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

Annotations already declare readOnlyHint=true and destructiveHint=false, making it clear this is a safe read operation. The description adds that it returns 'clean markdown', which is a useful output trait, but doesn't elaborate on rate limits, network failures, or handling of dynamic content. Given annotations cover safety, the description adds minimal but non-zero behavioral context, warranting a 3.

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 extremely concise—two sentences with zero fluff. It front-loads the primary purpose and output, then provides usage guidance. Every word earns its place. It's not under-specified because it covers the core behavior and usage.

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?

While the description clarifies the main use case and output, it fails to explain the four optional parameters that have defaults (maxAge, waitFor, maxChars, onlyMainContent). Given the output schema exists (though not detailed here), return values are covered, but the agent may not know how to fine-tune parameters like waitFor or onlyMainContent. For a tool with six parameters, the description is too thin on optional behavior, so a 3 is appropriate.

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 for undocumented parameters. The description does not explain any of the six parameters (url, maxAge, formats, waitFor, maxChars, onlyMainContent), leaving the agent to rely on names and defaults. However, the description clarifies the core purpose and output format, which indirectly informs that 'url' is the target and 'formats' might control output types. Yet, depth is lacking—for example, 'maxChars' and 'onlyMainContent' have no explanation. Since coverage is 0%, the description should have provided some parameter guidance; its silence is a significant gap. Score 2 would be more fitting than 5, but given the tool's simplicity and that 'url' is the only required param, 4 may be too generous. I'll adjust to 3.

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 ('Fetch') and resource ('a single web page'), explicitly names the output ('clean markdown'), and distinguishes itself from siblings by noting it's for when you have a specific URL, versus 'search' or 'map' for finding pages first. This fully differentiates from the sibling list.

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?

Explicitly says 'Use this when you have a specific URL and need to read what is on it. For finding pages first, use 'search' or 'map'.' This provides both a clear when-to-use condition and names the alternatives for the opposite case. No ambiguity.

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