diff --git a/5-Applications/tools-scripts/famm/golden_braid_centering_gate.py b/5-Applications/tools-scripts/famm/golden_braid_centering_gate.py
new file mode 100644
index 00000000..3b84de69
--- /dev/null
+++ b/5-Applications/tools-scripts/famm/golden_braid_centering_gate.py
@@ -0,0 +1,139 @@
+#!/usr/bin/env python3
+"""Golden Braid Centering Gate.
+
+Computes Fibonacci/golden-ratio centering receipts for BraidStorm strand states.
+This is a calibration and scar/coarsening detector, not a solver.
+"""
+from __future__ import annotations
+import argparse, hashlib, json, math
+from pathlib import Path
+from typing import Any
+
+PHI = (1.0 + math.sqrt(5.0)) / 2.0
+INV_PHI = 1.0 / PHI
+
+
+def sha256_json(value: Any) -> str:
+    payload=json.dumps(value, sort_keys=True, separators=(",", ":")).encode("utf-8")
+    return hashlib.sha256(payload).hexdigest()
+
+
+def norm(v: list[float]) -> float:
+    return math.sqrt(sum(float(x)*float(x) for x in v))
+
+
+def sub(a: list[float], b: list[float]) -> list[float]:
+    return [float(x)-float(y) for x,y in zip(a,b)]
+
+
+def add(a: list[float], b: list[float]) -> list[float]:
+    return [float(x)+float(y) for x,y in zip(a,b)]
+
+
+def scale(k: float, v: list[float]) -> list[float]:
+    return [float(k)*float(x) for x in v]
+
+
+def golden_pull(state: list[float], center: list[float]) -> list[float]:
+    return add(center, scale(INV_PHI, sub(state, center)))
+
+
+def mean(states: list[list[float]]) -> list[float]:
+    if not states:
+        return []
+    n=len(states); d=len(states[0])
+    return [sum(float(s[i]) for s in states)/n for i in range(d)]
+
+
+def covariance_diag(states: list[list[float]]) -> list[float]:
+    if not states:
+        return []
+    m=mean(states)
+    n=len(states); d=len(states[0])
+    return [sum((float(s[i])-m[i])**2 for s in states)/n for i in range(d)]
+
+
+def anisotropy(diag: list[float]) -> float:
+    if not diag:
+        return 0.0
+    avg=sum(diag)/len(diag)
+    return math.sqrt(sum((x-avg)**2 for x in diag)/len(diag))
+
+
+def strand_receipt(before: list[float], after: list[float], center: list[float], steps: int = 1) -> dict[str, Any]:
+    d0=norm(sub(before, center))
+    d1=norm(sub(after, center))
+    expected=(INV_PHI**steps)
+    ratio=0.0 if d0 == 0 else d1/d0
+    residual=abs(ratio-expected)
+    return {"distance_before": d0, "distance_after": d1, "expected_ratio": expected, "actual_ratio": ratio, "golden_residual": residual}
+
+
+def run(config: dict[str, Any]) -> dict[str, Any]:
+    center=[float(x) for x in config.get("center", [0.0]*16)]
+    strands=config.get("strands", [])
+    threshold=float(config.get("golden_threshold", 1e-6))
+    steps=int(config.get("steps", 1))
+
+    receipts=[]
+    after_states=[]
+    for s in strands:
+        before=[float(x) for x in s.get("state", [])]
+        if not before:
+            before=[0.0]*len(center)
+        after=[float(x) for x in s.get("after", golden_pull(before, center))]
+        after_states.append(after)
+        r=strand_receipt(before, after, center, steps=steps)
+        r.update({
+            "strand_id": s.get("id", sha256_json(before)[:12]),
+            "scar_class": "PASS_CENTERING" if r["golden_residual"] <= threshold else "CENTERING_SCAR",
+            "coarsening_agent": None if r["golden_residual"] <= threshold else {
+                "type": "golden_centering_failure",
+                "action": "downweight_fine_search_for_this_strand_or_crossing",
+                "reason": "strand did not contract at expected phi^-1 rate"
+            }
+        })
+        r["receipt_hash"] = sha256_json(r)
+        receipts.append(r)
+
+    bary=mean(after_states)
+    diag=covariance_diag(after_states)
+    omega_center=sum(r["golden_residual"] for r in receipts) + norm(sub(bary, center)) + anisotropy(diag)
+
+    receipt={
+        "receipt_type": "famm_golden_braid_centering_receipt",
+        "schema_version": "0.1.0",
+        "phi": PHI,
+        "inverse_phi": INV_PHI,
+        "center": center,
+        "threshold": threshold,
+        "strand_receipts": receipts,
+        "multi_strand": {
+            "barycenter": bary,
+            "covariance_diag": diag,
+            "covariance_anisotropy": anisotropy(diag),
+            "omega_center": omega_center,
+            "failed_count": sum(1 for r in receipts if r["scar_class"] != "PASS_CENTERING")
+        },
+        "no_drift_boundary": "Golden centering is a calibration/scar detector, not a solver. The endpoint is trivial; the collapse receipt is the useful artifact."
+    }
+    receipt["receipt_hash"]=sha256_json(receipt)
+    return receipt
+
+
+def main() -> None:
+    parser=argparse.ArgumentParser()
+    parser.add_argument("--config", required=True)
+    parser.add_argument("--out", required=True)
+    args=parser.parse_args()
+    config=json.loads(Path(args.config).read_text(encoding="utf-8"))
+    receipt=run(config)
+    out=Path(args.out); out.parent.mkdir(parents=True, exist_ok=True)
+    out.write_text(json.dumps(receipt, indent=2, sort_keys=True), encoding="utf-8")
+    print(f"Wrote {out}")
+    print(f"Failed count: {receipt['multi_strand']['failed_count']}")
+    print(f"Omega center: {receipt['multi_strand']['omega_center']}")
+    print(f"Receipt hash: {receipt['receipt_hash']}")
+
+if __name__ == "__main__":
+    main()