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

No annotations were provided, so the description carries the full burden and it does disclose non-obvious behavior: the tool is paid ($0.005 via x402/USDC on Base) and performs a read-only eth_call against a public RPC. It also describes the return shape (raw + human balance, decimals, symbol). Missing failure modes (invalid contract, non-ERC20, RPC errors) and any rate limits keep it from a 5.

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 dense sentence that front-loads the cost and core purpose before the mechanism and return values. No filler or repetition.

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?

With no output schema, the description usefully enumerates the returned fields, and the two required params are fully covered by the schema. It omits error handling and any network caveats beyond 'Base address', but for a simple two-param single-value lookup this is largely sufficient.

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 coverage is 100%, so both parameters are already documented as 0x... wallet and token contract addresses. The description adds only marginal framing ('any Base address', balanceOf) and no format or constraint details beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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?

States a specific verb and resource ('on-chain ERC20 token balance'), plus the exact mechanism (eth_call balanceOf on public Base RPC) and scope (any Base address). An agent can distinguish this from siblings like get_crypto_price or get_token_verdict without opening the schema.

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?

It discloses the price and payment rail, which is pre-call decision information, but gives no when-to-use guidance, no exclusions, and does not mention any sibling alternatives (e.g., get_token_verdict for judgment, get_usd_price for pricing). The agent must infer when this is the right tool.

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