Glossary

Action agent — A non-human visitor that acts on your site: an AI agent driving a browser for a user (ai_agent) or a scripted browser (automation).

Actor — Who produced an event: an agent, a human or a bot. Every event has an actor type, a family, a score and signals.

Actor filter — The switch at the top of every report: All, Agents + humans, Humans, Action agents, Indexing bots, Mixed sessions.

Actor score — Probability, from 0 to 1, that an activity is not human.

Actor segment — A run of consecutive events by the same actor within a session.

AI Assistants channel — Sessions arriving from a link in ChatGPT, Perplexity, Claude, Gemini, Copilot and similar assistants.

AI fetcher — An AI assistant reading a page because a user asked a question (ChatGPT-User, Claude-User, Perplexity-User).

Billable events — Agent and human events; they count toward your plan. Bot events are free.

Bridge — The part of the tag that reads another tool's calls (GA4, GTM, Matomo, Piano, AT Internet, Adobe, Segment, Meta).

Cookieless mode — Measurement with nothing stored on the device and a visitor ID that changes daily.

Element step — A funnel step defined by a click on an element (data-ah-name or CSS selector).

Indexing bot — A non-human visitor that reads your site: search crawler, AI crawler, AI fetcher, monitoring tool.

Ingest key — A secret key used by your server or CDN to send server-side hits.

MCP — Model Context Protocol, the standard AI assistants use to connect to tools. Eureka's MCP server lets Claude and other assistants query your analytics.

Mixed session — A session where a human and an agent took turns.

Navigation mode — The kind of session: agent, human, mixed or bot.

Property — A website (or group of sites) measured with one ID, like AH-1A2B3C.

Signal — One piece of evidence behind a classification, for example webdriver or center_click.

Spoofed bot — A visitor claiming to be a known crawler from an IP address its owner does not publish.

Web Bot Auth — A standard for agents to sign their requests (Signature-Agent header), so sites can identify them cryptographically.