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

The annotation declares readOnlyHint=true, which covers the read-only nature. The description adds no additional behavioral details beyond the obvious calculation function. It does not mention error handling, default settlement behavior (though the schema covers it), output format, or any special handling like yield-to-worst when a call schedule is provided. Since the annotation already covers mutability, the description should provide more context for full transparency, but it falls short.

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 exceptionally concise and well-structured. It opens with the core function, then provides the source/power note. Both sentences are informative and free of redundancy. The structure is ideal for quick comprehension.

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 absence of an output schema, the description does not need to explain return values. However, it lacks context about optional parameters like settlementDate and callSchedule, and does not mention that a call schedule triggers yield-to-worst calculation (though the schema hint covers this). The description is adequate but not complete; it relies heavily on the schema for full understanding. A score of 3 reflects this partial completeness.

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 schema descriptions fully cover all parameters (100% coverage), so the baseline is 3. The tool description itself does not add any parameter-specific semantics; it merely repeats the general purpose. No additional context beyond what the schema provides is included, so the score stays at the baseline.

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's purpose with a specific verb ('Calculate') and resource ('price, yield, and accrued interest for Periodic bonds'). It identifies the domain (fixed income) and the calculation type without ambiguity. The mention of 'Periodic bonds' distinguishes the input type, and since there are no sibling tools, there is no confusion.

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 does not explicitly state when to use this tool versus alternatives, but there are no sibling tools provided, so the primary function ('calculate') implicitly defines its applicability. It mentions the standard calculation method but does not provide conditions or exclusions. Given the absence of alternatives, a neutral score of 3 is appropriate.

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