Get native balance

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It conveys that the operation is a 'Fetch', but it does not state whether it is read-only in a formal sense, how blockTag affects the result, whether the return value is denominated in smallest units, or what errors may occur. This is insufficient for a tool with no annotation safety profile.

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 a single, front-loaded sentence that directly states the operation. There is no wasted text, and the core purpose is immediately visible.

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?

The tool is relatively simple, but the description omits key contextual details such as what 'native token' means per chain, the meaning of blockTag, and the returned balance format. With no output schema and no annotations, such context would be expected for a complete definition.

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 only 33%, with chainId documented in the schema and address partially constrained by a pattern. The description adds no explanation of the address parameter, chainId semantics, or blockTag behavior, so it fails to compensate for the low 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 states a clear verb and resource: 'Fetch the native token balance for an address.' It is specific enough to distinguish the tool from general RPC tools like rpc_get_block or rpc_get_transaction. However, it does not explicitly differentiate from rpc_call_contract or rpc_call, which could also be used to query balances.

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?

No guidance is given about when to use this tool versus alternatives such as rpc_call_contract for ERC-20 balances or rpc_call for other RPC queries. The description implies the use case through its wording, but it offers no explicit context, exclusions, or alternative routing.

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