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

Annotations already signal read-only, idempotent, and non-destructive behavior, so the description only needs to add output behavior, which it does: balances and ownership percentages. It doesn't mention limits or pagination, but that is acceptable given the strong annotation coverage.

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 sentences: a clear functional statement followed by a complete invocation example. No filler, and the core action is front-loaded.

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 simple, well-annotated read-only tool with three fully documented parameters, the description plus example covers what an agent needs to call it correctly. The only minor gap is no explicit statement of result count or ordering, but 'top holders' and ownership percentages are sufficient.

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?

All three parameters are fully documented in the schema, and the description's example supplies realistic values for address, chain, and _apiKey. This adds concrete usage meaning beyond the schema's field descriptions, though the prose itself adds no new parameter detail.

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 identifies the action ('returns') and the resource ('largest holders of an ERC20 token'), and specifies the output includes balances and ownership percentages. The 'Top holders of token X' phrasing plus token address example distinguishes it from wallet-focused siblings like moralis_wallet_tokens.

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 example shows how to invoke the tool, and 'Top holders of token X' implies the use case is holder distribution analysis. However, it never explicitly says when to prefer this over moralis_wallet_tokens or other sibling tools, nor does it state exclusions.

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