diff --git a/periscope/src/backend/periscopex/bom_summary.py b/periscope/src/backend/periscopex/bom_summary.py
new file mode 100644
index 0000000..fa35c6b
--- /dev/null
+++ b/periscope/src/backend/periscopex/bom_summary.py
@@ -0,0 +1,60 @@
+"""BOM summary rows grouped by MPN. Collation only."""
+
+from __future__ import annotations
+
+from backend.periscopex.models import ComponentType, DesignGraph
+from backend.periscopex.utils import natural_sort_key
+
+
+def build_bom_summary(
+    graph: DesignGraph,
+    datasheet_mpns: set[str] | None = None,
+    descriptions: dict[str, str] | None = None,
+) -> list[dict]:
+    by_key: dict[str, list] = {}
+    for comp in graph.components.values():
+        key = comp.mpn if comp.mpn else f"__no_mpn__{comp.value}__{comp.component_type}"
+        by_key.setdefault(key, []).append(comp)
+    rows: list[dict] = []
+    for comps in by_key.values():
+        first = comps[0]
+        designators = sorted([c.reference for c in comps], key=natural_sort_key)
+        specs_dict = None
+        if first.specs:
+            if hasattr(first.specs, "values"):
+                raw = {k: v for k, v in first.specs.values.items() if v is not None}
+            else:
+                raw = first.specs.model_dump(exclude={"specs_type"})
+                raw = {
+                    k: v for k, v in raw.items()
+                    if v is not None and k not in (
+                        "value_ohms", "value_farads", "value_henries", "impedance_ohm",
+                    )
+                }
+            specs_dict = raw or None
+        has_ds = bool(first.mpn and datasheet_mpns is not None and first.mpn in datasheet_mpns)
+        description = None
+        if descriptions is not None and first.mpn and first.component_type == ComponentType.IC:
+            description = descriptions.get(first.mpn)
+        rows.append({
+            "mpn": first.mpn,
+            "designators": designators,
+            "value": first.value,
+            "category": first.component_subtype,
+            "specs": specs_dict,
+            "description": description,
+            "has_datasheet": has_ds,
+        })
+
+    def sort_key(row: dict) -> tuple:
+        cat = row["category"] or ""
+        if cat.startswith("ic"):
+            group = 0
+        elif cat.startswith("passive"):
+            group = 1
+        else:
+            group = 2
+        return (group, cat, row["mpn"] or "")
+
+    rows.sort(key=sort_key)
+    return rows
diff --git a/periscope/src/backend/periscopex/derating.py b/periscope/src/backend/periscopex/derating.py
new file mode 100644
index 0000000..fa58a69
--- /dev/null
+++ b/periscope/src/backend/periscopex/derating.py
@@ -0,0 +1,151 @@
+"""Capacitor voltage derating + DC-bias C_eff stima (not a vendor lot curve)."""
+
+from __future__ import annotations
+
+import re
+
+from backend.periscopex.models import ComponentType, DesignGraph, NetType
+from backend.periscopex.resolve_passives import _format_value
+from backend.periscopex.utils import natural_sort_key
+
+_CERAMIC = {"X7R", "X5R", "C0G", "NP0", "Y5V", "X7S", "X6S", "X8R", "C0G (NP0)"}
+_CURVES: dict[str, list[tuple[float, float]]] = {
+    "c0g": [(0.0, 1.0), (1.2, 1.0)],
+    "x7r": [(0.0, 1.0), (0.25, 0.90), (0.50, 0.70), (0.75, 0.45), (1.0, 0.30), (1.2, 0.22)],
+    "x5r": [(0.0, 1.0), (0.25, 0.82), (0.50, 0.55), (0.75, 0.32), (1.0, 0.18), (1.2, 0.12)],
+    "y5v": [(0.0, 1.0), (0.25, 0.50), (0.50, 0.20), (0.80, 0.12), (1.0, 0.10)],
+}
+
+
+def _lerp(curve: list[tuple[float, float]], x: float) -> float:
+    if x <= curve[0][0]:
+        return curve[0][1]
+    for (x0, y0), (x1, y1) in zip(curve, curve[1:]):
+        if x <= x1:
+            if x1 == x0:
+                return y1
+            return y0 + (y1 - y0) * (x - x0) / (x1 - x0)
+    return curve[-1][1]
+
+
+def _bias_family(dielectric: str | None) -> str | None:
+    if not dielectric:
+        return None
+    u = dielectric.upper()
+    if "C0G" in u or "NP0" in u or "NPO" in u:
+        return "c0g"
+    if "Y5V" in u:
+        return "y5v"
+    if "X5R" in u or "X6S" in u:
+        return "x5r"
+    if "X7R" in u or "X7S" in u or "X8R" in u:
+        return "x7r"
+    return None
+
+
+def dc_bias_remaining(
+    dielectric: str | None, v_op: float | None, rated_v: float | None,
+) -> float | None:
+    family = _bias_family(dielectric)
+    if family is None or v_op is None or rated_v is None or rated_v <= 0:
