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

Annotations already cover readOnly, openWorld, idempotent and non-destructive, so the safety profile is set. The description adds genuinely useful context beyond that: 'free, no key' communicates the auth requirement, and the conditional series behavior tells the agent what each call shape returns.

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 tight sentences with no filler; the resource and auth note are front-loaded, the dual-mode behavior follows, and the usage scope closes. Every sentence earns its place.

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 no explanation, and the description covers auth, mode-switching, and domain scope for a simple read-only tool. Minor gaps remain — e.g., no hint on where to obtain valid series codes or how results are paginated beyond the limit.

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 the baseline is 3. The description adds value by explaining that the 'series' parameter switches the tool between catalogue listing and data retrieval, and that 'query' filters the catalogue — context not spelled out in the schema itself.

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 resource (UN Sustainable Development Goal indicators) and describes the dual-mode behavior (catalogue listing vs series data). It is clear what the tool does, though it does not explicitly name or differentiate from sibling indicator tools like world_bank_indicator or who_gho.

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?

Gives explicit conditional guidance: no series code means list/filter the catalogue, a series code returns that series' data. 'Use for official UN SDG statistics' scopes the domain, but no alternative sibling tool is named for comparison.

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