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

Annotations already declare the operation read-only, idempotent, and non-destructive. The description adds valuable behavioral context beyond annotations: the data source (HDX Humanitarian API), the maintainer (UN OCHA Centre for Humanitarian Data), the license (CC BY 4.0), and the fact that no authentication is required. This helps an agent understand access requirements and data provenance.

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 three sentences: the first states the core function and breakdown, the second lists filters, and the third provides data source/license/auth. Every sentence adds new information, and the most important purpose is front-loaded.

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 (8 optional parameters, no required ones), the description covers the essential functional aspects and provenance, while the output schema and parameter schemas handle the remaining details. The description is sufficient for an agent to select and invoke the tool correctly.

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 input schema provides full descriptions for all eight parameters, so the baseline is 3. The description briefly highlights five filterable parameters (location_code, sector_name, population_status, admin1_name, admin_level), but adds no new meaning beyond what the schema already states; for instance, it doesn't explain parameter relationships or combinations.

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 uses the specific verb 'Get' with the resource 'People-in-Need (PIN) figures' and immediately enumerates the breakdown dimensions (sector, category, population_status). This unambiguously identifies the tool's function and distinguishes it from sibling HDX HAPI tools like operational_presence or food.security_ipc, which address different datasets.

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 states that the tool returns PIN figures and lists available filters, which implies when it should be used (when PIN data is needed), but it does not explicitly state when to prefer this tool over alternatives or when not to use it. No sibling alternatives are mentioned.

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