diff --git a/src/modules/creator/creator-detail-no-trade-history.integration.test.ts b/src/modules/creator/creator-detail-no-trade-history.integration.test.ts
new file mode 100644
index 0000000..2b02b85
--- /dev/null
+++ b/src/modules/creator/creator-detail-no-trade-history.integration.test.ts
@@ -0,0 +1,119 @@
+// Integration test: creator stats endpoint — no trade history
+//
+// Verifies that:
+//   1. A creator with no trade history returns a valid response
+//   2. Supply and holder count fields are zero rather than null or absent
+//   3. All expected fields are present and not null
+//
+// Uses Jest mocks with a minimal fixture set — no database required.
+// Follows the same conventions as creator-detail-empty-social-links.integration.test.ts
+
+import { httpGetCreatorStats } from '../creators/creators.controllers';
+
+// ── Lightweight request/response mocks ────────────────────────────────────────
+
+function makeReq(params: Record<string, string> = {}): any {
+   return { params };
+}
+
+function makeRes(): any {
+   const res: any = {};
+   res.status = jest.fn().mockReturnValue(res);
+   res.json = jest.fn().mockReturnValue(res);
+   res.setHeader = jest.fn().mockReturnValue(res);
+   res.set = jest.fn().mockReturnValue(res);
+   return res;
+}
+
+function makeNext(): jest.Mock {
+   return jest.fn();
+}
+
+// ── Tests ─────────────────────────────────────────────────────────────────────
+
+describe('GET /api/v1/creators/:id/stats — no trade history', () => {
+   afterEach(() => {
+      jest.restoreAllMocks();
+   });
+
+   it('returns HTTP 200 for a creator with no trade history', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      expect(res.status).toHaveBeenCalledWith(200);
+   });
+
+   it('response includes holderCount field set to zero', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data).toHaveProperty('holderCount');
+      expect(body.data.holderCount).toBe(0);
+   });
+
+   it('response includes totalSupply field set to zero', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data).toHaveProperty('totalSupply');
+      expect(body.data.totalSupply).toBe(0);
+   });
+
+   it('response includes totalVolume field set to zero', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data).toHaveProperty('totalVolume');
+      expect(body.data.totalVolume).toBe(0);
+   });
+
+   it('holderCount is not null or absent', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data.holderCount).not.toBeNull();
+      expect(body.data.holderCount).toBeDefined();
+   });
+
+   it('totalSupply is not null or absent', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data.totalSupply).not.toBeNull();
+      expect(body.data.totalSupply).toBeDefined();
+   });
+
+   it('response envelope is well-formed with success field', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body).toHaveProperty('success', true);
+      expect(body).toHaveProperty('data');
+   });
+
+   it('all expected numeric fields are present in response', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      const expectedFields = ['holderCount', 'totalSupply', 'totalVolume'];
+      expectedFields.forEach(field => {
+         expect(body.data).toHaveProperty(field);
+         expect(typeof body.data[field]).toBe('number');
+      });
+   });
+});
diff --git a/src/modules/creator/creator-list-negative-page-size.integration.test.ts b/src/modules/creator/creator-list-negative-page-size.integration.test.ts
new file mode 100644
index 0000000..9b47d19
--- /dev/null
+++ b/src/modules/creator/creator-list-negative-page-size.integration.test.ts
@@ -0,0 +1,135 @@
+// Integration test: creator list endpoint — negative page size
+//
+// Verifies that:
+//   1. A request with a negative page size returns HTTP 400
+//   2. The error body matches the standard validation error shape
+//   3. No database query is issued for the invalid input
+//
+// Uses Jest mocks with a minimal fixture set — no database required.
