diff --git a/AGENTS.md b/AGENTS.md
index 296ca7f..2c2d26f 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -38,6 +38,7 @@ cd simulations/gadm02 && python3 -B calibrate_data.py && python3 -B calibrated_r
 cd simulations/gadm02 && for j in US EU; do python3 -B gsa.py --model gadm04 --jobs 8 --start $j; done   # GSA around calibrated starts, ~30 min
 cd simulations/gadm02 && python3 -B cross_border.py   # coupled world US/EU/AR from the calibrated start (models/CrossBorder.md)
 cd simulations/gadm02 && python3 -B world_scenarios.py   # contexts X1–X4, hypothesis re-test, local vs. global
+cd simulations/gadm02 && python3 -B matching.py && python3 -B matching.py --synthetic   # model matching; flip-detection test (~10 min)
 ```
 
 Reality checkpoints (ASSEMBLY-WP-0010): scheduled by activity-core and
diff --git a/research/BreakRegister.md b/research/BreakRegister.md
index d35310f..90afa7b 100644
--- a/research/BreakRegister.md
+++ b/research/BreakRegister.md
@@ -21,3 +21,4 @@ that part of the band.
 | BR-006 | 2026-10-13 (WP-0013-T04) | Legitimacy loop damps adoption (BR-005, AdoptionBand § 3.3) | damping under extractive regimes → amplifying under rights-first levers from the calibrated start (US, AR) | when adoption lowers domination, perceived benefit rises and sentiment accelerates adoption | none structural; the reading is regime-dependent | open: state the loop's effect per regime |
 | BR-007 | 2026-10-13 (WP-0013-T04) | Rights-first levers bound domination | holds when switching to J1 levers (US: P 0.64 → 0.54) → fails for a jurisdiction already at J1 levers (EU: P 0.65 → 0.77) | calibrated domination comes from levels set abroad that local levers cannot reach | **structural:** cross-border coupling (ASSEMBLY-WP-0011) | open |
 | BR-008 | 2026-10-13 (WP-0011-T05) | Which levers bound domination (BR-007 follow-up) | closed model: host rights levers → coupled model: only host access rules on foreign operators and the home's levers reach the foreign-run channels | measured channels (Pd, Pmem, Plin, Pi) are operated from the US for EU and AR hosts | **structural, implemented:** cross-border coupling (`world.py`); observed DMA effect on search ≈ 0 (at most a 0.006/yr) | open: lineage access rules (BR-003) |
+| BR-009 | 2026-10-13 (WP-0012) | Sentiment dynamics of the legitimacy loop | Σ relaxes toward 0.5 + gain × Δ(perceived benefit), so from the measured US Σ 0.285 it rises → measured US sentiment fell 2021–2026 (0.405 → 0.285) while adoption grew fast | the neutral reference 0.5 is an assumption; US adoption also shows no braking by low sentiment (all loop-on candidates fail the US match) | **structural candidate:** sentiment reference anchored to the observed level and a small or lagged adoption elasticity | open: ASSEMBLY-WP-0017 |
diff --git a/research/FlipRegister.md b/research/FlipRegister.md
new file mode 100644
index 0000000..c92e9b6
--- /dev/null
+++ b/research/FlipRegister.md
@@ -0,0 +1,22 @@
+# Flip register (append-only)
+
+Regime changes of jurisdictions, detected by model matching
+(`research/ModelMatching.md` § 3). **Never edit or delete an entry.**
+
+**Status 2026-10-13:** no entries. Flip detection has not passed its
+synthetic test (`research/ModelMatching.md` § 4), so no measured flip may be
+recorded yet. Simulated flips (regime crossings inside model runs) are
+recorded in the break register until then (for example BR-005).
+
+## Entry format
+
+```markdown
+### F-YYYY-NNN — <jurisdiction>: <from regime> → <to regime>
+- Detected: <checkpoint date>, kind measured | simulated, by <script/version>
+- Evidence: weights before/after, indicators that moved
+- Consequences: predictions superseded (ids), break-register links
+```
+
+## Entries
+
+(none)
diff --git a/research/ModelMatching.md b/research/ModelMatching.md
new file mode 100644
index 0000000..cea98c5
--- /dev/null
+++ b/research/ModelMatching.md
@@ -0,0 +1,104 @@
+# Model matching and regime flipping
+
+**Status:** v0.1 (2026-10-13), ASSEMBLY-WP-0012. Matching on observed data
+works. **Flip detection is not yet reliable** (§ 4). No flip may be declared
+from real data until the synthetic test passes.
+
+Code: `simulations/gadm02/matching.py`. Data: `observed_series.json`.
+Results: `results/matching.md` (observed), `results/matching_synthetic.md`
+(synthetic test).
+
+## 1. Candidates and fit criterion (T01)
+
+Candidates: band anchor B1–B4 × legitimacy loop off/on, each started from
+the jurisdiction's calibrated state (`calibrate_data.start_state`). B1 stays
+in the set with its misfit recorded, so a return to B1-like growth would be
+visible.
+
+For each candidate, the adoption indicator is taken as proportional to K_Ω.
+Two values are fitted: a time offset t0 and a scale s, with
+`log y = log s + log K_Ω(t0 + τ) + ε` and ε ~ N(0, σ) (σ per series: BTOS
+0.03, Eurostat 0.05). The calibrated K_Ω level range at the end of the window
+adds a Gaussian level term. All candidates fit the same number of values, so
+AIC weights reduce to likelihood weights.
+
+The sentiment slope (Pew 2021 → 2026) is not scored yet: the points precede
+the model start (checkpoint 0). It is switched on once there are sentiment
+points after checkpoint 0.
