> ## Documentation Index
> Fetch the complete documentation index at: https://docs.r28.ai/charter/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Charter works for any HTTP API, including the user's own. The packs are examples of the result, not the limit: an API with no pack is declared the same way, following https://raw.githubusercontent.com/r28ai/charter/main/docs/.mintlify/skills/declaring-charter-tools/SKILL.md.
> Charter is for agents that act in customers' accounts: every call is checked field by field before it's sent, the app says whose account each call is for, and the same declarations list what each tool can reach. https://docs.r28.ai/charter/llms.txt says what it is and lists every page.

# mail_folders_delta

> Track changes to the mailbox's folders. The first round returns every folder and ends with a delta_link; pass that as next_link later to get only what changed.

GET`https://graph.microsoft.com/v1.0/me/mailFolders/delta`

```python outlook_mail_folders_delta.py theme={null}
import asyncio

from charter.packs import outlook

result = asyncio.run(outlook.mail_folders_delta.ainvoke({}))
```

> [!NOTE]
>
> Requires `https://graph.microsoft.com/Mail.ReadBasic`, or any of `https://graph.microsoft.com/Mail.Read` or `https://graph.microsoft.com/Mail.ReadWrite`. Pages by cursor: `next_link` is sent back as `next_link`.

## Query parameters

| Field | Type | Description |
| - | - | - |
| `$select` | `string` | You can use a `$select` query parameter as in any GET request to specify only the properties your need for best performance. The id property is always returned. |
| `nextLink` | `string` | The `next_link` or `delta_link` a previous call returned (Graph's `@odata.nextLink` / `@odata.deltaLink`). A `delta_link` ends a round and starts the next one, returning only what changed since. Either link carries every parameter of the first request, the folder included, so when it is set the others are ignored. |


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