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

Annotations already establish readOnlyHint and openWorldHint, so the safety and external-network profile is covered. The description adds real behavioral detail beyond that: which resolvers are queried and that the response reports per-resolver answers and flags inconsistencies.

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?

Three tight sentences: purpose first, then when to use it, then a return-value note. Every sentence carries information an agent can act on, with no repetition of the title or schema.

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?

With no output schema, the description usefully summarizes the return shape (per-resolver answers plus inconsistencies). For a two-parameter read-only diagnostic it is nearly complete, though it says nothing about timeouts, partial resolver failures, or query cost/latency.

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% and the type enum is documented in the schema, so the baseline is 3. The description goes further by naming the resolver set (Google, Cloudflare, Quad9), which tells the agent that resolver selection is fixed rather than a parameter and frames how to interpret per-resolver output.

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 (resolve), resource (name), and an unusual scope (across several named public resolvers) with the added behavior of comparing answers. This distinguishes it immediately from sibling diagnostics like check_http, check_port, and ip_lookup, which probe different layers.

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?

Gives two concrete triggering scenarios: verifying propagation after a DNS record change, and diagnosing users who see a different IP or NXDOMAIN. Strong when-to-use guidance, though it never names an alternative tool or a when-not condition (e.g. single-resolver or reverse lookups).

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