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 adds genuinely non-derivable context: live chain-head semantics, the returned block number, an explicit cost of $0.003, and a scope disclaimer of what the read does not constitute.

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?

Two dense sentences with no filler; the chain list, return contents and cost are front-loaded, and the negative-scope clause clarifies boundaries in the same breath.

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 carries the return-shape burden and does so well by naming the payload fields and the block number. Combined with annotations covering safety and the explicit pricing, an agent has nearly everything needed, though wallet-format semantics remain thin.

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 33%, with only 'tokens' documented in the schema, so the description must compensate. It enumerates the six supported chains (mirroring the enum) and mentions requested ERC-20 balances, but adds nothing about the wallet address format or the 20-token cap beyond what the schema already encodes.

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 states a concrete verb (read) and resource (an EVM wallet across six named chains) and enumerates the returned payload (native balance, ERC-20 balances, token metadata, block number). It is clearly differentiated from token-oriented siblings like get_token_snapshot, though it never contrasts itself with the overlapping check_wallet sibling.

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 point-in-time framing and the negative scope ('not custody, valuation, proof of reserves or transaction authorization'), but there is no explicit when-to-use guidance or reference to an alternative tool. The agent must infer when this beats check_wallet.

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