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 adds one meaningful guarantee: 'Page content is not stored.' However, it does not disclose whether the URL is fetched server-side, what happens on failure, whether external requests are made, or how the unrelated params behave in terms of side effects.

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 short and front-loaded, stating the primary action in the first sentence. Every sentence earns its place, though the brevity leaves significant gaps in coverage.

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?

This is a nine-parameter tool with no output schema, yet the description only addresses URL-derived output. It does not explain what result the caller should expect for ref, city, feed, host, json, or path inputs, nor does it offer examples or error semantics. For an agent to invoke this tool with confidence across its declared parameters, substantially more context is needed.

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 input schema already provides descriptions for all nine parameters, so high schema coverage sets a baseline of 3. The description adds context for the url param (return host, scheme, and HTTP status) but adds no meaning for the other eight params, which remain disconnected from the stated purpose.

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 names a specific action and output ('Return host, scheme, and HTTP status for a URL'), which is clear for a URL-related subset of the tool. However, the input schema lists nine params including city, feed, json, ref, and path that the description never connects to, so the tool's overall purpose is ambiguous. It also does not distinguish itself from siblings like fetch-status or domain-shape.

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?

There is no explicit guidance about when to use this tool versus siblings such as fetch-status, normalize-url, or web-fetch. The phrase 'Page content is not stored' implies a safe/privacy-conscious choice, but it does not state when this tool should be preferred or avoided.

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