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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the read-only nature is covered. The description adds value by detailing what the tool returns (deliverability, provider/domain, breach exposure, platform registrations), giving the agent an expectation of the result. It does not mention rate limits or API key requirements beyond the schema, but with annotations present this is sufficient.

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: a purpose statement and an example. The purpose statement front-loads the core function and data categories, and the example is short. No fluff.

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?

The description is adequate for a read-only lookup with no output schema: it states the input (email and API key) and the expected output categories. The optional config parameter is only cursorily described in the schema ('see docs'), and the description doesn't elaborate, but for a simple enrichment tool this is probably acceptable. Still, a slightly more explicit description of the result structure would improve completeness.

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%, with each parameter described and examples provided in the schema itself. The description adds a copy of an example call, but this duplicates the schema examples and does not add new semantic meaning to the parameters beyond what the schema already provides.

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 opens with a specific action ('Look up the digital footprint of an email address') and enumerates concrete data categories (deliverability, provider/domain details, breach exposure, platform registrations). This clearly distinguishes it from sibling tools like seon_ip and seon_phone by the resource type (email), and the example reinforces the intended use.

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?

The description implies email-specific lookup via 'via SEON' and the example, but it never explicitly states when to prefer this over seon_ip, seon_phone, or seon_fraud, nor does it mention any exclusions. The usage context is inferable but not spelled out.

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