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

With no annotations, the description must disclose behavioral traits. It states 'Body discarded,' which conveys a key behavior (only status is returned). However, it omits error handling, authentication needs, or any side effects. The description gives minimal transparency but not a complete profile for an unannotated tool.

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?

One sentence, no fluff, and the core action is front-loaded. It is concise and to the point, but the brevity comes at the cost of completeness.

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 9 optional parameters, no output schema, and no annotations. The description only covers a narrow use case (library docs URL) while ignoring the rest of the schema. An agent has no way to understand what the tool actually does with the other parameters or when to use them. This is a severe gap for a tool of this complexity.

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 coverage is 100%, so parameter descriptions exist, but the tool description ignores them entirely. The description mentions only a 'URL' yet the schema has 9 parameters (city, feed, json, zone, query, etc.) that seem unrelated to 'public library docs URL.' This mismatch provides no help in selecting or using the right parameter for a given task, and may actively mislead an agent into thinking only URL is relevant.

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 specific action (HTTP status) and a resource (public library docs URL). It distinguishes by resource type, but does not differentiate from siblings like fetch-status or web-fetch. The verb-object pair is clear enough for an agent to grasp the core intent, though not uniquely distinguishing.

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 on when to use this tool over alternatives. Sibling tools include fetch-status, normalize-url, browser-url-ok, etc., and the description provides no exclusions or conditions. An agent cannot infer which tool to invoke for a given URL without additional reasoning.

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