pyfastmail-mcp

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool deletes files/folders, implying a destructive operation, but does not mention critical details like whether deletion is permanent or reversible, authentication requirements, rate limits, or error handling. This leaves significant gaps for a mutation 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 appropriately sized with two sentences: one stating the purpose and one explaining the parameter. It is front-loaded with the core action and wastes no words, though the structure could be slightly improved by integrating the parameter explanation more seamlessly.

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 1 parameter), lack of annotations, and presence of an output schema (which reduces need to explain return values), the description is minimally adequate. It covers the basic purpose and parameter but lacks details on behavior, usage context, and safety considerations, leaving room for improvement.

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 description includes an 'Args' section that explains the 'path' parameter with an example ('/Documents/old.txt'), adding meaning beyond the schema, which has 0% description coverage. However, it only covers the single parameter without detailing format constraints or edge cases, providing marginal compensation for the schema gap.

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 clearly states the action ('Delete') and resource ('a file or folder on Fastmail Files (WebDAV)'), making the purpose explicit. However, it does not distinguish this tool from other deletion tools like 'calendar_delete_event' or 'contacts_delete_contact', which are siblings in the same server context, so it misses full differentiation.

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 no guidance on when to use this tool versus alternatives, such as other deletion tools in the sibling list (e.g., 'files_move' for relocation instead of deletion) or prerequisites like permissions. It lacks explicit when/when-not statements or named alternatives, offering only basic usage context.

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