Get mailbox counts

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

Annotations already declare readOnlyHint=true, openWorldHint=true, and idempotentHint=true, which fully disclose the safe, read-only, and idempotent nature. The description adds that it is 'fast' but does not provide additional behavioral context such as error handling for nonexistent mailboxes or rate limits.

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 extremely concise with two sentences, no wasted words, and the most important verb ('Returns') appears first. Every sentence adds unique value: what it does and a typical use case.

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 low complexity (0 required parameters, output schema exists), the description fully covers what the tool returns (total, unseen, recent counts) and its intended use. No critical information is missing.

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% for the single 'mailbox' parameter, which is already adequately described with an example. The tool description does not add any new meaning beyond the schema's own description, so baseline score of 3 applies.

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 it returns 'total messages, unseen/unread count and recent count for a mailbox,' which is a specific verb+resource combination. It distinguishes itself from sibling tools like proton_list_emails by focusing on aggregate counts rather than listing individual messages.

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 explicitly suggests using this tool for routines to check unread mail, providing clear context for when to use it. However, it does not explicitly mention when not to use it or compare to alternatives like proton_list_emails for detailed views.

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