[▲ Vercel Community](/) · [Categories](/categories) · [Latest](/latest) · [Top](/top) · [Live](/live) [Discussions](/c/community/4) # How to hide experimental_attachments from the LLM? 174 views · 0 likes · 1 post Jessyan0913 (@jessyan0913) · 2025-04-16 **Title:** How to pass document resources via `experimental_attachments` without exposing them to the LLM? Hi everyone, I'm building a document-based chat experience using Vercel AI SDK, and I've hit a limitation that I’m hoping someone here can help with. ### Context: The LLM I’m using **does not support multimodal input** (e.g., file uploads or attachments), but the product requirement is to support document-grounded conversations. Here’s the architecture I’ve implemented so far: 1. When a user uploads a document, I store it in a custom RAG (Retrieval-Augmented Generation) service and generate a `resourceId`. 2. I register a tool with the LLM that queries the RAG service using the resource ID. 3. During the conversation, I include the resource ID in the user message so the tool can access relevant documents and respond accordingly. ### Problem: I want to **improve the UX by hiding the resource ID from the user-facing chat**. Ideally, I’d like to attach the document info using `experimental_attachments` rather than inserting it into the visible message content. However, the Vercel AI SDK appears to **automatically send everything inside `experimental_attachments` to the model**, which leads to issues since the LLM doesn’t support attachments or multimodal inputs — it errors out.  ### What I’m trying to achieve: * Use `experimental_attachments` to pass metadata like `resourceId` to the tool, * Prevent the LLM from seeing or processing these attachments, * Still allow the tool to access the attachment metadata for context. ### Question: Is there a way to intercept or modify how `experimental_attachments` is handled in the Vercel AI SDK, so that it **is passed to tools but not sent to the LLM**? Or is there an alternative recommended approach for passing hidden context (like a document ID) to the toolchain without exposing it to the model or user message? Any help or pointers would be greatly appreciated! Thanks in advance!
