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

No annotations are provided, so the description carries the behavioral disclosure burden. It reveals the pay-per-use cost ('0.002 USDC on Base') and, by mentioning 'balance', implies a read-only operation with no side effects. It does not disclose what happens on invalid addresses, network errors, or output format, leaving some behavioral gaps.

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 compact and efficient, with two sentences covering the core purpose, input format, and cost. Every element earns its place, and the most essential information (what the tool does) is front-loaded. No filler or redundant phrasing.

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 single-parameter tool with no output schema and no annotations, the description covers the essential elements: purpose, network, asset list, input format, and cost. It does not describe the return structure, but a balance check's output is reasonably predictable. Overall, an agent has enough context to invoke it correctly.

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 parameter description is generic ('service input'), but the tool description adds meaningful detail by specifying 'input=dirección 0x...', clarifying that the input must be a 0x-prefixed address. This goes beyond the schema and helps an agent construct a correct call. It could add an example, but the format hint is already valuable.

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's function: checking on-chain ETH and USDC balances for an address on Base. It specifies the resource (address), the assets (ETH and USDC), and the network (Base), which goes beyond a vague purpose. It does not explicitly contrast with the sibling 'wallet-balance', but the network and asset specificity help an agent differentiate.

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 implies usage context — when an agent needs ETH/USDC balances on Base — and provides input guidance ('input=dirección 0x...'). However, it does not explicitly state when not to use this tool or mention alternatives like the sibling 'wallet-balance'. Usage is inferable rather than explicitly routed.

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