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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds real context — chain-agnostic coverage, ENS resolution, and that screening runs against enabled sanctions and crime lists — but says nothing about cost, latency, or what an empty match means; return shape is covered by the output schema.

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?

Two sentences, zero filler, with the primary capability and its scope front-loaded before the optional parameter note. Nothing repeats the schema or annotations.

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?

An output schema exists so return values need not be described, and read-only annotations cover the safety profile. Remaining gaps are small — no guidance on slug discovery or on behavior when the screening lists are unconfigured — but an agent has enough to invoke it correctly.

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 0%, so the description must carry both parameters, and it partially does: it clarifies that 'address' accepts ENS names with a concrete example, and that 'lists' is an optional comma-separated set of list slugs. It does not say where valid slugs come from or what the null default means (presumably all enabled lists).

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 and resource ('Screen a crypto address') and broadens scope precisely: any chain, ENS names accepted, screened against sanctions and crime lists. The resource type alone separates it from siblings like screen_email and screen_pep, though no sibling is named explicitly.

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?

Usage is implied by the screening/sanctions context, and 'across the enabled sanctions and crime lists' hints that list configuration governs behavior. There is no explicit when-to-use guidance, no mention of what to do when no lists are enabled, and no routing to alternatives such as screen_pep for person-level checks.

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