diff --git a/backend/periscopex/derating.py b/backend/periscopex/derating.py
index 789d9f9..e460a6d 100644
--- a/backend/periscopex/derating.py
+++ b/backend/periscopex/derating.py
@@ -95,6 +95,18 @@ def _dielectric_category(component_subtype: str | None, dielectric: str | None)
     return "ceramic"
 
 
+def _stress(op: float | None, rated: float | None) -> str:
+    """PASS / MARGIN / RISK from Vop vs Vrated. No invented dielectric %."""
+    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]:
     """Build a capacitor voltage derating table from the design graph.
 
@@ -180,6 +192,7 @@ def build_derating_table(graph: DesignGraph) -> list[dict]:
             "c_eff_f": c_eff,
             "c_eff_formatted": c_eff_fmt,
             "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"]))
diff --git a/backend/periscopex/esd_return_check.py b/backend/periscopex/esd_return_check.py
new file mode 100644
index 0000000..11472b5
--- /dev/null
+++ b/backend/periscopex/esd_return_check.py
@@ -0,0 +1,164 @@
+"""ESD on connector nets and HS return path — REVIEW unless a MANDATORY FACT exists."""
+
+from __future__ import annotations
+
+from backend.periscopex.models import (
+    ComponentConstraints,
+    ComponentType,
+    DesignGraph,
+    Finding,
+    LayoutGraph,
+    NetType,
+)
+from backend.periscopex.pcb_net_match import kicad_nets_match, normalize_kicad_hierarchy_net
+from backend.periscopex.pcb_power_thermal import _HS_NET_RE, _is_gnd_name
+from backend.periscopex.validate import _match_constraints
+
+_USB_RE = __import__("re").compile(
+    r"(USB|DP|DM|D\+|D-|VBUS|CC1|CC2|HDMI|ESD)",
+    __import__("re").I,
+)
+
+
+def _is_esd_part(comp) -> bool:
+    sub = (comp.component_subtype or "").lower()
+    if "esd" in sub or "protection" in sub:
+        return True
+    if comp.component_type == ComponentType.DISCRETE and "esd" in (comp.value or "").lower():
+        return True
+    return False
+
+
+def check_esd(
+    graph: DesignGraph,
+    constraints_map: dict[str, ComponentConstraints] | None = None,
+) -> list[Finding]:
+    """Connector / USB net without an ESD part → REVIEW. On-die clamp is not a RULE."""
+    cmap = constraints_map or {}
+    out: list[Finding] = []
+    seen: set[str] = set()
+    connector_nets: set[str] = set()
+    for comp in graph.components.values():
+        if comp.component_type != ComponentType.CONNECTOR:
+            continue
+        connector_nets.update(n for n in comp.pins.values() if n)
+    for ref, comp in sorted(graph.components.items()):
+        if comp.component_type != ComponentType.IC:
+            continue
+        cons = _match_constraints(comp.mpn or comp.value, cmap)
+        clamp = list((cons.internal_features.esd_clamp_pins if cons and cons.internal_features else []) or [])
+        for pin_num, net in sorted(comp.pins.items(), key=lambda x: str(x[0])):
+            if not net or net in seen:
+                continue
+            interesting = net in connector_nets or bool(_USB_RE.search(net))
+            if clamp:
+                tokens = [net, str(pin_num)]
+                if cons:
+                    pin = cons.pin_by_number(pin_num)
+                    if pin and pin.name:
+                        tokens.append(pin.name)
+                if any(c.upper() in t.upper() for c in clamp for t in tokens):
+                    interesting = True
+            if not interesting:
+                continue
+            seen.add(net)
+            if any(_is_esd_part(graph.components[r]) for r in graph.components_on_net(net) if r in graph.components):
+                continue
+            rec = (
+                f"Add a datasheet-specified ESD device on {net}, or record a "
+                "designer decision if the connector is unused."
+            )
+            out.append(Finding(
+                designator=ref,
+                mpn=comp.mpn or "",
+                aspect="esd",
+                finding=f"{net} reaches {ref} with no ESD/protection part on the net.",
+                facts=f"Net {net}; ESD parts on net: 0; connector={net in connector_nets}.",
+                requirement=(
+                    "External ESD is recommended unless the extraction lists a "
+                    "mandatory clamp requirement with a measured FACT."
+                ),
+                inference="REVIEW — on-die esd_clamp_pins are not a board RULE.",
+                why="No invented IEC 61000 level.",
+                status="WARNING",
+                recommendation=rec,
+                action=rec,
+                source="esd_return_check",
+                rule_id="PE-ESD-001",
+                finding_class="REVIEW",
+                provenance="RECOMMENDED",
+                evidence_status="SUFFICIENT",
+                net=net,
+                pins=[f"{ref}.{pin_num}"],
+            ))
+    return out
+
+
+def check_return_path(
+    graph: DesignGraph,
+    layout: LayoutGraph | None,
+) -> list[Finding]:
+    """HS net over a GND pour without a GND via in the bbox → REVIEW, not ERROR."""
+    if layout is None:
+        return []
+    gnd_zones = [
+        z for z in layout.zones
+        if z.net and _is_gnd_name(z.net) and z.outlines
+    ]
+    if not gnd_zones:
+        return []
+    gnd_vias = [v for v in layout.vias if v.net and _is_gnd_name(v.net)]
+    out: list[Finding] = []
+    seen: set[str] = set()
+    for net_name, net in sorted(graph.nets.items()):
+        if net.net_type != NetType.SIGNAL:
+            continue
+        if not _HS_NET_RE.search(net_name or ""):
+            continue
+        key = normalize_kicad_hierarchy_net(net_name)
+        if key in seen:
+            continue
+        segs = [
+            s for s in layout.segments
+            if s.net and kicad_nets_match(s.net, net_name)
+        ]
+        if not segs:
+            continue
+        xs = [c for s in segs for c in (s.start[0], s.end[0])]
+        ys = [c for s in segs for c in (s.start[1], s.end[1])]
+        xmin, xmax, ymin, ymax = min(xs), max(xs), min(ys), max(ys)
+        if (xmax - xmin) < 8.0 and (ymax - ymin) < 8.0:
+            continue
+        if any(xmin <= v.x <= xmax and ymin <= v.y <= ymax for v in gnd_vias):
+            continue
+        seen.add(key)
+        refs = [p.component_ref for p in net.pins[:1]]
+        ref = refs[0] if refs else net_name
+        rec = f"Add a GND via in the return path of {net_name}, then re-run PCB review."
+        out.append(Finding(
+            designator=ref,
+            mpn="",
+            aspect="return_path",
+            finding=(
+                f"{net_name} spans {xmax - xmin:.1f}×{ymax - ymin:.1f} mm over a "
+                "GND pour with no GND via in that bbox."
+            ),
+            facts=(
+                f"bbox=({xmin:.1f},{ymin:.1f})-({xmax:.1f},{ymax:.1f}); "
+                f"GND vias in bbox=0; board GND vias={len(gnd_vias)}."
+            ),
+            requirement="High-speed return via next to the pair (typical, not IEC).",
+            inference="REVIEW — no creepage/IEC number in context.",
+            why="Return path without a mandatory datasheet millimetre is not RULE ERROR.",
+            status="WARNING",
+            recommendation=rec,
+            action=rec,
+            source="esd_return_check",
+            rule_id="PE-RET-001",
+            finding_class="REVIEW",
+            provenance="TYPICAL",
+            evidence_status="SUFFICIENT",
+            net=net_name,
+            pins=[],
+        ))
+    return out
diff --git a/backend/periscopex/finding_engine.py b/backend/periscopex/finding_engine.py
index 2ea9155..df52bdc 100644
--- a/backend/periscopex/finding_engine.py
+++ b/backend/periscopex/finding_engine.py
@@ -137,6 +137,24 @@ def _seed() -> None:
          requirement="Kelvin/sense pin should not share the load net.")
     _add("PE-STCH-001", "TYPICAL", "INFO", domain="pcb",
          requirement="GND stitch via in the bbox of a signal over a GND pour.")
+    _add("PE-HIER-001", "TYPICAL", "INFO", domain="pcb",
+         requirement="Every component pin should land on a named net.")
+    _add("PE-DRT-002", "RECOMMENDED", "RISK", domain="pcb",
+         requirement="Vop/Vrated utilization band (not an invented dielectric %).")
+    _add("PE-DRT-003", "TYPICAL", "INFO", domain="pcb",
+         requirement="Capacitors with Vop and Vrated at or below 80% utilization.")
+    _add("PE-TIM-001", "MANDATORY", "RULE", domain="pcb",
+         requirement="Reset RC delay vs datasheet t_reset when both numbers exist.")
+    _add("PE-TIM-002", "MANDATORY", "RULE", domain="pcb",
+         requirement="Strap divider voltage vs Vih/Vil when both numbers exist.")
+    _add("PE-PI-001", "RECOMMENDED", "RISK", domain="pcb",
+         requirement="IC supply net should have a local decoupling capacitor.")
+    _add("PE-PI-002", "RECOMMENDED", "REVIEW", domain="pcb",
+         requirement="Local vs bulk on a supply when capacitance values exist.")
+    _add("PE-ESD-001", "RECOMMENDED", "REVIEW", domain="pcb",
+         requirement="Connector/USB net ESD — REVIEW unless a mandatory FACT exists.")
+    _add("PE-RET-001", "TYPICAL", "REVIEW", domain="pcb",
+         requirement="High-speed net over a GND pour should have a nearby GND via.")
 
