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

With no annotations, the description must carry the behavioral disclosure burden. 'Page content is not stored' is a useful privacy guarantee, but the description does not disclose how the URL is fetched, whether redirects are followed, what happens with json or zone inputs, or any other side effects. The transparency is only partial.

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 two sentences with no fluff. The first sentence is action-oriented and front-loaded, and the second sentence adds a relevant privacy note. It earns its length, though it is arguably too short for the scope of the schema.

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?

For a tool with four parameters, no output schema, and no annotations, this description is incomplete. It does not explain how json and zone relate to the URL operation, what the return value looks like, or which combinations of parameters are valid. An agent would have to guess at the intended usage.

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 schema already documents all four parameters and provides a baseline of 3. The description adds context only for the URL parameter (host, scheme, HTTP status) and does not improve understanding of host, json, or zone beyond the schema.

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 states a concrete behavior: 'Return host, scheme, and HTTP status for a URL,' which is clear for a URL-checking tool. However, the schema also exposes host, json, and zone parameters, and the description does not explain how those fit, leaving the tool's overall purpose ambiguous despite the clear URL-focused sentence.

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 guidance on when to use this tool versus alternatives, nor any exclusions or prerequisites. The first sentence implies a URL-checking use case, but nothing says when to prefer citation over siblings like normalize-url, status, validate-json, or timezone, especially given the extra json and zone parameters.

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