diff --git a/CHANGELOG.md b/CHANGELOG.md
index f08c626..55c6bfc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,16 @@
 
 All notable changes to `@gethookmyapp/cli` are documented here.
 
+## Unreleased
+
+### Added
+
+- `sandbox env` now emits `VERIFY_TOKEN` (AIT-179) — the session's webhook verify token, distinct from `WEBHOOK_HMAC_SECRET`. `sandbox webhook set` runs the verify-GET handshake against it, so an unmodified starter-kit receiver configured via `sandbox env` now passes verification.
+
+### Changed
+
+- Sandbox session boundary parser requires `verifyToken` on every session; older backends without it surface as `MALFORMED_SANDBOX_SESSION`.
+
 ## 0.12.7 — 2026-05-30
 
 ### Breaking
diff --git a/README.md b/README.md
index f71f7fd..498fd02 100644
--- a/README.md
+++ b/README.md
@@ -276,6 +276,7 @@ WhatsApp sandbox:
 
 ```bash
 WEBHOOK_HMAC_SECRET=...
+VERIFY_TOKEN=...
 PORT=3000
 WHATSAPP_API_URL=...
 WHATSAPP_ACCESS_TOKEN=...
@@ -286,6 +287,7 @@ Instagram sandbox:
 
 ```bash
 WEBHOOK_HMAC_SECRET=...
+VERIFY_TOKEN=...
 PORT=3000
 INSTAGRAM_API_URL=...
 INSTAGRAM_ACCESS_TOKEN=...
@@ -293,8 +295,9 @@ INSTAGRAM_ACCOUNT_ID=...
 ```
 
 `WEBHOOK_HMAC_SECRET` is the secret that signs delivered webhook payloads
-(the `X-HookMyApp-Signature-256` header). Sandbox env blocks do not include
-`VERIFY_TOKEN`: the sandbox tunnel never issues the verify-GET handshake.
+(the `X-HookMyApp-Signature-256` header). `VERIFY_TOKEN` is a separate value:
+`sandbox webhook set` runs the verify-GET handshake against your URL and
+expects this token echoed back in the response body.
 
 ## Telemetry
 
diff --git a/src/__tests__/sandbox-listen/picker.test.ts b/src/__tests__/sandbox-listen/picker.test.ts
index 01f9dd9..e268db4 100644
--- a/src/__tests__/sandbox-listen/picker.test.ts
+++ b/src/__tests__/sandbox-listen/picker.test.ts
@@ -25,6 +25,7 @@ function makeSession(overrides: Partial<WhatsAppSandboxSession> = {}): WhatsAppS
     status: 'active',
     accessToken: 'ACT_test',
     hmacSecret: 'HMAC_test',
+    verifyToken: 'VT_test',
     origin: 'test',
     whatsappPhone: '+15550001',
     whatsappPhoneNumberId: 'PNID_test',
@@ -114,6 +115,7 @@ describe('pickSession', () => {
       senderInstagramUsername: 'ordvir',
       accessToken: 'ACT_ig',
       hmacSecret: 'HMAC_ig',
+      verifyToken: 'VT_test',
       status: 'active',
       origin: 'demo_handoff',
     };
diff --git a/src/api/__tests__/sandbox-session.test.ts b/src/api/__tests__/sandbox-session.test.ts
index 8169cbe..5c5bf1c 100644
--- a/src/api/__tests__/sandbox-session.test.ts
+++ b/src/api/__tests__/sandbox-session.test.ts
@@ -13,6 +13,7 @@ const baseShared = {
   id: 'ssn_TEST0001',
   accessToken: 'ACT_xxx',
   hmacSecret: 'HMAC_yyy',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'manual',
 };
@@ -72,6 +73,7 @@ describe('parseSandboxSession', () => {
       type: 'instagram',
       accessToken: 'ACT_xxx',
       hmacSecret: 'HMAC_yyy',
+      verifyToken: 'VT_test',
       status: 'active',
       origin: 'manual',
       senderInstagramId: '12345',
diff --git a/src/api/sandbox-session.ts b/src/api/sandbox-session.ts
index 0a139ed..4d52c36 100644
--- a/src/api/sandbox-session.ts
+++ b/src/api/sandbox-session.ts
@@ -23,6 +23,10 @@ interface SandboxSessionBase {
   id: string;
   accessToken: string;