+        return None
+    return _lerp(_CURVES[family], max(0.0, v_op) / rated_v)
+
+
+def _parse_voltage_rating(s: str | None) -> float | None:
+    if not s:
+        return None
+    m = re.match(r"([\d.]+)", s)
+    return float(m.group(1)) if m else None
+
+
+def _dielectric_category(subtype: str | None, dielectric: str | None) -> str | None:
+    if subtype:
+        low = subtype.lower()
+        if "tantalum" in low:
+            return "tantalum"
+        if "electrolytic" in low:
+            return "electrolytic"
+        if "ceramic" in low:
+            return "ceramic"
+    if dielectric:
+        upper = dielectric.upper().strip()
+        if upper in _CERAMIC or any(d in upper for d in _CERAMIC):
+            return "ceramic"
+        low = dielectric.lower()
+        if "tantalum" in low or low == "ta":
+            return "tantalum"
+        if "electrolytic" in low or low == "al":
+            return "electrolytic"
+    return "ceramic"
+
+
+def _stress(op: float | None, rated: float | None) -> str:
+    if op is None or rated is None or rated <= 0:
+        return "UNKNOWN"
+    ratio = op / rated
+    if ratio > 1.0:
+        return "RISK"
+    if ratio > 0.8:
+        return "MARGIN"
+    return "PASS"
+
+
+def build_derating_table(graph: DesignGraph) -> list[dict]:
+    rows: list[dict] = []
+    for comp in graph.components.values():
+        if comp.component_type != ComponentType.CAPACITOR:
+            continue
+        rated_v = value_fmt = dielectric = c_nom = None
+        if comp.specs and hasattr(comp.specs, "voltage_rating_v"):
+            rated_v = _parse_voltage_rating(comp.specs.voltage_rating_v)
+            value_fmt = getattr(comp.specs, "value_formatted", None)
+            dielectric = getattr(comp.specs, "dielectric", None)
+            c_nom = getattr(comp.specs, "value_farads", None)
+        op_voltage: float | None = None
+        op_source: str | None = None
+        for net_name in comp.pins.values():
+            net = graph.nets.get(net_name)
+            if net and net.voltage is not None and net.voltage > 0:
+                if op_voltage is None or net.voltage > op_voltage:
+                    op_voltage = net.voltage
+                    op_source = net_name
+        seen: set[str] = set()
+        connected: list[tuple[str, float | None, NetType | None]] = []
+        for net_name in comp.pins.values():
+            if net_name in seen:
+                continue
+            seen.add(net_name)
+            net = graph.nets.get(net_name)
+            connected.append((net_name, net.voltage if net else None, net.net_type if net else None))
+        net_plus = net_minus = None
+        if len(connected) == 1:
+            net_plus = connected[0][0]
+        elif len(connected) >= 2:
+            by_v = sorted(connected, key=lambda c: (
+                c[2] != NetType.GROUND, c[1] is not None, c[1] or 0,
+            ))
+            net_minus = by_v[0][0]
+            net_plus = by_v[-1][0]
+        factor = dc_bias_remaining(dielectric, op_voltage, rated_v)
+        c_eff = (c_nom * factor) if (c_nom is not None and factor is not None) else None
+        rows.append({
+            "designator": comp.reference,
+            "mpn": comp.mpn,
+            "value_formatted": value_fmt,
+            "rated_voltage_v": rated_v,
+            "operating_voltage_v": op_voltage,
+            "operating_voltage_source": op_source,
+            "net_plus": net_plus,
+            "net_minus": net_minus,
+            "dielectric_category": _dielectric_category(comp.component_subtype, dielectric),
+            "dielectric": dielectric,
+            "c_nominal_f": c_nom,
+            "dc_bias_factor": factor,
+            "c_eff_f": c_eff,
+            "c_eff_formatted": _format_value(c_eff, "F") if c_eff is not None else None,
+            "dc_bias_model": "stima" if factor is not None else None,
+            "stress": _stress(op_voltage, rated_v),
+        })
+    rows.sort(key=lambda r: natural_sort_key(r["designator"]))
+    return rows
diff --git a/periscope/src/backend/periscopex/led_current_check.py b/periscope/src/backend/periscopex/led_current_check.py
new file mode 100644
index 0000000..29d1773
--- /dev/null
+++ b/periscope/src/backend/periscopex/led_current_check.py
@@ -0,0 +1,264 @@
+"""LED I_f check: Ohm's law on the graph vs datasheet channel rating."""
