explorer_get_historical_token_balance

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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds the ERC-20 and historical block specifics, but these are more about input parameters than behavioral traits like error handling, return format, or rate limits. No contradiction with 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?

A single sentence that is clear, front-loaded with the verb 'Get', and contains no wasted words. Perfectly concise.

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 query with complete schema documentation and annotations, the description is sufficient. It lacks explicit return format details (no output schema), but the purpose is clear. Slightly more could be added about units or response shape, but not necessary for basic usability.

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 documented in the schema. The description reinforces that blockNumber is historical and that the target is an ERC-20 balance, but adds no parameter-specific details beyond what the schema already provides. Baseline 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 clearly states the verb 'Get', the resource 'ERC-20 token balance', and the specific scope 'of an address at a specific historical block number'. It distinguishes from sibling tools like explorer_get_historical_balance (likely native balance) and evm_get_token_balance (current 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 context is clear: use this tool for historical ERC-20 token balances. It does not explicitly mention alternatives or when-not-to-use, but the historical and ERC-20 qualifiers imply the appropriate use case versus other balance tools.

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