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

Beyond the readOnly/openWorld annotations, it discloses the recency limits per chain, the 50-result cap, deterministic non-LLM behavior, and — critically — the x402 payment requirement ($0.0045 USDC via _meta['x402/payment']). That payment/auth detail is exactly the kind of context annotations cannot carry.

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 the core purpose, then scope, then limits, then example, then price. The inline JSON example is long but justified since no output schema exists. Slightly dense as a single paragraph but every sentence 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?

No output schema exists, and the description supplies a concrete example response shape plus field meanings, along with chain support, caps, and payment mechanics. An agent has everything needed to call this correctly and interpret results.

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 already 100%, so baseline is 3; the description adds value by mapping the blocks parameter to concrete per-chain ceilings and by stating base as the default chain. It doesn't clarify the 'from or to' semantics of wallet beyond the schema's parenthetical, but overall it adds modest meaning.

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+resource ('Recent ERC20 Transfer events ... for a token contract, a wallet, or both') and enumerates the decoded fields returned. This distinguishes it clearly from siblings like base_wallet or wallet_portfolio, which are balance/portfolio oriented.

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?

Explicitly says it works for a token, a wallet, or both, and scopes usage to recent windows (~2,000 blocks on Base/Arbitrum/Optimism, ~500 on Ethereum). It doesn't name an alternative tool for historical or full-history lookups, so an agent must infer that this is recent-only.

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