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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description does add real behavioral context — that scripts, styles and tags are stripped and only body text is returned — which is beyond the annotations. However, nothing is said about timeouts, redirects, failure modes, or JS-rendered content, so the picture remains partial.

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 short sentences, front-loaded with the action and transformation. The example sentence is redundant with the schema's examples block, so it does not fully earn its place.

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 two-parameter read-only fetch tool with full schema coverage and annotations carrying the safety profile, the description covers what the tool does and what it returns (plain body text). Only edge-case behavior (failures, dynamic pages) is missing, which is a minor gap at this complexity.

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%, with both url and max_chars (including default 3000 and 上限 10000) fully documented in the schema. The description's only added nuance is that max_chars limits the extracted 正文, which is a marginal gain. The inline example duplicates the schema's own examples array verbatim, adding nothing.

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+resource (抓取指定 URL 网页) and, crucially, the transformation applied (提取正文纯文本，去脚本/样式/标签). No sibling overlaps this capability, so an agent can select it without ambiguity.

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?

Usage is only implied by the name and verb; there is no statement of when to prefer this over other approaches, no prerequisites, and no exclusions (e.g., pages requiring JavaScript rendering, non-HTML content, authentication). Adequate for a simple utility but leaves the agent to infer boundaries.

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