 
 _seed()
@@ -215,6 +233,11 @@ def complete_finding(f: Finding) -> Finding:
         if f.finding_class == "RULE":
             f.finding_class = "RISK"
 
+    # ERROR only for a measured MANDATORY RULE. REVIEW/RISK/INFO stay ≤ WARNING.
+    if f.status == "ERROR":
+        if f.finding_class != "RULE" or prov != "MANDATORY":
+            f.status = "WARNING"
+
     if f.finding_class == "RULE" and f.confidence is None:
         f.confidence = 0.9 if f.evidence_status == "SUFFICIENT" else 0.3
     elif f.finding_class == "REVIEW" and f.confidence is None:
diff --git a/backend/periscopex/hierarchy.py b/backend/periscopex/hierarchy.py
new file mode 100644
index 0000000..c36d6b5
--- /dev/null
+++ b/backend/periscopex/hierarchy.py
@@ -0,0 +1,160 @@
+"""Component → pin → net → block hierarchy (usable inventory, not a platform)."""
+
+from __future__ import annotations
+
+from pydantic import BaseModel
+
+from backend.periscopex.functional_groups import FunctionalGroupsReport
+from backend.periscopex.models import DesignGraph, Finding
+
+
+class HierarchyPin(BaseModel):
+    number: str
+    net: str = ""
+
+
+class HierarchyComponent(BaseModel):
+    ref: str
+    component_type: str
+    pins: list[HierarchyPin] = []
+    nets: list[str] = []
+    block_id: str | None = None
+
+
+class HierarchyNet(BaseModel):
+    name: str
+    net_type: str
+    components: list[str] = []
+    block_id: str | None = None
+
+
+class HierarchyBlock(BaseModel):
+    block_id: str
+    kind: str  # domain | group | rail
+    ic_refs: list[str] = []
+    nets: list[str] = []
+
+
+class HierarchyReport(BaseModel):
+    components: list[HierarchyComponent] = []
+    nets: list[HierarchyNet] = []
+    blocks: list[HierarchyBlock] = []
+
+
+def build_hierarchy(
+    graph: DesignGraph,
+    plan: FunctionalGroupsReport | None = None,
+) -> HierarchyReport:
+    """Walk component.pins → nets, then group into domains / rail blocks."""
+    ref_block: dict[str, str] = {}
+    blocks: list[HierarchyBlock] = []
+    if plan is not None:
+        for d in plan.domains:
+            blocks.append(HierarchyBlock(
+                block_id=d.domain_id,
+                kind="domain",
+                ic_refs=list(d.ic_refs),
+                nets=list(d.power_nets),
+            ))
+            for ref in d.ic_refs:
+                ref_block[ref] = d.domain_id
+        for g in plan.groups:
+            bid = ref_block.get(g.ref) or f"group:{g.ref}"
+            if g.ref not in ref_block:
+                blocks.append(HierarchyBlock(
+                    block_id=bid, kind="group", ic_refs=[g.ref], nets=[],
+                ))
+                ref_block[g.ref] = bid
+    else:
+        for net in graph.nets.values():
+            if net.net_type.value != "power":
+                continue
+            ics = [
+                p.component_ref for p in net.pins
+                if (graph.components.get(p.component_ref)
+                    and graph.components[p.component_ref].component_type.value == "ic")
+            ]
+            if not ics:
+                continue
+            bid = f"rail:{net.name}"
+            blocks.append(HierarchyBlock(
+                block_id=bid, kind="rail", ic_refs=sorted(set(ics)), nets=[net.name],
+            ))
+            for ref in ics:
+                ref_block.setdefault(ref, bid)
+
+    net_block: dict[str, str] = {}
+    for b in blocks:
+        for n in b.nets:
+            net_block[n] = b.block_id
+
+    comps: list[HierarchyComponent] = []
+    for ref, comp in sorted(graph.components.items()):
+        pins = [
+            HierarchyPin(number=str(num), net=n or "")
+            for num, n in sorted(comp.pins.items(), key=lambda x: str(x[0]))
+        ]
+        nets = sorted({p.net for p in pins if p.net})
+        bid = ref_block.get(ref)
+        if bid is None and nets:
+            for n in nets:
+                if n in net_block:
+                    bid = net_block[n]
+                    break
+        comps.append(HierarchyComponent(
+            ref=ref,
+            component_type=comp.component_type.value,
+            pins=pins,
+            nets=nets,
+            block_id=bid,
+        ))
+
+    hnets: list[HierarchyNet] = []
+    for name, net in sorted(graph.nets.items()):
+        refs = sorted({p.component_ref for p in net.pins})
+        bid = net_block.get(name)
+        if bid is None:
+            for r in refs:
+                if r in ref_block:
+                    bid = ref_block[r]
+                    break
+        hnets.append(HierarchyNet(
+            name=name,
+            net_type=net.net_type.value,
+            components=refs,
+            block_id=bid,
+        ))
+    return HierarchyReport(components=comps, nets=hnets, blocks=blocks)
+
+
+def check_hierarchy(graph: DesignGraph, plan: FunctionalGroupsReport | None = None) -> list[Finding]:
+    """FACT: IC pin with an empty net. Skip unnamed power-flags."""
+    out: list[Finding] = []
+    for ref, comp in sorted(graph.components.items()):
+        if comp.component_type.value != "ic":
+            continue
+        dangling = [str(n) for n, net in comp.pins.items() if not (net or "").strip()]
+        if not dangling:
+            continue
+        rec = f"Connect {ref} pin(s) {', '.join(dangling)} to a named net, or mark NC."
+        out.append(Finding(
+            designator=ref,
+            mpn=comp.mpn or "",
+            aspect="hierarchy",
+            finding=f"{ref} pin(s) {', '.join(dangling)} have no net.",
+            facts=f"{ref} pins {dangling} net=''.",
+            requirement="Every IC pin lands on a named net (or is explicitly NC).",
+            inference="Empty pin map is a graph FACT, not a layout millimetre claim.",
+            why="Component → pin → net hierarchy.",
+            status="INFO",
+            recommendation=rec,
+            action=rec,
+            source="hierarchy_check",
+            rule_id="PE-HIER-001",
+            finding_class="INFO",
+            provenance="TYPICAL",
+            evidence_status="SUFFICIENT",
+            pins=[f"{ref}.{p}" for p in dangling],
+        ))
+    _ = plan
+    return out
diff --git a/backend/periscopex/pcb_checks.py b/backend/periscopex/pcb_checks.py
index f820afe..ad914ae 100644
--- a/backend/periscopex/pcb_checks.py
+++ b/backend/periscopex/pcb_checks.py
@@ -5,7 +5,11 @@ from __future__ import annotations
 import logging
 from collections import Counter
 
