Marks Outlook messages as read or unread using a single message ID or up to 50 IDs, so MCP clients can update mailbox status individually or in bulk.
Mark a message as read or unread. Accepts id or ids (up to 50).
| Name | Required | Description | Default |
|---|---|---|---|
| id | No | A single message id | |
| ids | No | Several message ids (up to 50); give either id or ids, not both | |
| isRead | Yes |
Changes observed during successful MCP inspections.
v1.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full burden, yet it discloses nothing about whether the call requires authentication, whether it is idempotent, what happens when an id is already in the requested state, or what the response contains. For a mutation tool with zero annotation coverage, this leaves the behavior opaque.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short sentences with the action front-loaded and the batch limit second; nothing is wasted, though the second sentence largely duplicates structured schema constraints.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The core action is covered, but a mutation tool with no annotations, no output schema, and only 67% parameter coverage should say more about permissions, on-success behavior, and the read/unread semantics of isRead. It is minimally adequate rather than complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 67% and the description merely restates the id/ids alternative and the 50-item cap already encoded in maxItems. It adds no meaning for isRead, such as whether true marks as read and false reverts to unread, which is the key field the agent must set correctly.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names a specific verb and resource ("Mark a message") plus the two target states (read/unread), so an agent knows exactly what it does. It does not distinguish it from the nearby sibling flag_message, which is the one remaining ambiguity.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no when-to-use guidance, no prerequisites, and no mention of alternatives such as flag_message. The only usage-adjacent content is the batch cap, which the caller must infer is for bulk cleanup rather than search-driven flows.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.