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 clearly indicates a read-only operation, mentions the absence of auth requirements, and specifies that results include atomic amounts and the current block. It doesn't cover rate limits or error conditions, but for a simple read tool this is solid 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 with zero fluff. The main action, scope, and networks are front-loaded, followed by the auth note and a sample endpoint hint, making every word earn its place.

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 two-parameter tool with no output schema, the description covers purpose, supported networks, output highlights, auth requirements, and even a sample endpoint. It doesn't detail the exact output field names or structure, but that is a minor gap given the tool's simplicity.

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 schema only defines 'address' and 'network' as plain strings with 0% description coverage, so the description must compensate. It does so by explaining that address is any EVM wallet and by enumerating the supported networks for the 'network' parameter. However, it doesn't explicitly map these to parameter names or mention the default network, leaving a minor gap.

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 ('Read') with a precise resource ('native coin and USDC balances for any EVM wallet') and explicitly lists supported networks. This clearly differentiates it from the generic sibling tools like weather or search, and from financial siblings like gas_price by focusing on wallet 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?

The description gives clear context by noting it works across five networks and requires no RPC key or account, positioning it as a quick, credential-free balance check. It stops short of explicitly naming alternatives or stating when not to use it, so it earns a 4 rather than a 5.

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