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

Annotations only declare readOnlyHint, and the description adds real behavioral context beyond that: per-call cost of $0.05 USDC, settlement on Solana mainnet, and the challenge-then-retry protocol. It doesn't cover failure modes (e.g., what happens on underpayment or an invalid signature), which keeps it short of a 5.

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 load-bearing, with the purpose front-loaded ahead of the payment mechanics. The second sentence is dense but each clause (challenge, pay, retry with signature) is necessary.

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, the description carries the return-value burden and does so ('live price and deviation in basis points from $1.00'). Cost and the payment handshake are covered; error handling and whether the challenge expires are not, but nothing needed for a correct call is missing.

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%: both symbol (with allowed values) and payment_signature are fully documented in the schema. The description restates the payment flow but adds no format or constraint detail beyond what the schema already provides, so the baseline 3 applies.

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 and payload: stablecoin peg status with live price and deviation in basis points from $1.00. An agent immediately knows what it returns, though it never distinguishes itself from siblings like get_price or get_monitor_pegs, which could plausibly overlap.

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 sequences the two-call payment flow: omit payment_signature first to get the challenge, then call again with the signature after paying. Clear operational context, but no guidance on when to pick this over get_price vs get_monitor_pegs.

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