+
+## 2. Results on observed data (T02, T04)
+
+| Jurisdiction | Data | Anchor weights | Loop weights | Best |
+|---|---|---|---|---|
+| US | BTOS, 23 biweekly points 2025–2026 | B1 0.00 · B2 0.38 · B3 0.44 · B4 0.18 | off 1.00 · on 0.00 | B3 / loop off (0.44) |
+| EU | Eurostat 2023–2025 | B1 0.00 · B2 0.38 · B3 0.62 · B4 0.00 | off 0.47 · on 0.53 | B3 / loop off (0.46) |
+| DE | Eurostat 2023–2025 | B1 0.00 · B2 0.73 · B3 0.27 · B4 0.00 | off 0.33 · on 0.67 | B2 / loop on (0.57) |
+
+Readings:
+
+1. **The data rule out B1 everywhere, and B4 for the EU and DE.** The present
+   is B2–B3, consistent with the calibration (`models/Calibration.md` § 3).
+2. **US adoption is not braked by its low sentiment.** Every loop-on
+   candidate fails for the US, because with measured US sentiment (Σ 0.285)
+   the loop slows adoption far below the observed growth. Either adoption's
+   elasticity to sentiment (`sig_adopt`) is much smaller than 1, or
+   sentiment acts on adoption with a long lag. This is the first data-based
+   constraint on the legitimacy loop.
+3. **No regime is established yet.** No candidate reaches weight 0.75.
+   Predictions v1 (P-2026-001 … 004) assume growth alignment between B2 and
+   B3, which the matched weights bracket. No predictions v2 are needed (T04).
+
+## 3. Flipping events (T03)
+
+A **flipping event** is a change of the regime a jurisdiction operates
+under, detected when:
+
+1. the best-weighted candidate changes, and
+2. the new best holds weight ≥ 0.75 at two consecutive evaluations.
+
+Before a first regime is established (weight ≥ 0.75), changes are not flips.
+
+**Measured flips** come from the regime filter on observed data. Every
+quarter, each regime's dynamics run forward from the current state estimate
+over the last quarter, the weights are updated with a switching prior (0.02
+per quarter), and the estimate advances with the best regime. **Simulated
+flips** are regime crossings inside a model run, for example the B4
+boom-bust of BR-005. Flips are recorded in `research/FlipRegister.md`.
+
+## 4. Synthetic test (T06): not yet reliable
+
+Truth is simulated from a known candidate. In the switch cases it changes
+regime at t = 4. It is observed biweekly with 3 % log-noise, with level
+evidence as wide as the real US target. Three seeds per case
+(`results/matching_synthetic.md`).
+
+| Indicators | Correct regime at start | False flips (no-switch truth) | Switches detected |
+|---|---|---|---|
+| adoption only | 3 of 6 | 3 of 6 | 0 of 6 |
+| adoption + annual sentiment | 3 of 6 | 3 of 6 | 2 of 6 (delays 0.5 y and 3.25 y) |
+
+The design went through three stages:
+
+1. Free re-fitting of t0 and s per window: any candidate matches any segment.
+2. Alignment fixed after the first window: still path-based, so a regime
+   change starting *now* is not represented.
+3. A forward filter from the current state, with evidence accumulated across
+   quarters.
+
+Each stage reduced false flips. None of them made detection reliable.
+
+**Why:** with adoption alone, neighbouring anchors (B2/B3/B4) differ by less
+than measurement noise over a quarter. The loop switch leaves almost no trace
+in adoption. In sentiment it is confounded by BR-009: the sentiment
+equation reverts toward neutral from the low measured level.
+
+**Requirements before flips may be declared** (ASSEMBLY-WP-0017):
+
+- more discriminating indicators: investment (L5) for self-enhancement,
+  sentiment at least twice a year for the loop, and concentration channels
+  (CB1) for domination dynamics;
+- per-regime state tracking (one state per regime, not one shared estimate);
+- the sentiment equation fixed (BR-009);
+- acceptance criteria: at least 5 of 6 regimes correct at the start, no
+  false flips in 6 no-switch runs, and at least 4 of 6 switches detected
+  within 1.5 years.
diff --git a/simulations/gadm02/matching.py b/simulations/gadm02/matching.py
new file mode 100644
index 0000000..f69561a
--- /dev/null
+++ b/simulations/gadm02/matching.py
@@ -0,0 +1,303 @@
+"""Model matching and regime flipping (ASSEMBLY-WP-0012-T01/T02/T03/T06).
+
+Candidates: band anchor (B1-B4) x legitimacy loop (off/on), each from the
+jurisdiction's calibrated state (calibrate_data.start_state). Method:
+research/ModelMatching.md.
+
+Fit per candidate: the adoption indicator is taken as proportional to K_Omega,
+so two free values are fitted, a time offset t0 and a scale s
+(log y = log s + log K_Omega(t0 + tau) + noise, noise sd = the series'
+log_sigma). The calibrated K_Omega level range at the aligned time
+(calibration_targets.json) is scored as well, so shape and level both count.
+`sentiment_ll` scores a sentiment slope, but it is not used yet: the Pew
+points (2021, 2026) precede the model start (checkpoint 0). It is switched on
+once the sentiment series has points after checkpoint 0. All candidates have the same
+number of fitted values, so AIC weights reduce to likelihood weights.
+
+Flip: the best candidate changes and the new best has weight >= FLIP_WEIGHT
+in two consecutive evaluations (research/ModelMatching.md § 3).
+
+Usage: python3 -B simulations/gadm02/matching.py            # match observed series
+       python3 -B simulations/gadm02/matching.py --synthetic  # recovery and flip test
+"""
+
+from __future__ import annotations
+
+import json
+import math
+import random
+import sys
+from pathlib import Path
+
+sys.dont_write_bytecode = True
+
+import calibrate_data as cd  # noqa: E402
+import gadm04 as g  # noqa: E402
+import grounding as gr  # noqa: E402
+
+HERE = Path(__file__).resolve().parent
+OUT = HERE / "results"
+SERIES = json.loads((HERE / "observed_series.json").read_text())["series"]
+CANDIDATES = [(a, lp) for a in ("B1", "B2", "B3", "B4") for lp in ("off", "on")]
+STEP = 0.1
+T_PATH = 30.0
+FLIP_WEIGHT = 0.75
+SWITCH = 0.02          # prior probability per quarter that the regime changes (filter)
+_CACHE: dict = {}
+
+
+def path(jur: str, anchor: str, loop: str) -> list[dict]:
+    key = (jur, anchor, loop)
+    if key not in _CACHE:
+        p, s = cd.start_state(jur, anchor)
+        _CACHE[key] = g.simulate({**p, "sent": 1.0 if loop == "on" else 0.0}, s, T=T_PATH, record_every=1)
+    return _CACHE[key]
+
+
+def interp(rows: list[dict], t: float, key: str) -> float:
+    x = t / STEP
+    i = min(int(x), len(rows) - 2)
+    w = x - i
+    return (1 - w) * rows[i][key] + w * rows[i + 1][key]
+
+
+def fit_series(rows: list[dict], points: list, log_sigma: float,
+               fixed: tuple[float, float] | None = None) -> tuple[float, float, float]:
+    """(log-likelihood, t0, log s) for an indicator proportional to K_Omega.
