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

Beyond the readOnly, idempotent, and non-destructive annotations, the description adds meaningful detail: no third-party touch, no fetching, no invented data, and facts sourced only from request headers or a file this host publishes. This materially improves an agent's trust and expectations.

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 front-loaded with the essential safety and determinism facts, then elaborates on what is classified. It is somewhat verbose in the middle, but each sentence adds a distinct behavioral or output-related detail, so little is wasted.

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?

Without an output schema, the description does a good job enumerating the categories of returned information: user-agent, address, assigned class, prior-visit status, fetch-guard decision, and rate limit. It does not specify exact response keys or data types, so an agent would still need to discover the precise response shape by calling it.

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?

With zero parameters, the schema alone is nearly empty, but the description explicitly says 'Takes no arguments' and gives the example arguments={}. This fully clarifies the parameter contract and even explains why no arguments exist.

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 purpose: classify the current request and report caller identity, class, rate-limit, and fetch-guard behavior. It clearly distinguishes this from the sibling report/list tools by centering on zero-argument request introspection.

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 gives clear context for when to call it: it is safe, deterministic, makes no external fetches, and explains the request just sent. It does not explicitly list when to choose an alternative or when not to call it, so it stops short of a 5.

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