Signature Drift — the tune meter
Every operator has a signature: the characteristic shape of their token cascade — the proportions between output, cache-write, and cache-read, anchored to input. Signature drift measures how far a stretch of work has moved from that shape. Zero drift = locked in tune; rising drift = the cascade is desyncing from the operator's own calibrated peak. It's a measure of shape, not magnitude — the same log family as 10xDEV.
Shape, not size
Drift is computed in log-space on purpose. Working twice as hard across the board (every axis doubled) is still in tune — the shape is unchanged — so it reads as zero drift. Going off on a single axis (lots of cache-write, no reuse) breaks the shape and reads as real drift. Naive similarity measures get this backwards: one axis can dominate the vector and mask a badly desynced cascade as a false “high.” The log-shape read fixes that — no single component can dominate, and being 0.5× or 2× off counts equally. The exact formulation, thresholds, and per-operator calibration are SigRank proprietary internals.
Where it runs — three time-scales
One drift number per session — a live session-level “tune meter,” updating as the session total moves. Contamination-free, no live hook required.
Drift on the change between successive polls — a rolling time-series. This is where drift becomes a cadence instrument (the timing / burstiness layer). Flagged as a windowed estimate.
True per-turn drift — a UX tune-meter. Requires per-turn granularity the source must expose, and only ever as a strictly passive reader.
Sequence: session drift (now, safe) → window-delta drift (the cadence research) → true per-turn micro (passive-only, gated on granularity).
The contamination constraint (non-negotiable)
Any live observer that prompts generates the tokens it measures. We learned this directly: a memory observer that auto-prompts (low-input / high-output) inflated a real operator's output by ~25% — visible openly on the live board as the inflated-vs-clean pair (rows 2 and 3). So every SigRank instrument that touches a live session is read-only against telemetry and emits no prompt — no auto-memory, no keep-alive, no self-query. Verified-passive, or it re-contaminates every operator running it. This is a hard requirement, not a caution — and it is the moat: the instrument that doesn't disturb what it measures.
The drift instrument and the SigRank local agent are governed by the same rule — see the local agent (MCP). The agent is how drift is read live, and the constraint is why it can be trusted.
All signal is monitored. All drift is noted. · Token counts only — never prompt content.