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

Annotations already indicate a safe read operation, and the description adds valuable detail: it calls balanceOf, decimals, and symbol on the token contract, and returns raw plus formatted balance and symbol. This context is not present in the annotations and informs the agent about the underlying contract interactions.

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 sentences, front-loaded with the primary purpose, then efficiently summarizes return values and contract calls. Every word earns its place; no fluff or repetition of schema fields.

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?

Although there is no output schema, the description fully specifies the return values (raw balance, formatted balance, token symbol). Given the tool's simplicity, two well-defined parameters, and strong annotations, this description is complete for an agent to successfully invoke the tool.

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?

The input schema covers 100% of parameters with clear descriptions for 'token' and 'wallet'. The description does not add additional parameter semantics beyond what the schema already provides, so a baseline score of 3 is appropriate.

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 specific verb 'Get', a clear resource 'ERC-20 token balance', and the network 'Mezo'. It distinguishes itself from siblings like eth_get_token_balance (by explicitly mentioning Mezo) and mezo_get_balance (which likely handles native balance).

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 clearly indicates the tool is for ERC-20 token balances on Mezo, providing context for when to use it. It does not explicitly name alternatives or exclusions, but the context is unambiguous enough for an agent to choose this over similar sibling tools.

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