> ## Documentation Index
> Fetch the complete documentation index at: https://docs.trychannel3.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Collections

Pass `config.collection_id` on **every turn** to bind the chat to a saved catalog scope. Unlike [context](/conversations/context), the collection id is not stored on the thread. Unlike [filters](/conversations/filters), it is a reusable OR-of-clauses bound, not a one-off filter object.

Channel3 injects a description of the collection into the model (brands, categories, websites, pinned products) plus any filters on that turn. If the shopper asks for something outside the collection and search returns nothing, the assistant can say the chat is limited to that catalog and suggest a query that still fits.

Create the collection with [`POST /v1/collections`](/api-reference/v1/create-collection) (free). Full walkthrough: [Collections](/guides/collections).

<CodeGroup>
  ```typescript TypeScript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  const stream = await client.conversations.createTurnStream({
    message: {
      role: "user",
      parts: [{ type: "text", text: "Trail runners under $150" }],
    },
    config: { collection_id: collectionId },
  });
  ```

  ```python Python theme={"theme":{"light":"github-light","dark":"github-dark"}}
  stream = client.conversations.create_turn_stream(
      message={
          "role": "user",
          "parts": [{"type": "text", "text": "Trail runners under $150"}],
      },
      config={"collection_id": collection_id},
  )
  ```

  ```bash cURL theme={"theme":{"light":"github-light","dark":"github-dark"}}
  curl -N -X POST https://api.trychannel3.com/v1/conversations \
    -H "x-api-key: $CHANNEL3_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "message": {
        "role": "user",
        "parts": [{ "type": "text", "text": "Trail runners under $150" }]
      },
      "config": { "collection_id": "COLLECTION_ID" }
    }'
  ```
</CodeGroup>