+
+from __future__ import annotations
+
+import re
+
+from backend.periscopex.models import ComponentType, DesignGraph, Finding, NetType
+from backend.periscopex.resolve_passives import _parse_spice_value
+
+_COLOR = {
+    "R": "red", "RED": "red",
+    "G": "green", "GRN": "green", "GREEN": "green",
+    "B": "blue", "BLU": "blue", "BLUE": "blue",
+}
+
+
+def _num(v: object) -> float | None:
+    if v is None:
+        return None
+    if isinstance(v, (int, float)):
+        return float(v)
+    s = str(v).strip()
+    for cand in (s, *re.findall(r"[-+]?\d*\.?\d+\s*[a-zA-Zµ]*", s)):
+        cand = cand.strip()
+        if not cand:
+            continue
+        try:
+            return _parse_spice_value(cand)
+        except ValueError:
+            pass
+        m = re.match(r"^[-+]?\d*\.?\d+", cand)
+        if m:
+            try:
+                return float(m.group(0))
+            except ValueError:
+                pass
+    return None
+
+
+def _parse_resistance(v: object) -> float | None:
+    if v is None:
+        return None
+    if isinstance(v, (int, float)):
+        return float(v)
+    t = str(v).strip().upper().replace("OHMS", "").replace("OHM", "").replace("Ω", "").replace(" ", "")
+    if not t:
+        return None
+    mult = {"R": 1.0, "K": 1e3, "M": 1e6, "G": 1e9}
+    m = re.match(r"^(\d+)([RKMG])(\d+)$", t)
+    if m:
+        return (float(m.group(1)) + float(f"0.{m.group(3)}")) * mult[m.group(2)]
+    m = re.match(r"^(\d*\.?\d+)([RKMG])$", t)
+    if m:
+        return float(m.group(1)) * mult[m.group(2)]
+    try:
+        return float(t)
+    except ValueError:
+        return None
+
+
+def _spec(values: dict, *keys: str) -> float | None:
+    for k in keys:
+        if k in values:
+            n = _num(values[k])
+            if n is not None:
+                return n
+    return None
+
+
+def _imax(values: dict) -> float | None:
+    i = _spec(values, "forward_current_per_channel_a", "forward_current_a",
+              "max_forward_current_a", "if_max_a")
+    if i is None:
+        return None
+    if i >= 1.0:
+        i = i / 1000.0
+    return i
+
+
+def _vf(values: dict, color: str | None) -> float | None:
+    vf = _spec(values, f"forward_voltage_{color}_v") if color else None
+    if vf is None:
+        vf = _spec(values, "forward_voltage_v", "vf_v")
+    if vf is None:
+        cands = [c for c in (_spec(values, f"forward_voltage_{c}_v") for c in ("red", "green", "blue")) if c is not None]
+        vf = min(cands) if cands else None
+    if vf is not None and vf > 20:
+        vf = vf / 1000.0
+    return vf
+
+
+def _net_voltage(graph: DesignGraph, net_name: str | None) -> float | None:
+    if not net_name:
+        return None
+    net = graph.nets.get(net_name)
+    return net.voltage if net else None
+
+
+def _is_rail_net(graph: DesignGraph, net_name: str) -> bool:
+    net = graph.nets.get(net_name)
+    if not net:
+        return False
+    return net.net_type in (NetType.POWER, NetType.GROUND) or net.voltage is not None
+
+
+def _series_resistor(graph: DesignGraph, net_name: str, exclude_ref: str):
+    net = graph.nets.get(net_name)
+    if not net or len(net.pins) != 2:
+        return None
+    for pc in net.pins:
+        if pc.component_ref == exclude_ref:
+            continue
+        c = graph.components.get(pc.component_ref)
+        if not c or c.component_type != ComponentType.RESISTOR:
+            continue
+        rval = getattr(c.specs, "value_ohms", None) if c.specs else None
+        if rval is None:
+            rval = _parse_resistance(c.value)
+        if rval is None or rval <= 0:
+            continue
+        far = next((n for n in c.pins.values() if n != net_name), None)
+        return (pc.component_ref, float(rval), far)
+    return None
+
+
+def _leg_to_ic(graph: DesignGraph, net_name: str, exclude_ref: str) -> bool:
+    for r in graph.components_on_net(net_name):
+        if r == exclude_ref:
+            continue
+        c = graph.components.get(r)
+        if c and c.component_type == ComponentType.IC:
+            return True
+    return False
+
+
+def _leg_color(pid: str, comp) -> str | None:
+    if pid.upper() in _COLOR:
+        return _COLOR[pid.upper()]
+    specs = comp.specs
+    pin = specs.pin_by_number(pid) if specs and hasattr(specs, "pin_by_number") else None
+    if pin:
+        for tok in re.split(r"[\s_/-]+", pin.name.upper()):
+            if tok in _COLOR:
+                return _COLOR[tok]
+    return None
+
+
+def check_led_current(graph: DesignGraph) -> list[Finding]:
+    findings: list[Finding] = []
+    for ref in sorted(graph.components_by_subtype("discrete.led")):
+        comp = graph.components.get(ref)
+        if not comp or not comp.specs:
+            continue
+        values = getattr(comp.specs, "values", None)
+        if not values:
+            continue
+        imax = _imax(values)
+        if imax is None:
+            continue
+        finding = _check_led(graph, ref, comp, values, imax)
+        if finding is not None:
+            findings.append(finding)
+    return findings
+
+
+def _check_led(graph, ref, comp, values, imax) -> Finding | None:
+    pins = comp.pins
+    pin_volts = [v for v in (_net_voltage(graph, n) for n in pins.values()) if v is not None]
+    if len(pins) <= 2:
+        leg = next(
+            ((pid, net, _series_resistor(graph, net, ref))
+             for pid, net in pins.items() if _series_resistor(graph, net, ref)),
+            None,
+        )
+        if leg is None:
+            cand = next(((pid, net) for pid, net in pins.items() if not _is_rail_net(graph, net)), None)
+            legs = [(cand[0], cand[1], None)] if cand else []
+        else:
+            legs = [leg]
+    else:
+        legs = [
+            (pid, net, _series_resistor(graph, net, ref))
+            for pid, net in pins.items() if not _is_rail_net(graph, net)
+        ]
+    worst = None
+    no_res = None
+    for pid, net, res in legs:
+        color = _leg_color(pid, comp)
+        vf = _vf(values, color)
+        cand = list(pin_volts)
+        if res and res[2]:
+            fv = _net_voltage(graph, res[2])
+            if fv is not None:
+                cand.append(fv)
+        vrail = max(cand) if cand else None
+        if res is None:
+            if no_res is None and vrail is not None and vrail > 0 and not _leg_to_ic(graph, net, ref):
+                no_res = (color, net, vrail, vf)
+            continue
+        rref, rval, _far = res
+        if vrail is None or vf is None or vrail <= vf or rval <= 0:
+            continue
+        i = (vrail - vf) / rval
+        if i > imax and (worst is None or i > worst[0]):
+            worst = (i, color, net, vrail, vf, rval, rref)
+    if worst is not None:
+        i, color, net, vrail, vf, rval, rref = worst
+        return _over(ref, comp, net, color, vrail, vf, rval, rref, imax, i)
+    if no_res is not None:
+        color, net, vrail, vf = no_res
+        return _missing_r(ref, comp, net, color, vrail, vf, imax)
+    return None
+
+
+def _chan(color: str | None) -> str:
+    return f"{color} channel" if color else "LED"
+
+
+def _over(ref, comp, net, color, vrail, vf, rval, rref, imax, i) -> Finding:
+    rmin = (vrail - vf) / imax
+    return Finding(
+        designator=ref, mpn=comp.mpn or "", aspect="led_current",
+        source="led_current_check", source_page=None, status="ERROR",
+        finding=(
+            f"{ref} {_chan(color)} forward current is ~{i * 1000:.0f} mA, "
+            f"exceeding its {imax * 1000:.0f} mA forward-current rating."
