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

There are no annotations, so the description carries the burden. It adds useful behavioral context by disclosing the cost ($0.001 USDC via x402) and data source (Bank of Mauritius). However, it does not describe the output format, default behavior when currency is omitted, or any rate limits, leaving some ambiguity.

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 that efficiently conveys the core purpose and a key constraint (cost). No filler words; every clause adds value. It is front-loaded with the action and resource.

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 tool with one optional parameter and no output schema, the description is reasonably complete: it identifies the source, the data type, and the cost. It does not explain the return structure, but for a simple rate lookup this is a minor omission. Overall, the description provides enough context for correct use.

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 input schema covers the sole parameter 'currency' with full documentation, achieving 100% schema description coverage. The description adds no additional parameter semantics beyond what the schema already provides, so the baseline score of 3 is appropriate.

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 the tool retrieves MUR exchange rates from Bank of Mauritius. The verb 'Get' plus the specific resource 'MUR exchange rates from Bank of Mauritius' fully defines the purpose and distinguishes it from siblings like macro_indicators or stock_market.

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 conveys when to use the tool: whenever MUR exchange rates are needed. It does not mention alternatives, but no direct forex sibling exists, so the context is clear. A minor gap is the lack of an explicit 'use this when' statement.

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