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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new traits the annotations cannot express: that the call is free and that it returns 'every' issuer (i.e., no filtering or pagination caveat). It stops short of noting auth requirements or response size, but the added cost and completeness signals are real 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?

Three compact sentences with the highest-value fact ('Free.') front-loaded, then payload, then the routing instruction. No sentence is filler and the ordering matches how an agent would use it.

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 an output schema present, the description need not explain return structure, and it correctly focuses on scope and sequencing instead. For a zero-parameter registry listing, everything needed to call it correctly is present.

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 baseline is 4 per the rubric; there are no argument semantics that need explaining. The description cannot add parameter meaning because none exist.

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 (lists every issuer in the registry) and enumerates the exact fields returned, so an agent knows precisely what it gets. It is clearly distinguishable from the sibling stablecoin_reserves, which is a data-fetch rather than a registry enumeration.

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?

Explicitly prescribes ordering: 'Call it first to pick a symbol for stablecoin_reserves.' That names the alternative tool and the condition under which this one precedes it, leaving nothing to inference.

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