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

Beyond the readOnly/openWorld annotations, it discloses pricing and rate limits (25 free calls/day, then $0.001 USDC via x402) and the non-obvious resolution semantics: a name resolves to its target, not its owner, and an owner is never substituted on NOT_FOUND. It also explains the anti-spoofing rule for reverse lookups, which is exactly the kind of behavior an agent cannot infer from 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?

It is short and front-loads the cost/limit caveat before the semantics, with zero filler sentences. The density of the semantics clause makes it slightly hard to scan on first read, but nothing is redundant.

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 read-only, no-output-schema tool this covers the essential risk areas: cost, NOT_FOUND behavior, and trust of reverse records. It does not describe the return payload shape or how NOT_FOUND surfaces to the caller, which would round out invocation confidence.

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?

With only 33% schema coverage (only chain is documented in-schema), the description must carry the load for name and address, and it does: it defines their directionality and the mutual-exclusivity constraint. The chain parameter's meaning is left entirely to the schema, which is the one remaining gap.

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 states a precise bidirectional operation ("name -> address, or address -> primary name") and names the resource via the .apt title, so the agent knows exactly what the tool does. The "give exactly one" clause further pins the call shape, distinguishing it from a generic resolver such as ens_resolve by chain.

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 an explicit input rule (exactly one of name or address), which tells the agent how to invoke it, and the forward/reverse framing clarifies which form to supply for which goal. It stops short of naming alternatives or stating when not to use it (e.g., vs. aptos_address_validate for format-only checks).

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