fetch_url

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

No annotations are provided, so the description bears full burden for behavioral disclosure. It states the output (title and body) but does not disclose error handling, rate limits, rendering behavior, authentication needs, or what happens with invalid URLs. This is minimal transparency for a web fetching tool.

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 a single, front-loaded sentence with no extraneous content. Every word is essential, achieving maximum conciseness while conveying purpose and output.

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?

Given the tool's simplicity (1 parameter, no output schema), the description adequately covers its core function and return value. However, it could be more complete by briefly noting limitations or exceptions (e.g., 'if the page is not accessible, an error is returned'). Still, for a basic fetch tool, it is mostly sufficient.

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 100% (url parameter has a clear description). The tool description adds the overall purpose and output format, but does not provide additional semantic detail about the parameter beyond what the schema already says ('要提取内容的网页 URL'). Baseline 3 is appropriate as the description does not enhance parameter understanding further.

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 clearly states the verb '提取' (extract) and resource '单个网页内容' (single web page content), and specifies output '标题和正文' (title and body). It effectively distinguishes from siblings like batch_fetch_urls (which handles multiple URLs) and search_and_extract (which likely involves searching first).

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 explicit guidance on when to use this tool versus alternatives. While the description implies single-URL scope, it doesn't mention that batch operations should use batch_fetch_urls or that search scenarios should use search_and_extract. The agent is left to infer usage context.

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