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

With no annotations, the description carries the burden and does well: it discloses the paid x402 model, the exact price, accepted payment assets/chains, the unsigned-then-signed two-step flow, and that launcher data comes from an index and is 'never guessed'. It does not describe response shape on refusal or latency/timeout behavior, which keeps it from 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?

Front-loads what the tool returns, then moves to the refusal rule and the pricing/payment mechanics. Information-dense and mostly free of filler, though the final payment sentence packs several steps into one long clause chain that could be split for easier parsing.

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?

No annotations and no output schema, so the description must cover everything, and it nearly does: return fields are enumerated and the payment protocol is fully specified. Remaining minor gap is failure/error behavior beyond the 'wallet or non-token is refused' case.

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 100%, so baseline is 3; the description adds real meaning beyond the schema by explaining the payment parameter's role — first call without it returns terms, second call with the signed payload completes the purchase in-call. That sequencing is not derivable from the schema field text alone.

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?

Names a specific verb+resource ('Token info for an Arc token') and enumerates exactly what comes back — name, symbol, decimals, supply, Circle stablecoin status, launcher/timestamp, USDC pool count, deepest pool price and liquidity, risk signals. That enumeration clearly separates it from siblings like arc_holders, arc_trust_check, or arc_price, which each cover a subset.

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?

Gives clear context — call it 'before showing' a token — and a concrete edge-case rule that wallets and non-tokens are refused pre-payment. Also spells out the two-call paid flow. It stops short of naming sibling alternatives ('use arc_holders instead if you need X'), so it is clear but not fully routing.

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