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

Annotations already declare readOnly and openWorld; the description adds meaningful behavioral context on top of that by revealing the method ('generates and verifies') and, importantly, the probabilistic nature of the result ('most likely email format'), so the agent knows the output is a best-effort guess rather than a confirmed address. The description is consistent with the annotations; no contradiction.

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 sentences totaling roughly 27 words, with the core purpose front-loaded and the second sentence earning its place by adding the uncertainty caveat. No fluff, no repetition of schema content, no tangential detail.

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?

Adequate for a lookup tool: an output schema exists so the description need not explain return values, and annotations cover safety and open-world behavior. However, it leaves gaps — all seven parameters are optional and the description gives no hint about invocation constraints, domain-versus-company alternation, or how to route around the overlapping email_* sibling cluster.

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 every parameter is already documented and the baseline is 3. The description contributes only a mild combinatorial hint — name plus either company name or domain — but does not clarify the relationship between domain and company or full_name versus first_name/last_name beyond what the schema already says.

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 verb ('Find'), a specific resource ('email address of a specific person'), and the needed inputs (name plus company domain or company name) — clearly more than a tautology. However, it does not explicitly distance itself from closely related siblings like email_enrichment, email_verifier, or email_format, so an agent must infer the distinction.

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?

No guidance is offered for when to choose this tool over its near-neighbors. With siblings such as email_enrichment, email_verifier, email_format, and email_sources in the same toolset, the description gives no routing criteria and no exclusions (e.g., 'if you already have an email, use email_verifier'), leaving the agent to decide on its own.

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