+        ),
+        why=(
+            f"With the supply at {vrail:.1f} V and Vf≈{vf:.1f} V, series resistor "
+            f"{rref} ({rval:.0f} Ω) on net '{net}' passes "
+            f"~({vrail:.1f}−{vf:.1f})/{rval:.0f} = {i * 1000:.0f} mA (worst case, "
+            f"0 V driver drop) — above the {imax * 1000:.0f} mA rating."
+        ),
+        recommendation=(
+            f"Increase the series resistor to at least {rmin:.0f} Ω to keep the "
+            f"{_chan(color)} at or below {imax * 1000:.0f} mA."
+        ),
+        reference=f"{comp.mpn or ref} LED specs",
+    )
+
+
+def _missing_r(ref, comp, net, color, vrail, vf, imax) -> Finding:
+    rec = "Add a series current-limiting resistor, or confirm a constant-current driver."
+    if vf is not None and vrail > vf:
+        rec = (
+            f"Add a series resistor of at least {((vrail - vf) / imax):.0f} Ω "
+            f"(or confirm a constant-current driver)."
+        )
+    return Finding(
+        designator=ref, mpn=comp.mpn or "", aspect="led_current",
+        source="led_current_check", source_page=None, status="WARNING",
+        finding=(
+            f"Unverified: {ref} {_chan(color)} has no series current-limiting "
+            f"resistor on net '{net}'."
+        ),
+        why=(
+            f"The {_chan(color)} on net '{net}' has no series resistor between the "
+            f"LED and the {vrail:.1f} V supply. If it is not driven by a "
+            f"constant-current source, forward current can exceed the "
+            f"{imax * 1000:.0f} mA rating."
+        ),
+        recommendation=rec,
+        reference=f"{comp.mpn or ref} LED specs",
+    )
diff --git a/periscope/src/backend/periscopex/pin_function_tokens.py b/periscope/src/backend/periscopex/pin_function_tokens.py
new file mode 100644
index 0000000..46bcd82
--- /dev/null
+++ b/periscope/src/backend/periscopex/pin_function_tokens.py
@@ -0,0 +1,81 @@
+"""Canonical (peripheral, signal) tokens from net names and pin functions."""
+
+from __future__ import annotations
+
+import re
+
+_FAMILIES = (
+    "LPUART", "USART", "UART", "I2C", "OCTOSPI", "QSPI", "SPI",
+    "FDCAN", "CAN", "SDMMC", "SDIO", "I2S", "SAI", "USB",
+)
+_FAMILY_ALT = "|".join(_FAMILIES)
+_PERIPHERAL_RE = re.compile(rf"^({_FAMILY_ALT})(\d*)$")
+_FUNCTION_RE = re.compile(rf"^({_FAMILY_ALT})(\d*)_(.+)$")
+
+_SIGNALS = {"TX", "RX", "SDA", "SCL", "MOSI", "MISO", "SCK", "NSS", "DP", "DM"}
+_SYNONYMS = {
+    "TXD": "TX", "RXD": "RX",
+    "SCLK": "SCK", "CLK": "SCK",
+    "SS": "NSS", "CS": "NSS", "NCS": "NSS", "STE": "NSS",
+    "DPLUS": "DP", "DMINUS": "DM",
+    "PICO": "MOSI", "COPI": "MOSI",
+    "POCI": "MISO", "CIPO": "MISO",
+}
+_COMPLEMENT = {
+    "TX": "RX", "RX": "TX",
+    "SDA": "SCL", "SCL": "SDA",
+    "MOSI": "MISO", "MISO": "MOSI",
+    "DP": "DM", "DM": "DP",
+}
+_CS_INDEXED = re.compile(r"^(N?CS|SS|STE)\d+$")
+
+
+def _canon_signal(tok: str) -> str | None:
+    t = tok.upper()
+    m = _CS_INDEXED.match(t)
+    if m:
+        t = m.group(1)
+    t = _SYNONYMS.get(t, t)
+    return t if t in _SIGNALS else None
+
+
+def _tokens(name: str) -> list[str]:
+    s = name.upper().lstrip("/")
+    s = s.replace("D+", "DP").replace("D-", "DM")
+    s = re.sub(r"[._/]", "-", s)
+    return [p for p in s.split("-") if p]
+
+
+def parse_net_token(net_name: str) -> tuple[str, str] | None:
+    parts = _tokens(net_name)
+    for i in range(len(parts) - 1):
+        m = _PERIPHERAL_RE.match(parts[i])
+        if not m:
+            continue
+        sig = _canon_signal(parts[i + 1])
+        if sig is None:
+            continue
+        return (m.group(1) + m.group(2), sig)
+    return None
+
+
+def normalize_functions(functions: list[str] | None) -> set[tuple[str, str]]:
+    out: set[tuple[str, str]] = set()
+    for f in functions or []:
+        for alt in f.upper().replace("D+", "DP").replace("D-", "DM").split("/"):
+            m = _FUNCTION_RE.match(alt.strip())
+            if not m:
+                continue
+            sig = _canon_signal(m.group(3))
+            if sig is None:
+                continue
+            out.add((m.group(1) + m.group(2), sig))
+    return out
+
+
+def signals_for_peripheral(funcs: set[tuple[str, str]], peripheral: str) -> set[str]:
+    return {s for (p, s) in funcs if p == peripheral}
+
+
+def complement(signal: str) -> str | None:
+    return _COMPLEMENT.get(signal)
diff --git a/periscope/src/backend/periscopex/pin_mux_check.py b/periscope/src/backend/periscopex/pin_mux_check.py
new file mode 100644
index 0000000..e7f7165
--- /dev/null
+++ b/periscope/src/backend/periscopex/pin_mux_check.py
@@ -0,0 +1,125 @@
+"""Pin-mux feasibility: net-asserted function vs datasheet alt-function table.
