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

The description goes well beyond the annotations by explaining the ERC-20 limitation: balances are only returned for contracts in token_addresses because EVM RPC endpoints cannot enumerate wallet tokens, and a fixed list would under-report. It also adds cost and read-only context ('Free', 'no transaction notional'), which is valuable and does not contradict 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 tightly structured: purpose first, then the critical token_addresses caveat, then cost/read-only framing. Each sentence earns its place with no wasted words.

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 an output schema present and strong annotations, the description covers the main behavioral caveat, the chain default, and the free read nature. The remaining gaps are minor but real: caller_id semantics and accepted chain values are not addressed, though basic invocation is still clear.

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 0%, so the description must compensate. It does meaningfully explain chain's default and token_addresses' behavioral significance, and 'address' is clear from the first sentence. However, caller_id is left undocumented, and there is no guidance on address format or valid chain values.

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 that the tool returns native ETH and ERC-20 balances for an address on an EVM chain, which is specific about the resource and scope. It distinguishes itself from equity, perp, and strategy tools, though it does not explicitly differentiate from the sibling get_balances tool.

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 tool's intended context is implied: use it for EVM balance reads, with chain defaulting to 'base' and no transaction notional. However, it does not provide explicit when-to-use/when-not-to-use guidance or name alternative tools for different balance queries.

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