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

With no annotations, the description carries the full burden and does well: it discloses the query strategy (authoritative server when reachable, otherwise public resolvers over DoH), names all 8 resolvers, and states that results are marked up-to-date with remaining TTL for stale answers. It does not cover failure behavior when resolvers time out or expected latency, which keeps it below a 5.

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 with the purpose stated first and supporting detail after. The parenthetical and embedded resolver list make it dense, but every clause (authoritative source, DoH, staleness marking, TTL) adds real information.

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 2-parameter tool with no annotations and no output schema, the description supplies the output shape (per-source up-to-date markers, remaining TTL) and the query mechanism, which is the important missing context. Only the record-type parameter and timeout/failure handling are left unaddressed.

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 coverage is only 50%: `type` carries a schema note ('default A') but `domain` has no schema description. The description never mentions that the record type is selectable, so it fails to compensate for the gap. It does implicitly clarify that `domain` is the name whose propagation is compared rather than an arbitrary query target.

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 ('Check whether a DNS change has spread') and goes further to describe the mechanism: querying the authoritative NS plus 8 named public resolvers. This is clearly distinguishable from the sibling dns_lookup, which performs a plain lookup rather than a propagation comparison.

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 scenario is implied ('whether a DNS change has spread'), which points to post-change verification, but there is no explicit when-to-use statement, no mention of when dns_lookup or reverse_dns would be the better choice, and no prerequisites (e.g., that the change must already be published).

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