scan_token

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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds genuinely new operational context: unavailable metrics return null, and each call costs 0.003 USDC via x402 on Base. That payment requirement is the kind of pre-call constraint an agent must know. Rate limits and failure modes are not covered, keeping it below 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?

Three tight sentences, front-loaded with what it reads and closled by the cost. Every clause carries actionable information (scope, not-an-audit caveat, null behavior, price, payment rail); nothing is redundant.

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 idempotent read tool with no output schema, the description covers the essential gaps: what is returned, how missing values appear, the limitation of the heuristic, and the payment model. An agent has everything needed to decide and call 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?

Schema description coverage is 100%, so both parameters (chain with its default, token with address-or-symbol format) are fully documented in the schema. The description adds no additional parameter semantics, which is the correct baseline 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 (Read) and resource (GoPlus ERC-20 security flags plus a risk heuristic), and immediately bounds the claim with 'this is not an audit.' None of the siblings (prices, gas, quotes, whales, yields, funding, wallet profile) overlap, so an agent can route to it unambiguously.

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 'this is not an audit' clause functions as an explicit when-not boundary, and the micropayment cost implies a paid-scan context. It does not name an alternative tool or describe when a scan is warranted versus simply reading on-chain data, so it stops short of full routing guidance.

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