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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds value by enumerating returned fields (legal name, registry number, legal form, addresses, registration status) and by explicitly bounding scope to company-level data, which prevents misuse for natural-person screening. It does not discuss rate limits or empty-result behavior.

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?

Two sentences, zero filler: capability and modes first, returned data second, scope boundary last. Nothing redundant and nothing padded.

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 correctly compensates by listing the return fields, and the scope caveat covers the main risk. Minor gaps remain: no indication of pagination/limit behavior for name searches or what a no-match response looks like, though the limit parameter is documented in the schema.

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 pattern, maxLength, defaults and the LEI-precedence rule are all already documented in the schema. The description's '20-character LEI' and 'name and country' phrasing only restates schema content. Baseline 3 is appropriate when the schema carries the semantics.

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 (look up) and resource (LEI record / legal entities) and names the two operating modes: exact LEI lookup and name/country search. It also scopes the domain with 'Company-level data only', which helps distinguish it from person-oriented lookups. It stops short of explicitly contrasting with the nearby sibling nordic_company_lookup, which overlaps in the company-entity space.

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 description implies when each mode applies (LEI for exact record, name+country for search) but never states a preference rule or exclusion, and the precedence rule ('If set, name and country are ignored') lives in the schema, not here. No mention of when an agent should prefer a sibling like nordic_company_lookup. Usage is inferable but not guided.

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