diff --git a/scripts/ocp-cli.js b/scripts/ocp-cli.js
index 288e5f2..8571259 100644
--- a/scripts/ocp-cli.js
+++ b/scripts/ocp-cli.js
@@ -154,7 +154,7 @@ program.command('x402:settle')
         return;
       }
     } else if (process.env.STRICT_MANDATE_MODE === 'true') {
-      console.error(`Error: Mandate required for x402 settlement in STRICT_MANDATE_MODE.`);
+      console.error(`Zero Trust Validation Failed: Mandate required for x402 settlement in STRICT_MANDATE_MODE.`);
       return;
     }
 
diff --git a/src/services/a2aService.js b/src/services/a2aService.js
index 3c5c9d9..2b9125d 100644
--- a/src/services/a2aService.js
+++ b/src/services/a2aService.js
@@ -7,6 +7,7 @@
 
 const MandateService = require("./mandate");
 const logger = require("../utils/logger");
+const MandateService = require("./mandate");
 
 class A2AService {
   constructor(walletService, db, config = {}) {
@@ -67,10 +68,22 @@ class A2AService {
         );
       }
 
-      // 2. Policy Checks (Sender)
+      // 2. Zero Trust Mandate Validation
+      if (mandate) {
+        await this.mandateService.verifyMandate(mandate, {
+          amount,
+          recipient: toAgentId,
+        });
+      } else if (this.strictMandateMode) {
+        throw new Error(
+          "Zero Trust Validation Failed: Mandate required for A2A transfer in strict mode",
+        );
+      }
+
+      // 3. Policy Checks (Sender)
       await this._validateAgentPolicy(fromAgent, toAgentId, amount);
 
-      // 3. Execute Wallet Transfer
+      // 4. Execute Wallet Transfer
       const transferResult = await this.walletService.transfer({
         fromWalletId: fromAgent.walletId,
         toWalletId: toAgent.walletId,
@@ -136,6 +149,15 @@ class A2AService {
    */
   _handleError(method, error) {
     logger.error(`A2AService.${method} error:`, error);
+
+    // Normalize Zero Trust errors
+    if (
+      error.message &&
+      error.message.includes("Zero Trust Validation Failed:")
+    ) {
+      return error;
+    }
+
     return error instanceof Error ? error : new Error(error);
   }
 }
diff --git a/src/services/tokenization.js b/src/services/tokenization.js
index 924f3f0..441e2f3 100644
--- a/src/services/tokenization.js
+++ b/src/services/tokenization.js
@@ -382,6 +382,14 @@ class TokenizationService {
   _handleError(method, error) {
     logger.error(`TokenizationService.${method} error:`, error);
 
+    // Normalize Zero Trust errors
+    if (
+      error.message &&
+      error.message.includes("Zero Trust Validation Failed:")
+    ) {
+      return error;
+    }
+
     if (error.response) {
       const { status, data } = error.response;
       return new Error(
@@ -393,7 +401,7 @@ class TokenizationService {
       return new Error("Tokenization service unavailable");
     }
 
-    return error;
+    return error instanceof Error ? error : new Error(error);
   }
 }
 
diff --git a/tests/unit/mandate_context.spec.js b/tests/unit/mandate_context.spec.js
new file mode 100644
index 0000000..b4240a1
--- /dev/null
+++ b/tests/unit/mandate_context.spec.js
@@ -0,0 +1,65 @@
+const MandateService = require("../../src/services/mandate");
+const jwt = require("jsonwebtoken");
+
+describe("MandateService - Context Validation", () => {
+  let mandateService;
+  const signingKey = "test-secret";
+
+  beforeEach(() => {
+    mandateService = new MandateService({ signingKey });
+  });
+
+  it("should validate amount against intent mandate budget", async () => {
+    const mandate = await mandateService.issueIntentMandate({
+      userDid: "did:key:user",
+      agentDid: "did:key:agent",
+      maxBudget: 100,
+    });
+
+    // Valid amount
+    await expect(
+      mandateService.verifyMandate(mandate, { amount: 50 }),
+    ).resolves.toBeDefined();
+
+    // Invalid amount
+    await expect(
+      mandateService.verifyMandate(mandate, { amount: 150 }),
+    ).rejects.toThrow(
+      "Zero Trust Validation Failed: Amount 150 exceeds mandate budget of 100",
+    );
+  });
+
+  it("should validate recipient against allowed_merchants whitelist", async () => {
+    const mandate = await mandateService.issueIntentMandate({
+      userDid: "did:key:user",
+      agentDid: "did:key:agent",
+      maxBudget: 100,
+      allowedMerchants: ["did:key:merchant-1"],
+    });
+
+    // Authorized merchant
+    await expect(
+      mandateService.verifyMandate(mandate, { recipient: "did:key:merchant-1" }),
+    ).resolves.toBeDefined();
+
+    // Unauthorized merchant
+    await expect(
+      mandateService.verifyMandate(mandate, { recipient: "did:key:merchant-2" }),
+    ).rejects.toThrow(
+      "Zero Trust Validation Failed: Merchant did:key:merchant-2 not authorized by mandate",
+    );
+  });
+
+  it("should handle expired tokens with correct prefix", async () => {
+    const mandate = jwt.sign(
+      {
+        exp: Math.floor(Date.now() / 1000) - 60,
+      },
+      signingKey,
+    );
+
+    await expect(mandateService.verifyMandate(mandate)).rejects.toThrow(
+      "Zero Trust Validation Failed: Mandate has expired",
+    );
+  });
+});