+// Follows the same conventions as creator-list-page-size-boundary.integration.test.ts
+
+import { httpListCreators } from '../creators/creators.controllers';
+import * as creatorsUtils from '../creators/creators.utils';
+
+// ── Lightweight request/response mocks ────────────────────────────────────────
+
+function makeReq(query: Record<string, string> = {}): any {
+   return { query };
+}
+
+function makeRes(): any {
+   const res: any = {};
+   res.status = jest.fn().mockReturnValue(res);
+   res.json = jest.fn().mockReturnValue(res);
+   res.setHeader = jest.fn().mockReturnValue(res);
+   res.set = jest.fn().mockReturnValue(res);
+   return res;
+}
+
+function makeNext(): jest.Mock {
+   return jest.fn();
+}
+
+// ── Tests ─────────────────────────────────────────────────────────────────────
+
+describe('GET /api/v1/creators — negative page size', () => {
+   afterEach(() => {
+      jest.restoreAllMocks();
+   });
+
+   it('rejects limit=-1 with HTTP 400', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      expect(res.status).toHaveBeenCalledWith(400);
+      const body = res.json.mock.calls[0][0];
+      expect(body.success).toBe(false);
+   });
+
+   it('rejects limit=-10 with HTTP 400', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-10' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      expect(res.status).toHaveBeenCalledWith(400);
+      const body = res.json.mock.calls[0][0];
+      expect(body.success).toBe(false);
+   });
+
+   it('rejects limit=-100 with HTTP 400', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-100' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      expect(res.status).toHaveBeenCalledWith(400);
+      const body = res.json.mock.calls[0][0];
+      expect(body.success).toBe(false);
+   });
+
+   it('does not call fetchCreatorList when limit is negative', async () => {
+      const spy = jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-5' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      expect(spy).not.toHaveBeenCalled();
+   });
+
+   it('response body matches standard validation error shape', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body).toHaveProperty('success', false);
+      expect(body).toHaveProperty('message');
+      expect(body).toHaveProperty('data');
+      expect(Array.isArray(body.data)).toBe(true);
+   });
+
+   it('error details include the limit field', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data.length).toBeGreaterThan(0);
+      expect(body.data[0]).toHaveProperty('field');
+      expect(body.data[0].field).toBe('limit');
+   });
+
+   it('error message indicates invalid value', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data[0]).toHaveProperty('message');
+      expect(body.data[0].message).toBeDefined();
+   });
+
+   it('response does not include items array for negative limit', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data?.items).toBeUndefined();
+   });
+});
diff --git a/src/modules/creator/creator-profile.handlers.ts b/src/modules/creator/creator-profile.handlers.ts
index 8c25834..509c793 100644
--- a/src/modules/creator/creator-profile.handlers.ts
+++ b/src/modules/creator/creator-profile.handlers.ts
@@ -76,6 +76,27 @@ export async function upsertCreatorProfileHandler(req: Request, res: Response) {
 
       const bodyResult = UpsertCreatorProfileBodySchema.safeParse(req.body);
       if (!bodyResult.success) {
+         // Log missing required fields with structured context
+         const missingFields = bodyResult.error.issues
+            .filter(
+               (issue: any) =>
+                  issue.code === 'invalid_type' &&
+                  issue.received === 'undefined'
+            )
+            .map((issue: any) => issue.path.join('.'));
+
+         if (missingFields.length > 0) {
+            logger.warn(
+               {
+                  type: 'creator_profile_validation_error',
+                  handler: 'upsertCreatorProfileHandler',
+                  missingFields,
+                  ...(req.requestId ? { requestId: req.requestId } : {}),
+               },
+               'Missing required fields in creator profile payload'
+            );
+         }
+
          return sendValidationError(
             res,
             'Invalid creator profile payload',
diff --git a/src/modules/creators/creator-detail-no-trade-history.integration.test.ts b/src/modules/creators/creator-detail-no-trade-history.integration.test.ts
new file mode 100644
index 0000000..e6834b4
--- /dev/null
+++ b/src/modules/creators/creator-detail-no-trade-history.integration.test.ts
@@ -0,0 +1,119 @@
+// Integration test: creator stats endpoint — no trade history
+//
+// Verifies that:
+//   1. A creator with no trade history returns a valid response
+//   2. Supply and holder count fields are zero rather than null or absent
+//   3. All expected fields are present and not null
+//
+// Uses Jest mocks with a minimal fixture set — no database required.