   hmacSecret: string;
+  /** GET-handshake echo value for webhook verification. Distinct from
+   *  hmacSecret (Verify Token ≠ HMAC). Exported as VERIFY_TOKEN by
+   *  `sandbox env` (AIT-179). */
+  verifyToken: string;
   status: 'pending_activation' | 'active' | 'replaced' | 'expired';
   origin: string;
   // Optional fields tolerated when present (not required for parser success):
@@ -89,6 +93,7 @@ export function parseSandboxSession(dto: unknown): SandboxSession {
   if (!isNonEmptyString(d.id)) malformed(id, 'id missing');
   if (!isNonEmptyString(d.accessToken)) malformed(id, 'accessToken missing');
   if (!isNonEmptyString(d.hmacSecret)) malformed(id, 'hmacSecret missing');
+  if (!isNonEmptyString(d.verifyToken)) malformed(id, 'verifyToken missing');
   if (!isNonEmptyString(d.status)) malformed(id, 'status missing');
   // Validate status against the closed union declared on SandboxSessionBase.
   // A typo like 'pending_activision' would otherwise pass through and lie to
diff --git a/src/auth/__tests__/login.test.ts b/src/auth/__tests__/login.test.ts
index 6fe1249..1b5cd5a 100644
--- a/src/auth/__tests__/login.test.ts
+++ b/src/auth/__tests__/login.test.ts
@@ -195,6 +195,7 @@ describe('post-login wizard', () => {
           status: 'active',
           accessToken: 'abc12345',
           hmacSecret: 'secret',
+          verifyToken: 'VT_test',
           origin: 'sandbox',
         },
       ]);
diff --git a/src/commands/__tests__/sandbox-listen-banner.test.ts b/src/commands/__tests__/sandbox-listen-banner.test.ts
index 50af5f6..1900107 100644
--- a/src/commands/__tests__/sandbox-listen-banner.test.ts
+++ b/src/commands/__tests__/sandbox-listen-banner.test.ts
@@ -16,6 +16,7 @@ const SESSION: WhatsAppSandboxSession = {
   status: 'active',
   accessToken: 'ACT_banner',
   hmacSecret: 'HMAC_banner',
+  verifyToken: 'VT_test',
   origin: 'test',
   whatsappPhone: '+15551234567',
   whatsappPhoneNumberId: 'PNID_banner',
diff --git a/src/commands/__tests__/wizard.test.ts b/src/commands/__tests__/wizard.test.ts
index 643968a..a790f83 100644
--- a/src/commands/__tests__/wizard.test.ts
+++ b/src/commands/__tests__/wizard.test.ts
@@ -105,6 +105,7 @@ describe('wizard sandbox sub-flow — Phase 126 bind-code rework', () => {
         whatsappApiVersion: 'v20.0',
         accessToken: 'abc12345',
         hmacSecret: 'HMAC_only',
+        verifyToken: 'VT_test',
         status: 'active',
         origin: 'sandbox',
       },
@@ -130,6 +131,7 @@ describe('wizard sandbox sub-flow — Phase 126 bind-code rework', () => {
         whatsappApiVersion: 'v20.0',
         accessToken: 'tok_a',
         hmacSecret: 'hmac_a',
+        verifyToken: 'VT_test',
         status: 'active',
         origin: 'sandbox',
       },
@@ -143,6 +145,7 @@ describe('wizard sandbox sub-flow — Phase 126 bind-code rework', () => {
         whatsappApiVersion: 'v20.0',
         accessToken: 'tok_b',
         hmacSecret: 'hmac_b',
+        verifyToken: 'VT_test',
         status: 'active',
         origin: 'sandbox',
       },
@@ -157,6 +160,7 @@ describe('wizard sandbox sub-flow — Phase 126 bind-code rework', () => {
       whatsappApiVersion: 'v20.0',
       accessToken: 'tok_a',
       hmacSecret: 'hmac_a',
+      verifyToken: 'VT_test',
       status: 'active',
       origin: 'sandbox',
     });
