onion_lookup

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

Annotations already declare readOnlyHint true, destructiveHint false, and openWorldHint true, covering the safety profile. The description adds the useful fact that it returns certificates, ports, and associated Bitcoin addresses, which exceeds annotation info, but says nothing about rate limits, source reliability, or caching.

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 tight sentences: what it does and what it returns. Front-loaded with the verb and resource, no filler.

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?

Adequate for a simple single-param read tool with rich annotations. However, with no output schema, the description lists return fields but doesn't explain their shape or reliability, and omits any usage context among many sibling Tor tools.

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 single parameter is fully documented there. The description adds no parameter syntax but has zero parameters to compensate for, so baseline 4 is correct per the rules.

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?

Clear verb (look up) plus specific resource (metadata for a .onion address) and names the data source (CIRCL AIL). It distinguishes itself from siblings like tor_scrape_onion or tor_fetch_onion by focusing on metadata retrieval, though it doesn't explicitly say so.

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?

No when-to-use guidance. With many Tor-related siblings (tor_scrape_onion, tor_fetch_onion, tor_status, tor_search_onion), the description never explains when to pick this tool versus the alternatives.

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