mcp_iati_list_recipient_countries

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

With no annotations to lean on, the description takes on the burden of explaining behavior. It discloses the output shape (a table with country code, name, and activity count), clarifies that 'recipient countries' includes regions, and grounds the result in the loaded IATI data. This goes well beyond a tautological statement.

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 well structured with a clear lead sentence, a usage note, a returns summary, and relevant IATI terms. It is slightly longer than strictly necessary, and the IATI definitions are auxiliary, but every section earns its place and the main 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?

For a zero-parameter list tool, the description is complete: it states the scope, the intended use, the return format, and domain-relevant definitions. Since an output schema exists, the return value explanation is a bonus. Nothing needed to invoke the tool correctly is missing.

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 has zero parameters, so the baseline is 4. The description adds no parameter-specific detail, but none is needed because the input schema is empty. The usage guidance about discovering country codes is contextual rather than parameter-related.

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 opens with a specific verb and resource: 'List the recipient countries present in the loaded IATI data.' It clearly distinguishes this tool from sibling list tools like mcp_iati_list_sectors and mcp_iati_list_reporting_organisations by focusing on recipient countries and tying it to the filtering workflow.

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 explicitly states when to use it: 'Use this tool to discover which country codes are available before filtering activities by recipient country.' This gives clear context, although it does not mention any alternatives or when not to use it, so it stops short of a 5.

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