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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, and the description layers on genuinely non-obvious behavior: the one-time 30-credit charge, no charge for unknown CUI, full charge even when sections are missing, an unavailableSections field, and the direction of the 0-100 score (higher = fewer risk signals). These are exactly the economics and partial-failure semantics an agent cannot infer from structured fields.

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?

Front-loaded with the capability, then the cost/partial-failure rules, then the disclaimer — a logical order with no filler. It is dense and slightly overpacked into one paragraph, but every clause (credits, unbilled unknowns, unavailableSections) carries decision-relevant information.

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?

No output schema exists, so the description must convey the return shape itself, and it does: the four data sections, the 0-100 score with its direction, explained flags, and the unavailableSections fallback field. Combined with the annotation coverage, an agent has everything needed to call and interpret the result.

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?

With one parameter at 100% schema description coverage, the schema already documents CUI with examples ('14399840 or RO14399840'). The description only says 'by CUI' and adds no format, normalization, or prefix-handling detail beyond the schema, so the baseline of 3 applies.

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+resource ('one-call due-diligence report for a Romanian company (by CUI)') and enumerates the exact sections returned: ANAF status, 3 years of financials, court cases, ONRC registry data. This clearly positions it as the aggregate report versus granular siblings like get_company_financials and get_company_court_cases.

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 'one-call' framing plus the credit disclosure (30 credits once, included sub-reads not billed again) implicitly tells the agent to prefer this over chaining the individual data tools, and 'Informational only, NOT credit advice' sets a scope boundary. It never names an explicit alternative or when-not-to-use condition, so it stops short of a 5.

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