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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the useful context that the lookup 'answers without an API key', which is a practical behavioral detail. It does not describe return format, rate limits, or failure behavior, but with annotations covering the key traits, this is acceptable.

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 concise sentences front-load the purpose and include a concrete example call. Every element earns its place—there is no filler, and the example is genuinely useful for an agent to see invocation format.

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 single-parameter lookup tool with rich annotations, the description is adequate but not complete. There is no output schema, yet the description does not explain what Tor relay metadata the response contains or how to interpret results. Error or edge-case behavior is also absent, so an agent would have to infer the return structure.

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 description coverage is 100%, so the input parameter is already fully documented in the schema as accepting a domain, IP, ASN, or file hash. The description adds an example call format but no extra semantic detail about the parameter. The baseline of 3 applies because the schema handles the heavy lifting.

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 names a specific verb and resource: 'Look up Tor relay metadata for an address.' This clearly states the tool's purpose and the domain-specific resource makes it distinguishable from siblings like whisper_lookuptlsfingerprint. It does not explicitly call out sibling differences, but the resource focus is strong enough for an agent to identify the tool's role.

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 provides no guidance on when to choose this tool over alternatives. It states the example call and the no-API-key benefit, but never explains when to use Tor relay lookup versus other lookup tools such as whisper_lookuptlsfingerprint or whisper_origins. There are no exclusions or alternative routing hints.

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