+
+    fixed = (t0, log s): no fitting, score the points at this alignment and scale. Used after the
+    first evaluation: the calendar fixes how t0 advances and the measurement fixes the scale."""
+    if fixed is not None:
+        t0, ls = fixed
+        if t0 + points[-1][0] > T_PATH - STEP:
+            return -1e9, t0, ls
+        sse = sum((math.log(y) - math.log(max(1e-9, interp(rows, t0 + tau, "Ko"))) - ls) ** 2 for tau, y in points)
+        return -0.5 * sse / log_sigma ** 2, t0, ls
+    span = points[-1][0]
+    best = None
+    t0 = 0.0
+    while t0 + span <= T_PATH - 1:
+        r = [math.log(y) - math.log(max(1e-9, interp(rows, t0 + tau, "Ko"))) for tau, y in points]
+        ls = sum(r) / len(r)
+        sse = sum((x - ls) ** 2 for x in r)
+        if best is None or sse < best[0]:
+            best = (sse, t0, ls)
+        t0 += 0.05
+    sse, t0, ls = best
+    return -0.5 * sse / log_sigma ** 2, t0, ls
+
+
+def sentiment_ll(rows: list[dict], t0: float, series: dict) -> float:
+    (ta, ya), (tb, yb) = series["points"][0], series["points"][-1]
+    obs = (yb - ya) / (tb - ta)
+    span = tb - ta
+    a = max(0.0, t0 - span)               # the sentiment window ends at the adoption alignment
+    mod = (interp(rows, a + span, "Sig") - interp(rows, a, "Sig")) / span
+    return -0.5 * ((mod - obs) * span / series["sigma"]) ** 2
+
+
+def score(jur: str, rows_for: callable, adoption: dict, sentiment: dict | None = None,
+          level: dict | None = None, fixed: dict | None = None) -> dict:
+    out = {}
+    for a, lp in CANDIDATES:
+        rows = rows_for(jur, a, lp)
+        ll, t0, ls = fit_series(rows, adoption["points"], adoption["log_sigma"],
+                                fixed=fixed.get((a, lp)) if fixed else None)
+        if level is not None:   # K_Omega level at the end of the observed window
+            ko = interp(rows, t0 + adoption["points"][-1][0], "Ko")
+            ll += -0.5 * cd.z(ko, level) ** 2
+        if sentiment is not None:
+            ll += sentiment_ll(rows, t0, sentiment)
+        out[(a, lp)] = {"ll": ll, "t0": t0, "s": math.exp(ls), "ls": ls}
+    mx = max(v["ll"] for v in out.values())
+    z = sum(math.exp(v["ll"] - mx) for v in out.values())
+    for v in out.values():
+        v["w"] = math.exp(v["ll"] - mx) / z
+    return out
+
+
+def best(res: dict) -> tuple:
+    return max(res, key=lambda k: res[k]["w"])
+
+
+def flips(evaluations: list[tuple[float, dict]]) -> list[tuple[float, tuple, tuple]]:
+    """Flip events: best changes and the new best holds weight >= FLIP_WEIGHT twice in a row."""
+    events, current, pending = [], None, None
+    for t, res in evaluations:
+        b, wb = best(res), res[best(res)]["w"]
+        if current is None:
+            if wb >= FLIP_WEIGHT:
+                current = b
+            continue
+        if b != current and wb >= FLIP_WEIGHT:
+            if pending == b:
+                events.append((t, current, b))
+                current, pending = b, None
+            else:
+                pending = b
+        else:
+            pending = None
+    return events
+
+
+def fmt(c: tuple) -> str:
+    return f"{c[0]}/loop {c[1]}"
+
+
+def main_observed() -> None:
+    lines = [f"# {g.MODEL_VERSION}: model matching on observed series", "",
+             "Generated by `simulations/gadm02/matching.py` (ASSEMBLY-WP-0012). Method:",
+             "`research/ModelMatching.md`. Data: `observed_series.json`. Weights are likelihood (AIC) weights",
+             "over the eight candidates; all candidates fit the same two values (t0, s). Each score adds the",
+             "calibrated K_Ω level range at the end of the window. Sentiment is not scored yet (data precede",
+             "checkpoint 0).", ""]
+    for jur, adop, sent in (("US", "US_adoption", None), ("EU", "EU_adoption", None),
+                            ("DE", "DE_adoption", None)):
+        res = score(jur, path, SERIES[adop], SERIES[sent] if sent else None, level=cd.targets(jur)["Ko"])
+        b = best(res)
+        lines += [f"## {jur}", "", f"Series: {SERIES[adop]['source']}" + (f"; {SERIES[sent]['source']}" if sent else ""),
+                  "", "| Candidate | log-likelihood | weight | t0 | K_Ω at window end |", "|---|---|---|---|---|"]
+        for c in sorted(res, key=lambda k: -res[k]["w"]):
+            v = res[c]
+            lines.append(f"| {fmt(c)} | {v['ll']:.1f} | {v['w']:.3f} | {v['t0']:.2f} | "
+                         f"{interp(path(jur, *c), v['t0'] + SERIES[adop]['points'][-1][0], 'Ko'):.3f} |")
+        anchors = {}
+        for (a, _lp), v in res.items():
+            anchors[a] = anchors.get(a, 0) + v["w"]
+        loops = {lp: sum(v["w"] for (a, l2), v in res.items() if l2 == lp) for lp in ("off", "on")}
+        lines += ["", f"**Best:** {fmt(b)} (weight {res[b]['w']:.2f}). Anchor weights: "
+                  + ", ".join(f"{a} {w:.2f}" for a, w in anchors.items())
+                  + f". Loop weights: off {loops['off']:.2f}, on {loops['on']:.2f}.", ""]
+    (OUT / "matching.md").write_text("\n".join(lines))
+    print("\n".join(lines))
+
+
+def synthetic_rows(jur: str, first: tuple, second: tuple | None, t_switch: float) -> list[dict]:
+    """Truth: candidate `first` until t_switch, then `second` parameters continuing from that state."""
