net-mcp

Irr Autnum

irr_autnum

Retrieve an AS's registered routing policy from IRR databases by querying its aut-num object. Returns the AS name, description, import/export policies, and organisation handle to clarify how the AS is announced and routed.

Instructions

Look up an aut-num object in IRR databases.

Returns the AS name, description, import/export policies (capped at 20 lines each), and organisation handle. Useful for understanding an AS's registered routing policy. The ASN may be given as 'AS13335' or a bare '13335'.

One object is returned per queried registry: the first aut-num object in that registry's response whose aut-num matches the requested ASN. registry is the server queried and source is the object's own source: attribute (they differ for mirrored objects). If a registry cannot be reached, error is set and results from the remaining registries are still returned.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`asn`	Yes	ASN to look up (e.g. 'AS13335' or '13335')
`sources`	No	Comma-separated IRR sources (default: radb,ripe). Available: radb, ripe, arin, apnic, afrinic, lacnic, nttcom, level3, altdb.

Output Schema

TableJSON Schema

Name	Required	Description
`asn`	Yes	Normalised ASN that was looked up, e.g. 'AS13335'
`error`	No	Set when the whois query failed; other fields may be empty or partial.
`objects`	No	One aut-num object per registry that returned a match
`sources`	No	Registries queried, in order

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 22, 2026

TDQS

A4.5/5.0

Behavior5/5

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

With no annotations provided, the description carries the full burden and does so well. It discloses one-object-per-registry behavior, the registry/source distinction, error handling when a registry is unreachable, partial result continuation, and the 20-line cap on policies. This is rich behavioral context beyond what the schema alone could convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise, front-loaded with the main purpose, then organized into return behavior and edge-case handling. Every sentence adds useful information with no filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only lookup tool with an output schema, the description covers input formats, returned content, query semantics, registry/source meaning, and failure behavior. Nothing an agent needs to call or interpret this tool correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already provides 100% coverage of both parameters, including examples and allowed source values. The description reinforces the ASN format variants, but adds little beyond the schema, so the baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Look up an aut-num object in IRR databases.' It then details the exact returned fields, making the tool's purpose unmistakable and distinct from sibling tools like irr_route_lookup or irr_as_set_expand.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context for when to use the tool ('useful for understanding an AS's registered routing policy'), though it does not explicitly name alternatives or state when not to use it. This is clear context with no exclusions, but not quite full alternative-routing guidance.

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