+from backend.periscopex.derating import build_derating_table
+from backend.periscopex.esd_return_check import check_esd, check_return_path
 from backend.periscopex.finding_engine import complete_findings
+from backend.periscopex.functional_groups import FunctionalGroupsReport
+from backend.periscopex.hierarchy import check_hierarchy
 from backend.periscopex.models import DesignGraph, Finding, LayoutGraph
 from backend.periscopex.pcb_net_match import check_pcb_net_match
 from backend.periscopex.pcb_power_thermal import (
@@ -15,8 +19,10 @@ from backend.periscopex.pcb_power_thermal import (
     check_pcb_thermal_copper,
     check_pcb_via_current,
 )
+from backend.periscopex.pi_check import check_power_integrity
 from backend.periscopex.placement_check import check_placement
 from backend.periscopex.si_check import check_si
+from backend.periscopex.timing_check import check_timing
 
 log = logging.getLogger(__name__)
 
@@ -40,32 +46,89 @@ def assign_pcb_finding_ids(findings: list[Finding]) -> None:
 
 
 def check_pcb_derating(graph: DesignGraph) -> list[Finding]:
-    """ERROR only when both Vop and Vrated exist and Vop exceeds Vrated."""
+    """PASS / MARGIN / RISK (exceed) when both Vop and Vrated exist."""
     out: list[Finding] = []
+    n_pass = 0
     for row in build_derating_table(graph):
         rated = row.get("rated_voltage_v")
         op = row.get("operating_voltage_v")
+        stress = row.get("stress") or "UNKNOWN"
         if rated is None or op is None:
             continue
-        if float(op) <= float(rated):
-            continue
         ref = str(row.get("designator") or "")
-        out.append(Finding(
-            designator=ref,
-            mpn=str(row.get("mpn") or ""),
-            aspect="derating",
-            finding=(
-                f"{ref} operates at {op:g} V with a {rated:g} V rating."
-            ),
-            why="Capacitor voltage rating must exceed the rail (no invented derating %).",
-            status="ERROR",
-            recommendation=(
+        mpn = str(row.get("mpn") or "")
+        net = row.get("net_plus")
+        ratio = float(op) / float(rated)
+        if stress == "RISK":
+            rec = (
                 f"Replace {ref} with a capacitor rated above {op:g} V, "
                 "or lower the rail."
-            ),
+            )
+            out.append(Finding(
+                designator=ref,
+                mpn=mpn,
+                aspect="derating",
+                finding=(
+                    f"{ref} operates at {op:g} V with a {rated:g} V rating "
+                    f"(Vop/Vrated={ratio:.2f})."
+                ),
+                facts=f"Vop={op:g} V, Vrated={rated:g} V, ratio={ratio:.3f}.",
+                requirement="Operating voltage must not exceed the capacitor rating.",
+                inference="Exceeding Vr is a measured RULE, not a dielectric %.",
+                why="Capacitor voltage rating must exceed the rail (no invented derating %).",
+                status="ERROR",
+                recommendation=rec,
+                action=rec,
+                source="pcb_derating",
+                rule_id="PE-DRT-001",
+                evidence_status="SUFFICIENT",
+                net=net,
+                pins=[],
+            ))
+        elif stress == "MARGIN":
+            rec = (
+                f"Confirm {ref} voltage margin ({op:g}/{rated:g} V) or pick a "
+                "higher Vr. This is utilization, not a 50% ceramic rule."
+            )
+            out.append(Finding(
+                designator=ref,
+                mpn=mpn,
+                aspect="derating",
+                finding=(
+                    f"{ref} Vop/Vrated={ratio:.2f} ({op:g}/{rated:g} V) — MARGIN."
+                ),
+                facts=f"Vop={op:g} V, Vrated={rated:g} V, ratio={ratio:.3f}.",
+                requirement="Utilization > 0.8 of Vr is flagged as MARGIN (RISK).",
+                inference="Not an invented IPC/ceramic derating percentage.",
+                why="PASS/MARGIN/RISK from Vop and Vrated only.",
+                status="WARNING",
+                recommendation=rec,
+                action=rec,
+                source="pcb_derating",
+                rule_id="PE-DRT-002",
+                evidence_status="SUFFICIENT",
+                net=net,
+                pins=[],
+            ))
+        elif stress == "PASS":
+            n_pass += 1
+    if n_pass:
+        rec = "No voltage-rating change required for PASS capacitors."
+        out.append(Finding(
+            designator="C",
+            mpn="",
+            aspect="derating",
+            finding=f"{n_pass} capacitor(s) PASS (Vop/Vrated ≤ 0.8).",
+            facts=f"PASS count={n_pass} (both Vop and Vrated present).",
+            requirement="Rated voltage exists and Vop is ≤ 80% of Vr.",
+            inference="Summary INFO — per-cap PASS lives on the derating table.",
+            why="Avoid one INFO card per capacitor.",
+            status="INFO",
+            recommendation=rec,
+            action=rec,
             source="pcb_derating",
-            rule_id="PE-DRT-001",
-            net=row.get("net_plus"),
+            rule_id="PE-DRT-003",
+            evidence_status="SUFFICIENT",
             pins=[],
         ))
     return out
@@ -110,8 +173,9 @@ def run_pcb_checks(
     graph: DesignGraph,
     constraints_map: dict,
     layout: LayoutGraph | None,
+    plan: FunctionalGroupsReport | None = None,
 ) -> list[Finding]:
-    """Placement, SI, pad-net match, derating — skip individually on error."""
+    """Placement, SI, pad-net match, derating, hierarchy, timing, PI, ESD."""
     out: list[Finding] = []
     for name, fn in (
         ("pcb_net_match", lambda: check_pcb_net_match(graph, layout)),
@@ -123,6 +187,11 @@ def run_pcb_checks(
         ("pcb_thermal_copper", lambda: check_pcb_thermal_copper(graph, constraints_map, layout)),
         ("pcb_kelvin", lambda: check_pcb_kelvin(graph, constraints_map)),
         ("pcb_gnd_stitch", lambda: check_pcb_gnd_stitch(graph, layout)),
+        ("hierarchy_check", lambda: check_hierarchy(graph, plan)),
+        ("timing_check", lambda: check_timing(graph, constraints_map)),
+        ("pi_check", lambda: check_power_integrity(graph, constraints_map, layout)),
+        ("esd_check", lambda: check_esd(graph, constraints_map)),
+        ("return_path", lambda: check_return_path(graph, layout)),
     ):
         try:
             out.extend(fn())
diff --git a/backend/periscopex/pi_check.py b/backend/periscopex/pi_check.py
new file mode 100644
index 0000000..bfeafb8
--- /dev/null
+++ b/backend/periscopex/pi_check.py
@@ -0,0 +1,193 @@
+"""Power integrity: local vs bulk on IC supplies. Distance only with datasheet mm."""
+
+from __future__ import annotations
+
+import math
+
+from backend.periscopex.functional_groups import _BULK_F
+from backend.periscopex.models import (
+    CapacitorSpecs,
+    ComponentConstraints,
+    ComponentType,
+    DesignGraph,
+    Finding,
+    LayoutGraph,
+)
+from backend.periscopex.passive_rail_check import _is_ic_supply_pin
+from backend.periscopex.validate import _match_constraints
+
+_LOAD_KEYS = ("i_load_a", "i_load", "iout", "i_out")
+
+
+def _cap_farads(comp) -> float | None:
+    if comp.component_type != ComponentType.CAPACITOR:
+        return None
+    if isinstance(comp.specs, CapacitorSpecs) and comp.specs.value_farads > 0:
+        return float(comp.specs.value_farads)
+    return None
+
+
+def _i_load(comp) -> float | None:
+    specs = getattr(comp, "specs", None)
+    vals = getattr(specs, "values", None) if specs else None
+    if not isinstance(vals, dict):
