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

The annotations already declare readOnlyHint=true, so the description carries a lower burden. It adds useful context by specifying that only public post details are fetched ('公开帖子详情'). It does not discuss auth, rate limits, or error behaviors, but for a read-only getter this is a modest but acceptable amount of added context.

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 one compact, front-loaded sentence: it states the core operation first, then gives the priority usage rule and the key constraint. There is no filler or unnecessary repetition of schema 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?

For a single-parameter, read-only detail tool with rich schema coverage, an output schema, and safety annotations, the description is complete enough. It communicates the identifier source, the public scope, and the 'use by ID, not link' rule, while the input schema fills in the remaining parameter details.

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%, and the schema's parameter description is already very detailed: it requires a numeric string, lists valid sources for copying post_id, and forbids links, usernames, and share text. The tool description adds essentially no new parameter semantics, so the baseline score of 3 is appropriate.

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 states a clear verb and resource: '获取公开帖子详情' (get public post detail) by post ID. It also distinguishes itself from x_get_post_detail_by_post_url by explicitly saying not to pass a post link, so the tool's role among siblings is unambiguous.

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 says to use this tool when post_id is already known ('已知 post_id 时优先使用') and forbids passing a post link. However, it does not name the URL-based alternative x_get_post_detail_by_post_url directly, so the routing guidance stops just short of fully explicit.

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