net_dns_compare

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

No annotations are provided, so the description carries the burden. It does disclose the meaningful behavior: four named third-party resolvers are contacted, which implies external network egress and no local state change, and it frames the result as a comparison that surfaces disagreement. It says nothing about latency, timeout/failure semantics when one resolver is unreachable, or what the comparison output looks like, which matters for a tool with no output schema.

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?

Two sentences, zero filler, and the operational summary is front-loaded before the explanatory rationale. Every clause earns its place.

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 one-parameter read-only lookup with no output schema, the description covers what it queries, against whom, and why. The remaining gap is what the comparison actually returns (per-server answers? agreement flag? errors per resolver?), which would let the agent use the result without guessing.

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 100% for the single required 'host' parameter, so the schema already documents it. The description reinforces that the same question (hostname) is asked of every resolver, but adds no format or edge-case detail beyond that.

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+resource: query the same name against AliDNS, DNSPod, Cloudflare and Google and compare the answers. That is clearly distinct from the sibling tools (proxy status, hosts check, registry check), though it never explicitly names a sibling as the alternative for a general 'network is broken' investigation. The purpose is unambiguous on its own terms.

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 second sentence supplies a concrete trigger condition — 'a host resolves but does not work' — which tells the agent exactly when this tool is the right call versus generic diagnostics. It stops short of stating exclusions or naming the sibling tools to use instead for other failure modes, so it is clear context without alternatives.

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