Delete Outlook messages by ID or up to 50 IDs; by default moves them to Deleted Items for recovery, or set permanent to true for irreversible deletion.
Delete a message. By default moves it to Deleted Items (recoverable). With permanent: true it is deleted irreversibly. 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 | |
| permanent | No |
Changes observed during successful MCP inspections.
v1.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations supplied, the description carries the full burden and does well on the critical trait: it discloses that default deletion is recoverable (moves to Deleted Items) and that 'permanent: true' is irreversible. It omits other behavioral facts an agent would want — return value, behavior when an id is not found, and partial-failure semantics for batches.
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?
Three short sentences with zero filler, front-loading the action, then the default behavior, then the destructive variant, then the parameter shape. Nothing to cut and the most dangerous detail is not buried.
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?
For a 3-parameter destructive tool with no annotations and no output schema, the description covers the essentials: what it does, the safe default, and the irreversible mode. It does not state what the call returns (e.g., count deleted) or whether auth/folder permissions are required, which leaves a modest gap.
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 gap is the undocumented 'permanent' boolean, which the description explains in terms of consequence (recoverable vs. irreversible) — genuine value beyond the schema. The id/ids mutual-exclusivity note largely repeats the schema's own descriptions, and the 50-item cap is already encoded as maxItems.
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?
States a specific verb and resource ('Delete a message') with the scope ('Accepts id or ids (up to 50)'). It does not explicitly name the nearest sibling it is not (move_message, bulk_action), so an agent must infer the boundary, but the purpose itself is unmistakable.
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?
Gives clear conditional guidance for the most consequential decision: default behavior vs. 'permanent: true'. It stops short of saying when to prefer this over siblings like move_message or bulk_action, or what to do if the id is unknown.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.