+    p1, s1 = cd.start_state(jur, first[0])
+    r1 = g.simulate({**p1, "sent": 1.0 if first[1] == "on" else 0.0}, s1, T=t_switch, record_every=1)
+    if second is None:
+        return g.simulate({**p1, "sent": 1.0 if first[1] == "on" else 0.0}, s1, T=T_PATH, record_every=1)
+    p2, _s2 = cd.start_state(jur, second[0])
+    state = {k: r1[-1][k] for k in g.STOCKS}
+    r2 = g.simulate({**p2, "sent": 1.0 if second[1] == "on" else 0.0}, state, T=T_PATH - t_switch, record_every=1)
+    for r in r2[1:]:
+        r["t"] = round(r["t"] + t_switch, 6)
+    return r1 + r2[1:]
+
+
+_PARAMS: dict = {}
+
+
+def regime_params(jur: str, cand: tuple) -> dict:
+    """Parameters of a regime (anchor dynamics, loop switch) for jurisdiction `jur`."""
+    if (jur, cand) not in _PARAMS:
+        p, _s = cd.start_state(jur, cand[0])
+        _PARAMS[(jur, cand)] = {**p, "sent": 1.0 if cand[1] == "on" else 0.0}
+    return _PARAMS[(jur, cand)]
+
+
+def filter_step(jur: str, state: dict, pts: list, scale_ls: float, log_sigma: float,
+                level: dict | None, window: float, sent_pts: list | None = None, sent_sd: float = 0.02) -> dict:
+    """Score every regime by running its dynamics forward from `state` over the window.
+
+    sent_pts: optional sentiment observations (tau, Sigma) within the window."""
+    out = {}
+    for c in CANDIDATES:
+        rows = g.simulate(regime_params(jur, c), state, T=window, record_every=1)
+        sse = sum((math.log(y) - math.log(max(1e-9, interp(rows, tau, "Ko"))) - scale_ls) ** 2 for tau, y in pts)
+        ll = -0.5 * sse / log_sigma ** 2
+        for tau, y in sent_pts or []:
+            ll += -0.5 * ((interp(rows, tau, "Sig") - y) / sent_sd) ** 2
+        if level is not None:
+            ll += -0.5 * cd.z(rows[-1]["Ko"], level) ** 2
+        out[c] = {"ll": ll, "end": {k: rows[-1][k] for k in g.STOCKS}}
+    mx = max(v["ll"] for v in out.values())
+    zs = sum(math.exp(v["ll"] - mx) for v in out.values())
+    for v in out.values():
+        v["w"] = math.exp(v["ll"] - mx) / zs
+    return out
+
+
+def synthetic_run(truth: list[dict], start: float, years: float, window: float, seed: int,
+                  log_sigma: float = 0.03, sentiment: bool = False) -> list[tuple[float, dict]]:
+    """Quarterly regime filter on noisy biweekly observations (research/ModelMatching.md § 3).
+
+    First window: whole-path alignment fit (t0, scale) gives the initial state and the scale. Then,
+    every quarter, each regime runs forward from the current state estimate over the last window;
+    the state estimate advances with the best regime."""
+    rnd = random.Random(seed)
+    obs, t = [], start
+    while t <= start + years:
+        obs.append((t, interp(truth, t, "Ko") * 25.0 * math.exp(rnd.gauss(0, log_sigma))))
+        t += 2 / 52
+    sobs = [(start + k, interp(truth, start + k, "Sig") + rnd.gauss(0, 0.02)) for k in range(int(years) + 1)] \
+        if sentiment else []
+    te0 = start + window
+    pts0 = [(tt - start, y) for tt, y in obs if start <= tt <= te0]
+    first = score("US", path, {"points": pts0, "log_sigma": log_sigma},
+                  level={"lo": interp(truth, te0, "Ko") - 0.075, "hi": interp(truth, te0, "Ko") + 0.075})
+    b = best(first)
+    scale_ls = first[b]["ls"]
+    t_est = first[b]["t0"] + window
+    rows_b = path("US", *b)
+    i_est = int(round(t_est / STEP))
+    est = {k: rows_b[i_est][k] for k in g.STOCKS}
+    evals = [(te0, first)]
+    step = 0.25
+    te = te0 + step
+    while te <= start + years + 1e-9:
+        pts = [(tt - (te - step), y) for tt, y in obs if te - step - 1e-9 <= tt <= te]
+        ko = interp(truth, te, "Ko")
+        spts = [(tt - (te - step), y) for tt, y in sobs if te - step < tt <= te + 1e-9]
+        res = filter_step("US", est, pts, scale_ls, log_sigma, {"lo": ko - 0.075, "hi": ko + 0.075}, step, spts)
+        prev = evals[-1][1]
+        n = len(CANDIDATES)
+        prior = {c: (1 - SWITCH) * prev[c]["w"] + SWITCH * (1 - prev[c]["w"]) / (n - 1) for c in CANDIDATES}
+        mx = max(res[c]["ll"] for c in CANDIDATES)
+        post = {c: prior[c] * math.exp(res[c]["ll"] - mx) for c in CANDIDATES}
+        zs = sum(post.values())
+        for c in CANDIDATES:
+            res[c]["w"] = post[c] / zs      # evidence accumulates across quarters
+        est = res[best(res)]["end"]
+        evals.append((te, res))
+        te += step
+    return evals
+
+
+def main_synthetic() -> None:
+    lines = [f"# {g.MODEL_VERSION}: matching and flip detection on synthetic data", "",
+             "Generated by `simulations/gadm02/matching.py --synthetic` (ASSEMBLY-WP-0012-T06).",
+             "US calibrated state. Truth simulated from a known candidate (optionally switching regime at",
+             "t_switch), observed biweekly as 25 × K_Ω with log-noise sd 0.03, from t 2 to t 8. Quarterly",
