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

Annotations only declare readOnly/openWorld; the description adds materially more: per-row return shape (match_status, company record, embedded RFC 9457 problem), idempotency semantics, the billing model (per verified match, 404s unbilled), and the 100-row ceiling. This is exactly the behavioral context annotations cannot carry.

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?

Five dense sentences, front-loaded with what the tool does and its input contract before moving to return shape, use cases, overflow routing, idempotency, and pricing. No sentence is filler.

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?

With no output schema, the description still specifies the per-row response (match_status, company record, RFC 9457 error) plus limits, idempotency, and cost behavior. An agent has everything needed to call and interpret it correctly; only `include` is unexplained.

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 0%, so the description must compensate. It enriches idempotency_key (UUID form, safe-retry, no double-billing) and restates the country/registry_id requirement, but the `include` parameter (field_meta/provenance enums) is never explained, leaving the most opaque parameter undocumented.

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 verb (enrich) and resource (companies) with explicit scope (up to 100, synchronous, batch). The batch-of-100 framing cleanly distinguishes it from singletons like firmadb_get_company and lookup-by-name tools like firmadb_search_companies.

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 concrete use cases (CRM enrichment, due-diligence batches, KYB screens) and an explicit routing rule: for more than 100 rows, split client-side and call firmadb_estimate_cost first. That is a real alternative-plus-condition, not just context.

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