+        return None
+    for k in _LOAD_KEYS:
+        v = vals.get(k)
+        try:
+            n = float(v)
+        except (TypeError, ValueError):
+            continue
+        if n > 0:
+            return n
+    return None
+
+
+def _max_distance_mm(cons: ComponentConstraints | None) -> float | None:
+    if not cons:
+        return None
+    best = None
+    for rule in cons.layout_rules or []:
+        if rule.get("kind") != "decoupling_proximity":
+            continue
+        mm = rule.get("max_distance_mm")
+        if isinstance(mm, (int, float)) and mm > 0:
+            best = float(mm) if best is None else min(best, float(mm))
+    return best
+
+
+def _pad_xy(layout: LayoutGraph, ref: str) -> tuple[float, float] | None:
+    fp = layout.footprints.get(ref)
+    if not fp:
+        return None
+    return (fp.x, fp.y)
+
+
+def check_power_integrity(
+    graph: DesignGraph,
+    constraints_map: dict[str, ComponentConstraints] | None = None,
+    layout: LayoutGraph | None = None,
+) -> list[Finding]:
+    """Local cap presence (RISK). Local vs bulk (REVIEW). Distance only with mm."""
+    cmap = constraints_map or {}
+    out: list[Finding] = []
+    seen: set[str] = set()
+    for ref, comp in sorted(graph.components.items()):
+        if comp.component_type != ComponentType.IC:
+            continue
+        cons = _match_constraints(comp.mpn or comp.value, cmap)
+        i_load = _i_load(comp)
+        for pin_num, net in sorted(comp.pins.items(), key=lambda x: str(x[0])):
+            if not net or net in seen:
+                continue
+            if not _is_ic_supply_pin(graph, cons, pin_num, net):
+                continue
+            seen.add(net)
+            locals_: list[tuple[str, float]] = []
+            bulks: list[tuple[str, float]] = []
+            unvalued = 0
+            for cref in graph.components_on_net(net):
+                ccomp = graph.components.get(cref)
+                if not ccomp:
+                    continue
+                farads = _cap_farads(ccomp)
+                if farads is None:
+                    if ccomp.component_type == ComponentType.CAPACITOR:
+                        unvalued += 1
+                    continue
+                if farads >= _BULK_F:
+                    bulks.append((cref, farads))
+                else:
+                    locals_.append((cref, farads))
+            if not locals_ and unvalued == 0:
+                rec = f"Add a local decoupling capacitor on {net} at {ref}."
+                facts = f"{ref} supply {net}: 0 local caps (<1 µF); bulk={len(bulks)}."
+                if i_load is not None:
+                    facts = f"{facts} I_load={i_load:g} A."
+                out.append(Finding(
+                    designator=ref,
+                    mpn=comp.mpn or "",
+                    aspect="power_integrity",
+                    finding=f"{ref} supply net {net} has no local decoupling capacitor.",
+                    facts=facts,
+                    requirement="IC supply pins need a local bypass (recommended).",
+                    inference="Not a mandatory abs-max; RISK not RULE.",
+                    why="Local vs bulk: local is C < 1 µF (same split as functional groups).",
+                    status="WARNING",
+                    recommendation=rec,
+                    action=rec,
+                    source="pi_check",
+                    rule_id="PE-PI-001",
+                    evidence_status="SUFFICIENT",
+                    net=net,
+                    pins=[f"{ref}.{pin_num}"],
+                ))
+            elif locals_ and not bulks and i_load is not None and i_load >= 0.5:
+                rec = (
+                    f"Confirm bulk capacitance on {net} for I_load={i_load:g} A, "
+                    "or document why local-only is enough."
+                )
+                out.append(Finding(
+                    designator=ref,
+                    mpn=comp.mpn or "",
+                    aspect="power_integrity",
+                    finding=(
+                        f"{ref} {net} has local cap(s) {[c[0] for c in locals_]} "
+                        f"and no bulk (≥1 µF) with I_load={i_load:g} A."
+                    ),
+                    facts=(
+                        f"local={[(a, b) for a, b in locals_]}; bulk=[]; "
+                        f"I_load={i_load:g} A."
+                    ),
+                    requirement="Bulk on a loaded rail is recommended, not abs-max.",
+                    inference="REVIEW — no invented PSRR milliohms.",
+                    why="Local vs bulk split uses valued capacitors only.",
+                    status="INFO",
+                    recommendation=rec,
+                    action=rec,
+                    source="pi_check",
+                    rule_id="PE-PI-002",
+                    evidence_status="SUFFICIENT",
+                    net=net,
+                    pins=[f"{ref}.{pin_num}"],
+                ))
+            limit = _max_distance_mm(cons)
+            if layout is None or limit is None or not locals_:
+                continue
+            ic_xy = _pad_xy(layout, ref)
+            if ic_xy is None:
+                continue
+            nearest = None
+            for cref, _f in locals_:
+                xy = _pad_xy(layout, cref)
+                if xy is None:
+                    continue
+                dist = math.hypot(xy[0] - ic_xy[0], xy[1] - ic_xy[1])
+                if nearest is None or dist < nearest[0]:
+                    nearest = (dist, cref)
+            if nearest is None or nearest[0] <= limit:
+                continue
+            # Distance vs datasheet mm is PE-PLC-001's job; PI only records FACT if PLC didn't.
+            rec = f"Move {nearest[1]} within {limit:g} mm of {ref} (layout_rules)."
+            out.append(Finding(
+                designator=ref,
+                mpn=comp.mpn or "",
+                aspect="power_integrity",
+                finding=(
+                    f"{nearest[1]} is {nearest[0]:.2f} mm from {ref} on {net} "
+                    f"(max_distance_mm={limit:g})."
+                ),
+                facts=f"euclidean {nearest[0]:.2f} mm; limit {limit:g} mm from layout_rules.",
+                requirement=f"layout_rules decoupling_proximity max_distance_mm={limit:g}.",
+                inference="Same millimetres as PE-PLC-001; PI records the supply view.",
+                why="Distance judged only with datasheet millimetres.",
+                status="WARNING",
+                recommendation=rec,
+                action=rec,
+                source="pi_check",
+                rule_id="PE-PI-001",
+                evidence_status="SUFFICIENT",
+                net=net,
+                pins=[f"{ref}.{pin_num}"],
+            ))
+    return out
diff --git a/backend/periscopex/timing_check.py b/backend/periscopex/timing_check.py
new file mode 100644
index 0000000..4248e8d
--- /dev/null
+++ b/backend/periscopex/timing_check.py
@@ -0,0 +1,185 @@
+"""Reset RC and strap dividers — only when R, C, and datasheet times/levels exist."""
+
+from __future__ import annotations
+
+from backend.periscopex.models import (
+    CapacitorSpecs,
+    ComponentConstraints,
+    ComponentType,
+    DesignGraph,
+    Finding,
+    ResistorSpecs,
+)
+from backend.periscopex.passive_rail_check import (
+    _is_reset_pin,
+    _pin_name_tokens,
+    _resistor_to_ground,
+    _resistor_to_power,
+)
+from backend.periscopex.validate import _match_constraints
+
+_T_RESET_KEYS = ("t_reset_min_s", "t_reset_min_ms", "reset_delay_ms", "t_por_ms")
+_VIH_KEYS = ("vih", "vih_min_v", "v_ih_min", "vih_min")
