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

Annotations already declare readOnly, openWorld, idempotent and non-destructive, so safety is covered without the description. The description adds the markdown output form, which is genuinely useful, but stays silent on notable behavior implied by defaults: a large `maxAge` cache window, `maxChars` truncation, and `waitFor` rendering delay.

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, no filler, with the core capability front-loaded ahead of the routing hint. Every sentence earns 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?

An output schema exists, so return values need no explanation, but the tool exposes six parameters with zero documented semantics and undisclosed caching/truncation behavior. For a 6-param tool with 0% schema coverage, the description should do substantially more than it does.

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% across 6 parameters, so the description carries the full burden and largely fails it. Only the `url` parameter is addressed implicitly ('a specific URL'); `maxAge`, `formats`, `waitFor`, `maxChars` and `onlyMainContent` are given no meaning at all, despite defaults that materially change output.

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 gives a specific verb and resource ('Fetch a single web page') plus the output form ('clean markdown'), which is more than a name restatement. It differentiates from the page-discovery tools, but does not draw any boundary against the closer sibling `parse`, leaving that distinction to inference.

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?

It states a clear trigger ('when you have a specific URL and need to read what is on it') and names an alternative path ('use `search` or `map`') for the discovery case. One named alternative (`map`) is not in the sibling list, and no when-not condition against `parse` is offered, so it falls short of a full routing spec.

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