+
+Feasibility only. Inter-device same-peripheral links are skipped.
+"""
+
+from __future__ import annotations
+
+from backend.periscopex.constraints_lookup import match_constraints as _match_constraints
+from backend.periscopex.models import ComponentConstraints, ComponentType, DesignGraph, Finding
+from backend.periscopex.pin_function_tokens import (
+    complement,
+    normalize_functions,
+    parse_net_token,
+    signals_for_peripheral,
+)
+
+
+def check_pin_mux_feasibility(
+    graph: DesignGraph,
+    constraints_map: dict[str, ComponentConstraints],
+) -> list[Finding]:
+    findings: list[Finding] = []
+    for ref, comp in sorted(graph.components.items()):
+        if comp.component_type != ComponentType.IC:
+            continue
+        cons = _match_constraints(comp.mpn or comp.value, constraints_map)
+        if not cons:
+            continue
+        for pin_num, net_name in comp.pins.items():
+            token = parse_net_token(net_name)
+            if token is None:
+                continue
+            peripheral, signal = token
+            pin = cons.pin_by_number(pin_num)
+            if pin is None or not pin.functions:
+                continue
+            exposed = signals_for_peripheral(normalize_functions(pin.functions), peripheral)
+            if not exposed or signal in exposed:
+                continue
+            if _peer_exposes(graph, constraints_map, net_name, ref, peripheral):
+                continue
+            findings.append(
+                _finding(ref, comp.mpn or "", pin_num, pin.name, net_name,
+                         peripheral, signal, exposed, pin.functions)
+            )
+    return findings
+
+
+def _peer_exposes(
+    graph: DesignGraph,
+    constraints_map: dict[str, ComponentConstraints],
+    net_name: str,
+    self_ref: str,
+    peripheral: str,
+) -> bool:
+    net = graph.nets.get(net_name)
+    if not net:
+        return False
+    for pc in net.pins:
+        if pc.component_ref == self_ref:
+            continue
+        other = graph.components.get(pc.component_ref)
+        if not other or other.component_type != ComponentType.IC:
+            continue
+        ocons = _match_constraints(other.mpn or other.value, constraints_map)
+        if not ocons:
+            continue
+        opin = ocons.pin_by_number(pc.pin_number)
+        if opin is None or not opin.functions:
+            continue
+        if signals_for_peripheral(normalize_functions(opin.functions), peripheral):
+            return True
+    return False
+
+
+def _finding(
+    ref: str, mpn: str, pin_num: str, pin_name: str, net_name: str,
+    peripheral: str, signal: str, exposed: set[str], functions: list[str],
+) -> Finding:
+    listed = ", ".join(functions) if functions else "(none listed)"
+    other = complement(signal)
+    swap = bool(other and other in exposed)
+    rec = (
+        f"Move '{net_name}' to a pin whose alternate functions include "
+        f"{peripheral}_{signal}."
+    )
+    hint = ""
+    if swap:
+        hint = (
+            f" This pin's {peripheral} role is {peripheral}_{other} — the "
+            f"complement of {peripheral}_{signal} — so the {signal}/{other} "
+            f"nets are most likely swapped."
+        )
+        rec = (
+            f"Move '{net_name}' to a {peripheral}_{signal}-capable pin, or swap "
+            f"it with the paired {peripheral}_{other} net if that resolves both."
+        )
+    return Finding(
+        designator=ref,
+        mpn=mpn,
+        aspect="pin_mux",
+        source="pin_mux_check",
+        source_page=None,
+        status="ERROR",
+        finding=(
+            f"Net '{net_name}' assigns {ref} pin {pin_num} ({pin_name}) the "
+            f"{peripheral}_{signal} function, but this pin cannot be muxed as "
+            f"{peripheral}_{signal}."
+        ),
+        why=(
+            f"The intended function {peripheral}_{signal} was inferred from the "
+            f"net name '{net_name}'. Per the datasheet alternate-function table, "
+            f"pin {pin_num} ({pin_name}) can be muxed as: {listed}. "
+            f"{peripheral}_{signal} is not in that list, so the silicon cannot "
+            f"route it here regardless of downstream wiring." + hint +
+            f" If '{net_name}' is not actually configured for {peripheral} in "
+            f"firmware (e.g. bit-banged GPIO, or a label carried over from the "
+            f"connected part), disregard this finding."
