AI agents like Meta's Muse now change their behavior to avoid detection, so header checks and IP lists fall behind. Fullstory's behavioral data let us rebuild detection in hours from sessions we'd already captured. We expect agents to self-identify by the end of 2027, and until then our detection methods stay private.
Insights • 3 min read
Agent observability in the age of undercover AI shoppers. Game on.
David Wang
Principal Product Manager at Fullstory
Article summary
More and more of your e-commerce visitors aren't human.
They're AI agents acting on someone else's behalf, and some of the biggest ones don't announce themselves upon arrival (looking at you Muse)... If you run a retail or travel site, that traffic is already in your funnels, skewing your conversion rates and personalization. You're optimizing for the wrong audience.
We built an AI agent detector. Muse adapted within days
Earlier this month we gave customers a way to spot Meta's Muse agent in their Fullstory data, and many started tracking it right away. Around October 16, Muse traffic in those segments dropped sharply. People didn't stop using Muse. Muse changed how it behaves.
Hiding is easy
One of our engineers ran a simple experiment by telling an agent to browse his own site "like a human" and attempt to avoid detection. Muse added curved mouse paths and pauses, and it passed multiple simple ‘human-or-agent’ checks. This experiment proved that last week’s bullseye will quickly become this month's blind spot. Header checks and IP lists can't keep up in this game of cat-and-mouse. Comprehensive behavioral data can.
Only Fullstory has the behavioral data to stay in the game
Fullcapture records every click, scroll and tap, from people and agents alike, with no manual tagging. When Muse changed, we went back to sessions we'd already captured and rebuilt detection in hours. No new tracking. No waiting for fresh data. Bot blockers can tell you an AI agent visited your site. Only Fullstory can tell you what it was trying to do, whether it succeeded, and what to do about it.
Hot take: The hiding will end in 2027
Market forces are pushing AI agents towards self-identification:
Amazon proved that blocking unidentified agents works.
Visa and Mastercard built their agent payment protocols only for agents that say who they are.
Banks turn away anonymous agents logging into accounts as fraud.
Shopify offers Muse a supported checkout, and
proactively forces every visiting agent to create a profile via direct connection using their WebMCP.
OpenAI's ChatGPT, Google’s Gemini, and Anthropic’s Claude agents already self-identify.
Our bet: by the end of 2027, any AI agent that engages with online retailers, banks, insurance, or payment networks will identify itself.
Until then, we're doubling down on agent monitoring. We're investing more so that Fullstory is the only behavioral intelligence platform that can detect and analyze Muse (plus every other agent that is trying to conceal its identity). And when all AI agents eventually self-identify, the same data will show how agents behave differently than humans, and what that means for your company.
We're done giving away the playbook
Previously, we shared our detection methods publicly as a show of good faith. Unfortunately, we learned the hard way that gives a company with Meta's resources an unfair advantage in staying hidden. From now on, how we detect agents stays locked away as Fullstory’s secret sauce, to benefit our customers only.
Today it's Muse. Tomorrow it's Claude Duet and whatever ships next. Game on!
Want more like this in your Google results? Add Fullstory as a preferred source.David Wang
Principal Product Manager, Fullstory
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