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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: certain chains have records 'behind right now' and cannot be vouched for, and the `coins` array is a strictly smaller set than the claimed coverage. It stops short of describing pagination or the exact shape of the staleness signal.

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-loaded with what it returns, then the call-to-action, then the field-level distinctions. Every sentence carries information, though the single dense paragraph and the final run-on clause about issuer naming are slightly harder to parse than they need to be.

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 no parameters, the description carries the full burden of explaining return content, and it names the key fields (chains_claimed, coins_covered, contracts_checked, companies_checked) plus the caveat about lagging chains. It does not fully specify the response structure, leaving some gaps an agent must discover at call time.

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?

The tool takes zero parameters, so the schema has nothing to document and the baseline is 4. The description correctly spends no effort on parameter semantics.

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 resource (the coverage of the stablecoin blacklist/freeze record) and enumerates what it returns: covered blockchains and coins, the date of the most recent recorded event, and which chains are currently behind. It is clearly distinguishable from event-listing siblings like list_freeze_events because it is metadata about the record itself, not the events.

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?

Gives explicit when-to-use guidance: call it to determine whether a chain or coin is in scope before relying on an answer, and to check whether any part of the record is lagging. It does not name an alternative or state when-not to use it, but no sibling competes for this purpose.

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