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

No annotations are provided, so the description carries the full behavioral burden. It does disclose a genuinely useful non-schema trait — that each call is paid at $0.015 USDC via x402 — but says nothing about rate limits, error behavior, or output structure, leaving significant behavioral gaps for a tool with zero annotation coverage.

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?

A single front-loaded sentence delivers purpose, supported record types, the default parameter behavior, and the pricing model with no wasted words. The bracketed pricing note is clearly demarcated and easy to scan.

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 two-parameter read-only lookup with no output schema and full schema coverage, the description supplies what an agent needs: what it fetches, the type options, the default, and the payment requirement. Only minor omissions (response shape hints, failure behavior) keep it from a 5.

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 'domain' and 'type' fully documented including the ALL default, so the schema already does the heavy lifting. The description largely restates the same type list and default without adding format examples, validation rules, or edge-case behavior, matching the baseline of 3.

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 specific verb and resource ('DNS records for any domain via DNS-over-HTTPS') and enumerates the record types returned (A, AAAA, MX, TXT, NS, CNAME), which clearly separates it from siblings like liminal-domain-age or liminal-http-headers. It does not, however, explicitly name a sibling it should not be confused with, so it falls just short of a 5.

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 explains how to use the tool's main parameter ('Pass type ALL (default) or a single type'), which is implied usage guidance rather than explicit when-to-use vs alternatives. There is no statement of when this tool is the wrong choice versus the other liminal-* lookup tools, so usage is only partially addressed.

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