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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior. The description usefully adds that the register is returned in full (no parameterization or partial fetch) and that it is 'a descriptive roster, never inference', clarifying the epistemic nature of the payload beyond the annotation set.

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?

Front-loaded with the verb and resource, then the payload contents, then the boundary versus get_methodology. It is dense with em-dash-separated clauses and a touch long, but every clause carries information rather than filler.

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 available, the description carries the return-value burden well: it enumerates fields (bloc assignment, universal category, evidence, source URLs, metadata, snapshot history, changelog, pre-register decisions). Combined with annotations covering safety, an agent has everything needed to call it and interpret results.

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 tool takes zero parameters, so the baseline is 4. The description reinforces this by saying the register is 'served whole', implying no filtering or pagination arguments exist, which matches the empty 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?

States a specific verb (Retrieve) plus the exact resource (WEO Bloc Membership Register) and enumerates the contents: nations, bloc assignment, membership category, evidence/source URLs, document metadata, sectioned provenance. It clearly distinguishes itself from get_methodology, which is named as the home of category definitions.

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?

Frames the tool as the 'machine mirror of the public blocs register', 'served whole and free', which tells the agent this is an unfiltered full-roster read, and routes the agent to get_methodology for definitions. It stops short of explicit when-not-to-use guidance or naming other roster-shaped alternatives among the siblings.

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