+        ),
+        recommendation=rec,
+        reference=f"{mpn or ref} alternate-function table",
+        net=net_name,
+        pins=[f"{ref}.{pin_num}"],
+        rule_id="PE-MUX-001",
+    )
diff --git a/periscope/src/backend/periscopex/resolve_passives.py b/periscope/src/backend/periscopex/resolve_passives.py
new file mode 100644
index 0000000..429ecbd
--- /dev/null
+++ b/periscope/src/backend/periscopex/resolve_passives.py
@@ -0,0 +1,301 @@
+"""Passive MPN pattern matching and typed-spec conversion."""
+
+from __future__ import annotations
+
+import json
+import re
+from collections import defaultdict
+from pathlib import Path
+
+from backend.periscopex.models import (
+    CapacitorSpecs,
+    ComponentSpecs,
+    ComponentType,
+    InductorSpecs,
+    PassivePattern,
+    ResistorSpecs,
+    ResolvedPassive,
+    SimpleComponentSpecs,
+    ValueDecoder,
+)
+from backend.periscopex.parsers import parse_bom
+
+
+def _multiplier(digit: str, letter_multipliers: dict[str, int | str]) -> float:
+    if digit in letter_multipliers:
+        val = letter_multipliers[digit]
+        if val == "decimal_point":
+            raise ValueError(f"Letter '{digit}' is a decimal-point marker, not a multiplier")
+        return 10.0 ** int(val)
+    return 10.0 ** int(digit)
+
+
+def _decode_eia3_pf(digits: str) -> float:
+    return float(int(digits[:2]) * (10 ** int(digits[2])))
+
+
+def _decode_r_notation(digits: str, decimal_letters: set[str]) -> float | None:
+    for letter in decimal_letters:
+        if letter in digits:
+            return float(digits.replace(letter, "."))
+    return None
+
+
+def _decode_eia4_ohm(digits: str, tolerance_code: str, decoder: ValueDecoder) -> float:
+    if decoder.zero_code and digits == decoder.zero_code:
+        return 0.0
+    decimal_letters = {k for k, v in decoder.letter_multipliers.items() if v == "decimal_point"}
+    if decimal_letters:
+        r_val = _decode_r_notation(digits, decimal_letters)
+        if r_val is not None:
+            return r_val
+    cond = decoder.conditional_on or {}
+    high_tol = cond.get("high_tolerance", [])
+    layout = cond.get("high_tolerance_layout", {}) if tolerance_code in high_tol else cond.get("low_tolerance_layout", {})
+    sig_start = layout.get("significant_start", 0)
+    sig_count = layout.get("significant_count", 3)
+    mult_idx = layout.get("multiplier_index", 3)
+    sig = int(digits[sig_start:sig_start + sig_count])
+    return float(sig) * _multiplier(digits[mult_idx], decoder.letter_multipliers)
+
+
+def _decode_letter_decimal(digits: str, decoder: ValueDecoder) -> float:
+    for letter, mult in decoder.letter_multipliers.items():
+        if letter in digits:
+            before, after = digits.split(letter, 1)
+            value = float(f"{before}.{after}") if after else float(before)
+            return value * float(mult)
+    return float(digits)
+
+
+def decode_value(digits: str, decoder: ValueDecoder, tolerance_code: str | None = None) -> float:
+    if decoder.type == "eia3_pf":
+        pf = _decode_eia3_pf(digits)
+        return pf * 1e-12 if decoder.output_unit == "F" else pf
+    if decoder.type == "eia4_ohm_conditional":
+        return _decode_eia4_ohm(digits, tolerance_code or "", decoder)
+    if decoder.type == "letter_decimal_ohm":
+        return _decode_letter_decimal(digits, decoder)
+    raise ValueError(f"Unknown decoder type: {decoder.type}")
+
+
+_SI_OHM = [(1e6, "Mohm"), (1e3, "kohm"), (1.0, "ohm"), (1e-3, "mohm")]
+_SI_F = [(1e-3, "mF"), (1e-6, "uF"), (1e-9, "nF"), (1e-12, "pF"), (1e-15, "fF")]
+
+
+def _format_value(value: float, unit: str) -> str:
+    if value == 0.0:
+        return f"0 {unit}"
+    prefixes = _SI_OHM if unit == "ohm" else _SI_F
+    for threshold, label in prefixes:
+        if abs(value) >= threshold * 0.999:
+            scaled = value / threshold
+            if scaled == int(scaled):
+                return f"{int(scaled)} {label}"
+            return f"{scaled:.2f}".rstrip("0").rstrip(".") + f" {label}"
+    return f"{value} {unit}"
+
+
+def resolved_to_specs(resolved: ResolvedPassive) -> ComponentSpecs:
+    if resolved.component_type == ComponentType.RESISTOR:
+        return ResistorSpecs(
+            value_ohms=resolved.value, value_formatted=resolved.value_formatted,
+            tolerance=resolved.tolerance, package=resolved.package,
+            power_rating_w=resolved.power_rating,
+        )
+    if resolved.component_type == ComponentType.CAPACITOR:
+        return CapacitorSpecs(
+            value_farads=resolved.value, value_formatted=resolved.value_formatted,
+            tolerance=resolved.tolerance, package=resolved.package,
+            voltage_rating_v=resolved.voltage_rating, dielectric=resolved.dielectric,
+        )
+    if resolved.component_type == ComponentType.INDUCTOR:
+        return InductorSpecs(
+            value_henries=resolved.value, value_formatted=resolved.value_formatted,
+            tolerance=resolved.tolerance, package=resolved.package,
+        )
+    raise ValueError(f"Unsupported component type: {resolved.component_type}")
+
+