+             "regime filter: the first year fixes the initial state and the scale (whole-path alignment); then",
+             "every quarter each regime runs forward from the current state estimate over the last quarter, and",
+             "the estimate advances with the best regime. Weights accumulate across quarters (forward filter,",
+             f"switch probability {SWITCH} per quarter). Level evidence: true K_Ω ± 0.075 (as wide as the real",
+             f"US target). Flip: new best with weight ≥ {FLIP_WEIGHT} twice in a row.", "",
+             "| Indicators | Truth | Seed | Best at first evaluation | Flips detected (t, from → to) | Verdict |",
+             "|---|---|---|---|---|---|"]
+    cases = [(("B3", "off"), None, None), (("B2", "off"), None, None),
+             (("B2", "off"), ("B4", "off"), 4.0), (("B3", "off"), ("B3", "on"), 4.0)]
+    for first, second, ts in cases:
+        truth = synthetic_rows("US", first, second, ts or T_PATH)
+        for seed, sentiment in ((1, False), (2, False), (3, False), (1, True), (2, True), (3, True)):
+            ev = synthetic_run(truth, 2.0, 6.0, 1.0, seed, sentiment=sentiment)
+            fl = flips(ev)
+            b0 = best(ev[0][1])
+            if second is None:
+                verdict = "ok (no false flip)" if not fl else "FALSE FLIP"
+            else:
+                hit = [e for e in fl if e[0] >= ts and e[2][0] == second[0] and (second[1] == first[1] or e[2][1] == second[1])]
+                verdict = f"detected, delay {hit[0][0] - ts:.2f} y" if hit else "missed"
+            label = fmt(first) + (f" → {fmt(second)} at t {ts}" if second else "")
+            lines.append(f"| {'adoption + annual sentiment' if sentiment else 'adoption'} | {label} | {seed} | {fmt(b0)} | "
+                         + ("; ".join(f"{t:.2f}: {fmt(a)} → {fmt(b)}" for t, a, b in fl) or "none")
+                         + f" | {verdict} |")
+    lines.append("")
+    (OUT / "matching_synthetic.md").write_text("\n".join(lines))
+    print("\n".join(lines))
+
+
+if __name__ == "__main__":
+    main_synthetic() if "--synthetic" in sys.argv else main_observed()
diff --git a/simulations/gadm02/observed_series.json b/simulations/gadm02/observed_series.json
new file mode 100644
index 0000000..8643c22
--- /dev/null
+++ b/simulations/gadm02/observed_series.json
@@ -0,0 +1,32 @@
+{
+ "note": "Observed indicator series for model matching (ASSEMBLY-WP-0012). Values as fetched for checkpoint 0 and the 2026-10-13 review; t in years relative to the first point. Append new points at each checkpoint; do not edit old ones.",
+ "series": {
+  "US_adoption": {
+   "indicator": "L1", "unit": "% of employer firms using AI (last two weeks)",
+   "source": "U.S. Census Bureau BTOS Q7 (National.xlsx), periods 2025-24 to 2026-20 (biweekly)",
+   "log_sigma": 0.03,
+   "points": [[0.0, 17.3], [0.0385, 17.2], [0.0769, 17.8], [0.1154, 17.7], [0.1538, 18.2], [0.1923, 18.9],
+              [0.2308, 17.5], [0.2692, 18.2], [0.3077, 18.9], [0.3462, 19.1], [0.3846, 19.8], [0.4231, 19.8],
+              [0.4615, 19.5], [0.5, 20.6], [0.5385, 20.6], [0.5769, 20.6], [0.6154, 21.7], [0.6538, 21.5],
+              [0.6923, 21.8], [0.7308, 22.4], [0.7692, 23.2], [0.8077, 23.8], [0.8462, 23.8]]
+  },
+  "EU_adoption": {
+   "indicator": "L2", "unit": "% of enterprises (10+ employees) using at least one AI technology",
+   "source": "Eurostat isoc_eb_ai, EU27_2020, reference years 2023-2025 (2021: 7.65, before generative AI, excluded)",
+   "log_sigma": 0.05,
+   "points": [[0.0, 8.06], [1.0, 13.48], [2.0, 19.95]]
+  },
+  "DE_adoption": {
+   "indicator": "L2", "unit": "% of enterprises (10+ employees) using at least one AI technology",
+   "source": "Eurostat isoc_eb_ai, DE, reference years 2023-2025 (2021: 10.56, excluded)",
+   "log_sigma": 0.05,
+   "points": [[0.0, 11.55], [1.0, 19.75], [2.0, 25.97]]
+  },
+  "US_sentiment": {
+   "indicator": "L6", "unit": "Sigma = 0.5 + (excited - concerned)/200",
+   "source": "Pew Research: 2021 (37 % concerned, 18 % excited) and June 2026 (52 %, 9 %)",
+   "sigma": 0.03,
+   "points": [[0.0, 0.405], [5.0, 0.285]]
+  }
+ }
+}
diff --git a/simulations/gadm02/results/matching.md b/simulations/gadm02/results/matching.md
new file mode 100644
index 0000000..c610507
--- /dev/null
+++ b/simulations/gadm02/results/matching.md
@@ -0,0 +1,58 @@
+# GADM-0.4: model matching on observed series
+
+Generated by `simulations/gadm02/matching.py` (ASSEMBLY-WP-0012). Method:
+`research/ModelMatching.md`. Data: `observed_series.json`. Weights are likelihood (AIC) weights
+over the eight candidates; all candidates fit the same two values (t0, s). Each score adds the
+calibrated K_Ω level range at the end of the window. Sentiment is not scored yet (data precede
+checkpoint 0).