+_VIL_KEYS = ("vil", "vil_max_v", "v_il_max", "vil_max")
+_STRAP_RE = __import__("re").compile(
+    r"(?:PSEL|BOOT|STRAP|VSENSE|VSET|CFG)",
+    __import__("re").I,
+)
+
+
+def _specs_map(comp) -> dict:
+    specs = getattr(comp, "specs", None)
+    if specs is None:
+        return {}
+    vals = getattr(specs, "values", None)
+    return dict(vals) if isinstance(vals, dict) else {}
+
+
+def _first_num(values: dict, keys: tuple[str, ...]) -> float | None:
+    for k in keys:
+        v = values.get(k)
+        if isinstance(v, bool) or v is None:
+            continue
+        try:
+            n = float(v)
+        except (TypeError, ValueError):
+            continue
+        if k.endswith("_ms"):
+            n = n / 1000.0
+        return n
+    return None
+
+
+def _r_on_net(graph: DesignGraph, net: str) -> list[float]:
+    out: list[float] = []
+    for ref in graph.components_on_net(net):
+        comp = graph.components.get(ref)
+        if not comp or comp.component_type != ComponentType.RESISTOR:
+            continue
+        if isinstance(comp.specs, ResistorSpecs) and comp.specs.value_ohms > 0:
+            out.append(float(comp.specs.value_ohms))
+    return out
+
+
+def _c_on_net(graph: DesignGraph, net: str) -> list[float]:
+    out: list[float] = []
+    for ref in graph.components_on_net(net):
+        comp = graph.components.get(ref)
+        if not comp or comp.component_type != ComponentType.CAPACITOR:
+            continue
+        if isinstance(comp.specs, CapacitorSpecs) and comp.specs.value_farads > 0:
+            out.append(float(comp.specs.value_farads))
+    return out
+
+
+def check_timing(
+    graph: DesignGraph,
+    constraints_map: dict[str, ComponentConstraints] | None = None,
+) -> list[Finding]:
+    """PE-TIM-001 RC vs t_reset; PE-TIM-002 strap vs Vih/Vil. Skip without numbers."""
+    cmap = constraints_map or {}
+    out: list[Finding] = []
+    seen: set[str] = set()
+    for ref, comp in sorted(graph.components.items()):
+        if comp.component_type != ComponentType.IC:
+            continue
+        cons = _match_constraints(comp.mpn or comp.value, cmap)
+        values = _specs_map(comp)
+        t_min = _first_num(values, _T_RESET_KEYS)
+        vih = _first_num(values, _VIH_KEYS)
+        vil = _first_num(values, _VIL_KEYS)
+        for pin_num, net in sorted(comp.pins.items(), key=lambda x: str(x[0])):
+            if not net or net in seen:
+                continue
+            if _is_reset_pin(graph, cons, pin_num, net) and t_min is not None:
+                rs = _r_on_net(graph, net)
+                cs = _c_on_net(graph, net)
+                if not rs or not cs:
+                    continue
+                tau = min(rs) * min(cs)
+                seen.add(net)
+                if tau + 1e-18 >= t_min:
+                    continue
+                rec = (
+                    f"Increase R or C on {net} so τ=RC ≥ {t_min:g} s "
+                    f"(measured τ={tau:g} s)."
+                )
+                out.append(Finding(
+                    designator=ref,
+                    mpn=comp.mpn or "",
+                    aspect="timing",
+                    finding=(
+                        f"{ref} reset net {net} has τ=RC={tau:g} s "
+                        f"below t_reset={t_min:g} s."
+                    ),
+                    facts=f"R={min(rs):g} Ω, C={min(cs):g} F, τ={tau:g} s.",
+                    requirement=f"Datasheet t_reset_min={t_min:g} s.",
+                    inference="τ=R·C compared to t_reset; no 10 ms default.",
+                    why="Reset delay only when R, C, and t_reset are numeric.",
+                    status="ERROR",
+                    recommendation=rec,
+                    action=rec,
+                    source="timing_check",
+                    rule_id="PE-TIM-001",
+                    calculation=f"τ=R·C={tau:g}; t_min={t_min:g}",
+                    evidence_status="SUFFICIENT",
+                    net=net,
+                    pins=[f"{ref}.{pin_num}"],
+                ))
+                continue
+            tokens = _pin_name_tokens(cons, pin_num) or [net, str(pin_num)]
+            if not any(_STRAP_RE.search(t or "") for t in tokens):
+                continue
+            if vih is None and vil is None:
+                continue
+            if not (_resistor_to_power(graph, net) and _resistor_to_ground(graph, net)):
+                continue
+            rs = _r_on_net(graph, net)
+            if len(rs) < 2:
+                continue
+            rhi, rlo = max(rs), min(rs)
+            vrail = None
+            nobj = graph.nets.get(net)
+            # Strap mid-point: need rail voltage on the pull-up net.
+            for rref in graph.components_on_net(net):
+                rcomp = graph.components.get(rref)
+                if not rcomp or rcomp.component_type != ComponentType.RESISTOR:
+                    continue
+                for pnet in rcomp.pins.values():
+                    other = graph.nets.get(pnet)
+                    if other and other.voltage and other.voltage > 0:
+                        vrail = float(other.voltage)
+            if vrail is None:
+                continue
+            vstrap = vrail * rlo / (rhi + rlo)
+            seen.add(net)
+            fail = (vih is not None and vstrap < vih) or (vil is not None and vstrap > vil and vih is None)
+            if not fail:
+                continue
+            rec = f"Adjust the strap divider on {net} so Vstrap meets Vih/Vil."
+            out.append(Finding(
+                designator=ref,
+                mpn=comp.mpn or "",
+                aspect="timing",
+                finding=(
+                    f"{ref} strap {net} V={vstrap:g} V from {rhi:g}/{rlo:g} Ω "
+                    f"on {vrail:g} V rail."
+                ),
+                facts=f"Vstrap={vstrap:g} V; Rhi={rhi:g}; Rlo={rlo:g}; Vrail={vrail:g}.",
+                requirement=(
+                    f"Vih={vih if vih is not None else '—'} V, "
+                    f"Vil={vil if vil is not None else '—'} V from specs."
+                ),
+                inference="Divider ratio vs Vih/Vil; no 50% default.",
+                why="Strap level only when divider ohms and Vih/Vil exist.",
+                status="ERROR",
+                recommendation=rec,
+                action=rec,
+                source="timing_check",
+                rule_id="PE-TIM-002",
+                calculation=f"V=Vrail·Rlo/(Rhi+Rlo)={vstrap:g}",
+                evidence_status="SUFFICIENT",
+                net=net,
+                pins=[f"{ref}.{pin_num}"],
+            ))
+    return out
diff --git a/backend/services/pcb_pipeline.py b/backend/services/pcb_pipeline.py
index b66a313..1d382a9 100644
--- a/backend/services/pcb_pipeline.py
+++ b/backend/services/pcb_pipeline.py
@@ -137,9 +137,16 @@ async def run_pcb_pipeline(
             fg_path = ws.local_path("functional_groups.json")
             fg_path.write_text(plan.model_dump_json(indent=2) + "\n")
             ws._upload_file("functional_groups.json")
+            from backend.periscopex.hierarchy import build_hierarchy
+
+            hier = build_hierarchy(graph, plan)
+            hier_path = ws.local_path("hierarchy.json")
+            hier_path.write_text(hier.model_dump_json(indent=2) + "\n")
+            ws._upload_file("hierarchy.json")
             _step(
                 project_id, "classify", "complete",
-                f"{len(plan.domains)} domains, {len(plan.groups)} groups",
+                f"{len(plan.domains)} domains, {len(plan.groups)} groups, "
+                f"{len(hier.blocks)} blocks",
             )
 
