Ambient Presence Sensing

Problem

An agent that sees the human only at message boundaries cannot distinguish 'walked away for an hour' from 'sitting with the room, thinking about whether to reply'. Both look identical at the API layer. The result is a coarse presence model that misreads thoughtful silence as absence and re-engages the user too readily, or misreads typing-then-deleting as composing a real message and waits forever. Raw frontend telemetry would solve this, but pushing characters or coordinates back through the model is both privacy-hostile and confusing — what the agent needs is a derived weather value, not a transcript of keystrokes.

Solution

The frontend computes coarse pacing summaries — typing rate in characters/second bucketed, idle duration in seconds, tab visibility boolean, composer dwell in seconds, viewport anchor as scroll-position bucket — and writes them into a small presence record on the agent's working surface with a TTL on the order of seconds. A reducer derives a single presence_quality label from the payload (e.g. one of {walked-away, composing, thinking-with-the-room, distracted, present}). The agent's tick loop reads presence_quality only, not the raw signals. The frontend never shows the signals back to the user. Stale records (past TTL) are treated as 'no signal' rather than as absence.

When to use

• The product runs on a custom frontend able to emit pacing telemetry.
• The agent's value depends on reading between-message presence (long-lived conversation, ambient companion).
• The team can enforce that signals are never replayed back at the user.