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

Since annotations are absent, the description must convey behavioral traits. It discloses the source (U.S. Treasury Fiscal Data), public domain status, and no key required, which is valuable for the agent. The verb 'Get' implies read-only with no side effects. However, it doesn't mention the return format or whether data is historical/current, leaving some 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?

Exactly one sentence, front-loaded with action and resource. Includes essential source and access details without waste.

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?

This is a low-complexity, zero-parameter tool with no output schema. The description covers what, frequency, source, and access. It could mention the return types explicitly, but for a simple public data fetch, it is adequate.

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 tool has zero parameters, so the schema provides no parameter details. The description mentions 'by type (monthly)' but this is a data characteristic, not a parameter. The description doesn't mislead; with an empty schema, the agent understands there are no arguments. Baseline 4 for zero params applies.

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 verb 'Get' plus specific resource 'average interest rates on U.S. Treasury securities' clearly states what the tool does. The frequency 'monthly' and source distinguish it from sibling treasury tools like auctions and debt.

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 gives clear context for when to use: when Treasury interest rate data is needed. It does not explicitly mention alternatives or exclusions, but the specificity of the tool makes its use case obvious. No direct comparison to 'get_rates' or other financial tools, so not a 5.

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