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

注解已声明 readOnlyHint 为 true，描述无需重复只读性质；描述额外提供了“自动识别”“分享文案/短链接支持”等行为特征，超越了注解本身。描述与注解无矛盾。

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?

描述为一句紧凑的句子，目的和支持格式前置，没有空话、套话或对工具名的机械重复。每个分句都提供了有效信息。

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?

该工具只有一个参数，输入 schema 完整，且具备 readOnly/openWorld 注解和输出 schema，说明已覆盖正确调用所需的核心信息。缺少对 by_id 兄弟工具的显式引导，但工具名和参数描述已足以消除歧义。

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?

输入 schema 对 url 参数的覆盖率为 100%，已详细说明合法输入类型以及禁止传入用户主页、BV 号、aid 和纯数字 ID。工具描述中的链接类型列表基本是 schema 的重复，未带来额外参数语义。

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?

描述以具体动作“自动识别并读取”和明确资源“视频详情、专栏详情或动态详情”开头，并列出了接受的链接/分享文案形式。这与按 ID、评论、点赞和用户信息等兄弟工具清楚区分开来。

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?

描述给出了明确的使用情境：当拿到 Bilibili 链接、短链接或分享文案并需要内容详情时使用。但未显式点名替代工具（如 ID 类工具 bilibili_get_content_detail_by_id），因此虽清晰但未达 5 分。

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