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

Annotations are all false, so the description carries the burden of behavioral disclosure. It adds meaningful context by stating the returned fields—authority, instrument, source URL, and effective date—and by saying the tool is 'Free and unlimited.' It does not explicitly discuss side effects, but 'List' strongly implies a read-only operation and there is no contrary annotation.

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 compact and front-loaded: it states the core action, the contained data, and the filtering options in three short sentences. There is no repetitive or extraneous wording, and every sentence adds relevant information.

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 optional-parameter list tool, the description covers the main return contents, filtering capability, and operational characteristics. It does not explicitly say that omitting `scheme` returns all schemes, but the schema already documents that, and no output schema exists to describe further.

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 description coverage is 100%, so the parameters are already well-described, including the enum values and country matching behavior. The description contributes a high-level 'filter by country or city' idea but does not add new parameter-level meaning beyond what the schema already provides.

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 verb and resource: 'List a scheme's bundled daily allowance rates' and clarifies the included provenance fields. The name and title are reinforced rather than merely restated, and the list purpose is clearly distinct from calculation/report siblings.

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 that this tool is for retrieving or listing rates with optional country/city filtering, and 'Free and unlimited' suggests no usage constraints. However, it does not explicitly distinguish when to use this tool versus perdiem_calc or perdiem_report, leaving alternatives to be inferred from sibling names.

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