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

Annotations already provide readOnlyHint, openWorldHint, idempotentHint, and non-destructive hints. The description adds transparency by specifying 'Keyless' (no auth) and enumerating the exact output fields (peering policy, traffic level, info type, scope, prefix counts), which is useful beyond the annotations. It does not contradict 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 appropriately concise: two sentences with no fluff. It front-loads the purpose, then states key output fields and input requirements. Every clause adds information, and the keyless note is a compact way to convey authentication status.

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 absence of an output schema, the description compensates by listing the returned attributes. It covers the purpose, input requirements (currently query/ASN), and the data returned, making it self-contained. It is complete enough for a search tool, especially given the rich annotations and parameter descriptions.

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?

The schema covers all three parameters with descriptions, so the baseline is 3. The description adds meaning by indicating that query and ASN are alternative inputs ('Provide a name query or an ASN'), which clarifies their relationship. It also notes 'Keyless' implicitly affecting usage, but the main added value is the mutual exclusivity hint.

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 identifies the tool as a lookup for PeeringDB networks by name or ASN, with a specific verb ('Look up') and resource ('networks in PeeringDB'). It also lists the returned attributes, which distinguishes it from sibling search tools like search_exchanges or search_facilities.

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 clear context on how to invoke the tool: 'Provide a name query or an ASN' and 'Keyless' indicates no authentication prerequisites. It does not explicitly mention alternative tools, but the coverage of input modes is clear. Since no exclusions or when-not-to-use guidance is given, it gets a 4 rather than 5.

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