evm_get_token_balance

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the ERC-20 vs native distinction, but does not disclose other behavioral aspects like return format (raw vs decimal-adjusted), error cases, or chain defaults. It provides some value beyond annotations but not rich context.

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 a requirement, then an alternative. Every sentence serves a distinct function and there is no redundant information.

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 read-only tool with good schema and annotations, the description covers the core purpose and usage. However, it does not specify the return value format (e.g., raw integer vs. decimal-adjusted), which is a notable gap since there is no output schema. The description is adequate but incomplete.

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 all parameters are already documented. The description's mention of 'token contract address' and 'owner address' restates schema information without adding new meaning. No extra details on formats, defaults, or examples are provided, so baseline 3 applies.

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 gets ERC-20 token balances for an owner address, specifying verb, resource, and scope. It distinguishes itself from evm_get_balance by explicitly noting native balances should use the alternative 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 description explicitly tells the agent when to use this tool (for ERC-20 tokens) and when not to (native tokens, with a specific alternative named: evm_get_balance). It also emphasizes the requirement of a token contract address, giving clear prerequisite guidance.

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