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

Annotations already mark this as read-only, idempotent, and non-destructive, and the description adds valuable behavioral detail beyond those fields: reverse DNS is never actually run here; only the exact commands are handed back. It also discloses that the same functionality is available over plain HTTP, which is useful for non-MCP callers. There is no contradiction with the annotations.

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 but purposeful: the JSON-RPC example, the HTTP alternative, the reverse-DNS caveat, and the freshness note all contribute useful information. It is front-loaded with 'FIRST CALL' and organized clearly with an example. It is longer than strictly necessary, but the length is justified by the invocation alternatives and behavioral caveats.

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?

Despite having no output schema, the description covers what the tool returns, how fresh the information is, when to call it, and how to invoke it both via MCP and HTTP. The single optional parameter is fully explained by the schema and examples. An agent has everything needed to select and call this tool correctly.

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?

The input schema already documents the sole optional parameter at 100% coverage, including that omitting it returns all crawlers. The description reinforces this with the 'needs nothing' note and the claudebot example, but it does not add substantive semantics beyond what the schema already provides. With full schema coverage, a 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 states a precise purpose: report per-crawler whether the operator publishes IP ranges, documents reverse DNS, or publishes no verification method, including exact source URLs or dig commands and freshness. It also includes a concrete JSON-RPC invocation and example. This clearly distinguishes it from siblings like verify_batch or lookup_prefix by focusing on available verification methods rather than executing verification or prefix lookups.

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 explicitly labels this as the 'FIRST CALL' and instructs calling it before interpreting addresses that matched nothing, giving clear when-to-use context. It also notes that it needs no arguments, so no prerequisites are hidden. However, it does not explicitly name sibling alternatives or state when not to use this tool, so it falls just short of full routing guidance.

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