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

With no annotations, the description carries the full burden. It does disclose the payload shape and freshness cadence ('latest daily', 'vs. the previous day, a month and a year ago'), which is useful, plus a disclaimer ('Data, not investment advice'). But it says nothing about auth, rate limits, caching, latency, or whether the underlying feed can be delayed — gaps for a zero-annotation tool.

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?

A single dense sentence that front-loads the resource and then layers detail from most to least important — yields, spreads, inversion flags, then changes. No filler; every clause names a distinct data element. The closing disclaimer is short and earns its place for a financial tool.

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 no input schema, the description must specify return contents, and it largely does: instruments, spreads, inversion flags, and comparison periods. The remaining shortfall is operational (auth, source, delay) and the comparison baseline for 'changes' is stated but not the format of the flags.

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 takes no parameters, so the baseline is 4 and there is nothing for the description to compensate for. The enumeration of included metrics arguably documents the (empty) selection surface, confirming no filtering options exist.

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 (U.S. Treasury yield curve) with a crisp enumeration of what it contains: daily yields 1M-30Y, 10Y-2Y and 10Y-3M spreads, inversion flags, and period-over-period changes. It is clearly distinct from the other wallstreet_* siblings (company_brief, events, financials, insider_trades), though it never explicitly diffs against them.

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?

No explicit when-to-use or when-not-to-use statement, and no alternatives are named. Usage is only implied by the content — an agent infers 'call this when you need current Treasury curve data or a recession-signal read.' The parenthetical that inversion is 'a closely watched recession signal' hints at intent but does not constitute routing guidance.

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