fix: harden workflow console runtime

web/apps/console/src/connection/api.test.ts

@@ -64,6 +64,25 @@ describe("connectToServer", () => {
       expect(result.error.code).toBe("invalid_target");
     }
   });
+
+  it("accepts future server error codes without rejecting the response", async () => {
+    mockFetch.mockReturnValue(
+      jsonResponse(
+        {
+          ok: false,
+          error: { code: "new_server_code", message: "future failure" },
+          exchange: { request: null, response: null },
+        },
+        502,
+      ),
+    );
+
+    const result = await connectToServer("http://127.0.0.1:8000/rpc");
+    expect(result.ok).toBe(false);
+    if (!result.ok) {
+      expect(result.error.code).toBe("new_server_code");
+    }
+  });
 });
 
 describe("callOperation", () => {
@@ -135,7 +154,7 @@ describe("error handling", () => {
 
     await expect(
       connectToServer("http://127.0.0.1:8000/rpc"),
-    ).rejects.toThrow("empty response");
+    ).rejects.toThrow("console backend returned an empty response (HTTP 200)");
   });
 
   it("throws for structurally malformed JSON response", async () => {
@@ -143,7 +162,7 @@ describe("error handling", () => {
 
     await expect(
       connectToServer("http://127.0.0.1:8000/rpc"),
-    ).rejects.toThrow("malformed response");
+    ).rejects.toThrow("malformed response from server:");
   });
 
   it("throws on network failure", async () => {

web/apps/console/src/connection/api.ts

@@ -13,7 +13,9 @@ const fetchJson = async <T>(
   const res = await fetch(url, init);
   const text = await res.text();
   if (!text) {
-    throw new Error("empty response from server");
+    throw new Error(
+      `console backend returned an empty response (HTTP ${res.status})`,
+    );
   }
   let data: unknown;
   try {

web/apps/console/src/connection/contracts.ts

@@ -1,6 +1,6 @@
 import * as v from "valibot";
 
-const BrowserErrorCodeSchema = v.union([
+const KnownBrowserErrorCodeSchema = v.union([
   v.literal("invalid_target"),
   v.literal("unknown_operation"),
   v.literal("upstream_unreachable"),
@@ -10,6 +10,7 @@ const BrowserErrorCodeSchema = v.union([
   v.literal("rpc_decode_error"),
   v.literal("response_too_large"),
 ]);
+const BrowserErrorCodeSchema = v.union([KnownBrowserErrorCodeSchema, v.string()]);
 
 const ExchangeSchema = v.object({
   request: v.nullish(v.unknown(), null),
@@ -67,8 +68,9 @@ export type OperationName = v.InferOutput<typeof OperationNameSchema>;
 const parseDto = <T>(schema: v.GenericSchema<unknown, T>, data: unknown): T => {
   try {
     return v.parse(schema, data);
-  } catch {
-    throw new Error("malformed response from server");
+  } catch (error) {
+    const details = error instanceof Error ? `: ${error.message}` : "";
+    throw new Error(`malformed response from server${details}`);
   }
 };