+_SPICE = {"T": 1e12, "G": 1e9, "M": 1e6, "k": 1e3, "m": 1e-3, "u": 1e-6, "n": 1e-9, "p": 1e-12}
+_UNITS = ("ohm", "F", "H", "V", "W", "A", "Hz")
+
+
+def _parse_spice_value(s: str) -> float:
+    s = s.strip()
+    for sep in (" at ", " @ ", "@"):
+        idx = s.find(sep)
+        if idx > 0:
+            s = s[:idx].strip()
+            break
+    for suffix in _UNITS:
+        if s.endswith(suffix):
+            s = s[: -len(suffix)]
+            break
+    try:
+        return float(s)
+    except ValueError:
+        pass
+    for i in range(len(s) - 1, -1, -1):
+        ch = s[i]
+        if ch in _SPICE:
+            return float(s[:i] + s[i + 1 :]) * _SPICE[ch]
+    raise ValueError(f"Cannot parse SPICE value: {s!r}")
+
+
+def simple_to_typed_passive_specs(simple: SimpleComponentSpecs) -> ComponentSpecs:
+    subtype = simple.component_subtype or ""
+    vals = simple.values
+    value_formatted = str(vals.get("value_formatted") or "")
+    tolerance = str(vals.get("tolerance")) if vals.get("tolerance") else None
+    package = str(vals.get("package")) if vals.get("package") else None
+    st = subtype or None
+    if subtype.startswith("passive.resistor") or subtype == "passive.resistor":
+        raw = vals.get("value_ohms")
+        if raw is None:
+            raise ValueError("Missing value_ohms in auto-resolved resistor specs")
+        ohms = _parse_spice_value(str(raw)) if isinstance(raw, str) else float(raw)
+        return ResistorSpecs(
+            component_subtype=st, value_ohms=ohms,
+            value_formatted=value_formatted or _format_value(ohms, "ohm"),
+            tolerance=tolerance, package=package,
+            power_rating_w=str(vals.get("power_rating_w")) if vals.get("power_rating_w") else None,
+        )
+    if subtype.startswith("passive.capacitor"):
+        raw = vals.get("value_farads")
+        if raw is None:
+            raise ValueError("Missing value_farads in auto-resolved capacitor specs")
+        farads = _parse_spice_value(str(raw)) if isinstance(raw, str) else float(raw)
+        return CapacitorSpecs(
+            component_subtype=st, value_farads=farads,
+            value_formatted=value_formatted or _format_value(farads, "F"),
+            tolerance=tolerance, package=package,
+            voltage_rating_v=str(vals.get("voltage_rating_v")) if vals.get("voltage_rating_v") else None,
+            dielectric=str(vals.get("dielectric")) if vals.get("dielectric") else None,
+        )
+    if subtype == "passive.ferrite_bead":
+        raw = vals.get("impedance_ohm") or vals.get("value_ohms")
+        if raw is None:
+            raise ValueError("Missing impedance_ohm in auto-resolved ferrite bead specs")
+        z = _parse_spice_value(str(raw)) if isinstance(raw, str) else float(raw)
+        dcr_raw = vals.get("dcr_ohms")
+        dcr = None
+        if dcr_raw is not None:
+            dcr = _parse_spice_value(str(dcr_raw)) if isinstance(dcr_raw, str) else float(dcr_raw)
+        return InductorSpecs(
+            component_subtype=st, value_henries=None,
+            value_formatted=value_formatted or _format_value(z, "ohm"),
+            tolerance=tolerance, package=package,
+            current_rating_a=str(vals.get("current_rating_a")) if vals.get("current_rating_a") else None,
+            dcr_ohms=dcr, impedance_ohm=z,
+        )
+    if subtype.startswith("passive.inductor"):
+        raw = vals.get("value_henries")
+        if raw is None:
+            raise ValueError("Missing value_henries in auto-resolved inductor specs")
+        h = _parse_spice_value(str(raw)) if isinstance(raw, str) else float(raw)
+        dcr_raw = vals.get("dcr_ohms")
+        dcr = None
+        if dcr_raw is not None:
+            dcr = _parse_spice_value(str(dcr_raw)) if isinstance(dcr_raw, str) else float(dcr_raw)
+        return InductorSpecs(
+            component_subtype=st, value_henries=h, value_formatted=value_formatted,
+            tolerance=tolerance, package=package,
+            current_rating_a=str(vals.get("current_rating_a")) if vals.get("current_rating_a") else None,
+            dcr_ohms=dcr,
+        )
+    raise ValueError(f"Unsupported passive subtype for conversion: {subtype!r}")
+
+
+class SkippedItem:
+    __slots__ = ("identifier", "stage", "error")
+
+    def __init__(self, identifier: str, stage: str, error: str) -> None:
+        self.identifier = identifier
+        self.stage = stage
+        self.error = error
+
+    def to_dict(self) -> dict[str, str]:
+        return {"identifier": self.identifier, "stage": self.stage, "error": self.error}
+
+
+def load_patterns(
+    patterns_dir: str | Path, skipped: list[SkippedItem] | None = None,
+) -> list[PassivePattern]:
+    patterns_dir = Path(patterns_dir)
+    out: list[PassivePattern] = []
+    for f in sorted(patterns_dir.glob("*.json")):
+        try:
+            out.append(PassivePattern(**json.loads(f.read_text())))
+        except Exception as exc:
+            if skipped is not None:
+                skipped.append(SkippedItem(f.stem, "passive_pattern_load", str(exc)))
+    return out
+
+
+def resolve_mpn(mpn: str, patterns: list[PassivePattern]) -> tuple[PassivePattern, dict[str, str]] | None:
