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

Annotations already cover readOnly/idempotent/non-destructive, and the description adds genuinely useful context beyond them: the ONRC monthly snapshot as data source (implying possible staleness), a 5-credit cost, and the notable billing exception when the CUI is not found. It does not cover invalid-CUI handling or rate limits, but the cost and failure-billing disclosure is high-value.

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?

A single dense sentence front-loads the resource and source before the field list and pricing. Parenthetical asides (decoded status, role examples) are informative rather than filler, though the sentence is long enough to strain readability.

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 correctly compensates by enumerating returned fields, and it adds source, cost, and failure behavior. For a single-parameter read tool this is close to complete; only input-validation behavior is unstated.

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?

Only one parameter with 100% schema description coverage, including an example format (14399840 or RO14399840). The description adds only the 'by CUI' framing, which the schema already conveys; baseline 3 applies when the schema does the work.

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 resource (trade-register data for a Romanian company by CUI) and enumerates the returned fields — registration number, EUID, legal form, status, CAEN codes, representatives — so the agent knows exactly what this retrieves. It is distinguishable from get_company_financials and get_company_court_cases by its field list, though it never explicitly names a sibling to contrast with.

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?

Usage is implied by the 'by CUI' input and the representative-focused field list, but there is no explicit when-to-use or when-not-to-use guidance, and no routing against lookup_company or the other company tools. An agent must infer the choice from the field contents alone.

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