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

With no annotations, the description carries the transparency burden. It identifies the tool as 'reference data', implying a read-only lookup operation. It also describes the scope of data it returns, which is useful behavioral context. It does not explicitly state that it has no side effects or require authentication, but for a zero-parameter reference tool this is sufficient.

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 tool's purpose, and every phrase adds concrete information. No filler or repetition of the title or schema.

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 that the tool has zero parameters and an output schema exists, the description completely covers purpose, content, and usage. No additional details about return structure or edge cases are necessary for this simple lookup 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?

The tool has no parameters, so the baseline is 4. The description adds value by explaining what the returned reference data is used for, which is the relevant semantic context in place of parameter documentation.

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 clearly states that this tool provides reference data for reporters/partners and enumerates the contents (EU/Euro-area/member states, presets, groups, translations). It also names the specific query fields it supports, distinguishing it from the many analytics-focused sibling tools.

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 gives explicit usage guidance: 'Use this to find valid values for the reporter, partner_set, partners and reporter_members fields used throughout the other tools' query argument.' This clearly indicates when to use the tool, though it does not mention when not to use it or name direct alternatives.

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