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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior, and the description adds substantial context beyond that: no cookies or credentials, bounded clean text, truncation flags, redirect hops, final URL, status, hashes, and safety metadata. It also discloses rejection behavior for private/local targets, with no contradiction to the annotations.

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 dense sentence that front-loads the action and key constraint before the long enumeration of return fields. It is compact relative to the amount of behavioral and return information it conveys, though the long list could have been more visually structured.

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?

With no output schema present, the description appropriately enumerates the return fields: text, title, meta description, canonical URL, headings, outbound links, final URL, redirect hops, status, byte count, truncation flags, hashes, retrieval time, and safety metadata. It also covers the main invocation constraints, making the tool complete enough for an agent to call correctly.

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?

The single url parameter is fully documented in the input schema with 100% coverage, including the public HTTP(S) requirement and rejection of credential-bearing URLs. The description restates this constraint but does not add new parameter-level meaning, so the schema already does the heavy lifting.

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 opens with a specific verb and resource: 'Fetch one public HTTP(S) URL'. The singular 'one' distinguishes it from the sibling fetch_urls, and the explicit scope constraint 'without cookies or credentials' makes the tool's purpose immediately clear.

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?

The description clearly defines when this tool applies: a single public HTTP(S) URL, with no cookies or credentials. It also states exclusions by rejecting private/local targets and credential-bearing URLs. However, it does not explicitly name or contrast sibling tools such as fetch_urls or route_web_request, so it stops short of full alternative guidance.

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