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

With no annotations, the description carries the full burden and does a good job: it discloses the upstream method (eth_getTransactionCount), the cost ($0.005 per call), and the payment rail (x402/USDC). It omits edge-case behavior such as what nonce is returned for an address with no history and any rate limits.

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?

Four short sentences, each earning its place: core function, use-case, backend source, and pricing. The primary purpose is front-loaded with no filler.

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 simple two-parameter read operation with no output schema, the description supplies the return values, the use case, the data source, and cost/payment details an agent needs before calling. Nothing material is missing.

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 are already documented, and the enum-like chain list lives in the schema. The description adds no syntax, format, or default details for chain or address, so the baseline 3 applies.

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 names a specific verb+resource ('Next transaction nonce for any address') and adds a second return value (contract detection). It is clear, but the contract-detection clause overlaps with the sibling evm_is_contract, so an agent gets no explicit guidance on which to prefer, which slightly weakens differentiation.

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?

'What an agent needs before signing a transaction' gives a concrete usage context that routes the agent to the right moment in a workflow. It stops short of naming alternatives (e.g., evm_is_contract for the boolean alone) or stating when-not to use it, so it is clear context without exclusions.

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