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

With no annotations, the description carries the behavioral burden. It discloses the method, the public-scope requirement, and the status-only output, making the operation's read-only nature evident. It omits redirect/timeout/error details, but the core behavior is transparent.

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?

A single sentence with no filler, front-loading the verb, resource, and result. Every word earns its place.

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?

A one-sentence URL description is insufficient for a tool with nine optional parameters, no required parameters, no annotations, and no output schema. The agent cannot tell which parameter to use for non-URL inputs or what the status response looks like.

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 3. The description adds no parameter-specific guidance; with nine optional parameters and no required fields, the connection between 'public URL' and the other properties (ref, city, feed, json, path, query, timezone) is left entirely to 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 names a specific HTTP verb (HEAD), a resource type (public URL), and a narrow result (status only). This clearly distinguishes fetch-status from body-fetching siblings such as web-fetch and from browser-based URL checks.

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 word 'only' implies lightweight status checks rather than content retrieval, but the description never states when to use this tool versus web-fetch, browser-url-ok, or playwright-url-ok, nor does it give exclusions.

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