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

Goes well past the readOnlyHint/openWorldHint annotations by disclosing the commercial model: 3 free calls per day across all tools, then $0.0025 USDC via x402 or card credits, paid in-band through params._meta["x402/payment"]. It also names the price data source (DefiLlama), notes a confidence value accompanies the price, and caps batching at 10 addresses — all behavior an agent needs before deciding to call.

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 cost/payment disclosure is valuable and front-loaded, but the usage guidance is literally stated twice in near-identical form ("Use it before showing, pricing or converting a token amount" then "When to use: Use token-info before displaying, converting or pricing an ERC-20 amount"). That redundancy plus the title-repeating phrasing wastes roughly a fifth of the text.

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 an output schema present, the description needn't explain return values, and it covers cost, rate limits, chains, batching and data provenance — enough to call correctly. The only soft spot is that "confidence" on the USD price is named but never characterized, leaving the agent unsure how to interpret a low-confidence quote.

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% and both enums are documented inline, so the schema already carries the parameter burden. The description reinforces the 10-address comma-list limit and the five supported chains, but adds no syntax, defaulting or format detail beyond what the schema states — baseline 3.

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: ERC-20 token lookup returning name, symbol, decimals, total supply, USD price and FDV across five named chains, batchable to 10 addresses. The returned field set implicitly separates it from price-only siblings like token_price or token_prices, but it never names those siblings explicitly, so an agent must infer the boundary.

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?

"Use it before showing, pricing or converting a token amount" gives a clear triggering context, and the supported chains narrow scope usefully. However, it offers no exclusions or alternative routing, despite siblings token_price, token_prices, token_compare and token_risk that an agent could plausibly confuse with this one.

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