             if _cancelled(storage, user_id, project_id):
@@ -180,7 +187,7 @@ async def run_pcb_pipeline(
                 return
 
             _step(project_id, "checks", "running")
-            findings = run_pcb_checks(graph, cmap, layout)
+            findings = run_pcb_checks(graph, cmap, layout, plan)
             _step(
                 project_id, "checks", "complete",
                 f"{len(findings)} deterministic findings",
diff --git a/docs/motore-finding.md b/docs/motore-finding.md
index f531a06..7c15a83 100644
--- a/docs/motore-finding.md
+++ b/docs/motore-finding.md
@@ -109,6 +109,8 @@ Geometria board: width/thickness, via, pour courtyard, placement mm, return/stit
 
 ## 9. Fasi (non fingere completezza)
 
-**Fase A (questa slice):** oggetto finding + clamp provenance/class + decisions + UI schema/PCB + libreria condivisa + check geometria già gated.
+**Fase A:** oggetto finding + clamp provenance/class (**ERROR solo se RULE e MANDATORY**) + decisions + UI schema/PCB + libreria condivisa + check geometria già gated.
 
-**Fase B (pianificata):** gerarchia component→system; timing; energy/thermal solo con θJA/P/I_load; ratings; derating PASS/MARGIN/RISK; PI; SI oltre skew mm; return path oltre stitch INFO; ESD/EMI; thermal FEM; BOM↔PCB↔datasheet; SPOF come REVIEW.
+**Fase B (questa slice):** gerarchia component→pin→net→block; derating PASS/MARGIN/RISK da Vop/Vrated; timing RC/strap solo con numeri; PI local vs bulk; ESD e return path come REVIEW.
+
+**Fase B ancora aperta:** thermal FEM; SI oltre skew mm; BOM↔PCB↔datasheet; SPOF; EMI oltre ESD.
diff --git a/docs/piano-pcb-review.md b/docs/piano-pcb-review.md
index 5adb155..c64d163 100644
--- a/docs/piano-pcb-review.md
+++ b/docs/piano-pcb-review.md
@@ -55,8 +55,14 @@ Mutex vs analisi e vs placement. SSE `pcb_*`. IDs `PCB-{ref}-{001}`. KiCad `/net
 | PE-LAY-001…003 | pad/ref/hierarchy nets |
 | PE-PLC-001…004 | `layout_rules` numerici |
 | PE-SI-001 | `length_match` mm |
-| PE-DRT-001 | Vop e Vrated |
 | PE-PWR-001 | I_load + width; IPC solo con thickness e Tjmax |
+| PE-DRT-001 | Vop e Vrated, Vop > Vr → RULE ERROR |
+| PE-DRT-002 | 0.8 < Vop/Vr ≤ 1 → RISK MARGIN |
+| PE-DRT-003 | Vop/Vr ≤ 0.8 → PASS summary INFO |
+| PE-HIER-001 | pin IC senza net |
+| PE-TIM-001/002 | RC / strap solo con numeri |
+| PE-PI-001/002 | local vs bulk; mm solo da layout_rules |
+| PE-ESD-001 / PE-RET-001 | REVIEW unless mandatory FACT |
 | PE-VIA-001 | via count + I_load (INFO, no tabella inventata) |
 | PE-THM-001 | P=I_load×drop, courtyard senza pour/via |
 | PE-KEL-001 | sense/Kelvin pintable + ≥2 altri sul net |
@@ -70,10 +76,22 @@ AI PCB: skip IC senza pintable (`run schematic review first`).
 
 ## Fasi
 
-**A — shipped (questa slice):** oggetto finding condiviso, clamp provenance/class, decisions, UI, libreria unica, geometria gated, net-slash.
+**A — shipped:** oggetto finding condiviso, clamp provenance/class (**ERROR solo RULE+MANDATORY**), decisions, UI, libreria unica, geometria gated, net-slash, Action on card, geometria in contesto AI.
 
-**B — pianificata (non finta):** gerarchia component→system; timing; energy/thermal solo con parametri; ratings; derating PASS/MARGIN/RISK; PI; SI oltre skew; return path oltre stitch INFO; ESD/EMI; thermal FEM; BOM↔PCB↔datasheet; SPOF come REVIEW.
+**B — questa slice (shipped, gated):**
 
-**C — fuori:** auto-place, write-back pcbnew, unire i job, sshd/keys.
+| ID | Cosa | Gate |
+| --- | --- | --- |
+| Gerarchia | `hierarchy.json` component→pin→net→block | grafo (+ domains se `classify`) |
+| PE-HIER-001 | pin IC senza net | FACT net='' |
+| PE-DRT-001/002/003 | RISK / MARGIN / PASS | Vop **e** Vrated; niente % dielettrico inventato |
+| PE-TIM-001/002 | RC reset / strap | R, C e t_reset o Vih/Vil numerici |
+| PE-PI-001/002 | local vs bulk, I se noto | cap valorizzati; distanza solo con `max_distance_mm` |
+| PE-ESD-001 | ESD connettore/USB | REVIEW se manca parte ESD |
+| PE-RET-001 | return HS senza via GND | REVIEW, non ERROR |
+
+**B — ancora aperta:** energy/thermal FEM; SI oltre skew mm; BOM↔PCB↔datasheet completo; SPOF; EMI oltre ESD REVIEW.
+
+**C — fuori:** auto-place, write-back pcbnew, unire i job, sshd/keys, PinScope identity/fork.
 
