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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive). The description adds genuine behavioral context beyond that: the settled-only filter, the exclusion of announced-but-unsettled auctions, and the reopening-to-original-term matching rule.

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?

Front-loaded with the resource and returned fields, followed by the two behaviorally important caveats (reopening matching, settled-only). Dense but every sentence earns its place; slightly long for the simplicity of the operation.

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?

No output schema exists, so the description carries the burden of describing return values — and it does, listing yield/rate, bid-to-cover, offering/accepted amounts, and CUSIP. With annotations covering safety and the settled/unsettled boundary disclosed, nothing material is missing for correct invocation.

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 value beyond the schema by explaining the reopening semantics (a "9-Year 10-Month" reopening is matched by its original nominal term, so term:"10-Year" catches it), which directly informs how the term parameter behaves.

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 (US Treasury auction results) and enumerates exactly what it returns: high yield/rate, bid-to-cover ratio, offering/accepted amounts, with CUSIP, from the Treasury Fiscal Data auctions dataset. This clearly separates it from sibling tools like treasury_avg_interest_rates, treasury_debt, and treasury_receipts.

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?

Provides clear operational context: only settled auctions are returned and upcoming announced-but-unsettled auctions are excluded, and explains how reopening matching works so an agent knows how to query. However, it names no alternative sibling tool or explicit when-not-to-use condition.

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