Microsoft 365 MCP Server

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

Annotations provide readOnlyHint=false, destructiveHint=true, and openWorldHint=true, indicating a destructive write operation. The description adds value by specifying 'Delete' action, aligning with annotations. However, it lacks details on side effects (e.g., permanent deletion, no undo), authentication needs, or rate limits, which would enhance transparency for a destructive tool.

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?

The description is a single, concise sentence that directly states the action. It's front-loaded with the verb 'Delete', making the purpose immediately clear. However, the phrase 'navigation property' adds unnecessary jargon without explanation, slightly reducing efficiency.

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?

Given the tool's complexity (destructive operation with 5 parameters) and rich annotations, the description is minimally adequate. It states the action but lacks details on output (no schema provided), error handling, or behavioral nuances. For a destructive tool, more context on consequences would improve completeness.

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 description coverage is 100%, with clear parameter documentation (e.g., messageId, attachmentId as path parameters). The description adds no additional parameter semantics beyond the schema, such as format examples or constraints. With high schema coverage, the baseline score of 3 is appropriate as the description doesn't compensate but doesn't detract.

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 'Delete navigation property attachments for me' uses a specific verb ('Delete') and resource ('attachments'), but the phrase 'navigation property' is vague and technical without clear meaning. It doesn't explicitly distinguish from sibling tools like 'delete-mail-message' or 'delete-onedrive-file', leaving ambiguity about what exactly is being deleted.

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?

No guidance is provided on when to use this tool versus alternatives. The description doesn't mention prerequisites (e.g., needing a messageId and attachmentId), exclusions, or comparisons to siblings like 'delete-mail-message' or 'get-mail-attachment'. Usage context is implied but not stated.

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