get_mailbox_stats

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 disclosing behavioral traits. It does not specify whether the tool is read-only, if it requires authentication, or what happens with invalid mailbox IDs. While it mentions the scope (one or all mailboxes), other critical behavioral details are missing.

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 short sentences, all front-loaded with the main purpose. Every sentence adds value, and there is no redundancy or wasted text. The structure is efficient and clear.

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 (1 parameter, no nested objects) and the presence of an output schema, the description provides sufficient context for invocation. It explains the main behavior and parameter semantics. However, it does not detail what the 'email count statistics' include (e.g., total, unread), which could be inferred from the output schema but is not explicitly stated.

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 input schema has 0% coverage (no descriptions), so the description must explain the parameter. It does so effectively: 'mailbox_id: Specific mailbox ID (empty for all mailboxes).' This adds clear meaning beyond the schema, specifying valid values and behavior, which compensates for the lack of schema descriptions.

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 tool's function: 'Get email count statistics for one or all mailboxes.' It uses a specific verb ('Get') and resource ('email count statistics' for mailboxes), which distinguishes it from sibling tools like list_mailboxes or get_emails. The purpose is immediately understandable.

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 implies usage for obtaining email counts but does not explicitly state when to use this tool versus alternatives, nor does it provide conditions or exclusions. No guidance is given on when not to use it or what other tools cover different use cases, leaving ambiguity for the agent.

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