List UNDP regions

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

With no annotations, the description carries the behavioral burden; it does disclose that the output contains aggregate budget, expenditure, project counts, and optionally embedded countries. However, it does not mention likely relevant traits such as pagination, output size limits, authentication, or a return envelope, and the 'Adds substantial output' warning lives only in the parameter schema, not the tool description.

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?

A single dense sentence front-loads the resource and action, enumerates the exact bureaux, and mentions the optional parameter. Every clause carries useful information with no 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?

Given the low complexity, complete schema coverage, and no output schema, the description is nearly complete for selecting and invoking the tool: it identifies the region set, the returned aggregate fields, and the optional include_countries behavior. The omission of return envelope or pagination details is minor for a simple list tool.

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 for the single parameter is 100%, so the baseline is 3. The description mostly restates the schema's 'member-country list' idea as 'optionally including the countries in each region' and adds no deeper semantic detail about include_countries, while the schema itself already provides the useful output-size warning.

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 a specific verb and resource: it says 'List the UNDP regional bureaux' and names the exact bureaux (RBA, RBAP, RBEC, RBLAC, RBAS, and global units). This clearly distinguishes it from sibling list tools like undp_list_operating_units and undp_list_sdgs by identifying a unique resource and the aggregate metrics returned.

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 implies when the tool is appropriate (when a caller wants UNDP regional bureau rollups), but it does not explicitly state when to prefer it over alternatives such as undp_list_operating_units or undp_aggregate_projects, and it gives no when-not-to-use guidance. For a simple list tool the context is adequate but the routing is left implicit.

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