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

The description adds only "Page content is not stored," which is a useful non-retention guarantee. With no annotations, the description carries the full burden, but it does not disclose that the tool likely performs a network fetch, what error/status behavior to expect, or how the json and zone inputs behave beyond their schema descriptions. This is a significant transparency gap for a tool with four unrelated optional inputs.

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 with the primary action and output front-loaded, and no filler words. The brevity is efficient, though it partly contributes to the description's incompleteness regarding the other schema fields.

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?

The tool has four optional parameters, no output schema, no annotations, and overlapping siblings (e.g., normalize-url, validate-json, timezone-clock), yet the description references only the URL behavior. The mismatch between the URL-only description and the json/zone schema fields leaves an agent unable to reliably select or invoke the tool 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?

Schema description coverage is 100%, so the baseline is met without needing the tool description to document each parameter. The description adds some meaning to the url parameter by mapping it to host/scheme/status output, but it adds nothing to host, json, or zone, and it does not clarify whether parameters are alternatives, combinable, or mutually exclusive.

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 and resource: "Return host, scheme, and HTTP status for a URL." This clearly distinguishes it from siblings like normalize-url (which returns a normalized URL rather than status) and validate-json (which validates JSON). However, the input schema also exposes json and zone parameters that the description never mentions, so the overall purpose is somewhat ambiguous beyond the URL behavior.

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?

No when-to-use guidance, no exclusions, and no reference to alternatives such as normalize-url or validate-json. With 0 required parameters and four heterogeneous optional fields (url, host, json, zone), the agent cannot determine which invocation mode is appropriate or when to prefer this tool over its siblings.

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