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

Annotations already declare the tool read-only, idempotent, and non-destructive Mend. The description adds useful context about cross-chain support via Covalent/GoldRush and the universal ERC-20/native token scope, but does not disclose details like rate limits or response structure. It neither contradicts the annotations nor adds substantial behavioral depth beyond them.

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 two concise sentences plus an example, with the core function front-loaded. Every part earns its place: what the tool returns, cross-chain scope, the backing service, and a concrete invocation example. 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 tool with three well-documented parameters and no output schema, the description provides sufficient context for an agent to select and invoke it: it names the input semantics, the returned data (balances with USD quotes), and the API key requirement. The absence of explicit output formatting or error details is a minor gap, but not blocking for correct invocation.

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 100%, so the three parameters are already fully documented in the schema. The description contributes only a usage example and does not add meaning beyond what the schema provides, which aligns with the baseline score for complete schema coverage.

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 returns token balances for a given wallet on a given chain, including every ERC-20/native token and USD quotes. It is specific enough to be distinguished from siblings like covalent_token_holders and covalent_transactions, though it does not explicitly name or contrast them.

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 provides clear context: use this tool when you need an address's full token holdings across a chain, with USD valuations. It does not state when not to use it or mention alternatives, but the intended usage is directly implied by the wording.

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