@@ -190,6 +194,7 @@ describe('wizard sandbox sub-flow — Phase 126 bind-code rework', () => {
         whatsappApiVersion: 'v20.0',
         accessToken: 'tok_a',
         hmacSecret: 'hmac_a',
+        verifyToken: 'VT_test',
         status: 'active',
         origin: 'sandbox',
       },
@@ -203,6 +208,7 @@ describe('wizard sandbox sub-flow — Phase 126 bind-code rework', () => {
         whatsappApiVersion: 'v20.0',
         accessToken: 'tok_b',
         hmacSecret: 'hmac_b',
+        verifyToken: 'VT_test',
         status: 'active',
         origin: 'sandbox',
       },
diff --git a/src/commands/sandbox-listen/__tests__/listen-positional.test.ts b/src/commands/sandbox-listen/__tests__/listen-positional.test.ts
index 5e80f16..f30d9c0 100644
--- a/src/commands/sandbox-listen/__tests__/listen-positional.test.ts
+++ b/src/commands/sandbox-listen/__tests__/listen-positional.test.ts
@@ -30,6 +30,7 @@ const ig: InstagramSandboxSession = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'ACT_ig',
   hmacSecret: 'HMAC_ig',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'demo_handoff',
 };
diff --git a/src/commands/sandbox/__tests__/env.test.ts b/src/commands/sandbox/__tests__/env.test.ts
index c3e6035..bbb06e3 100644
--- a/src/commands/sandbox/__tests__/env.test.ts
+++ b/src/commands/sandbox/__tests__/env.test.ts
@@ -31,6 +31,7 @@ const wa: WhatsAppSandboxSession = {
   whatsappApiVersion: 'v24.0',
   accessToken: 'ACT_wa_xxx',
   hmacSecret: 'HMAC_wa_yyy',
+  verifyToken: 'VT_wa_zzz',
   status: 'active',
   origin: 'manual',
 };
@@ -43,6 +44,7 @@ const ig: InstagramSandboxSession = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'ACT_ig_xxx',
   hmacSecret: 'HMAC_ig_yyy',
+  verifyToken: 'VT_ig_zzz',
   status: 'active',
   origin: 'demo_handoff',
 };
@@ -60,6 +62,7 @@ describe('buildEnvBlock — WhatsApp regression', () => {
     expect(out).toBe(
       [
         'WEBHOOK_HMAC_SECRET=HMAC_wa_yyy',
+        'VERIFY_TOKEN=VT_wa_zzz',
         'PORT=3000',
         'WHATSAPP_API_URL=https://proxy.test/v24.0',
         'WHATSAPP_ACCESS_TOKEN=ACT_wa_xxx',
@@ -83,6 +86,7 @@ describe('buildEnvBlock — Instagram (D2)', () => {
     expect(out).toBe(
       [
         'WEBHOOK_HMAC_SECRET=HMAC_ig_yyy',
+        'VERIFY_TOKEN=VT_ig_zzz',
         'PORT=3000',
         'INSTAGRAM_API_URL=https://proxy.test/v25.0',
         'INSTAGRAM_ACCESS_TOKEN=ACT_ig_xxx',
@@ -137,6 +141,7 @@ describe('runSandboxEnv --json — flat {KEY: VALUE} object', () => {
     const parsed = JSON.parse((writeSpy.mock.calls[0][0] as string).trim());
     expect(parsed).toEqual({
       WEBHOOK_HMAC_SECRET: 'HMAC_ig_yyy',
+      VERIFY_TOKEN: 'VT_ig_zzz',
       PORT: '3000',
       INSTAGRAM_API_URL: 'https://proxy.test/v25.0',
       INSTAGRAM_ACCESS_TOKEN: 'ACT_ig_xxx',
diff --git a/src/commands/sandbox/__tests__/helpers.test.ts b/src/commands/sandbox/__tests__/helpers.test.ts
index 924f3a4..bd298e2 100644
--- a/src/commands/sandbox/__tests__/helpers.test.ts
+++ b/src/commands/sandbox/__tests__/helpers.test.ts
@@ -18,6 +18,7 @@ const wa: WhatsAppSandboxSession = {
   whatsappApiVersion: 'v24.0',
   accessToken: 'ACT_wa_xxx',
   hmacSecret: 'HMAC_wa',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'manual',
 };
@@ -30,6 +31,7 @@ const igWithUsername: InstagramSandboxSession = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'ACT_ig_xxx',
