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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context: per-report pricing ($0.03 per company-report) and the guarantee that every value links back to its official source record. It omits what happens on an ambiguous or unmatched company, which is the main remaining gap.

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 core answer is front-loaded, which is good, but the body is a single very long run-on sentence with a dense parenthetical country inventory. Every clause is informative, yet the lack of structure makes it harder to scan than it needs to be.

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 lookup with full schema coverage and no output schema, the description covers return content, country-specific depth, sourcing guarantees and cost. The only missing pieces an agent would want are ambiguity/not-found behavior and any pagination or truncation rules for multi-year results.

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%, so the schema already documents query, country, include and maxYears. The description adds some indirect meaning by mapping country coverage (France/Finland/Estonia industry data, UK directors, Polish KRS, US banks FDIC) and 'last fiscal years' to the relevant parameters. That is helpful framing but not syntax or format detail beyond the schema.

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-plus-resource ('who is this company and what are its numbers') and enumerates concrete returned data: legal name, LEI, registration number, status, financials, SEC filings, directors/PSC, KRS entries, FDIC records. It is far more than a restatement of the name. It stops short of naming which sibling to prefer (sec_company_financials, company_accounts, identifier_resolver), so it does not fully differentiate itself.

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?

It gives an audience/context ('research, KYB or due diligence', 'quick, sourced company profile'), which implies when to reach for it. However, it never states when NOT to use it or which sibling covers a narrower need, leaving the agent to infer routing from the sibling list.

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