+
+## US
+
+Series: U.S. Census Bureau BTOS Q7 (National.xlsx), periods 2025-24 to 2026-20 (biweekly)
+
+| Candidate | log-likelihood | weight | t0 | K_Ω at window end |
+|---|---|---|---|---|
+| B3/loop off | -8.3 | 0.443 | 1.20 | 0.172 |
+| B2/loop off | -8.5 | 0.376 | 0.20 | 0.077 |
+| B4/loop off | -9.2 | 0.176 | 1.90 | 0.278 |
+| B4/loop on | -12.8 | 0.005 | 0.00 | 0.065 |
+| B3/loop on | -19.4 | 0.000 | 0.00 | 0.062 |
+| B1/loop off | -80.7 | 0.000 | 0.00 | 0.054 |
+| B2/loop on | -82.7 | 0.000 | 3.70 | 0.069 |
+| B1/loop on | -110.1 | 0.000 | 9.60 | 0.045 |
+
+**Best:** B3/loop off (weight 0.44). Anchor weights: B1 0.00, B2 0.38, B3 0.44, B4 0.18. Loop weights: off 1.00, on 0.00.
+
+## EU
+
+Series: Eurostat isoc_eb_ai, EU27_2020, reference years 2023-2025 (2021: 7.65, before generative AI, excluded)
+
+| Candidate | log-likelihood | weight | t0 | K_Ω at window end |
+|---|---|---|---|---|
+| B3/loop off | -2.2 | 0.456 | 0.50 | 0.198 |
+| B2/loop on | -2.4 | 0.366 | 0.00 | 0.107 |
+| B3/loop on | -3.3 | 0.159 | 0.55 | 0.222 |
+| B2/loop off | -5.6 | 0.016 | 0.00 | 0.098 |
+| B4/loop off | -7.5 | 0.002 | 1.00 | 0.308 |
+| B4/loop on | -11.4 | 0.000 | 1.05 | 0.356 |
+| B1/loop on | -49.8 | 0.000 | 0.00 | 0.061 |
+| B1/loop off | -58.0 | 0.000 | 0.00 | 0.058 |
+
+**Best:** B3/loop off (weight 0.46). Anchor weights: B1 0.00, B2 0.38, B3 0.62, B4 0.00. Loop weights: off 0.47, on 0.53.
+
+## DE
+
+Series: Eurostat isoc_eb_ai, DE, reference years 2023-2025 (2021: 10.56, excluded)
+
+| Candidate | log-likelihood | weight | t0 | K_Ω at window end |
+|---|---|---|---|---|
+| B2/loop on | -0.1 | 0.573 | 0.00 | 0.110 |
+| B3/loop off | -1.3 | 0.178 | 0.65 | 0.214 |
+| B2/loop off | -1.4 | 0.152 | 0.00 | 0.101 |
+| B3/loop on | -1.9 | 0.097 | 0.70 | 0.240 |
+| B4/loop off | -8.3 | 0.000 | 1.35 | 0.370 |
+| B4/loop on | -11.0 | 0.000 | 1.35 | 0.415 |
+| B1/loop on | -36.2 | 0.000 | 0.00 | 0.063 |
+| B1/loop off | -43.4 | 0.000 | 0.00 | 0.059 |
+
+**Best:** B2/loop on (weight 0.57). Anchor weights: B1 0.00, B2 0.73, B3 0.27, B4 0.00. Loop weights: off 0.33, on 0.67.
diff --git a/simulations/gadm02/results/matching_synthetic.md b/simulations/gadm02/results/matching_synthetic.md
new file mode 100644
index 0000000..89c1479
--- /dev/null
+++ b/simulations/gadm02/results/matching_synthetic.md
@@ -0,0 +1,37 @@
+# GADM-0.4: matching and flip detection on synthetic data
+
+Generated by `simulations/gadm02/matching.py --synthetic` (ASSEMBLY-WP-0012-T06).
+US calibrated state. Truth simulated from a known candidate (optionally switching regime at
+t_switch), observed biweekly as 25 × K_Ω with log-noise sd 0.03, from t 2 to t 8. Quarterly
+regime filter: the first year fixes the initial state and the scale (whole-path alignment); then
+every quarter each regime runs forward from the current state estimate over the last quarter, and
+the estimate advances with the best regime. Weights accumulate across quarters (forward filter,
+switch probability 0.02 per quarter). Level evidence: true K_Ω ± 0.075 (as wide as the real
+US target). Flip: new best with weight ≥ 0.75 twice in a row.
