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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing the cost model ($0.005 per result after 5 free calls a day), that blocked or empty sites are free, and that email/SPF/DMARC come from DNS rather than page scraping. These are decision-relevant facts an agent cannot get from structured fields.

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?

Two tight sentences: the first front-loads what is returned, the second handles cost and sibling routing. No filler, no repetition of the title, and the ordering puts the payload description before the caveats.

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?

Output schema exists, so return values need not be explained; coverage of categories in the description plus pricing and the no-result-free policy covers what an agent needs to call it responsibly. Nothing material is missing for a read-only, single-required-param lookup.

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 coverage is 100%, so the domain format constraint ('without a URL scheme, path or port') and the context field are already fully documented in the schema. The description adds no parameter-level detail beyond that, so the 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?

States a specific resource and scope: tech stack for a company domain, then enumerates the categories returned (ad pixels, analytics, tag managers, CMS, e-commerce, hosting, payments, plus email provider/SPF/DMARC from DNS). This is specific enough that an agent can tell exactly what comes back and how it differs from profile-oriented siblings.

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?

Explicitly gives both the when-to-use and the when-not-to-use with the named alternative: 'Use for technology-only research; use get_company_profile when hiring, ads and contacts are also needed.' The routing rule is stated, not inferred.

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