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 action is to 'move' emails, implying a mutation, but lacks details on permissions required, whether the operation is reversible, rate limits, or what happens if email IDs are invalid. This is a significant gap for a mutation tool with zero annotation coverage.

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 and front-loaded, with the main purpose stated first and parameter details in a separate section. Both sentences earn their place by conveying essential information without redundancy, though it could be slightly more structured for clarity.

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 (mutation with 1 parameter) and the presence of an output schema (which reduces the need to describe return values), the description is somewhat complete but has gaps. It covers the basic action and parameter semantics but lacks usage guidelines and behavioral details, making it adequate but not fully helpful.

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 0%, so the description must compensate. It adds meaning by specifying that 'email_ids' are 'JMAP email IDs to archive', clarifying the format and purpose beyond the schema's basic array of strings. However, it doesn't detail constraints like minimum list length or ID validity, leaving some gaps.

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 ('Move') and target ('one or more emails to the Archive mailbox'), making the purpose evident. However, it doesn't explicitly differentiate from sibling tools like 'mail_move_email' or 'mail_delete_email', which would require mentioning specific distinctions like archive vs. delete or general move operations.

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. It doesn't mention sibling tools like 'mail_move_email' for general moves or 'mail_delete_email' for deletion, nor does it specify prerequisites such as needing valid email IDs or access to the Archive mailbox.

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