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

Annotations cover the safety profile (readOnlyHint, openWorldHint), and the description adds genuinely new context: the call is free, the returned offer is unpaid, and the payload includes a raw PAYMENT-REQUIRED header. That tells an agent the operation has no cost and no side effect, and hints at the payment handshake. It stops short of explaining how to act on the returned offer.

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 short sentences with the most decision-relevant fact ("Free.") front-loaded. The parenthetical field list is dense but earns its place by previewing the return payload in the absence of an output schema. No filler.

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 does carry the burden of describing returns and partially does so by listing the offer fields. But it omits what an agent should do with the offer (how to satisfy the 402), and the six chain values remain unmapped, leaving real gaps for a tool whose whole purpose is a payment handshake.

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 50%: address is documented in-schema, but the chain enum values carry no descriptions. The phrase "a token check or a Hyperliquid data call" loosely maps the enum into two groups (solana/robinhood vs hl_*), which adds some meaning, but it does not disambiguate individual values like hl_funding vs hl_whales vs hl_brief. Partial compensation only.

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: returns the unpaid HTTP 402 offer, and enumerates what the offer contains (networks, USDC amount, payTo, raw PAYMENT-REQUIRED). This is clearly a pricing/quote tool, distinguishable from the sibling data tools. It does not explicitly name a sibling, but the resource is specific enough to stand apart.

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?

"for a token check or a Hyperliquid data call" implies the context in which a quote is needed, which is useful routing information. However, it never says to call this before paying, never states when-not to use it, and never names an alternative tool. Usage is implied rather than prescribed.

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