mail_search_messages

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

Annotations already indicate readOnlyHint and idempotentHint. The description adds behavioral context beyond annotations: optional filters, pagination details. No contradiction, but could mention null results or error handling.

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?

Two concise sentences, well-structured with no wasted words. Front-loads the core purpose and key behavioral details.

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?

Despite no output schema, the description lacks completeness: no info on return format, ordering, error handling, or how filters combine. For a search tool with 8 parameters, this is insufficient.

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%. The description mentions some parameters (read status, flagged status, subject/sender substring, limit) but not all 8, notably missing required parameters (accountName, mailboxPath) and offset. Insufficient compensation for schema lack.

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 verb (search/list), resource (messages in a mailbox), and specific filters (read status, flagged status, subject/sender substring). It differentiates from sibling tools like mail_get_message or mail_list_mailboxes.

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 mentions pagination behavior (default limit 50, max 500) which is a usage guideline, but does not explicitly state when to use this tool versus alternatives or any exclusions. The guidance is implicit rather than explicit.

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