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

Even though annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, the description adds substantial behavioral detail: it reads from sitemap.xml or falls back to homepage links, reports counts and the pages actually read, and explicitly states it never returns a score. This goes well beyond annotation metadata.

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 compact and front-loaded: it opens with the core operation and output, then gives a brief rationale, return-value semantics, and a clear usage trigger. Every sentence earns its place; there is no filler or repetition of schema details.

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 two-parameter tool with no output schema, the description fully equips an agent to select and invoke it: it explains how pages are discovered, what counts as consistency, what is returned, and when to prefer this tool. No critical operational context 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?

Schema description coverage is 100%, so the schema already documents the url and pages parameters completely. The description reinforces that pages are a sample and ties url to site-wide discovery, but does not add new parameter-level 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 states a specific, observable behavior: read a sampled set of pages from a single site and report which design tokens, colors, fonts, radii, and spacing values are consistent across them. It explicitly contrasts this with single-page analysis ('One page shows what a page uses'), clearly distinguishing it from decode_url and other sibling tools.

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 provides an explicit when-to-use statement: 'Use when the user asks whether a site is really on a system, or wants the system rather than one page of it.' It implies when not to use it (single-page questions) but does not name decode_url or other alternatives explicitly, so it stops just short of full exclusion guidance.

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