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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context: 'No login required' (an auth prerequisite the agent couldn't otherwise know) and the concrete return shape. It doesn't mention rate limits, caching, or what an empty result means for an unreachable site.

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 capability and followed by return shape then usage triggers; each sentence carries distinct information. The vendor example lists ('WordPress, Shopify, Drupal, etc.') add mild bulk but are functional for intent matching.

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?

No output schema exists, and the description compensates fully by spelling out the returned object ({ domain, cms, cdn, server, framework, metaGenerator, analytics[] }). Combined with the auth note, an agent has everything needed to call this correctly on the first attempt.

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?

There is a single parameter with 100% schema description coverage, and the schema already provides the format example ('example.com'). The description adds no detail on domain normalization, subdomains, or URL-vs-domain input, so it does not exceed the baseline the schema already earns.

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 (detect) and resource (technologies of a website) and then enumerates exactly what it covers: CMS, CDN, web server, frontend framework, analytics, with concrete vendor examples. An agent can distinguish this from lookup_whois or check_ssl purely from the description.

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 four explicit user-intent triggers ('what platform a site runs on', 'what CMS a competitor uses', 'what CDN a site is behind', 'what stack powers a website'), which is strong positive routing. It stops short of naming a sibling like detect_web_host or lookup_ip_hosting to say when this tool is the wrong choice, so no exclusions are specified.

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