fix(project): show platform list on invalid platform API error

When the API returns 400 for an invalid platform string, show the same
helpful platform list instead of a raw JSON error body.

Author: betegon

src/commands/project/create.ts

@@ -162,6 +162,12 @@ async function resolveTeam(
   );
 }
 
+/** Check whether an API error is about an invalid platform value */
+function isPlatformError(error: ApiError): boolean {
+  const detail = error.detail ?? error.message;
+  return detail.includes("platform") && detail.includes("Invalid");
+}
+
 /**
  * Create a project with user-friendly error handling.
  * Wraps API errors with actionable messages instead of raw HTTP status codes.
@@ -182,6 +188,17 @@ async function createProjectWithErrors(
             `View it: sentry project view ${orgSlug}/${name}`
         );
       }
+      if (error.status === 400 && isPlatformError(error)) {
+        const list = PLATFORMS.map((p) => `  ${p}`).join("\n");
+        throw new CliError(
+          `Invalid platform '${platform}'.\n\n` +
+            "Specify it using:\n" +
+            `  sentry project create ${orgSlug}/${name} <platform>\n\n` +
+            "Or:\n" +
+            `  - Available platforms:\n\n${list}\n` +
+            "  - Full list: https://docs.sentry.io/platforms/"
+        );
+      }
       if (error.status === 404) {
         throw new CliError(
           `Team '${teamSlug}' not found in ${orgSlug}.\n\n` +

test/commands/project/create.test.ts

@@ -227,6 +227,28 @@ describe("project create", () => {
     expect(err.message).toContain("--team <team-slug>");
   });
 
+  test("handles 400 invalid platform with platform list", async () => {
+    createProjectSpy.mockRejectedValue(
+      new ApiError(
+        "API request failed: 400 Bad Request",
+        400,
+        '{"platform":["Invalid platform"]}'
+      )
+    );
+
+    const { context } = createMockContext();
+    const func = await createCommand.loader();
+
+    const err = await func
+      .call(context, { json: false }, "my-app", "node")
+      .catch((e: Error) => e);
+    expect(err).toBeInstanceOf(CliError);
+    expect(err.message).toContain("Invalid platform 'node'");
+    expect(err.message).toContain("Available platforms:");
+    expect(err.message).toContain("javascript-nextjs");
+    expect(err.message).toContain("docs.sentry.io/platforms");
+  });
+
   test("wraps other API errors with context", async () => {
     createProjectSpy.mockRejectedValue(
       new ApiError("API request failed: 403 Forbidden", 403, "No permission")