+// Follows the same conventions as creator-detail-empty-social-links.integration.test.ts
+
+import { httpGetCreatorStats } from './creators.controllers.js';
+
+// ── Lightweight request/response mocks ────────────────────────────────────────
+
+function makeReq(params: Record<string, string> = {}): any {
+   return { params };
+}
+
+function makeRes(): any {
+   const res: any = {};
+   res.status = jest.fn().mockReturnValue(res);
+   res.json = jest.fn().mockReturnValue(res);
+   res.setHeader = jest.fn().mockReturnValue(res);
+   res.set = jest.fn().mockReturnValue(res);
+   return res;
+}
+
+function makeNext(): jest.Mock {
+   return jest.fn();
+}
+
+// ── Tests ─────────────────────────────────────────────────────────────────────
+
+describe('GET /api/v1/creators/:id/stats — no trade history', () => {
+   afterEach(() => {
+      jest.restoreAllMocks();
+   });
+
+   it('returns HTTP 200 for a creator with no trade history', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      expect(res.status).toHaveBeenCalledWith(200);
+   });
+
+   it('response includes holderCount field set to zero', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data).toHaveProperty('holderCount');
+      expect(body.data.holderCount).toBe(0);
+   });
+
+   it('response includes totalSupply field set to zero', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data).toHaveProperty('totalSupply');
+      expect(body.data.totalSupply).toBe(0);
+   });
+
+   it('response includes totalVolume field set to zero', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data).toHaveProperty('totalVolume');
+      expect(body.data.totalVolume).toBe(0);
+   });
+
+   it('holderCount is not null or absent', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data.holderCount).not.toBeNull();
+      expect(body.data.holderCount).toBeDefined();
+   });
+
+   it('totalSupply is not null or absent', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data.totalSupply).not.toBeNull();
+      expect(body.data.totalSupply).toBeDefined();
+   });
+
+   it('response envelope is well-formed with success field', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body).toHaveProperty('success', true);
+      expect(body).toHaveProperty('data');
+   });
+
+   it('all expected numeric fields are present in response', async () => {
+      const req = makeReq({ id: 'creator-1' });
+      const res = makeRes();
+      await httpGetCreatorStats(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      const expectedFields = ['holderCount', 'totalSupply', 'totalVolume'];
+      expectedFields.forEach(field => {
+         expect(body.data).toHaveProperty(field);
+         expect(typeof body.data[field]).toBe('number');
+      });
+   });
+});
diff --git a/src/modules/creators/creator-list-negative-page-size.integration.test.ts b/src/modules/creators/creator-list-negative-page-size.integration.test.ts
new file mode 100644
index 0000000..4ee4e1c
--- /dev/null
+++ b/src/modules/creators/creator-list-negative-page-size.integration.test.ts
@@ -0,0 +1,135 @@
+// Integration test: creator list endpoint — negative page size
+//
+// Verifies that:
+//   1. A request with a negative page size returns HTTP 400
+//   2. The error body matches the standard validation error shape
+//   3. No database query is issued for the invalid input
+//
+// Uses Jest mocks with a minimal fixture set — no database required.
+// Follows the same conventions as creator-list-page-size-boundary.integration.test.ts
+
+import { httpListCreators } from './creators.controllers.js';
+import * as creatorsUtils from './creators.utils.js';
+
+// ── Lightweight request/response mocks ────────────────────────────────────────
+
+function makeReq(query: Record<string, string> = {}): any {
+   return { query };
+}
+
+function makeRes(): any {
+   const res: any = {};
+   res.status = jest.fn().mockReturnValue(res);
+   res.json = jest.fn().mockReturnValue(res);
+   res.setHeader = jest.fn().mockReturnValue(res);
+   res.set = jest.fn().mockReturnValue(res);
+   return res;
+}
+
+function makeNext(): jest.Mock {
+   return jest.fn();
+}
+
+// ── Tests ─────────────────────────────────────────────────────────────────────
+
+describe('GET /api/v1/creators — negative page size', () => {
+   afterEach(() => {
+      jest.restoreAllMocks();
+   });
+
+   it('rejects limit=-1 with HTTP 400', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      expect(res.status).toHaveBeenCalledWith(400);
+      const body = res.json.mock.calls[0][0];
+      expect(body.success).toBe(false);
+   });
+
+   it('rejects limit=-10 with HTTP 400', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-10' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      expect(res.status).toHaveBeenCalledWith(400);
+      const body = res.json.mock.calls[0][0];
+      expect(body.success).toBe(false);
+   });
+
+   it('rejects limit=-100 with HTTP 400', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-100' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      expect(res.status).toHaveBeenCalledWith(400);
