diff --git a/apps/web/app/api/mcp/route.test.ts b/apps/web/app/api/mcp/route.test.ts
index 74c4be6b4f82..7cc1c7de3df7 100644
--- a/apps/web/app/api/mcp/route.test.ts
+++ b/apps/web/app/api/mcp/route.test.ts
@@ -43,6 +43,7 @@ vi.mock("@formbricks/database", () => ({
 }));
 
 vi.mock("@/modules/auth/lib/oauth-urls", () => ({
+  MCP_RESOURCE_SCOPES: ["surveys:read", "surveys:write"],
   getAuthIssuerUrl: () => "http://localhost/api/auth",
   getMcpOrigin: () => "http://localhost",
   getMcpProtectedResourceMetadataUrl: () => "http://localhost/.well-known/oauth-protected-resource/api/mcp",
@@ -160,7 +161,7 @@ describe("POST /api/mcp", () => {
     expect(response.status).toBe(401);
     expect(response.headers.get("Content-Type")).toBe("application/problem+json");
     expect(response.headers.get("WWW-Authenticate")).toBe(
-      'Bearer resource_metadata="http://localhost/.well-known/oauth-protected-resource/api/mcp" scope="surveys:read"'
+      'Bearer resource_metadata="http://localhost/.well-known/oauth-protected-resource/api/mcp" scope="surveys:read surveys:write"'
     );
     expect(applyIPRateLimit).toHaveBeenCalled();
   });
@@ -410,7 +411,7 @@ describe("POST /api/mcp", () => {
     expect(authenticateApiKeyFromHeaders).not.toHaveBeenCalled();
     expect(applyIPRateLimit).toHaveBeenCalled();
     expect(response.headers.get("WWW-Authenticate")).toBe(
-      'Bearer resource_metadata="http://localhost/.well-known/oauth-protected-resource/api/mcp" scope="surveys:read"'
+      'Bearer resource_metadata="http://localhost/.well-known/oauth-protected-resource/api/mcp" scope="surveys:read surveys:write"'
     );
   });
 
diff --git a/apps/web/modules/auth/lib/mcp-oauth-dcr.test.ts b/apps/web/modules/auth/lib/mcp-oauth-dcr.test.ts
index 0a743fdff7d0..710c04d5e2e8 100644
--- a/apps/web/modules/auth/lib/mcp-oauth-dcr.test.ts
+++ b/apps/web/modules/auth/lib/mcp-oauth-dcr.test.ts
@@ -114,6 +114,33 @@ describe("MCP OAuth Dynamic Client Registration → authorize (real-client shape
     expect(registration.body.scope?.split(" ")).toEqual(expect.arrayContaining(advertisedScopes));
   });
 
+  test("default registration (no scope requested) grants read + write", async () => {
+    const auth = createAuthInstance();
+
+    // A client that registers without an explicit scope must receive write by default — otherwise the
+    // consent screen only offers "Read surveys" and every write tool 403s (the ENG-1055 QA regression:
+    // clients that key off the challenge/defaults rather than the PRM never requested write).
+    const response = await auth.handler(
+      new Request(`${BASE_URL}/api/auth/oauth2/register`, {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({
+          client_name: "MCP DCR default-scope client",
+          redirect_uris: [REDIRECT_URI],
+          grant_types: ["authorization_code", "refresh_token"],
+          response_types: ["code"],
+          token_endpoint_auth_method: "none",
+        }),
+      })
+    );
+    const body = (await response.json()) as { scope?: string };
+
+    expect(response.status).toBe(200);
+    expect(body.scope?.split(" ")).toEqual(
+      expect.arrayContaining(["surveys:read", "surveys:write", "offline_access"])
+    );
+  });
+
   test("authorize accepts the PRM-advertised scopes for a DCR client (no invalid_scope)", async () => {
     const auth = createAuthInstance();
     const advertisedScopes = await fetchAdvertisedScopes();
diff --git a/apps/web/modules/auth/lib/mcp-oauth-provider-options.ts b/apps/web/modules/auth/lib/mcp-oauth-provider-options.ts
index 70b0c28e13f0..8b22f229c7da 100644
--- a/apps/web/modules/auth/lib/mcp-oauth-provider-options.ts
+++ b/apps/web/modules/auth/lib/mcp-oauth-provider-options.ts
@@ -20,8 +20,18 @@ export const getMcpOauthProviderOptions = (): TOauthProviderOptions => ({
   validAudiences: [getMcpResourceUrl()],
   allowDynamicClientRegistration: true,
   allowUnauthenticatedClientRegistration: true,
-  clientRegistrationDefaultScopes: ["openid", "profile", "email", "offline_access", "surveys:read"],
-  clientRegistrationAllowedScopes: ["surveys:write"],
+  // Register MCP clients with read + write by default so the consent screen offers write and the
+  // write tools are reachable (clients derive their DCR/authorize scopes from what we advertise, and
+  // the plugin validates authorize against the client's registered scopes). Granting the write scope
+  // is safe: actual write access is still enforced downstream by the user's workspace permissions.
+  clientRegistrationDefaultScopes: [
+    "openid",
+    "profile",
+    "email",
+    "offline_access",
+    "surveys:read",
+    "surveys:write",
+  ],
   accessTokenExpiresIn: 15 * 60,
   refreshTokenExpiresIn: 30 * 24 * 60 * 60,
   scopeExpirations: {
diff --git a/apps/web/modules/mcp/auth.test.ts b/apps/web/modules/mcp/auth.test.ts
index 8c29135e1024..7fbef0a52ca4 100644
--- a/apps/web/modules/mcp/auth.test.ts
+++ b/apps/web/modules/mcp/auth.test.ts
@@ -105,6 +105,9 @@ describe("authenticateMcpRequest", () => {
     expect(result.ok).toBe(false);
     if (!result.ok) {
       expect(result.response.status).toBe(401);
+      // The challenge must advertise read + write so clients request write at consent and can reach
+      // the write tools (advertising only read is why write was unreachable — ENG-1055 QA).
+      expect(result.response.headers.get("WWW-Authenticate")).toContain('scope="surveys:read surveys:write"');
       expect(await result.response.json()).toMatchObject({
         code: "not_authenticated",
         detail: "API key or OAuth access token required",
diff --git a/apps/web/modules/mcp/auth.ts b/apps/web/modules/mcp/auth.ts
index c3491823730b..ac5bc39d11ff 100644
--- a/apps/web/modules/mcp/auth.ts
+++ b/apps/web/modules/mcp/auth.ts
@@ -19,6 +19,7 @@ import { parseApiKeyV2 } from "@/lib/crypto";
 import { authenticateApiKeyFromHeaders, getBearerTokenFromHeaders } from "@/modules/api/lib/api-key-auth";
 import { auth } from "@/modules/auth/lib/auth";
 import {
+  MCP_RESOURCE_SCOPES,
   getAuthIssuerUrl,
   getMcpOrigin,
   getMcpProtectedResourceMetadataUrl,
@@ -36,7 +37,13 @@ const QUERY_CREDENTIAL_PARAMS = new Set([
   "authorization",
 ]);
 
