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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description goes further with quota and cost (10 calls/day free, then $0.002/call) and the exact auth mechanisms (x402 via params._meta["x402/payment"] or HTTP, or X-API-Key credits) – real operational context an agent must know before calling. It stops short of describing pagination/timeout or partial-chain failure behavior, which keeps it off a 5.

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 capability and returned fields, then the commercial/access terms – a sensible ordering with little wasted wording. The trailing "[served by tools.moneytools.dev]" tag and the stacked payment options add density but each conveys actionable 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?

For a two-parameter read tool with an output schema, full annotation coverage, and 100% schema description coverage, the description supplies what the structured fields cannot: cost, quota, auth paths, chain coverage, and the semantic categories of the response. An agent has everything needed to decide and call correctly.

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 schema already explains both parameters and the 3 baseline is met. The description adds meaning beyond it by naming the seven supported chains (Ethereum, Base, Arbitrum, Optimism, Polygon, BSC, Avalanche), which the schema only refers to as "all 7", and by clarifying that ENS names are accepted alongside 0x addresses.

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 ("Profile") and resource ("EVM address or ENS name") and enumerates exactly what is returned: EOA vs contract vs EIP-7702 delegated, nonce, native balances, primary ENS name, known-contract label. This makes it clearly distinguishable from the validation/encoding siblings that merely inspect a single aspect of an address.

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?

Usage is implied by the verb and the enumerated outputs – an agent can infer it should call this when it needs a multi-chain account summary. However, no explicit when-to-use/when-not guidance is given, and no sibling (e.g. address_validate, chain_info) is named as an alternative for narrower needs.

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