crawl_single

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It transparently reveals the auto-degradation algorithm (fast extraction first, then browser rendering on failure, short content, or SPA detection) and clarifies parameter interactions (e.g., 'enhanced=True：只影响浏览器路径的等待时间'). However, it does not mention potential rate limits, timeouts, or error handling beyond the fallback behavior, so it falls slightly short of a perfect score.

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 well-structured: it begins with a concise summary line, then details the core use case, follow with alternative tool guidance, and ends with parameter combination explanations. While it is somewhat lengthy, every sentence contributes essential information, and the structure aids readability. It earns a 4 rather than 5 due to slight redundancy in the parameter combos section.

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?

Despite having no annotations, the description is remarkably complete for a tool with 5 parameters and an output schema. It covers the core behavior (auto-degradation), usage context, alternatives, and all parameter interplay. The presence of an output schema means return values don't need description, and the schema fully documents each parameter. There are no major knowledge gaps for an agent to invoke this tool correctly.

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?

Since schema description coverage is 100%, the baseline is 3. The description adds meaningful value by explaining parameter combinations and edge cases not explicitly in the schema, such as '如需强制浏览器增强模式，请同时设置 prefer_fast=False, enhanced=True' (to force browser enhanced mode, set both prefer_fast=False and enhanced=True). This enriches understanding beyond the 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 explicitly states the tool's function: '爬取单个网页' (crawl a single webpage) and '提取该页面正文 Markdown' (extract main content as Markdown), providing a specific verb, resource, and output format. It further differentiates from siblings by naming crawl_site and crawl_batch for alternative use cases, making the purpose 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 clearly specifies when to use this tool: '适用于已经知道一个明确 URL、需要提取该页面正文 Markdown 的场景' (for scenarios where you already know a specific URL and need to extract the page content as Markdown). It also provides explicit alternatives: '若要从一个入口页继续发现站内链接，请使用 crawl_site；若已有多个明确 URL，请使用 crawl_batch', with no ambiguity.

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