+
+| Indicators | Truth | Seed | Best at first evaluation | Flips detected (t, from → to) | Verdict |
+|---|---|---|---|---|---|
+| adoption | B3/loop off | 1 | B3/loop off | none | ok (no false flip) |
+| adoption | B3/loop off | 2 | B3/loop off | 4.50: B3/loop off → B4/loop off; 7.75: B4/loop off → B3/loop off | FALSE FLIP |
+| adoption | B3/loop off | 3 | B3/loop off | 4.75: B4/loop off → B3/loop off | FALSE FLIP |
+| adoption + annual sentiment | B3/loop off | 1 | B3/loop off | none | ok (no false flip) |
+| adoption + annual sentiment | B3/loop off | 2 | B3/loop off | 4.50: B3/loop off → B4/loop off; 7.75: B4/loop off → B3/loop off | FALSE FLIP |
+| adoption + annual sentiment | B3/loop off | 3 | B3/loop off | 4.75: B4/loop off → B3/loop off | FALSE FLIP |
+| adoption | B2/loop off | 1 | B4/loop on | none | ok (no false flip) |
+| adoption | B2/loop off | 2 | B3/loop on | 8.00: B3/loop on → B2/loop off | FALSE FLIP |
+| adoption | B2/loop off | 3 | B3/loop on | none | ok (no false flip) |
+| adoption + annual sentiment | B2/loop off | 1 | B4/loop on | none | ok (no false flip) |
+| adoption + annual sentiment | B2/loop off | 2 | B3/loop on | none | ok (no false flip) |
+| adoption + annual sentiment | B2/loop off | 3 | B3/loop on | 8.00: B2/loop off → B4/loop on | FALSE FLIP |
+| adoption | B2/loop off → B4/loop off at t 4.0 | 1 | B4/loop on | none | missed |
+| adoption | B2/loop off → B4/loop off at t 4.0 | 2 | B3/loop on | none | missed |
+| adoption | B2/loop off → B4/loop off at t 4.0 | 3 | B3/loop on | none | missed |
+| adoption + annual sentiment | B2/loop off → B4/loop off at t 4.0 | 1 | B4/loop on | none | missed |
+| adoption + annual sentiment | B2/loop off → B4/loop off at t 4.0 | 2 | B3/loop on | 4.50: B2/loop off → B4/loop off | detected, delay 0.50 y |
+| adoption + annual sentiment | B2/loop off → B4/loop off at t 4.0 | 3 | B3/loop on | none | missed |
+| adoption | B3/loop off → B3/loop on at t 4.0 | 1 | B3/loop off | none | missed |
+| adoption | B3/loop off → B3/loop on at t 4.0 | 2 | B3/loop off | none | missed |
+| adoption | B3/loop off → B3/loop on at t 4.0 | 3 | B3/loop off | none | missed |
+| adoption + annual sentiment | B3/loop off → B3/loop on at t 4.0 | 1 | B3/loop off | none | missed |
+| adoption + annual sentiment | B3/loop off → B3/loop on at t 4.0 | 2 | B3/loop off | 8.00: B3/loop off → B4/loop on | missed |
+| adoption + annual sentiment | B3/loop off → B3/loop on at t 4.0 | 3 | B3/loop off | 7.25: B4/loop off → B3/loop on | detected, delay 3.25 y |
diff --git a/simulations/gadm02/test_matching.py b/simulations/gadm02/test_matching.py
new file mode 100644
index 0000000..47d868a
--- /dev/null
+++ b/simulations/gadm02/test_matching.py
@@ -0,0 +1,29 @@
+"""Tests for the matching engine (ASSEMBLY-WP-0012)."""
+
+import math
+import unittest
+
+import gadm04 as g
+import matching as m
+
+
+class TestMatching(unittest.TestCase):
+    def test_fit_recovers_alignment_and_scale(self):
+        rows = g.simulate(T=m.T_PATH, record_every=1)
+        pts = [(tau, 25.0 * m.interp(rows, 3.0 + tau, "Ko")) for tau in (0.0, 0.25, 0.5, 0.75, 1.0)]
+        ll, t0, ls = m.fit_series(rows, pts, 0.03)
+        self.assertAlmostEqual(t0, 3.0, places=6)
+        self.assertAlmostEqual(math.exp(ls), 25.0, places=4)
+        self.assertGreater(ll, -1e-6)
+
+    def test_flip_needs_two_consecutive_strong_evaluations(self):
+        a, b = ("B2", "off"), ("B3", "off")
+        def ev(t, wa):
+            return (t, {a: {"w": wa}, b: {"w": 1 - wa}})
+        self.assertEqual(m.flips([ev(0, 0.9), ev(1, 0.1), ev(2, 0.9)]), [])
+        self.assertEqual(m.flips([ev(0, 0.9), ev(1, 0.1), ev(2, 0.1)]), [(2, a, b)])
+        self.assertEqual(m.flips([ev(0, 0.5), ev(1, 0.1), ev(2, 0.1)]), [])   # nothing established yet
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/workplans/ASSEMBLY-WP-0012-model-matching-flipping.md b/workplans/ASSEMBLY-WP-0012-model-matching-flipping.md
index f8c081f..1cb7b99 100644
--- a/workplans/ASSEMBLY-WP-0012-model-matching-flipping.md
+++ b/workplans/ASSEMBLY-WP-0012-model-matching-flipping.md
@@ -4,7 +4,7 @@ type: workplan
 title: "Model matching and regime flipping"
 domain: communication
 repo: assembly-economics
-status: ready
+status: finished
 flavor: implementation
 depends_on: [ASSEMBLY-WP-0013, ASSEMBLY-WP-0015, ASSEMBLY-WP-0010]
 owner: claude-code
@@ -43,11 +43,13 @@ reality-aligned baseline.
 
 ```task
 id: ASSEMBLY-WP-0012-T01
-status: todo
+status: done
 priority: high
 state_hub_task_id: "e2c8b5f3-67aa-5f69-b654-b589d990105e"
 ```
 
+**Done 2026-10-13:** `research/ModelMatching.md` § 1; candidates B1–B4 × loop off/on; likelihood with level term.
+
 Start with a small candidate set that the data can already separate:
 anchors B2, B3, B4 × legitimacy loop off/on × the fitted adoption speed k
 from `calibrate_data.py`. Keep B1 as a candidate with its current misfit
@@ -63,11 +65,13 @@ Write `research/ModelMatching.md`.
 
 ```task
 id: ASSEMBLY-WP-0012-T02
-status: todo
+status: done
 priority: high
 state_hub_task_id: "a3eae0d5-c5cf-5af2-b419-ab72dfd504f7"
 ```
 
+**Done 2026-10-13:** `matching.py`, `observed_series.json`, `results/matching.md`. US B3/B2 with loop off; EU B3/B2; DE B2. No regime established (weights < 0.75).
+
 Build on `calibrate_data.py` (its alignment by growth and the z-scores per
 target are the first score). Implement `matching.py`: for each jurisdiction, fit each candidate to the
 checkpoint series (using the WP-0013 calibration routine), score it, and
@@ -79,11 +83,13 @@ checkpoint.
 
 ```task
 id: ASSEMBLY-WP-0012-T03
-status: todo
+status: done
 priority: high
 state_hub_task_id: "a7a9a42a-8703-56c8-ab0d-b7505e22dfef"
 ```
 
+**Done 2026-10-13:** flip definition and regime filter (`research/ModelMatching.md` § 3), `research/FlipRegister.md` (empty), `test_matching.py`.
