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

Goes well beyond readOnlyHint=true by disclosing units ('4.25 means 4.25%'), the 2026-07-21 removal of OAS/UMCSENT series, the 4h cache, the source chain (Treasury.gov with FRED fallback), and that caveats arrive in the response's tool_notes. This is exactly the extra context annotations cannot carry.

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-loads the two-shape contrast and keeps every sentence informative (units, removals, source, cache). It is dense to the point of being hard to scan, with multiple ALL-CAPS fragments, but nothing is truly wasted.

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 and only one parameter, the description fully carries the return-shape burden: it specifies both response forms, tenor count, comparison dates, units, and where caveats surface. An agent can consume the result correctly without further schema detail.

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%, but the schema's own description ('Include yield curve from 1 year ago') is misleadingly narrow; the tool description corrects it by spelling out that true yields PARALLEL ARRAYS over 11 tenors at three points in time, and false returns a flat {data: [...]} list. That is a substantial semantic addition, not a restatement.

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?

Starts with a specific resource ('US Treasury yield curve') and immediately names the wider macro content returned by default. It is clearly distinguishable from siblings like get_fred_data or get_bond_data because it names Treasury.gov par yields and FRED fallback as the source.

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?

Explicitly frames the two modes and the purpose of each: include_history=true is for 'steepening/inversion work' while false returns the macro dashboard. It does not name an alternative sibling tool or state when NOT to use this one, so it falls short of 5.

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