In the Agent, multiple selected model items are added.

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### 1. Is this request related to a challenge you're experiencing? Tell me about your story.

The model in the Agent can add multiple selected model items, which is convenient for automatically using alternative models or enabling multi-model collaboration when model abnormalities occur. This can enhance the stability of the Agent's operation. Multi-model collaboration can be used to handle text and multimedia content.

### 2. Additional context or comments

The model in the Agent can add multiple selected model items, which is convenient for automatically using alternative models or enabling multi-model collaboration when model abnormalities occur. This can enhance the stability of the Agent's operation. Multi-model collaboration can be used to handle text and multimedia content.

### 3. Can you help us with this feature?

- [ ] I am interested in contributing to this feature.

The issue names no files, tests, or entry points. First locate the Agent's model-selection interface and the execution path for selected models, then define how multiple models should be coordinated for fallback or collaboration across text and multimedia; done means the Agent can add and use multiple selected model items reliably.

Written by the indexing model from the issue text.