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

With no annotations, the description carries the burden, and it does disclose a critical operational fact: the tool is pay-per-call at $0.003 USDC via x402 on Base. However, it says nothing about data freshness (real-time vs end-of-day), update cadence, or failure behavior, which matter for a market-data 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?

Two sentences, both front-loaded with the returned content before the pricing note. Nothing is redundant or padded.

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 or annotations, the description does the work of enumerating the return payload (slopes, inversion flags, three spreads) and the payment mechanics. The main omission is data timing/freshness, which an agent would want before relying on the numbers.

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 zero parameters, so the baseline is 4. The description reinforces this by making clear the coverage set is fixed (three regions and a specific spread list) rather than configurable.

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 description names the specific quantities returned (2s10s and 3m10y slopes in bp, inversion flags, cross-market 10Y spreads) and the exact geographies covered (US, euro area, Morocco). An agent can tell this is a yield-curve analytics tool, though it does not explicitly distinguish itself from siblings like yields_curve or yields_rate.

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?

There is no guidance on when to pick this over yields_curve or yields_rate, and no stated prerequisites or exclusions. The reader must infer usage purely from the enumerated outputs.

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