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

Annotations already cover safety (readOnly, idempotent, openWorld, non-destructive), yet the description adds substantial operational context beyond them: no JS execution, a 10-second wall-clock budget, a 2 MB HTML ceiling, and a port restriction. It also pre-declares the response shape, including final URL and text length. This is exactly the value-add the dimension rewards.

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?

Three sentences, front-loaded with the purpose, then returns, then constraints. Every sentence carries distinct information with no filler or restatement of the tool name.

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?

There is no output schema, but the description enumerates the return fields, so an agent can anticipate the response. The one gap is that it never explains what separates 'suspect' from 'broken', which matters for interpreting the verdict; otherwise nothing needed for correct invocation is missing.

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?

With one parameter at 100% schema coverage, the structural baseline is 3. The description adds meaning the schema does not: the URL must be public, must be http/https, and is effectively limited to ports 80/443, which constrains what values will actually succeed.

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?

States a specific verb and resource: 'Check whether one public HTML page shows content,' and immediately names the concrete output vocabulary (working, suspect, broken). This is clearly distinguishable from conversion-oriented siblings like page_to_markdown, which do not return a health verdict.

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?

Provides real selection conditions through exclusions: 'No JavaScript rendering; 10 seconds overall, 2 MB HTML. Public HTTP/HTTPS ports 80/443 only.' An agent knows this tool is unsuitable for JS-rendered pages, slow hosts, or non-standard ports. It does not name an alternative tool for those cases, so it stops 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.