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

Annotations only declare readOnlyHint=true, but the description discloses cost ($0.01 USDC per call), the payment rail (USDC on Solana), and the mandatory two-call challenge/retry sequence. That is exactly the kind of behavioral context annotations cannot carry, and it is fully consistent with the read-only hint.

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, zero waste. Purpose and cost come first, then the invocation sequence, so the most decision-relevant facts are front-loaded.

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?

There is no output schema, so the description carries some return-value burden; it explains the first-call return (payment challenge) but not the shape of the metric payload itself. For a paid tool the critical flow is covered, so this is nearly complete.

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 description coverage is 100%, so both parameters are already documented in the schema, including the first-call/retry semantics of payment_signature. The description reinforces the flow and adds the price, but contributes no new syntax or format detail beyond the schema, which is the baseline-3 case.

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 verb and resource ('Get one verified stablecoin/RWA market metric') and adds a distinguishing qualifier ('verified'), which separates it from vague siblings like get_price or get_peg. It does not, however, explicitly contrast itself with those siblings, so it lands at clear-but-undifferentiated.

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 two-step payment flow is spelled out precisely: call without payment_signature to get the challenge, pay, then call again with the signature. That is strong operational guidance. What is missing is any when-to-use-this-vs-alternatives guidance relative to get_price, get_peg, or get_monitor_pegs.

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