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

With no annotations, the description carries the full burden. It discloses that only status/content type are returned and the body is discarded, but it omits behavior around redirects, errors, timeouts, and whether any request side effects occur.

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 main description is a concise one-liner, but the tool definition is bloated with nine optional parameters, most of which are irrelevant to the stated purpose. The overall structure lacks focus and includes many unnecessary 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?

For a tool with nine parameters and no output schema, the description is severely incomplete. It does not explain which parameters are meaningful, what the response format looks like, or how the caller should construct a valid request.

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 parameter descriptions are incoherent for a web-fetch tool: ref, city, feed, json, path, zone, and query appear unrelated to fetching a URL, and even the 'url' description mentions normalization/citation rather than fetching. Schema coverage is 100%, but the descriptions actively mislead.

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 the tool returns HTTP status and content type for a public URL and explicitly says the body is discarded. This distinguishes it from full-page fetchers, though it does not use an explicit verb like 'fetch'.

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 guidance is provided about when to use this tool instead of siblings like fetch-status, browser-url-ok, or normalize-url. The description gives the basic purpose but no selection criteria or alternative exclusions.

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