Ærr Sensor

Operational toolkit for The Ærr Trinity. An MCP server that measures κ, Ærr Rate, and Chain Drift on real systems.

Status: v0.1 — the math we are operationalizing is in the Trinity paper.

What this is

The Ærr Trinity formalizes a recurring failure mode: systems accepting cheaper local substitutes for globally satisfying answers. It supplies three measurements — a floor (the cost any genuine answer must pay), a discipline (how often that floor is paid), and a drift (how fast surrogates accumulate when it isn't).

Ærr Sensor turns those measurements into MCP tools you can call from Claude Code or any MCP client.

v0.1 tool surface

Tool	Paper	Status
measure_kappa	§6.2 floor-weighted compliance estimator κ^F	working
aerr_rate	§7 count-rate and floor-weighted drift identities	working
chain_drift	§8 closed-form S_n recurrence with coupling number x_i	working
compute_floor	§5.1 cost-floor function f(C(D))	schema-only stub
convergence_watch	§10 scan for adjacent Ærr framings	seed-list stub

The three measurement tools (measure_kappa, aerr_rate, chain_drift) implement the paper's formulae directly and are numerically usable. compute_floor returns status: "schema_only" rather than manufacturing a number for unconfigured domains — honest theater applied to the toolkit itself. convergence_watch returns no_signal: true until the xAI/X Search API is wired in v0.2.

Roadmap

Version	What lands
v0.1 (this release)	5 tools as above; math tools working, two stubs
v0.2	convergence_watch wired to xAI + X Search; researcher_beat and thread_fetch tools from the original sensor integration brief
v0.3	compute_floor calibrated for {code-review, proof-verification, peer-review}

Install

git clone https://github.com/artseabra/aerr-sensor
cd aerr-sensor
pip install -e ".[dev]"

Or with uv:

uv sync

Run

Stdio mode (for Claude Code / local clients):

aerr-sensor
# or
python -m aerr_sensor.server

Add to your Claude Code MCP config:

{
  "mcpServers": {
    "aerr-sensor": {
      "command": "aerr-sensor"
    }
  }
}

Quick example

from aerr_sensor.measurement.measure_kappa import measure_kappa

samples = [
    {"floor": 10.0, "cost": 12.0},   # paid
    {"floor": 5.0,  "cost": 4.0},    # surrogate
    {"floor": 20.0, "cost": 25.0},   # paid
    {"floor": 8.0,  "cost": 8.0},    # exactly at floor (paid)
]

result = measure_kappa(samples)
# {"kappa_f": 0.882..., "n": 4, "floor_sum": 43.0, "paid_count": 3, ...}

The atom

Ærr Sensor is one corner of the publishing atom for the Ærr Frame:

• Ærr Frame — papers (umbrella, with the Trinity at its center)
• Ærr Sensor — this repo (operational toolkit)
• github.com/artseabra/ic-cs — historical mirror (IC|CS before the rename)

License

MIT. The Trinity paper itself is CC BY 4.0 in the Ærr Frame repo.

Author

Art Seabra · Ifthis Research · Philadelphia, PA