Get US Treasury yield curve

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

Annotations already declare readOnly, idempotent, and non-destructive behavior, so the burden is lower. The description adds useful behavioral context: data source, daily par yield curve, default to latest date, and fallback to the closest prior date. This goes beyond the annotations without contradicting them.

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, no filler, with the most important information front-loaded: what the tool fetches, from where, and why it's useful. Every clause contributes value, and the date semantics occupy the second sentence without redundancy.

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 read-only tool with zero required parameters, the description covers source, purpose, default behavior, and date fallback. It does not describe the JSON output shape, but the response_format parameter and the straightforward nature of the data make this a minor gap.

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 coverage is 100%, so the baseline is 3. The description adds meaningful semantics for the 'date' parameter by clarifying it returns the latest available date by default and the closest date on/before the requested date. This is supplemental information not fully captured in the schema description.

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 specifies a clear verb ('Get'), a concrete resource ('official US Treasury daily par yield curve'), the source domain (treasury.gov), and the relevant maturity range. It clearly distinguishes itself from market stock/dividend tools and macro series tools, so an agent can tell what this tool does without opening the schema.

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?

It provides a clear use case ('useful as the risk-free rate in valuations (typically the 10-year)') and explains the date behavior ('closest date on/before'). It does not explicitly name sibling alternatives or state when not to use this tool, but the context is sufficiently clear.

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