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

With no annotations, the description carries the full burden, but it does add useful traits: the board is public (implying no authorization needed), messages are returned most-recent-first, and there is a hard cap of 200. It says nothing about pagination, ordering guarantees, or what happens above/below the range, which a read tool with zero annotations should ideally cover.

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?

A single front-loaded sentence with no filler; the count constraint is embedded where it is useful. Nothing to trim.

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 tool is simple (one optional scalar parameter) and an output schema exists, so return values need no explanation. Scope, ordering, and range are covered; only pagination/auth behavior is unstated, which is a minor gap at this complexity level.

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 0% and the schema only shows a default of 20 with no bounds, so the description's '1-200 条' is the only source of the valid range for limit — genuine value beyond the schema. It does not restate the default, but 'limit' is self-describing.

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?

States a specific verb (读取) and resource (公开留言板上最近的消息) with a bounded scope (1-200 条). It is functionally distinguishable from post_message (write) and visitor_stats (aggregate), though it never names those siblings explicitly.

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?

No when-to-use or when-not-to-use guidance. The agent must infer that this is the read path versus post_message from the verb alone; nothing states prerequisites or alternative tools.

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