Defined term
Machine Relations Index
(MRI)The Machine Relations Index (MRI) is a public source-behavior dataset tracking which root domains answer engines cite when responding to B2B buyer-intent questions. It classifies every observed source by function, measures engine coverage and vertical spread, and publishes the full cited-domain set with query evidence.
Explore the MRI →What the Machine Relations Index tracks
The MRI monitors how answer engines — ChatGPT, Perplexity, Gemini, Claude, and Google AI Mode — select sources when they respond to commercial research questions. It captures every root domain cited across a monitored B2B buyer-query set and classifies each domain by its source function using deterministic rules.
The index is not a ranking of brands or a quality score. It is a behavioral map of the source layer that machines use when constructing answers to buyer-intent queries. A domain appears in the MRI because at least one engine cited it in at least one observed query.
Source-role taxonomy
Every domain in the MRI is classified into one of nine source roles:
- Editorial publication — news and trade media
- Analyst and consulting research — advisory and consulting firms
- Market and company database — data platforms and market research
- Academic and government source — institutional knowledge
- Community and social platform — user-generated surfaces
- Wire and press-release distribution — syndication networks
- Search or media platform — discovery infrastructure
- Vendor-owned source — explicitly identified company domains
- Other observed source — long-tail domains not yet classified by deterministic rules
Four dimensions of measurement
- Citation volume — total citation events in the observation window
- Engine coverage — which engines cite this source, revealing cross-engine trust patterns
- Vertical spread — how many B2B industry verticals the source appears in
- Query evidence — sample prompts that triggered citations
Why the MRI matters
For Machine Relations practitioners, the MRI answers a direct question: when a buyer asks an AI engine about your category, which sources does the engine reach for — and is yours among them?
The MRI was coined by Jaxon Parrott and is maintained as a public research artifact at machinerelations.ai/index. Machine-readable versions are available as JSON and Markdown.
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