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

With no annotations provided, the description carries the full burden. It discloses the data source (U.S. Treasury), output ordering (oldest first), a hard limit (max 31 calendar days), and a disclaimer ('not financial advice'). It does not mention authentication, rate limits, or return structure, but for a read-only data retrieval tool this is reasonably transparent.

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 tightly written sentences: the first front-loads the purpose and scope, the second adds source and disclaimer. No filler or 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 two-parameter range query with full schema coverage and no output schema, the description covers the essential purpose, constraints, and source. It could be slightly more complete by hinting at the return structure (e.g., a list of curves by date), but nothing critical is missing.

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 description coverage is 100%, so both parameters are fully documented in the input schema. The description only repeats the 31-day cap already present in the endDate schema description and adds no new meaning. Baseline 3 applies when the schema does the heavy lifting.

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 names a specific resource (US Treasury par yield curves) and scope (every business day between startDate and endDate), making it clear this is a range retrieval. However, it does not explicitly distinguish itself from the sibling yield_curve tool, leaving the agent to infer the difference from the 'history' implication.

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?

Usage is implied by the date-range constraint (max 31 calendar days) and the phrase 'between startDate and endDate', suggesting a range query. There is no explicit statement of when to use this over the alternative yield_curve, nor any exclusions or prerequisites.

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