diff --git a/server/service/agent/collaboration.ts b/server/service/agent/collaboration.ts
index 32d527e..77ca39b 100644
--- a/server/service/agent/collaboration.ts
+++ b/server/service/agent/collaboration.ts
@@ -2,7 +2,8 @@ import { generateText, stepCountIs } from "ai";
 import type { AgentInvocation, AgentInvocationResult } from "./types";
 import { getAgentBySlug } from "./agent";
 import { getAgentToolsForChatByAgentId } from "#server/service/agent-tool";
-import { resolveModelForUser, toLanguageModel } from "#server/service/llm/model-resolver";
+import { resolveModelForUser, resolveModelAny, toLanguageModel } from "#server/service/llm/model-resolver";
+import { getConfigGlobal } from "#server/utils/context";
 import log4js from "logger";
 
 const logger = log4js.getLogger("APP");
@@ -50,13 +51,17 @@ export async function invokeAgent(
     };
   }
 
-  if (!agent.defaultModelId) {
-    return { agentSlug, output: "", ok: false, error: `agent ${agentSlug} has no defaultModelId` };
+  const globalDefaultModelId = (await getConfigGlobal("agentDefaultModelId")) ?? null;
+  const targetModelId = agent.defaultModelId ?? globalDefaultModelId;
+  if (!targetModelId) {
+    return { agentSlug, output: "", ok: false, error: `agent ${agentSlug} has no defaultModelId and no global default model configured` };
   }
 
-  const resolved = await resolveModelForUser(agent.defaultModelId, userId);
+  const resolved = userId
+    ? await resolveModelForUser(targetModelId, userId)
+    : await resolveModelAny(targetModelId);
   if (!resolved) {
-    return { agentSlug, output: "", ok: false, error: `model ${agent.defaultModelId} not resolvable for agent ${agentSlug}` };
+    return { agentSlug, output: "", ok: false, error: `model ${targetModelId} not resolvable for agent ${agentSlug}` };
   }
 
   const languageModel = toLanguageModel(resolved);