# create-mail-attachment-upload-session

Create an upload session that allows an app to iteratively upload ranges of a file, so as to attach the file to the specified Outlook item. The item can be a message or event. Use this approach to attach a file if the file size is between 3 MB and 150 MB. To attach a file that's smaller than 3 MB, do a POST operation on the attachments navigation property of the Outlook item; see how to do this for a message or for an event. As part of the response, this action returns an upload URL that you can use in subsequent sequential PUT queries. Request headers for each PUT operation let you specify the exact range of bytes to be uploaded. This allows transfer to be resumed, in case the network connection is dropped during upload. The following are the steps to attach a file to an Outlook item using an upload session: See attach large files to Outlook messages or events for an example. 💡 TIP: For attachments 3MB to 150MB. Graph rejects smaller files with ErrorAttachmentSizeShouldNotBeLessThanMinimumSize, so under 3MB use add-mail-attachment instead. Body: { AttachmentItem: { attachmentType: 'file', name: 'report.pdf', size: 5000000 } }. Returns a pre-authenticated uploadUrl; the caller PUTs the bytes there itself in ranges up to 4MB. This server does not perform the PUT.

Agent View of the PolicyLayer registry record for `create-mail-attachment-upload-session`. HTML page: https://policylayer.com/tools/jo3zik-ms-365-mcp-server/create-mail-attachment-upload-session

## Facts

- Tool: `create-mail-attachment-upload-session`
- Server: Ms 365 (`@jo3zik/ms-365-mcp-server`) — https://policylayer.com/tools/jo3zik-ms-365-mcp-server.md
- Install: `npx -y @jo3zik/ms-365-mcp-server`
- Homepage: https://www.npmjs.com/package/@jo3zik/ms-365-mcp-server
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 5 (2 required)
- Recommended policy verdict: Rate-limited

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `body` | object | yes |  |
| `confirm` | boolean | no | For destructive operations when the confirm gate is enabled (MS365_MCP_REQUIRE_CONFIRM=true; off by default). Set to true only after the user has explicitly app |
| `messageId` | string | yes | Value for the 'messageId' path segment. Pass it under the name 'messageId', not as 'id'. Use the 'id' field of the message object as returned by Microsoft Graph |
| `includeHeaders` | boolean | no | Include response headers (including ETag) in the response metadata |
| `excludeResponse` | boolean | no | Exclude the full response body and only return success or failure indication |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "create-mail-attachment-upload-session",
    "arguments": {
      "body": {},
      "messageId": "<messageId>"
    }
  }
}
```

## Why create-mail-attachment-upload-session is rated Medium

An AI agent can call create-mail-attachment-upload-session faster than any human can review: one bad instruction and it creates or modifies resources in Ms 365 by the hundred, each call as confident as the last.

Risk signals: Accepts raw HTML/template content (body) · High parameter count (12 properties)

## Use case

AI agents use create-mail-attachment-upload-session to create or update resources in Ms 365, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Ms 365 environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Ms 365:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "create-mail-attachment-upload-session": {
      "limits": [
        {
          "counter": "create-mail-attachment-upload-session_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Ms 365 (193)

- `cancel-calendar-event` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/cancel-calendar-event.md
- `clear-excel-range` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/clear-excel-range.md
- `delete-calendar` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-calendar.md
- `delete-calendar-event` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-calendar-event.md
- `delete-contact-folder` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-contact-folder.md
- `delete-drive-item-permission` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-drive-item-permission.md
- `delete-excel-range` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-excel-range.md
- `delete-excel-table-row` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-excel-table-row.md
- `delete-focused-inbox-override` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-focused-inbox-override.md
- `delete-mail-attachment` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-mail-attachment.md
- `delete-mail-folder` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-mail-folder.md
- `delete-mail-message` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-mail-message.md
- `delete-mail-rule` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-mail-rule.md
- `delete-my-calendar-permission` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-my-calendar-permission.md
- `delete-onedrive-file` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-onedrive-file.md
- `delete-onenote-page` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-onenote-page.md
- `delete-outlook-contact` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-outlook-contact.md
- `delete-planner-bucket` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-planner-bucket.md
- `delete-planner-task-message` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-planner-task-message.md
- `delete-specific-calendar-event` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-specific-calendar-event.md
- `delete-subscription` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-subscription.md
- `delete-todo-linked-resource` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-todo-linked-resource.md
- `delete-todo-task` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-todo-task.md
- `delete-todo-task-list` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/delete-todo-task-list.md
- `graph-batch` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/graph-batch.md
- `logout` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/logout.md
- `remove-account` — Destructive — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/remove-account.md
- `parse-teams-url` — Execute — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/parse-teams-url.md
- `tentatively-accept-calendar-event` — Execute — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/tentatively-accept-calendar-event.md
- `dismiss-calendar-event-reminder` — Read — https://policylayer.com/tools/jo3zik-ms-365-mcp-server/dismiss-calendar-event-reminder.md
- …and 163 more: https://policylayer.com/tools/jo3zik-ms-365-mcp-server.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=jo3zik-ms-365-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/jo3zik-ms-365-mcp-server