Mechanism
How it works
Three sources feed one decision about what's happening on the page. They don't carry equal weight, and the ordering is the product, not an implementation detail.
Read left to right: an answer overrides telemetry, telemetry overrides the camera, and the camera never gets the final word by itself.
The state vocabulary
Six states. Every one is an observation, not a feeling
None of this claims to read what you're thinking. Each state names something measurable: a pace, a pattern of movement, a period without signal. Never an internal state like confusion or boredom, which no browser can see.
| State | What it observes |
|---|---|
| on pace | Reading speed is consistent with the paragraph's difficulty and your own baseline. |
| skimming | Moving faster than the text's difficulty would predict for careful reading. |
| struggling | Moving markedly slower than baseline, or re-reading the same lines repeatedly. |
| drifting | Scroll and dwell patterns that don't match active reading of the visible text. |
| away | The tab lost focus, or. with the camera on. no one is at the screen. |
| unknown | Not enough signal to say anything. Common, normal, and nothing interrupts on it. |
Limitations, stated plainly
States are inferred from behaviour, and inference is imperfect. Someone can read carefully at an unusual pace and get misread as skimming; someone can stare at a page while thinking about something else and get read as on pace. That's exactly why the system doesn't act on an inference alone. it asks a question and treats the answer as the only thing that settles it. When there isn't enough signal to guess responsibly, the honest answer is unknown, and the system does nothing with it. That's a design choice, not a gap: guessing confidently from thin signal would be worse than saying nothing.
Why a question, not a summary
Summaries feel like understanding. Recall produces it
A summary is something you're shown. A question is something you have to answer, using the passage you just read rather than the assistant's paraphrase of it. That distinction is the entire mechanism, and it isn't ours. it's retrieval practice, one of the more replicated findings in reading research.
D'Mello et al. (2016) ran a randomised trial interrupting drifting readers with just-in-time questions and found it recovered comprehension losses (d = 0.47). alcoia's interruption policy. one question at most every three minutes, five a session, never twice on the same paragraph, never on unknown. is built around not spending that effect on questions the reader doesn't need.
Curious what the site can't claim, and why: /research
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