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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful context the annotations lack: that results are ordered newest-first and that coverage spans tenors from 1 month to 30 years. It says nothing about source freshness, caching, or business-day gaps.

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 short sentences, front-loaded with what is returned and immediately followed by how to shape the request. No filler, though the parenthetical example is slightly redundant with the schema.

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?

With no output schema, the description carries the burden of describing the return, and it does so at a high level (yields keyed by tenor, newest first). For a two-optional-parameter read tool with rich annotations, that is nearly sufficient; row-level shape and units (percent) are the only gaps.

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% and the schema itself documents both parameters, including tenor naming and the 1-30 day bound. The description's example tenor list (["2 Yr", "10 Yr"]) largely restates the schema's examples rather than adding format or edge-case guidance.

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?

States a specific resource (Treasury daily par yield curve) with its shape (yields by tenor, 1 Mo to 30 Yr) and ordering (newest first). It never names a sibling such as get_reference_rates, which is the nearest overlap, so differentiation is left implicit.

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?

"Ask for the last N days, and optionally only some tenors" describes how to use the parameters rather than when to choose this tool over get_reference_rates or other rate-like siblings. No exclusions or preconditions are stated.

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