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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description goes beyond them by disclosing the pagination contract ('pass next_cursor to get the next page') and enumerating the returned fields, which is real behavioral context for a cursor-paged endpoint.

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?

Two sentences, front-loaded with the resource and then the pagination and field contract. The field list is dense but earns its place given there is no output schema; nothing is padded.

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?

Listing the return fields compensates for the missing output schema, and pagination is explained. However, for an eight-parameter tool with zero required parameters, it never says what happens with no filters, nor how the inclusive year bounds interact with the exact year filter.

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 description coverage is 100%, so the baseline is 3. The description's field legend largely restates the schema's region_code wording and says nothing about the relationship between year, year_gte and year_lte or the limit default/ceiling.

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 and scope: population records keyed by region and year. An agent knows it is a filtered statistics query. It does not distinguish itself from the sibling population_latest, which is the obvious competing choice for the same data.

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?

No when-to-use guidance at all. With population_latest, municipal_figures and municipal_figures_latest in the sibling list, the agent gets no signal about when this historical/filterable endpoint is preferable, nor any note that all eight filters are optional.

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