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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds the domain context (currency ids/codes for currencyFK) but does not disclose response formats or other behavioral details. With annotations covering the core, this is adequate but not rich.

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 a single sentence, directly front-loaded with the action ('List valid currency ids/codes'), and contains no unnecessary words. It is optimally concise.

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 simplicity (no parameters, no output schema), the description provides sufficient context about its purpose and output. It could specify the exact return structure (e.g., array of strings), but the phrase 'List valid currency ids/codes' already implies the output shape, making it nearly complete.

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, and the schema coverage is 100%, so there is no need to explain parameters. The description compensates by clarifying what the output represents (valid currency ids/codes), earning the baseline score of 4 for parameterless tools.

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 'List valid currency ids/codes' with a specific purpose ('for use as a package's currencyFK'). The verb 'List' and the resource definition make it distinct from siblings like getCountryOptions or getRoomTypeOptions, which target different fields.

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 phrase 'for use as a package's currencyFK' provides clear context on when to use this tool, implying it is appropriate when setting or validating the currency of a package. However, it does not explicitly mention alternatives or when not to use it, so it falls short of a full 5.

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