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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the read-only nature is covered. The description adds valuable behavioral context beyond annotations: the check covers specific risk categories, requires passing `from` to detect look-alikes, returns a verdict with reasons, and exposes a cost model (5 free checks/day, then $0.002 via x402). This is strong supplemental disclosure.

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 description is three tightly packed sentences with no filler. The core usage directive is front-loaded ('Before sending crypto on Base, check the destination'), followed by concrete risk categories, parameter guidance, and pricing. Every sentence earns its place.

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 tool with no output schema, the description covers key operational details: what is checked, how to enable the poisoning check, what the return looks like, and the pricing model. It is slightly light on describing the exact verdict format, but the annotation set already covers read-only and open-world behavior, making the description adequate for selecting and invoking the tool.

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 the baseline is 3. The description additionally clarifies the real-world purpose of the `from` parameter by linking it to address poisoning ('pass `from` = your wallet'), which enriches the schema description. It does not mention `known` explicitly, but the schema already documents it, so no significant gap exists.

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 clearly states the verb ('check'), the resource ('the destination' / address safety), and the specific scope (Base) in the first sentence. It enumerates distinct threat categories (scam blacklists, address poisoning, token contracts, burn addresses, never-used addresses) and explicitly says it returns a verdict with reasons, making the purpose unambiguous and distinct from the sibling check_token_safety.

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 description gives an explicit when-to-use directive: 'Before sending crypto on Base, check the destination.' It also explains how to use the `from` parameter for the address-poisoning check. However, it does not explicitly contrast this tool with the sibling check_token_safety or state when not to use it, so a small guidance gap remains.

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