folder_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. It discloses that the tool returns live data and lists the fields. It does not mention destructive actions or rate limits, but given the tool's simple read-only nature, the disclosure is adequate.

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 sentences, no wasted words. The key information is front-loaded: purpose and return values are stated upfront.

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?

The description fully explains what the tool returns (message count, unseen count, uidNext, uidValidity) and its parameters. For a simple health-check tool with no output schema, this is complete and actionable.

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 coverage is 100% and both parameters have descriptions. The description adds context by explaining that scanLimit controls speed vs accuracy and that folder defaults to INBOX, going beyond the schema.

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 live message count, unseen count, uidNext, and uidValidity for a mailbox folder. It specifies the purpose 'for health checks and to monitor unread counts without fetching messages,' which differentiates it from tools that retrieve full 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 recommends using this tool for health checks and monitoring unread counts without fetching messages. While it does not name specific sibling tools as alternatives, it provides clear guidance on when to use it versus fetching messages.

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