 Deploy: `ssh periscope` + `/root/periscope/scripts/update-periscope.sh`.
diff --git a/frontend/content/changelog.md b/frontend/content/changelog.md
index b140a52..1f13516 100644
--- a/frontend/content/changelog.md
+++ b/frontend/content/changelog.md
@@ -2,6 +2,17 @@
 
 What's new in Periscope.
 
+## 2.33.0 — 2026-09-20 — Fase B: hierarchy, derating bands, timing, PI, ESD/return
+
+Usable slices (not a platform): component→pin→net→block inventory, capacitor PASS/MARGIN/RISK from Vop/Vrated, RC/strap timing only with numbers, local vs bulk PI, ESD and HS return as REVIEW.
+
+- [Fixed] `complete_finding` clamps ERROR unless `finding_class=RULE` and `provenance=MANDATORY` (LLM REVIEW cannot stay ERROR).
+- [New] `hierarchy.json` + `PE-HIER-001` dangling IC pins.
+- [New] Derating table `stress` PASS/MARGIN/RISK; findings `PE-DRT-001/002/003`.
+- [New] `PE-TIM-001/002` skip without R/C and t_reset or Vih/Vil.
+- [New] `PE-PI-001/002` local vs bulk; distance only with `layout_rules` mm.
+- [New] `PE-ESD-001`, `PE-RET-001` are REVIEW, never RULE ERROR.
+
 ## 2.32.1 — 2026-09-20 — PCB Action on card + parsed geometry in AI context
 
 Finding cards always show an **Action.** sentence (`action`, else `recommendation`, else a default). PCB AI context now includes vias under the footprint, copper thickness, nearby trace widths, courtyard, and keepout polygons from `.kicad_pcb`.
diff --git a/frontend/src/app/(app)/project/[id]/page.tsx b/frontend/src/app/(app)/project/[id]/page.tsx
index 309f3df..ffbe476 100644
--- a/frontend/src/app/(app)/project/[id]/page.tsx
+++ b/frontend/src/app/(app)/project/[id]/page.tsx
@@ -943,6 +943,7 @@ function DeratingTable({
                   <th className="pb-2 pr-4 font-medium">Value</th>
                   <th className="pb-2 pr-4 font-medium">C_eff</th>
                   <th className="pb-2 pr-4 font-medium">Type</th>
+                  <th className="pb-2 pr-4 font-medium">Engine</th>
                   <th className="pb-2 pr-4 font-medium">Net+</th>
                   <th className="pb-2 pr-4 font-medium">Net−</th>
                   <th className="pb-2 pr-4 font-medium text-right">Rated V</th>
@@ -1003,6 +1004,15 @@ function DeratingTable({
                           <span className="text-muted-foreground">—</span>
                         )}
                       </td>
+                      <td className="py-2 pr-4 text-xs">
+                        {row.stress && row.stress !== "UNKNOWN" ? (
+                          <Badge variant="outline" className="text-[10px] px-1.5 py-0">
+                            {row.stress}
+                          </Badge>
+                        ) : (
+                          <span className="text-muted-foreground">—</span>
+                        )}
+                      </td>
                       <td className="py-2 pr-4 font-mono text-xs">
                         {row.net_plus ?? <span className="text-muted-foreground">—</span>}
                       </td>
diff --git a/frontend/src/lib/layout-finding.ts b/frontend/src/lib/layout-finding.ts
index 4e82a48..fdb7b3d 100644
--- a/frontend/src/lib/layout-finding.ts
+++ b/frontend/src/lib/layout-finding.ts
@@ -11,6 +11,10 @@ export function isLayoutFinding(f: {
     id.startsWith("PCB-") ||
     f.source === "pcb_review" ||
     f.source === "pcb_power_thermal" ||
+    f.source === "hierarchy_check" ||
+    f.source === "timing_check" ||
+    f.source === "pi_check" ||
+    f.source === "esd_return_check" ||
     rid.startsWith("PE-PLC") ||
     rid.startsWith("PE-LAY") ||
     rid.startsWith("PE-SI") ||
@@ -19,7 +23,12 @@ export function isLayoutFinding(f: {
     rid.startsWith("PE-THM") ||
     rid.startsWith("PE-VIA") ||
     rid.startsWith("PE-KEL") ||
-    rid.startsWith("PE-STCH")
+    rid.startsWith("PE-STCH") ||
+    rid.startsWith("PE-HIER") ||
+    rid.startsWith("PE-TIM") ||
+    rid.startsWith("PE-PI") ||
+    rid.startsWith("PE-ESD") ||
+    rid.startsWith("PE-RET")
   );
 }
 
@@ -31,10 +40,19 @@ export function isPcbExamFinding(f: {
   return (
     f.source === "pcb_review" ||
     f.source === "pcb_power_thermal" ||
+    f.source === "hierarchy_check" ||
+    f.source === "timing_check" ||
+    f.source === "pi_check" ||
+    f.source === "esd_return_check" ||
     rid.startsWith("PE-PWR") ||
     rid.startsWith("PE-THM") ||
     rid.startsWith("PE-VIA") ||
     rid.startsWith("PE-KEL") ||
-    rid.startsWith("PE-STCH")
+    rid.startsWith("PE-STCH") ||
+    rid.startsWith("PE-HIER") ||
+    rid.startsWith("PE-TIM") ||
+    rid.startsWith("PE-PI") ||
+    rid.startsWith("PE-ESD") ||
+    rid.startsWith("PE-RET")
   );
 }
diff --git a/frontend/src/lib/types.ts b/frontend/src/lib/types.ts
index 73bcc34..236c856 100644
--- a/frontend/src/lib/types.ts
+++ b/frontend/src/lib/types.ts
@@ -413,6 +413,7 @@ export interface DeratingRow {
   c_eff_f?: number | null;
   c_eff_formatted?: string | null;
   dc_bias_model?: "stima" | null;
+  stress?: "PASS" | "MARGIN" | "RISK" | "UNKNOWN";
 }
 
