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

With no annotations, the description carries the full burden. It does disclose a significant behavioral trait: 'Costs $0.002 USDC via x402' — important for an agent deciding whether to invoke. The verb 'Get' implies a read-only operation, but no further details are given about return format, error handling, or rate limits. 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?

Two sentences, perfectly front-loaded: the first states the purpose, the second the cost. No filler or redundant information. Every word earns its place, fulfilling conciseness expectations.

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, no-parameter getter with no output schema, the description captures the essential data points (Key Repo Rate and Prime Lending Rates) plus the cost. It could add update frequency or units, but given the tool's simplicity and the lack of output schema, it is reasonably complete. Sibling differentiation is absent, which slightly lowers the score.

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, so schema coverage is 100% by default. The baseline for 0 params is 4, and the description doesn't need to elaborate on parameters. It does not attempt to describe non-existent parameters, so the score fits.

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 explicitly states the tool's function: 'Get Bank of Mauritius Key Repo Rate and Prime Lending Rates.' It uses a specific verb ('Get') and resource (the two rates), distinguishing it from sibling tools like macro_indicators or forex_rates by naming the exact data source and 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?

No guidance is provided on when to use this tool versus alternatives (e.g., macro_indicators might also contain repo rates). The description merely states what it does, leaving the agent to infer usage context. There is no mention of exclusions or preferred scenarios.

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