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

Beyond the annotations (readOnly, idempotent, openWorld), the description discloses significant behavioral traits: it aggregates multiple external sources, includes specific data enrichment types, and, most valuably, explains the 402 failure mode for NL/DE on free tiers with explicit 'do NOT retry' guidance and quota cost multipliers. This goes far beyond what annotations provide.

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 description is moderately long but every part serves a purpose: it enumerates data components, lists supported countries, and ends with a critical tier note. It's structured logically (data → coverage → caveat) and avoids filler, though it could be slightly more compact without losing 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?

Given the tool's complexity (multiple sources, 15 countries, tier-dependent behavior), the description covers all essential aspects: what data is returned, the one-call model, country coverage, and the critical failure/quota semantics. An output schema exists, so return structure is already documented; the description fills the behavioral gaps completely.

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%: both `id` and `country` have descriptions, and `country` has a full enum. The description adds the list of countries in text but this duplicates the schema's enum. The `id` reference to 'same format as lookup_company' is in the schema, not the description. So the description adds minimal semantic value beyond the schema, keeping the score at the baseline for high coverage.

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 clearly states the tool provides enriched company data with a specific list of components (registry data, validated address, industry stats, Wikidata enrichment). It distinguishes itself from sibling tools like lookup_company by emphasizing 'One call, multiple sources' and the enriched nature, making its purpose specific and differentiated.

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 to use this tool (when enriched multi-source data is needed) versus basic lookup, though it doesn't explicitly name alternatives. It provides strong usage guidance by detailing the 15 supported countries and the crucial tier note about NL/DE paid registries, including the 402 error and retry prohibition—very actionable usage context.

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