Delete a message

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the destructiveHint annotation, the description discloses critical behavioral details: the operation is a soft delete, the message is recoverable in Outlook, no server-side undo exists, and deleting from Deleted Items is permanent. This gives the agent the full side-effect picture needed to decide safely.

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, each carrying essential information: the action, the soft-delete behavior and recoverability, the lack of server-side undo with a confirmation instruction, and the permanent-deletion edge case. No filler or repetition; the most important warning is front-loaded.

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 destructive single-id operation with one documented parameter and no output schema, the description covers the key contextual needs: what happens, what the user can do to recover, what the server cannot do, and when deletion becomes permanent. The agent has enough information to invoke the tool responsibly.

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?

The schema already documents the single required id parameter with full coverage and a clear description ('Id of the message to delete'). The tool description adds no additional parameter-level semantics, so the baseline of 3 is appropriate.

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 opens with 'Deletes a message,' a specific verb and resource that clearly identifies the operation. It further clarifies the exact behavior (soft delete moving the message to Deleted Items), which distinguishes this from sibling tools like mail_move_message or mail_mark_read. The purpose is unambiguous and immediately actionable.

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?

The description provides clear practical guidance: confirm with the user first, since the server has no undo tool, and warns that deleting a message already in Deleted Items is permanent. This establishes when caution is required, though it does not explicitly compare to alternatives like mail_move_message or state when not to use this tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.