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

Beyond the read-only/idempotent annotations, the description discloses that the tool is 'deterministic', does not execute JavaScript, does not bypass access controls, and uses caching controlled by the 'fresh' parameter. These are valuable behavioral traits that inform the agent's expectations and usage, exceeding the basic annotation coverage.

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 three sentences, front-loaded with the core purpose, followed by limitations and parameter guidance. Every sentence adds value without redundancy or unnecessary detail, achieving excellent conciseness and logical structure.

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 two simple parameters, full schema coverage, and an output schema, the description covers the essential context: purpose, usage constraints, behavioral caveats, and parameter usage. It is complete enough for an agent to select and call the tool correctly without needing additional information.

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 input schema already fully describes both parameters ('url' with format, length, and SSRF rejection; 'fresh' with default and explanation). The description largely restates these details ('Pass url as an absolute public HTTP(S) URL' and 'Keep fresh=false...'), adding no new semantic meaning beyond what the schema provides.

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 explicitly states the tool 'Return deterministic thin-content and page-structure quality signals', clearly identifying the specific resource and output. This distinguishes it from sibling tools like web.url.extract or web.url.text, which focus on content extraction rather than quality analysis.

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 gives clear usage context: 'Use only for public HTTP(S) resources' and 'does not execute JavaScript or bypass access controls', which helps the agent know when not to use it. It also provides guidance on the 'fresh' parameter (set false for cache reuse, true only for new fetch). However, it does not explicitly name alternative tools for JavaScript-dependent or restricted resources, so it falls short of a 5.

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