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

Annotations already declare readOnlyHint=true, and the description reinforces this with 'Does not spend money.' It adds useful behavioral context beyond annotations: the unclaimed vs claimed response shape, payment/HTTP 402 paths, payTo/noSelfPay/TTL, and the free GET endpoints for alternative flows. This goes well beyond a bare read-only hint, though some details remain cryptic.

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 dense and every clause carries information, but the structure is a run-on telegraphic block with cryptic abbreviations ('payTo + noSelfPay + TTL 30d', 'how/next') and no logical breakdown. It is concise in length but not well-structured for quick agent consumption.

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?

There is no output schema, so the description carries the burden of explaining return values; it does describe the key fields for both unset/unclaimed (taken false, how/next, payment details) and set (origin, ownerHint?, expiresAt) cases. It also covers cost and access alternatives. It leaves some details ambiguous (e.g., exact format of origin, ownerHint?), but for a simple lookup tool it is reasonably complete.

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 'n' and 'name' already documented in the input schema. The description repeats the lowercase [a-z0-9-] 3-32 constraint and mentions 'n=' but adds no new semantic meaning beyond what the schema already provides, so the baseline of 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 clearly identifies the tool as a free ENS-style agent name lookup, with a specific verb and resource ('name lookup'). It is clear in function, but it does not explicitly distinguish itself from sibling tools like name_register, ens, or find, instead only noting that REST GET /name is the same SKU.

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?

The description implies usage for read-only lookups ('FREE', 'Does not spend money') and explains behavior for unset vs set names, but it never explicitly states when to use this tool vs alternatives, nor does it mention exclusion criteria or related tools. There is no guidance about when not to use it or under what circumstances a sibling would be more appropriate.

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