fetch_html

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

With no annotations, the description carries the burden of behavioral disclosure. It does add useful behavior: the tool returns unmodified raw HTML and supports max_length/start_index for content limits. However, it does not disclose handling of HTTP errors, redirects, timeouts, encodings, or non-HTML responses.

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 structure is clean and front-loaded: one purpose sentence, an Args list, and a Returns line. Each parameter earns its place because the schema lacks descriptions. The Returns line is somewhat redundant with the opening sentence, which costs a point for conciseness.

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 simple read-only fetch tool with four parameters and no annotations, the definition covers the core behavior and every parameter meaning. Because an output schema exists, the return value needs less explanation. The main completeness gap is the lack of guidance on selecting this tool over the sibling fetch_* tools.

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 0%, but the description fully compensates by explaining all four parameters: the URL to fetch, optional headers, max character limit, and start index. Defaults are also restated clearly, giving the agent enough meaning to invoke the tool correctly.

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 first sentence states a specific action and result: 'Fetch a website and return its unmodified contents as HTML.' This clearly identifies the resource and output format, and the 'unmodified HTML' wording differentiates it from the siblings fetch_json, fetch_txt, and fetch_markdown.

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 when-to-use or when-not-to-use guidance is given, and none of the sibling tools are mentioned. The phrase 'return its unmodified contents as HTML' implies it should be chosen when raw HTML is needed, but the agent is left to infer this distinction.

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