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

No annotations are provided, so the description carries the burden, and it discloses meaningful limits: 'Best-effort — not exhaustive, no additional paths are probed.' It also reveals the detection method (headers plus HTML markers), which sets expectations about false negatives. It stops short of stating auth/cost/rate behavior or the exact return shape.

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?

Front-loaded with the action and detection method, then routing guidance, then the limitation clause. Every clause carries distinct information with no repetition or filler.

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?

With no output schema and no annotations, the description still covers method, purpose, alternatives, and the best-effort limitation. It does not spell out the returned structure or depth of evidence per detection, a minor gap for a single-param tool.

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?

Only one parameter with 100% schema description coverage, so the schema already documents 'url' fully. The description implies the fetch target but adds no format, protocol, or validation detail beyond the schema. Baseline 3 applies.

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?

Specific verb+resource ('fetch a URL and fingerprint its likely tech stack') with concrete evidence sources (response headers, HTML markers) and a plain-language restatement ('what is this site built with?'). It explicitly names siblings seo_audit and structured_data_extract, so an agent can distinguish it without opening any schema.

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?

Gives explicit routing: on-page SEO/content signals go to seo_audit, raw structured data goes to structured_data_extract. The 'what is this site built with?' framing and the best-effort/no-extra-paths caveat further bracket when this tool is the right choice.

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