fix(api-client): Handle generic 400 responses in validateEvents

packages/mcp-core/src/api-client/client.test.ts

@@ -3,6 +3,38 @@ import { http, HttpResponse } from "msw";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { ConfigurationError } from "../errors";
 import { SentryApiService } from "./client";
+import { ApiValidationError } from "./errors";
+import { z } from "zod";
+
+describe("validateEvents error bodies", () => {
+  afterEach(() => mswServer.resetHandlers());
+
+  it.each([400, 200])(
+    "preserves error classification for HTTP %i",
+    async (status) => {
+      mswServer.use(
+        http.get(
+          "https://sentry.io/api/0/organizations/test-org/events/validate/",
+          () => HttpResponse.json({ detail: "Invalid query" }, { status }),
+        ),
+      );
+      const api = new SentryApiService({
+        host: "sentry.io",
+        accessToken: "test-token",
+      });
+      const result = api.validateEvents({ organizationSlug: "test-org" });
+      if (status === 400) {
+        await expect(result).rejects.toBeInstanceOf(ApiValidationError);
+        await expect(result).rejects.toMatchObject({
+          status: 400,
+          detail: "Invalid query",
+        });
+      } else {
+        await expect(result).rejects.toBeInstanceOf(z.ZodError);
+      }
+    },
+  );
+});
 
 describe("getIssueUrl", () => {
   it("should work with sentry.io", () => {

packages/mcp-core/src/api-client/client.ts

@@ -3390,7 +3390,20 @@ export class SentryApiService {
       { ...opts, allowStatuses: [400] },
     );
     const body = await this.parseJsonResponse(response);
-    return EventsValidationResponseSchema.parse(body);
+    try {
+      return EventsValidationResponseSchema.parse(body);
+    } catch (err) {
+      if (response.status === 400 && err instanceof z.ZodError) {
+        // The API returned a 400 with a generic error body (e.g. {detail: "..."})
+        // rather than a structured validation result. Treat it as an API client error.
+        const detail =
+          body && typeof body === "object" && "detail" in body
+            ? String((body as { detail: unknown }).detail)
+            : "Invalid request";
+        throw createApiError(detail, 400, detail, body);
+      }
+      throw err;
+    }
   }
 
   private async fetchTraceItemAttributes(