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

With no annotations, the description fully carries the burden, and it delivers. It discloses credit costs per URL, the 10-URL limit, that failed URLs are not charged, the behavior of include_raw_html, and the exact return shape including success and error fields.

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 and front-loaded: purpose, then costs/limits, then optional behavior, then returns and args. Every sentence provides operational value without filler.

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 two-parameter tool with no output schema, the description covers everything needed to invoke it correctly: required URLs, max count, cost, raw_html semantics, and the complete return object. No important gap remains for a straightforward fetch operation.

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%, so the description must compensate. It adds meaningful semantics for include_raw_html (inspection use cases, null for non-HTML, same cost) and failure charging. The urls argument is still thin, with no mention of URL format, absolute vs relative URLs, or per-item failure behavior beyond cost.

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 action ('Fetch one or more URLs and return their content as clean markdown') and clarifies it is for complete text rather than a search snippet. However, it explicitly distinguishes from the search sibling but not from extract or research, so sibling differentiation is incomplete.

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?

Gives explicit guidance: 'Use this to read articles, documentation, blog posts, or any page where you need the complete text.' The 'not just a snippet from search' phrase implies when search might be preferred, but it does not tell an agent when to choose extract or research instead.

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