+// Minimum scope required to authenticate against the MCP server at all.
 const DEFAULT_OAUTH_SCOPE = "surveys:read";
+// Scopes advertised in the 401 WWW-Authenticate challenge. Clients build their DCR + authorize
+// requests from this, so it must list every resource scope (read + write) or clients only ever
+// request read and can never reach the write tools. Actual write access is still gated downstream
+// by the user's workspace permissions in the v3 layer.
+const MCP_CHALLENGE_SCOPE = MCP_RESOURCE_SCOPES.join(" ");
 const oauthResourceClient = oauthProviderResourceClient(auth);
 
 export type TMcpAuthInfo = AuthInfo & {
@@ -198,7 +205,7 @@ export function withMcpResponseHeaders(response: Response, requestId: string): R
   });
 }
 
-function withOAuthChallenge(response: Response, scope = DEFAULT_OAUTH_SCOPE): Response {
+function withOAuthChallenge(response: Response, scope = MCP_CHALLENGE_SCOPE): Response {
   const headers = new Headers(response.headers);
   headers.set(
     "WWW-Authenticate",
diff --git a/apps/web/modules/mcp/tools/surveys.test.ts b/apps/web/modules/mcp/tools/surveys.test.ts
index 8f015729aa17..08caa1bfd84e 100644
--- a/apps/web/modules/mcp/tools/surveys.test.ts
+++ b/apps/web/modules/mcp/tools/surveys.test.ts
@@ -503,8 +503,11 @@ describe("registerSurveyTools", () => {
     });
   });
 
-  test("validate_survey rejects write validations for read-only OAuth scopes", async () => {
+  test("validate_survey allows patch validations for read-only OAuth scopes", async () => {
     const { tools } = createToolServer();
+    vi.mocked(validateV3SurveyFromRawInput).mockResolvedValue(
+      successResponse({ valid: true, operation: "patch", invalid_params: [] }, { requestId: "req_tool" })
+    );
 
     const result = await tools.get("validate_survey")!.handler(
       {
@@ -517,12 +520,10 @@ describe("registerSurveyTools", () => {
       { authInfo: readOnlyOAuthAuthInfo }
     );
 
-    expect(validateV3SurveyFromRawInput).not.toHaveBeenCalled();
-    expect(result.isError).toBe(true);
-    expect(result.structuredContent.error).toMatchObject({
-      status: 403,
-      code: "forbidden",
-      detail: "OAuth token does not include the required MCP scope",
+    expect(validateV3SurveyFromRawInput).toHaveBeenCalled();
+    expect(result.isError).toBeFalsy();
+    expect(result.structuredContent).toEqual({
+      data: { valid: true, operation: "patch", invalid_params: [] },
       requestId: "req_tool",
     });
   });
diff --git a/apps/web/modules/mcp/tools/surveys.ts b/apps/web/modules/mcp/tools/surveys.ts
index f680a65bb4f6..8c2d24f1d91e 100644
--- a/apps/web/modules/mcp/tools/surveys.ts
+++ b/apps/web/modules/mcp/tools/surveys.ts
@@ -215,10 +215,10 @@ export function registerSurveyTools(server: McpServer): void {
     },
     async (input: TMcpValidateSurveyInput, extra) => {
       const requestId = getMcpRequestId(extra.authInfo);
-      const requiredScopes =
-        input.operation === "patch" || input.operation === "create" ? ["surveys:write"] : ["surveys:read"];
-
-      const scopeError = await guardMcpScopes(extra.authInfo, requiredScopes, requestId);
+      // validate_survey never persists changes (readOnlyHint) — a dry-run validation of a create or
+      // patch payload only needs read access. The actual write permission is enforced by the v3 layer
+      // when create_survey / patch_survey run.
+      const scopeError = await guardMcpScopes(extra.authInfo, ["surveys:read"], requestId);
       if (scopeError) {
         return scopeError;
       }