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

Annotations already cover read-only, idempotent, and non-destructive behavior; the description reinforces this with 'it only looks the address up, it never changes anything' and adds valuable return-shape detail (AML score, risk_level, category, sanctioned exposure, source-of-funds). No contradiction with annotations.

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 concise and front-loaded with purpose and return fields. The read-only sentence is somewhat redundant with the annotations but is brief and not distracting. Overall it is well-structured with minimal waste.

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 only two fully documented parameters and no output schema, the description adequately covers what the tool returns, confirms it is read-only, and tells the agent this is the authoritative risk source. It does not discuss error cases or rate limits, but those are minor for such a simple lookup 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 description coverage is 100%, with both address and chain described and chain also having an enum. The description adds AML context but does not provide extra semantic detail beyond what the schema already supplies, so the baseline 3 is appropriate.

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 uses a specific verb and resource ('Screen a crypto wallet address for AML/KYT risk') and lists concrete return fields. It asserts it is the ONLY authoritative source for address risk, which helps distinguish it from web-searching, but it does not explicitly contrast with sibling tools trace_funds or list_counterparties.

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?

It gives clear usage context: use this tool to screen addresses for AML/KYT risk and do not guess or web-search instead. It does not provide exclusions or guidance on when to prefer sibling tools, so it stops short of a full 5.

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