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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true), so the bar is lower. The description still adds real behavioral context beyond them: it discloses the crawl surface (contact/about/team pages), that results are de-obfuscated, that role-based addresses are flagged, and the $0.03/domain cost — the last being operationally important and not derivable from any structured field.

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 content is short and front-loaded, but the first sentence is duplicated verbatim ('Find company email addresses by domain — crawls contact/about/team pages…'), which is pure waste in a five-line description. The pricing and positioning sentences do earn their place.

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 read-only, open-world scraper with no output schema, the description does cover what is returned conceptually (emails, de-obfuscated, role-flagged) and the cost. It is still thin on how input is structured and on any limits or failure modes, and the duplicated sentence suggests an editing error rather than intentional emphasis.

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 only one parameter and schema description coverage is nominally 100%, but that 'description' is just a pointer to an external URL, so it conveys no actual input semantics. The prose mentions 'by domain' but never says how domains are supplied (single value, list, nested input object). Baseline 3 applies given the declared coverage.

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 gives a specific verb+resource ('Find company email addresses by domain') and adds mechanism detail ('crawls contact/about/team pages, de-obfuscates, flags role-based') that makes it identifiable against generic enrichment siblings. It doesn't name a specific sibling to contrast with, but no sibling in the list does the same job, so the purpose is unambiguous.

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?

Usage is implied rather than stated: 'Hunter.io alternative' positions it competitively and '$0.03/domain' hints at a cost-sensitive, per-domain lookup. There is no explicit when-to-use, when-not-to-use, or routing to a sibling such as ai_company_enrichment or google_maps_lead_enricher, so the agent must infer the selection criteria.

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