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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds the data scope (daily yields, maturity range) which is useful context beyond annotations. However, it does not disclose other behavioral traits like pagination, rate limits, or data freshness, though these are less critical given the simple read-only nature.

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 two sentences with zero redundancy. It front-loads the primary action and data scope, then adds a brief justification for its usefulness. Every word contributes to understanding the tool.

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, high schema coverage, existing output schema, and comprehensive annotations, the description sufficiently covers the purpose and data scope. It does not elaborate on return format, but the output schema handles that. It is complete enough for an agent to call it correctly.

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 has 100% coverage, with the single parameter 'days' fully described including default, min, max, and meaning. The description does not add any additional parameter-level information, so it meets the baseline of 3 but does not exceed it.

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 it retrieves U.S. Treasury yield curve data with daily yields across maturities from 1-month to 30-year. The verb 'Get' and specific resource 'Treasury yield curve data' make the purpose unambiguous. It does not explicitly differentiate from sibling tools like get_fed_rates, but the resource is distinct enough for an agent to identify it.

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 mentions it is 'essential for understanding interest rate environment and yield curve shape,' which implies a use case but provides no guidance on when to prefer this tool over alternatives such as get_fed_rates or get_economic_indicators. There is no exclusion criteria or mention of when not to use it.

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