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

Annotations already indicate readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false, establishing a safe, non-destructive read-only tool. The description adds value by specifying that it queries the 'current routing state on the global BGP table' and returns 'origin ASNs and AS-path lengths', giving behavioral insight into data refresh and output scope beyond 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 concise—one sentence with embedded examples and uses—covering purpose, return details, and use cases. It is front-loaded with example queries and efficiently communicates key information without redundancy, though it could be slightly more structured for skimmability.

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?

Given the simple single-parameter input and the existence of an output schema, the description sufficiently explains what the tool does, what it returns, and why to use it. It omits details about pagination, result limits, or global coverage, but these are common expectations and the output schema likely fills gaps. Overall, it is complete for its class.

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% with a clear description for the 'resource' parameter ('IP, prefix, or ASN'), so baseline is 3. The description reinforces this with examples but does not add new semantic details like input format constraints or allowed ranges. It is adequate but not enhanced beyond the schema.

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 clearly states the tool returns origin ASNs and AS-path lengths for a given IP, prefix, or ASN from the global BGP table. It provides usage examples ('BGP routes for [prefix]', 'what AS announces [IP]') and explicit use cases (detect BGP hijacks, audit route propagation, find anycast announcers), making the purpose unambiguous and distinguishable from sibling tools like whois or as_overview.

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 lists three specific use cases (hijack detection, route audit, anycast identification), which guides when to use the tool. However, it does not mention when not to use it or provide comparisons to alternative sibling tools (e.g., as_overview, prefix_overview), leaving the agent without explicit exclusion criteria.

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