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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering safety. The description adds behavioral context by specifying the exact scope (460 items), the code format (M49 numeric), and providing concrete examples. It also indicates the output is a list of codes usable in queries, which goes beyond the annotations. However, it does not detail return structure or pagination, though output schema likely covers that.

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 sentences with no redundancy. The main purpose is front-loaded, and the examples are illustrative without bloat. The mention of unsdg.data.query is relevant and adds utility.

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 simple read-only lookup tool with one optional filter parameter and an output schema present, the description covers all essential aspects: what it returns, how to filter, and how to use the results. No missing information for an agent to call it 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?

Schema coverage is 100% with a description for the filter parameter. The tool description adds meaning by explaining the filter is case-insensitive and provides examples ('Africa', 'Asia', 'Latin'), plus clarifies the output is codes for use with unsdg.data.query. This enriches the bare schema.

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 states a specific action (List all 460 countries, territories, and world regions) and resource (UN SDG database), with clear format (UN M49 numeric codes). It includes concrete examples (India = 356, USA = 840) and differentiates itself from sibling tools by focusing solely on geo area enumeration.

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 implicitly tells when to use this tool: when you need geo area codes for unsdg.data.query. It explicitly says 'Use these geo area codes with unsdg.data.query to filter data by location,' which is a clear usage directive. It doesn't explicitly name alternatives like unsdg.goals.list or unsdg.indicators.list, but the purpose is distinct enough that an agent can infer the right context.

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