diff --git a/src/types/combo.ts b/src/types/combo.ts
deleted file mode 100644
index b5befd8e57..0000000000
--- a/src/types/combo.ts
+++ /dev/null
@@ -1,27 +0,0 @@
-/**
- * Combo — a routing group that distributes requests across provider nodes.
- */
-export interface Combo {
-  id: string;
-  name: string;
-  model: string;
-  strategy: ComboStrategy;
-  isActive: boolean;
-  nodes: ComboNode[];
-  maxRetries: number;
-  retryDelayMs: number;
-  fallbackDelayMs?: number;
-  timeoutMs: number;
-  healthCheckEnabled: boolean;
-  createdAt: string;
-  updatedAt: string;
-}
-
-export type ComboStrategy = "priority" | "weighted" | "round-robin" | "context-relay";
-
-export interface ComboNode {
-  connectionId: string;
-  provider: string;
-  weight: number;
-  priority: number;
-}
diff --git a/src/types/index.ts b/src/types/index.ts
index f32fb2a5b5..0f49a4a5b4 100644
--- a/src/types/index.ts
+++ b/src/types/index.ts
@@ -7,7 +7,6 @@
 
 export type { ProviderConnection, ProviderNode, ModelCooldownErrorPayload } from "./provider";
 export type { ApiKey } from "./apiKey";
-export type { Combo, ComboStrategy, ComboNode } from "./combo";
 export type { UsageEntry, UsageStats, ProviderUsageStats, ModelUsageStats, CallLog } from "./usage";
 export type { DatabaseSettings } from "./databaseSettings";
 export { DEFAULT_DATABASE_SETTINGS } from "./databaseSettings";
diff --git a/tests/unit/error-message-sanitization.test.ts b/tests/unit/error-message-sanitization.test.ts
index 6c4a1d7192..3224a65d55 100644
--- a/tests/unit/error-message-sanitization.test.ts
+++ b/tests/unit/error-message-sanitization.test.ts
@@ -342,6 +342,21 @@ test("createErrorResult — exposes error code/type on the result object", async
   assert.equal(result.errorType, "timeout");
 });
 
+test("buildModelCooldownBody returns the public cooldown error payload shape", async () => {
+  const { buildModelCooldownBody } = await import("../../open-sse/utils/error.ts");
+  const body = buildModelCooldownBody({ model: "gpt-4o", retryAfterSec: 1.2 });
+
+  assert.deepEqual(body, {
+    error: {
+      message: "All credentials for model gpt-4o are cooling down",
+      type: "rate_limit_error",
+      code: "model_cooldown",
+      model: "gpt-4o",
+      reset_seconds: 2,
+    },
+  });
+});
+
 test("regression: upstream_details never contains stack trace text", async () => {
   const { createErrorResult } = await import("../../open-sse/utils/error.ts");
   const upstream = { error: { message: "err" }, stack: "Error\n    at /abs/path.ts:1:2" };