+    for pat in patterns:
+        m = re.match(pat.regex, mpn)
+        if m:
+            return pat, m.groupdict()
+    return None
+
+
+def resolve_bom(
+    bom_path: str | Path,
+    patterns_dir: str | Path = "component-patterns",
+    *,
+    reference_col: str = "Reference",
+    mpn_col: str = "Manufacturer Part Number",
+    skipped: list[SkippedItem] | None = None,
+) -> list[ResolvedPassive]:
+    patterns = load_patterns(patterns_dir, skipped=skipped)
+    bom = parse_bom(bom_path, reference_col=reference_col, mpn_col=mpn_col)
+    mpn_refs: dict[str, list[str]] = defaultdict(list)
+    for ref, info in bom.items():
+        mpn = info.get("mpn")
+        if mpn:
+            mpn_refs[mpn].append(ref)
+    resolved: list[ResolvedPassive] = []
+    for mpn, refs in sorted(mpn_refs.items()):
+        match = resolve_mpn(mpn, patterns)
+        if match is None:
+            continue
+        try:
+            pat, groups = match
+            by_name = {f.name: f for f in pat.fields}
+            digits = groups.get("resistance") or groups.get("capacitance") or ""
+            tol_code = groups.get("tolerance", "")
+            value = decode_value(digits, pat.value_decoder, tol_code)
+            formatted = _format_value(value, pat.value_decoder.output_unit)
+
+            def _lookup(field: str, group: str) -> str | None:
+                fd = by_name.get(field)
+                code = groups.get(group, "")
+                if fd and fd.lookup:
+                    return fd.lookup.get(code, code)
+                return code or None
+
+            raw_fields: dict[str, str] = {}
+            for fname, fval in groups.items():
+                fd = by_name.get(fname)
+                if fd and fd.lookup:
+                    raw_fields[fname] = fd.lookup.get(fval, fval)
+                else:
+                    raw_fields[fname] = fval
+            resolved.append(ResolvedPassive(
+                mpn=mpn, references=sorted(refs),
+                component_type=pat.component_type, component_subtype=pat.component_subtype,
+                manufacturer=pat.manufacturer, series=pat.series,
+                value=value, value_formatted=formatted,
+                tolerance=_lookup("tolerance", "tolerance"),
+                package=_lookup("size", "size") or groups.get("size"),
+                voltage_rating=_lookup("voltage", "voltage"),
+                power_rating=_lookup("wattage", "wattage"),
+                dielectric=_lookup("dielectric", "dielectric"),
+                raw_fields=raw_fields,
+            ))
+        except Exception as exc:
+            if skipped is not None:
+                skipped.append(SkippedItem(mpn, "passive_resolve", str(exc)))
+    return resolved
diff --git a/periscope/src/backend/periscopex/validate.py b/periscope/src/backend/periscopex/validate.py
new file mode 100644
index 0000000..ec194e6
--- /dev/null
+++ b/periscope/src/backend/periscopex/validate.py
@@ -0,0 +1,27 @@
+"""Compatibility names for native datasheet lookup and review parse.
+
+Live review is ``review_session`` / ``services.validation``. These aliases keep
+tests and leftover callers on one API.
+"""
+
+from __future__ import annotations
+
+from backend.periscopex.constraints_lookup import (
+    build_constraints_map as _build_constraints_map,
+    load_datasheets as _load_datasheets,
+    match_constraints as _match_constraints,
+)
+from backend.periscopex.review_parse import (
+    ReviewResult,
+    assign_finding_ids,
+    parse_submit_review as _parse_review,
+)
+
+__all__ = [
+    "ReviewResult",
+    "assign_finding_ids",
+    "_build_constraints_map",
+    "_load_datasheets",
+    "_match_constraints",
+    "_parse_review",
+]
diff --git a/periscope/src/backend/periscopex/validation_tools.py b/periscope/src/backend/periscopex/validation_tools.py
new file mode 100644
index 0000000..4be3888
--- /dev/null
+++ b/periscope/src/backend/periscopex/validation_tools.py
@@ -0,0 +1,7 @@
+"""Compatibility dispatcher for native graph-query review tools."""
+
+from __future__ import annotations
+
+from backend.periscopex.review_tools import execute_tool
+
+__all__ = ["execute_tool"]
diff --git a/tests/test_periscope_analysis_rewrite.py b/tests/test_periscope_analysis_rewrite.py
new file mode 100644
index 0000000..992f8ac
--- /dev/null
+++ b/tests/test_periscope_analysis_rewrite.py
@@ -0,0 +1,21 @@
+"""Prove leftover analysis modules live in periscope/src."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+
+def test_analysis_leftovers_are_src():
+    import backend.periscopex.validate as v
+    import backend.periscopex.validation_tools as vt
+    import backend.periscopex.resolve_passives as rp
+    import backend.periscopex.derating as d
+    import backend.periscopex.bom_summary as bs
+    import backend.periscopex.pin_mux_check as mux
+    import backend.periscopex.led_current_check as led
+    import backend.periscopex.pin_function_tokens as tok
+
+    for mod in (v, vt, rp, d, bs, mux, led, tok):
+        parts = Path(mod.__file__).resolve().parts
+        assert "src" in parts
+        assert "dependency" not in parts[-6:]