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

With no annotations, the description carries the burden and does well: it discloses that no API key or account is needed and states the cost ($0.005 per call, paid over x402 in USDC) plus the returned fields, which tells the agent this is a cheap read. It stops short of describing failure behavior for a non-contract or wrong-chain address, which matters for a lookup keyed on an arbitrary string.

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?

Front-loaded with the trigger condition and the returned fields, then exclusions, then cost. The decimals aside ("a million times too big") is colloquial but earns its place as a usage rationale; the endpoint paths in parentheses are slightly redundant with the sibling names.

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?

No output schema and no annotations, but the description enumerates the returned fields and the pricing/auth model, which is most of what an agent needs. The remaining gap is edge-case behavior (unknown chain, address with no code) for a tool whose only input is an unvalidated address string.

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 baseline is 3, and the description adds real meaning on top: it stresses that the input is a bare token address (not a symbol or pair) and explains why decimals is returned, which frames how the output should be used. It adds no guidance on default chain behavior when the optional chain parameter is omitted.

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 bundle and resource: returns name, symbol, decimals and total supply for any ERC-20 from a single address, in one call. It explicitly contrasts with evm_erc20_balance, evm_token_price and evm_token_safety, so the agent can distinguish it from its closest siblings without opening a 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?

Gives an explicit trigger condition ("a bare token address and must label or format it before showing or computing anything") and an explicit exclusion list naming three alternative endpoints with their paths. Both when-to-use and when-not-to-use are covered, leaving nothing to inference.

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