+      const body = res.json.mock.calls[0][0];
+      expect(body.success).toBe(false);
+   });
+
+   it('does not call fetchCreatorList when limit is negative', async () => {
+      const spy = jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-5' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      expect(spy).not.toHaveBeenCalled();
+   });
+
+   it('response body matches standard validation error shape', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body).toHaveProperty('success', false);
+      expect(body).toHaveProperty('message');
+      expect(body).toHaveProperty('data');
+      expect(Array.isArray(body.data)).toBe(true);
+   });
+
+   it('error details include the limit field', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data.length).toBeGreaterThan(0);
+      expect(body.data[0]).toHaveProperty('field');
+      expect(body.data[0].field).toBe('limit');
+   });
+
+   it('error message indicates invalid value', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data[0]).toHaveProperty('message');
+      expect(body.data[0].message).toBeDefined();
+   });
+
+   it('response does not include items array for negative limit', async () => {
+      jest.spyOn(creatorsUtils, 'fetchCreatorList');
+
+      const req = makeReq({ limit: '-1' });
+      const res = makeRes();
+      await httpListCreators(req, res, makeNext());
+
+      const body = res.json.mock.calls[0][0];
+      expect(body.data?.items).toBeUndefined();
+   });
+});
diff --git a/src/modules/wallet/wallet.utils.ts b/src/modules/wallet/wallet.utils.ts
index 73a5ab2..f2710f6 100644
--- a/src/modules/wallet/wallet.utils.ts
+++ b/src/modules/wallet/wallet.utils.ts
@@ -1,5 +1,6 @@
 import { prisma } from '../../utils/prisma.utils';
 import { MapUserToWalletType } from './wallet.schemas';
+import { logger } from '../../utils/logger.utils';
 
 /**
  * Service boundary for Stellar wallet identity mapping.
@@ -11,54 +12,87 @@ import { MapUserToWalletType } from './wallet.schemas';
  * If the user already has a wallet, it updates the address.
  * Ensures the address is unique across the system.
  */
-export const upsertStellarWallet = async (input: MapUserToWalletType) => {
-  return await prisma.stellarWallet.upsert({
-    where: {
-      userId: input.userId,
-    },
-    update: {
-      address: input.address,
-    },
-    create: {
-      userId: input.userId,
-      address: input.address,
-    },
-  });
+export const upsertStellarWallet = async (
+   input: MapUserToWalletType,
+   requestId?: string
+) => {
+   try {
+      return await prisma.stellarWallet.upsert({
+         where: {
+            userId: input.userId,
+         },
+         update: {
+            address: input.address,
+         },
+         create: {
+            userId: input.userId,
+            address: input.address,
+         },
+      });
+   } catch (error: any) {
+      // Log duplicate wallet address errors with structured context
+      if (error.code === 'P2002' && error.meta?.target?.includes('address')) {
+         // Mask the address for logging (show first 8 and last 4 characters)
+         const maskedAddress = maskWalletAddress(input.address);
+
+         logger.warn(
+            {
+               type: 'wallet_address_duplicate',
+               userId: input.userId,
+               maskedAddress,
+               ...(requestId ? { requestId } : {}),
+            },
+            'Duplicate wallet address detected during upsert'
+         );
+      }
+      throw error;
+   }
 };
 
+/**
+ * Masks a wallet address for logging purposes.
+ * Shows first 8 and last 4 characters with asterisks in between.
+ */
+function maskWalletAddress(address: string): string {
+   if (!address || address.length < 12) {
+      return '***';
+   }
+   return `${address.slice(0, 8)}...${address.slice(-4)}`;
+}
+
 /**
  * Retrieves the Stellar wallet associated with a user ID.
  */
 export const getStellarWalletByUserId = async (userId: string) => {
-  return await prisma.stellarWallet.findUnique({
-    where: {
-      userId,
-    },
-  });
+   return await prisma.stellarWallet.findUnique({
+      where: {
+         userId,
+      },
+   });
 };
 
 /**
  * Retrieves the user associated with a Stellar address.
  */
 export const getUserByStellarAddress = async (address: string) => {
-  return await prisma.stellarWallet.findUnique({
-    where: {
-      address,
-    },
-    include: {
-      user: true,
-    },
-  });
+   return await prisma.stellarWallet.findUnique({
+      where: {
+         address,
+      },
+      include: {
+         user: true,
+      },
+   });
 };
 
 /**
  * Checks if a Stellar address is already registered in the system.
  */
 export const isStellarAddressRegistered = async (address: string) => {
-  const wallet = await prisma.stellarWallet.findUnique({
-    where: {
-      address,
-    },
-  });
-  return !!wallet;
+   const wallet = await prisma.stellarWallet.findUnique({
+      where: {
+         address,
+      },
+   });
+   return !!wallet;
 };