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

Annotations already cover read-only/non-destructive, but the description adds non-obvious behavior: malformed addresses rejected with 400 and uncharged, $0.01/call via x402 or card key, first 25 free, failed calls free, and repeats not free because each call is charged — which explains the idempotentHint=false. That is substantial context beyond structured fields.

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 purpose, then scoping, then the alternative, then pricing caveats — logical order with no filler. The pricing/free-tier clause is somewhat compressed and competes with the core usage signal, keeping it just under a 5.

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 output schema exists, yet the description enumerates the return shape (direction, counterparty, amount, transaction, newest first, max 50), so an agent knows what comes back. Cost, error behavior, and scope are all covered; nothing needed to call it correctly 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 the baseline is 3, but the description adds meaning: token accepts a ticker or a 0x contract and defaults to USDC on Sei, blocks is 1-2,000 with default 1,000, plus a concrete address example. It does not add much on the block window's time semantics beyond the schema's note.

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?

Specific verb plus resource plus chain and scope: 'List a wallet's recent transfers of one ERC-20 token (default USDC) on Sei, in and out, over the last N blocks'. It also states the returned fields and cap (up to 50, newest first), which distinguishes it immediately from siblings like sei_token_balance or sei_logs.

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 explicit use cases ('confirm a payment arrived or see what was sent') and an explicit alternative ('for the current balance use sei_token_balance'). The when-not path is named rather than implied.

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