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

Annotations already mark this read-only/non-destructive/open-world, and the description adds meaningful behavior beyond that: an exact RETURNS object, a guaranteed enriched boolean, and the explicit {enriched:false} fallback when enrichment fails or targeting is not configured. No contradiction with annotations.

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 short, front-loaded statements: action, use-case/scope, and return contract. Every sentence adds information and there is no filler, making it easy to scan.

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 one-parameter, no-output-schema enrichment tool, this is complete: it defines input semantics, scope boundaries, the full success return, and the failure representation. An agent has enough to call it correctly without further investigation.

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?

The schema already documents the single domain parameter at 100% coverage, so the description doesn't need to compensate. It adds useful context by relating the domain to a lead's email domain or an account, which tells the agent what values are acceptable beyond the schema's bare example.

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?

Description opens with a specific verb-resource pair ('Enrich a company DOMAIN') and lists the exact firmographic attributes returned, so an agent knows exactly what this tool does and can distinguish it from audience-creation and account-stat tools. The 'Company-level only (no contact PII)' boundary further sharpens the scope.

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 explicit use cases: 'Use to enrich a lead's email domain or an account' and states an exclusion ('Company-level only, no contact PII'). It doesn't name an alternative sibling or say when not to use it beyond the PII exclusion, so it falls just short of full routing guidance.

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