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

Goes well beyond the annotations: discloses error behavior (malformed addresses rejected with 400, uncharged), billing model ($0.01/call via x402 or card key, first 25 free, failed calls free), repeat-call cost, and result shape/ordering (newest first, capped at 50). The "each call is charged, so repeats are not free" line also correctly reinforces idempotentHint=false.

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-loaded with what it returns and how it is scoped, then use case, then error/pricing caveats — all sentences carry information. It is densely packed into essentially one paragraph, with pricing and example details competing for the same block, which slightly hurts scannability.

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 takes on the burden of describing the return fields (direction, counterparty, amount, transaction), ordering, and the 50-row cap — which it does. Combined with cost, error and network context, nothing an agent needs before calling 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 coverage is 100%, so token, blocks range and defaults are already documented in the schema, and the description mostly restates them (default USDC, 1-2,000 blocks). The only genuine addition is a worked address example, which is marginal — 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 verb and resource ("List a wallet's recent transfers of one ERC-20 token ... on Mantle, in and out") plus scope (last N blocks, newest first, up to 50). The default token (USDC) and the network are named, and it explicitly separates itself from mantle_token_balance, so an agent can pick it without opening the schema.

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 concrete intent ("confirm a payment arrived or see what was sent") and names the alternative for the neighboring question ("for the current balance use mantle_token_balance"). It does not address the other plausible route to the same data — raw Transfer logs via mantle_logs — or when token_info would be needed first to resolve a contract, so guidance is clear but not exhaustive.

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