update-mail-message
Update an existing Outlook email message by its message ID — for example mark it read or unread (isRead), flag it (flag), change its categories, importance, or edit a draft's subject, body, or recipients.
This record as markdown: /tools/jo3zik-ms-365-mcp-server/update-mail-message.md
What update-mail-message does on Ms 365
AI agents use update-mail-message 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.
| Parameter | Type | Required | Description |
|---|---|---|---|
body | object | Yes | |
confirm | boolean | — | 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 | — | Include response headers (including ETag) in the response metadata |
excludeResponse | boolean | — | Exclude the full response body and only return success or failure indication |
Parameters from the server's own tool schema.
Why update-mail-message is rated Medium
An AI agent can call update-mail-message 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 signalsAccepts raw HTML/template content (body) · High parameter count (66 properties)
Attacks that exploit this kind of access
The rule that runs update-mail-message safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Ms 365, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For update-mail-message, this is the rule to start with:
update-mail-message stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Ms 365, apply this rule, and every update-mail-message call is checked against it from then on.
Questions about update-mail-message
Update an existing Outlook email message by its message ID — for example mark it read or unread (isRead), flag it (flag), change its categories, importance, or edit a draft's subject, body, or recipients. It is categorised as a Write tool in the Ms 365 MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
update-mail-message accepts 5 parameters: body, confirm, messageId, includeHeaders, excludeResponse. Required: body, messageId. The full parameter table on this page comes from the server's own tool schema.
Register the Ms 365 MCP server in PolicyLayer and add a rule for update-mail-message: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Ms 365. Nothing to install.
update-mail-message is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the update-mail-message rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for update-mail-message. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
update-mail-message is provided by the Ms 365 MCP server (@jo3zik/ms-365-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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