   hmacSecret: 'HMAC_ig',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'demo_handoff',
 };
diff --git a/src/commands/sandbox/__tests__/logs-default-format.test.ts b/src/commands/sandbox/__tests__/logs-default-format.test.ts
index e84ed62..16284ed 100644
--- a/src/commands/sandbox/__tests__/logs-default-format.test.ts
+++ b/src/commands/sandbox/__tests__/logs-default-format.test.ts
@@ -19,6 +19,7 @@ const ig = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'tok',
   hmacSecret: 'hmac',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'demo_handoff',
 };
diff --git a/src/commands/sandbox/__tests__/logs.test.ts b/src/commands/sandbox/__tests__/logs.test.ts
index f33cb68..5cd592a 100644
--- a/src/commands/sandbox/__tests__/logs.test.ts
+++ b/src/commands/sandbox/__tests__/logs.test.ts
@@ -28,6 +28,7 @@ const wa: WhatsAppSandboxSession = {
   whatsappApiVersion: 'v24.0',
   accessToken: 'ACT_wa',
   hmacSecret: 'HMAC_wa',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'manual',
 };
@@ -40,6 +41,7 @@ const ig: InstagramSandboxSession = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'ACT_ig',
   hmacSecret: 'HMAC_ig',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'demo_handoff',
 };
diff --git a/src/commands/sandbox/__tests__/picker.test.ts b/src/commands/sandbox/__tests__/picker.test.ts
index 921ffea..ee78389 100644
--- a/src/commands/sandbox/__tests__/picker.test.ts
+++ b/src/commands/sandbox/__tests__/picker.test.ts
@@ -15,6 +15,7 @@ const wa: WhatsAppSandboxSession = {
   whatsappApiVersion: 'v24.0',
   accessToken: 'ACT_wa',
   hmacSecret: 'HMAC_wa',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'manual',
 };
@@ -27,6 +28,7 @@ const ig: InstagramSandboxSession = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'ACT_ig',
   hmacSecret: 'HMAC_ig',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'demo_handoff',
 };
diff --git a/src/commands/sandbox/__tests__/send-positional.test.ts b/src/commands/sandbox/__tests__/send-positional.test.ts
index 72afa1a..ac0ff30 100644
--- a/src/commands/sandbox/__tests__/send-positional.test.ts
+++ b/src/commands/sandbox/__tests__/send-positional.test.ts
@@ -30,6 +30,7 @@ const ig: InstagramSandboxSession = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'tok',
   hmacSecret: 'hmac',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'demo_handoff',
 };
diff --git a/src/commands/sandbox/__tests__/send.test.ts b/src/commands/sandbox/__tests__/send.test.ts
index 7b02360..093e962 100644
--- a/src/commands/sandbox/__tests__/send.test.ts
+++ b/src/commands/sandbox/__tests__/send.test.ts
@@ -24,6 +24,7 @@ const wa: WhatsAppSandboxSession = {
   whatsappApiVersion: 'v24.0',
   accessToken: 'ACT_wa',
   hmacSecret: 'HMAC_wa',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'manual',
 };
@@ -36,6 +37,7 @@ const ig: InstagramSandboxSession = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'ACT_ig',
   hmacSecret: 'HMAC_ig',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'demo_handoff',
 };
diff --git a/src/commands/sandbox/__tests__/status.test.ts b/src/commands/sandbox/__tests__/status.test.ts
index cb3e71a..4bb362d 100644
--- a/src/commands/sandbox/__tests__/status.test.ts
+++ b/src/commands/sandbox/__tests__/status.test.ts
