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

Annotations already declare readOnly, non-destructive, idempotent=false, and openWorld, so the safety profile is covered. The description adds genuinely useful context beyond them: malformed-address handling (400, uncharged), pricing and free-call policy, and the fact that repeats are charged (consistent with idempotentHint=false). It stops short of describing response shape, but with annotations present this is solid additive value.

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-loads purpose and outputs, then usage, then edge cases and pricing. Dense but each clause carries information; the trailing pricing/free-call sentences are somewhat lengthy but still relevant to cost-aware invocation.

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 and a single-parameter tool, the description fully specifies return contents (bytecode size, minimal-proxy detection, implementation pointer), error behavior, and cost model. Nothing essential to correct invocation 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 coverage is 100% and there is only one parameter, so the schema already documents 'address'. The description reinforces the 0x format and supplies a worked example, which is marginal added meaning over structured data.

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 gives a concrete verb and resource ('Check whether a 0x address on Linea is a smart contract or a plain wallet') plus the specific outputs (bytecode size, EIP-1167 minimal-proxy status, implementation address). It distinguishes itself from the risk-verdict sibling check_counterparty, though it does not clarify how it differs from the closely related linea_proxy tool.

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?

Explicit when-to-use ('before sending funds or approving a spender') and a named alternative with its selection condition ('for a fuller risk verdict use check_counterparty'). The agent needs no inference to route correctly.

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