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

Annotations already establish readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavior beyond them: a 100-result cap, a 2,000-block scan ceiling, and an explicit price of $0.01 USDC via x402, which an agent must know before calling. Return shape and pagination behavior remain unstated.

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?

A single front-loaded sentence that packs scope, filters, limits, and cost with no filler. It is dense to the point of being run-on, but every clause carries information.

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 sketch the return shape ('who sent how much to whom') and covers the key operational facts an agent needs: scan window, result cap, and payment requirement. Missing details on output fields and ordering keep it short of fully complete.

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 0%, so the description must carry parameter meaning, and it does partially: token = the ERC-20, address = the wallet, blocks = the recent-block scan window (up to 2,000). It never clarifies that 'blocks' is a lookback count rather than a range, nor the format/precision of the address filter, leaving real gaps at 0% coverage.

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 ('Recent ERC-20 transfers on Base') plus the entity shape ('who sent how much to whom') and the filter dimensions (token, wallet, or both). This distinguishes it cleanly from siblings like base_tx (single transaction), base_erc20_balance (balance), and base_token (metadata).

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?

The phrase 'for a token, a wallet, or both' implies the valid filter combinations, which is useful usage guidance. However, it never says when to prefer this over base_tx, base_receipt, or base_portfolio, nor any exclusion conditions, so usage remains inferred rather than stated.

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