[BUG]For the source-deployed coze-loop using the Deepseek-v3 model to build an evaluator, an error occurs when using the evaluator.

### 📋 CheckList

- [x] I have searched existing issues to avoid duplicates
- [x] I am using a recently maintained version of Coze Loop
- [x] I have provided all required information
- [x] I understand this is a bug report and not a feature request
- [x] I have submitted this report in English (otherwise it will not be processed)

### 🐛 Bug Description

When creating an evaluator, clicking 'Debug' sometimes returns a normal response, but sometimes displays an error: 'Invalid model output.
When testing with this evaluator, checking the call trace also shows 'Invalid model output.
On the official website, using the web version to build prompts and evaluators in the same way does not result in errors.

Question: Does the official Doubao model's evaluator output have a fixed format requirement? If so, what is this format?
Additionally, must the evaluator be built exclusively with the Doubao model? Are other models incompatible (e.g., a locally deployed coze-loop)?

### 🔄 Steps to Reproduce

1. Using source-deployed coze-loop
2. Employing locally hosted DS-v3 model
3. When constructing the evaluator and clicking debug, intermittent model output errors occur during multiple runs

### ✅ Expected Behavior

no error

### ❌ Actual Behavior

invalid output from model,code=601205015 message=invalid output from model

### 🚨 Severity

None

### 🔧 Component

None

### 💻 Environment

_No response_

### 🔧 Go Environment

_No response_

### 📋 Logs

```shell

```

### 📝 Additional Context

_No response_