node:fs";
 import { join } from "node:path";
 import { tmpdir } from "node:os";
 import { deliverToSandbox, processOutboxOnce } from "../src/utils/relay.js";
@@ -170,6 +170,65 @@ describe("relay utils", () => {
     expect(msg.body).toBe("hello team member");
   });
 
+  test("relays branch→branch mail to the recipient's workspace inbox, not the host path (ops-16)", async () => {
+    const out = outboxNew("brancha");
+    // branchb is a registered branch (has a branch-office dir) → reads its workspace inbox.
+    const recipBranch = join(root, ".tps", "branch-office", "branchb");
+    mkdirSync(recipBranch, { recursive: true });
+    writeJson(join(out, "m1.json"), {
+      id: "msg-bb", from: "brancha", to: "branchb",
+      body: "hello branch b", timestamp: new Date().toISOString(),
+    });
+
+    const res = await processOutboxOnce("brancha");
+    expect(res.processed).toBe(1);
+
+    // Lands in branchb's workspace inbox (branch-office/branchb/mail/new)...
+    const wsInbox = join(recipBranch, "mail", "new");
+    expect(readdirSync(wsInbox).filter((f) => f.endsWith(".json")).length).toBe(1);
+    // ...not the flat host path (~/.tps/mail/branchb/new).
+    const hostPath = join(root, ".tps", "mail", "branchb", "new");
+    const hostCount = existsSync(hostPath) ? readdirSync(hostPath).filter((f) => f.endsWith(".json")).length : 0;
+    expect(hostCount).toBe(0);
+  });
+
+  test("relays to a team member's workspace inbox, not the host path (ops-16)", async () => {
+    const out = outboxNew("brancha");
+    const teamDir = join(root, ".tps", "branch-office", "team1");
+    const workspaceMail = join(teamDir, "workspace", "mail");
+    mkdirSync(teamDir, { recursive: true });
+    writeJson(join(teamDir, "team.json"), {
+      teamId: "team1", members: ["member1"], workspaceMail, createdAt: new Date().toISOString(),
+    });
+    writeJson(join(out, "m1.json"), {
+      id: "msg-m1", from: "brancha", to: "member1",
+      body: "hello member", timestamp: new Date().toISOString(),
+    });
+
+    const res = await processOutboxOnce("brancha");
+    expect(res.processed).toBe(1);
+
+    expect(readdirSync(join(workspaceMail, "new")).filter((f) => f.endsWith(".json")).length).toBe(1);
+    const hostPath = join(root, ".tps", "mail", "member1", "new");
+    const hostCount = existsSync(hostPath) ? readdirSync(hostPath).filter((f) => f.endsWith(".json")).length : 0;
+    expect(hostCount).toBe(0);
+  });
+
+  test("relays to a non-branch (host) recipient via the host mail path (ops-16 regression guard)", async () => {
+    const out = outboxNew("brancha");
+    writeJson(join(out, "m1.json"), {
+      id: "msg-host", from: "brancha", to: "kern",
+      body: "hello host agent", timestamp: new Date().toISOString(),
+    });
+
+    const res = await processOutboxOnce("brancha");
+    expect(res.processed).toBe(1);
+
+    // kern has no branch-office presence → host path, unchanged.
+    const hostInbox = join(root, ".tps", "mail", "kern", "new");
+    expect(readdirSync(hostInbox).filter((f) => f.endsWith(".json")).length).toBe(1);
+  });
+
   test("relay pauses duplicate messages (loop detection)", async () => {
     const agentId = "brancha";
     const out = outboxNew(agentId);