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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered. The description adds useful behavioral context beyond that: results are ranked candidates rather than exact matches, and the output carries registry identifier, country, legal form and status. It omits paging/ordering caveats, so it is strong but not exhaustive.

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?

Three sentences, each earning its place: purpose, return shape, then workflow routing with an explicit exclusion. Front-loaded with the verb and resource, nothing redundant.

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?

An output schema exists so return values need not be enumerated, and annotations carry the safety profile; the description still supplies the workflow position (first step, hand-off to lookup_company/company_brief) and the boundary against advanced_search. Nothing an agent needs to call this correctly is missing.

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 query, limit and country are all documented in the schema itself, including the tie-break rationale for country. The description only echoes 'name (or name fragment)' and alludes to carrying country forward, adding little syntax or format meaning beyond the schema. Baseline 3 is appropriate.

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 and resource ('Find companies by name'), names the scope ('pan-European dataset'), and previews the payload (registry identifier, country, legal form, status). It is immediately distinguishable from siblings like get_company_details or list_rankings.

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?

Explicit routing: use this FIRST when only a name is known, then feed the identifier + country into lookup_company or company_brief. It also states the negative case — do not use it to filter by industry or size, use advanced_search instead. Both the trigger and the excluded alternatives are named.

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