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

# ContainerFile

## Fields

| Field          | Type                                                                    | Required             | Description                                                                                       | Example                    |
| -------------- | ----------------------------------------------------------------------- | -------------------- | ------------------------------------------------------------------------------------------------- | -------------------------- |
| `bytes_`       | *int*                                                                   | :heavy\_check\_mark: | File size in bytes.                                                                               | 123                        |
| `container_id` | *str*                                                                   | :heavy\_check\_mark: | The container the file belongs to — echoes the `container_id` path parameter (OpenAI field name). | sess\_abc123               |
| `created_at`   | *int*                                                                   | :heavy\_check\_mark: | Unix timestamp (seconds) when the file was last synced.                                           | 1755640000                 |
| `id`           | *str*                                                                   | :heavy\_check\_mark: | Container file id: `cfile_` + base64url of the file path.                                         | cfile\_b3V0L3JlcG9ydC5jc3Y |
| `object`       | [components.ContainerFileObject](../components/containerfileobject.mdx) | :heavy\_check\_mark: | N/A                                                                                               | container.file             |
| `path`         | *str*                                                                   | :heavy\_check\_mark: | Container-relative file path.                                                                     | out/report.csv             |
| `source`       | [components.ContainerFileSource](../components/containerfilesource.mdx) | :heavy\_check\_mark: | Container files are always produced by the assistant sandbox.                                     | assistant                  |