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

With no annotations, the description carries the full burden of explaining behavior. It transparently lists what is returned and explicitly states that page content is not fetched and no payment is made. However, it does not mention potential side effects, errors, or network behavior, so a small gap remains.

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 concise sentence that packs the action, output list, and constraints without unnecessary words. It is well-structured and immediately comprehensible.

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?

Given there is no output schema, the description usefully enumerates the returned fields (fetchability, size, final URL, title, content hash). It omits details about error conditions or status codes, but for a simple preflight tool the listed information is reasonably complete.

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 only parameter, 'url', has no schema description, but the tool description clarifies that it must be a 'public URL'. This provides the essential meaning and constraint for the parameter, though it lacks additional details like expected URL formats or examples.

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 clearly specifies the action ('Fetch a public URL') and the exact outputs returned (fetchability, size, final URL, title, content hash). It also states constraints ('without page content or payment'), making the tool's purpose unambiguous and distinct from typical fetch or monitoring tools.

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 does not explicitly state when to use this tool versus the sibling tools like check_now, create_monitor, or offer. It implies preflight usage by listing fetchability and excluding payment, but it lacks direct guidance on the appropriate context or relative ordering.

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