@@ -22,6 +22,7 @@ const rawWaWire = {
   whatsappApiVersion: 'v24.0',
   accessToken: 'wa-secret-token',
   hmacSecret: 'wa-hmac-secret',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'manual',
   webhookUrl: null,
@@ -41,6 +42,7 @@ const rawIgWire = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'ig-secret-token',
   hmacSecret: 'ig-hmac-secret',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'demo_handoff',
   webhookUrl: 'https://my.example/hook',
diff --git a/src/commands/sandbox/__tests__/stop.test.ts b/src/commands/sandbox/__tests__/stop.test.ts
index 48d2f84..c9a57e0 100644
--- a/src/commands/sandbox/__tests__/stop.test.ts
+++ b/src/commands/sandbox/__tests__/stop.test.ts
@@ -25,6 +25,7 @@ const wa: WhatsAppSandboxSession = {
   whatsappApiVersion: 'v24.0',
   accessToken: 'ACT_wa',
   hmacSecret: 'HMAC_wa',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'manual',
 };
diff --git a/src/commands/sandbox/__tests__/webhook.test.ts b/src/commands/sandbox/__tests__/webhook.test.ts
index b9fd9e1..7db1708 100644
--- a/src/commands/sandbox/__tests__/webhook.test.ts
+++ b/src/commands/sandbox/__tests__/webhook.test.ts
@@ -28,6 +28,7 @@ const wa: WhatsAppSandboxSession = {
   whatsappApiVersion: 'v24.0',
   accessToken: 'ACT_wa',
   hmacSecret: 'HMAC_wa',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'manual',
 };
@@ -40,6 +41,7 @@ const ig: InstagramSandboxSession = {
   senderInstagramUsername: 'ordvir',
   accessToken: 'ACT_ig',
   hmacSecret: 'HMAC_ig',
+  verifyToken: 'VT_test',
   status: 'active',
   origin: 'demo_handoff',
 };
diff --git a/src/commands/sandbox/env.ts b/src/commands/sandbox/env.ts
index d3c7d58..084b21d 100644
--- a/src/commands/sandbox/env.ts
+++ b/src/commands/sandbox/env.ts
@@ -5,10 +5,9 @@
 // Per D2: WA block uses the WHATSAPP_* prefix (including the WA quirk where
 // WHATSAPP_PHONE_NUMBER_ID carries the tester's phone, per spec D4). IG block
 // uses the INSTAGRAM_* prefix. Both blocks carry the session's webhook HMAC
-// signing secret as WEBHOOK_HMAC_SECRET. No VERIFY_TOKEN is written: the
-// sandbox tunnel never issues the verify-GET handshake, and the temporary
-// compat alias for pre-split starter-kits was dropped alongside
-// webhook-starter-kit v3 (AIT-126).
+// signing secret as WEBHOOK_HMAC_SECRET and, since AIT-179, the session's
+// VERIFY_TOKEN — `sandbox webhook set` runs the verify-GET handshake against
+// it (distinct from the HMAC secret; Verify Token ≠ HMAC).
 
 import * as fs from 'node:fs';
 import type { Command } from 'commander';
@@ -42,6 +41,7 @@ export function buildEnvPairs(session: SandboxSession): [string, string][] {
     case 'whatsapp':
       return [
         ['WEBHOOK_HMAC_SECRET', session.hmacSecret],
+        ['VERIFY_TOKEN', session.verifyToken],
         ['PORT', '3000'],
         ['WHATSAPP_API_URL', `${proxyBase}/${session.whatsappApiVersion}`],
         ['WHATSAPP_ACCESS_TOKEN', session.accessToken],
@@ -50,6 +50,7 @@ export function buildEnvPairs(session: SandboxSession): [string, string][] {
     case 'instagram':
       return [
         ['WEBHOOK_HMAC_SECRET', session.hmacSecret],
+        ['VERIFY_TOKEN', session.verifyToken],
         ['PORT', '3000'],
         ['INSTAGRAM_API_URL', `${proxyBase}/${INSTAGRAM_GRAPH_VERSION}`],
         ['INSTAGRAM_ACCESS_TOKEN', session.accessToken],