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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, so the description adds value by explaining the data source (Base RPC), the pricing model, the x402 payment requirement, the prepaid x-credit-token option, and the free daily call. It also states that no wallet or API key is required, which is useful access context beyond the annotations.

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?

The description is compact and front-loaded: the tool's core output appears first, followed by use cases, then required input, then pricing/access details. Every sentence adds relevant information, and there is no redundant or filler content.

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?

For a single-parameter read-only tool with rich annotations, the description is nearly complete: it names the output fields, use cases, required input, pricing, and access model. It could more deeply explain what 'activity level' means, but the provided detail is enough for an agent to invoke the tool confidently.

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?

With only one parameter and a minimal schema description that simply says 'Address', the description compensates by clarifying that the address must be a Base address and that it is required. This adds meaningful network-level specificity beyond the schema.

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?

The description clearly states the tool provides an instant profile of any Base address, listing specific outputs: EOA vs contract, ETH + USDC balance, transaction count, and activity level. The scope is well-defined, though it does not explicitly distinguish itself from sibling tools such as wallet_summary or counterparty_check.

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 description gives clear context by stating it is useful for counterparty and wallet checks, and notes the required input is an address. It does not name alternative sibling tools or explicitly say when not to use it, but the use case is clear enough for an agent to make a reasonable selection.

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