ASN / BGP lookup

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

Annotations already declare readOnly, openWorld, idempotent, non-destructive, so the safety profile is covered. The description adds meaningful behavioral context beyond that: result caching for 6h and the truncation policy on prefixes (first 100, IPv4 then IPv6, with totals). It stops short of stating rate limits or error behavior, so not a 5.

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?

Front-loaded with the return shape, then usage, then the sibling disambiguation, then the caching note. Four dense sentences with no filler, though the parenthetical about prefix ordering is slightly crammed mid-sentence.

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?

No output schema, so the description carries the return-value burden itself and does so by enumerating the returned fields and prefix truncation. Caching and sibling routing are covered. It omits error handling and rate-limit behavior, but for a read-only lookup tool this is close to complete.

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 both parameters carry descriptive text including accepted query syntax and default values. The description's note about prefixes being limited to the first 100 adds runtime behavior the schema does not, but otherwise the schema does the heavy lifting. Baseline 3.

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 (look up) and resource (IP or AS number), enumerates exactly what is returned (announcing AS, covering prefix, holder, announcement status, prefixes), and clarifies it works for every RIR, not just RIPE. An agent can distinguish it from ip_whois and dns_lookup without opening any schema.

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 explicit use cases (find hosting/network provider behind an IP, map an organisation's address space) and names the alternative (ip_whois) with the condition that routes to it (registration record and abuse contact). Clear when-to-use and when-to-use-something-else.

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