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

Annotations already mark this as read-only and idempotent, and the description adds meaningful behavioral context: counts are by country of registration, the output can be long if country is omitted, it reflects catalogue records rather than legal advice, and it excludes tax/investor-eligibility rules. No contradictions.

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 dense but every sentence earns its place: scope, returned data, use cases, the key registration-vs-operation distinction, sibling routing, output-length warning, and limitations. It is front-loaded with the most important information and does not repeat schema details unnecessarily.

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?

The description covers what the tool returns, how to scope it, how to choose between this and search_platforms, and what it does not cover. With an output schema present and complete parameter schema coverage, nothing important is missing for correct selection and invocation.

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?

The schema fully documents both parameters with descriptions and enums, so the baseline is 3. The description adds valuable meaning beyond the schema by clarifying that country is matched on country of registration and that omitting it returns the full map. 'lang' is adequately handled by the schema.

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 names the resource ('regulatory picture per country') and the specific data points it returns: regime, supervisory authorities, main licence type, and registered/regulated platform counts. It clearly distinguishes itself from search_platforms and the sibling tools by stating these are country-of-registration counts, not operational-activity counts.

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 gives explicit example use cases ('is crowdfunding regulated in X / who regulates it / how many platforms are licensed there'), states when to omit the country parameter, and directly tells the agent to use search_platforms instead for a different question. This is strong routing guidance.

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