+
 First flip candidates to watch: B3 → B2 (an adoption slowdown in the BTOS
 series, compare P-2026-001) and loop off → on (sentiment falling faster than
 adoption). Define a flipping event: the best-fitting regime changes **and** the
@@ -97,11 +103,13 @@ flip register (`research/FlipRegister.md`), linked to the break register.
 
 ```task
 id: ASSEMBLY-WP-0012-T04
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "20c370c2-2989-54ba-b3a4-0ba056532f88"
 ```
 
+**Done 2026-10-13:** matched weights bracket the v1 assumption (B2–B3); no predictions v2 needed.
+
 Use the best-fitting regime, or a weighted ensemble, for the prediction
 register (`checkpoints/predictions.md`). Each prediction states which
 regime produced it. After a flip, new predictions use the new regime; old
@@ -111,11 +119,13 @@ predictions remain and are scored as they were made.
 
 ```task
 id: ASSEMBLY-WP-0012-T05
-status: todo
+status: cancel
 priority: medium
 state_hub_task_id: "88940a83-d078-5346-94da-d49de570f4f3"
 ```
 
+**Moved 2026-10-13 to ASSEMBLY-WP-0017-T05** (waits for a reliable filter).
+
 Run matching at every full checkpoint (and optionally at light ones), and
 report the current regime per jurisdiction and any flip candidates in the
 checkpoint record. Coordinate the runner change with WP-0010.
@@ -124,12 +134,22 @@ checkpoint record. Coordinate the runner change with WP-0010.
 
 ```task
 id: ASSEMBLY-WP-0012-T06
-status: todo
+status: done
 priority: high
 state_hub_task_id: "3a3ec337-322e-5b4c-86f7-db3cfe463d6d"
 ```
 
+**Done 2026-10-13, negative result:** flip detection is not yet reliable (3 of 6 false flips, at most 2 of 6 switches detected). Requirements in `research/ModelMatching.md` § 4; work in ASSEMBLY-WP-0017.
+
 Before trusting real flips: generate synthetic indicator series from a known
 regime that switches at a known time, add realistic noise and gaps, and
 check that matching recovers the regime and detects the flip with an
 acceptable delay and false-alarm rate.
+
+## Close-out 2026-10-13
+
+T01–T04 and T06 are done (`research/ModelMatching.md`, `matching.py`,
+`research/FlipRegister.md`, BR-009). The synthetic test shows that flip
+detection is not yet reliable. The residuals are handed off to
+ASSEMBLY-WP-0017: the sentiment equation, more indicators, a per-regime
+filter, passing the acceptance test, and checkpoint integration.
diff --git a/workplans/ASSEMBLY-WP-0017-reliable-flip-detection.md b/workplans/ASSEMBLY-WP-0017-reliable-flip-detection.md
new file mode 100644
index 0000000..ccdd35c
--- /dev/null
+++ b/workplans/ASSEMBLY-WP-0017-reliable-flip-detection.md
@@ -0,0 +1,89 @@
+---
+id: ASSEMBLY-WP-0017
+type: workplan
+title: "Reliable flip detection: indicators, per-regime filter, sentiment equation"
+domain: communication
+repo: assembly-economics
+status: proposed
+flavor: residual
+depends_on: [ASSEMBLY-WP-0012]
+owner: claude-code
+topic_slug: coulomb-social
+created: "2026-10-13"
+updated: "2026-10-13"
+---
+
+# Reliable flip detection
+
+Residuals of ASSEMBLY-WP-0012. Matching on observed data works
+(`research/ModelMatching.md` § 2). Flip detection does not yet pass its
+synthetic test (§ 4): 3 of 6 false flips, at most 2 of 6 switches detected.
+No flip may be recorded in `research/FlipRegister.md` until T04 passes.
+
+## Fix the sentiment equation (BR-009)
+
+```task
+id: ASSEMBLY-WP-0017-T01
+status: todo
+priority: high
+```
+
+Σ relaxes toward 0.5 + gain × Δ(perceived benefit), so from the measured US
+level (0.285) it rises, while measured US sentiment fell 2021–2026. Add a
+sentiment reference parameter: neutral 0.5 (the default, keeps old results)
+or anchored to the observed level. Fit `sig_adopt` (and an optional lag) to
+the US finding that adoption grows fast despite low sentiment. Re-run
+`legitimacy.py`, `calibrated_readings.py` and `world_scenarios.py`, and
+record which readings change.
+
+## More discriminating indicators in the filter
+
+```task
+id: ASSEMBLY-WP-0017-T02
+status: todo
+priority: high
+```
+
+Add to `filter_step` and to `observed_series.json`: investment (L5,
+quarterly; separates self-enhancement and B4), concentration channels (CB1,
+monthly; domination dynamics), and sentiment at least twice a year where
+surveys allow it. Each indicator needs an observation operator and a noise
+level.
+
+## Per-regime state tracking
+
+```task
+id: ASSEMBLY-WP-0017-T03
+status: todo
+priority: medium
+```
+
+Today the filter carries one shared state estimate, advanced by the best
+regime. Track one state per regime (interacting multiple-model filter), so
+that a regime that becomes true later is not judged from another regime's
+state.
+
+## Pass the synthetic acceptance test
+
+```task
+id: ASSEMBLY-WP-0017-T04
+status: todo
+priority: high
+```
+
+Acceptance: at least 5 of 6 regimes correct at the first evaluation, no false
+flips in 6 no-switch runs, and at least 4 of 6 switches detected within 1.5
+years (`matching.py --synthetic`). Add the criteria as a slow test.
+
+## Checkpoint integration (from WP-0012-T05)
+
+```task
+id: ASSEMBLY-WP-0017-T05
+status: wait
+priority: medium
+```
+
+Waits for T04. Then run matching at every full checkpoint (optionally at
+light ones), report the current regime and any flip candidates in the
+checkpoint record, and coordinate the runner change with WP-0014 (governed
+execution profile).