 export interface DeratingSettings {
diff --git a/tests/test_fase_b_checks.py b/tests/test_fase_b_checks.py
new file mode 100644
index 0000000..e5fe17a
--- /dev/null
+++ b/tests/test_fase_b_checks.py
@@ -0,0 +1,308 @@
+"""Fase B slices: hierarchy, derating stress, timing, PI, ESD/return."""
+
+from __future__ import annotations
+
+from backend.periscopex.esd_return_check import check_esd, check_return_path
+from backend.periscopex.finding_engine import complete_finding
+from backend.periscopex.hierarchy import build_hierarchy, check_hierarchy
+from backend.periscopex.models import (
+    CapacitorSpecs,
+    Component,
+    ComponentConstraints,
+    ComponentType,
+    DesignGraph,
+    Finding,
+    InternalFeatures,
+    LayoutFootprint,
+    LayoutGraph,
+    LayoutSegment,
+    LayoutVia,
+    LayoutZone,
+    Net,
+    NetType,
+    Pin,
+    PinConnection,
+    ResistorSpecs,
+    SimpleComponentSpecs,
+)
+from backend.periscopex.pcb_checks import check_pcb_derating
+from backend.periscopex.pi_check import check_power_integrity
+from backend.periscopex.timing_check import check_timing
+
+
+def test_hierarchy_component_pin_net_block():
+    graph = DesignGraph(
+        components={
+            "U1": Component(
+                reference="U1", value="LDO", footprint="",
+                component_type=ComponentType.IC, mpn="LDO",
+                pins={"1": "VIN", "2": "+3V3", "3": ""},
+            ),
+        },
+        nets={
+            "VIN": Net(
+                name="VIN", net_type=NetType.POWER, voltage=5.0,
+                pins=[PinConnection(component_ref="U1", pin_number="1")],
+            ),
+            "+3V3": Net(
+                name="+3V3", net_type=NetType.POWER, voltage=3.3,
+                pins=[PinConnection(component_ref="U1", pin_number="2")],
+            ),
+        },
+    )
+    hier = build_hierarchy(graph)
+    assert hier.components[0].ref == "U1"
+    assert {p.number: p.net for p in hier.components[0].pins}["1"] == "VIN"
+    assert any(b.kind == "rail" for b in hier.blocks)
+    dangling = check_hierarchy(graph)
+    assert dangling and dangling[0].rule_id == "PE-HIER-001"
+    assert dangling[0].status == "INFO"
+    assert dangling[0].facts
+
+
+def test_derating_pass_margin_risk():
+    def cap(ref, rated, net="3V3"):
+        return Component(
+            reference=ref, value="", footprint="",
+            component_type=ComponentType.CAPACITOR,
+            component_subtype="passive.capacitor.ceramic",
+            mpn=ref,
+            pins={"1": net, "2": "GND"},
+            specs=CapacitorSpecs(
+                value_farads=1e-6, value_formatted="1uF",
+                voltage_rating_v=f"{rated}V", dielectric="X7R",
+            ),
+        )
+
+    g = DesignGraph(
+        components={
+            "C1": cap("C1", 16),
+            "C2": cap("C2", 4.0),
+            "C3": cap("C3", 3.0),
+        },
+        nets={
+            "3V3": Net(
+                name="3V3", net_type=NetType.POWER, voltage=3.3,
+                pins=[
+                    PinConnection(component_ref="C1", pin_number="1"),
+                    PinConnection(component_ref="C2", pin_number="1"),
+                    PinConnection(component_ref="C3", pin_number="1"),
+                ],
+            ),
+            "GND": Net(name="GND", net_type=NetType.GROUND, voltage=0.0, pins=[]),
+        },
+    )
+    from backend.periscopex.derating import build_derating_table
+
+    by = {r["designator"]: r["stress"] for r in build_derating_table(g)}
+    assert by["C1"] == "PASS"
+    assert by["C2"] == "MARGIN"
+    assert by["C3"] == "RISK"
+    findings = check_pcb_derating(g)
+    ids = {f.rule_id for f in findings}
+    assert "PE-DRT-001" in ids
+    assert "PE-DRT-002" in ids
+    assert "PE-DRT-003" in ids
+    exceed = next(f for f in findings if f.rule_id == "PE-DRT-001")
+    complete_finding(exceed)
+    assert exceed.status == "ERROR"
+    assert exceed.finding_class == "RULE"
+    margin = next(f for f in findings if f.rule_id == "PE-DRT-002")
+    complete_finding(margin)
+    assert margin.status == "WARNING"
+    assert margin.finding_class == "RISK"
+
+
+def test_timing_skips_without_numbers():
+    graph = DesignGraph(
+        components={
+            "U1": Component(
+                reference="U1", value="", footprint="",
+                component_type=ComponentType.IC, mpn="MCU",
+                pins={"1": "NRST"},
+            ),
+            "R1": Component(
+                reference="R1", value="10k", footprint="",
+                component_type=ComponentType.RESISTOR, mpn="",
+                pins={"1": "NRST", "2": "+3V3"},
+            ),
+        },
+        nets={"NRST": Net(name="NRST", net_type=NetType.SIGNAL, pins=[])},
+    )
+    cons = ComponentConstraints(
+        mpn="MCU",
+        pintable=[Pin(number="1", name="NRST")],
+        absolute_maximum_ratings=[],
+        rules=[],
+    )
+    assert check_timing(graph, {"MCU": cons}) == []
+
+
+def test_timing_reset_rc_vs_t_reset():
+    graph = DesignGraph(
+        components={
+            "U1": Component(
+                reference="U1", value="", footprint="",
+                component_type=ComponentType.IC, mpn="MCU",
+                pins={"1": "NRST"},
+                specs=SimpleComponentSpecs(
+                    specs_type="discrete",
+                    values={"t_reset_min_s": 0.01},
+                ),
+            ),
+            "R1": Component(
+                reference="R1", value="1k", footprint="",
+                component_type=ComponentType.RESISTOR, mpn="",
+                pins={"1": "NRST", "2": "+3V3"},
+                specs=ResistorSpecs(value_ohms=1000, value_formatted="1k"),
+            ),
+            "C1": Component(
+                reference="C1", value="100n", footprint="",
+                component_type=ComponentType.CAPACITOR, mpn="",
+                pins={"1": "NRST", "2": "GND"},
+                specs=CapacitorSpecs(value_farads=100e-9, value_formatted="100n"),
+            ),
+        },
+        nets={
+            "NRST": Net(
+                name="NRST", net_type=NetType.SIGNAL,
+                pins=[
+                    PinConnection(component_ref="U1", pin_number="1"),
+                    PinConnection(component_ref="R1", pin_number="1"),
+                    PinConnection(component_ref="C1", pin_number="1"),
+                ],
+            ),
+            "+3V3": Net(name="+3V3", net_type=NetType.POWER, voltage=3.3, pins=[]),
+            "GND": Net(name="GND", net_type=NetType.GROUND, pins=[]),
+        },
+    )
+    cons = ComponentConstraints(
+        mpn="MCU",
+        pintable=[Pin(number="1", name="NRST")],
+        absolute_maximum_ratings=[],
+        rules=[],
+    )
+    findings = check_timing(graph, {"MCU": cons})
+    assert findings and findings[0].rule_id == "PE-TIM-001"
+    complete_finding(findings[0])
+    assert findings[0].status == "ERROR"
+    assert findings[0].finding_class == "RULE"
+
+
+def test_pi_missing_local_is_risk_not_error():
+    graph = DesignGraph(
+        components={
+            "U1": Component(
+                reference="U1", value="LDO", footprint="",
+                component_type=ComponentType.IC, mpn="LDO",
+                pins={"1": "VIN"},
+            ),
+        },
+        nets={
+            "VIN": Net(
+                name="VIN", net_type=NetType.POWER, voltage=5.0,
+                pins=[PinConnection(component_ref="U1", pin_number="1")],
+            ),
+        },
+    )
+    cons = ComponentConstraints(
+        mpn="LDO",
+        pintable=[Pin(number="1", name="VIN")],
+        absolute_maximum_ratings=[],
+        rules=[],
+    )
+    findings = check_power_integrity(graph, {"LDO": cons})
+    assert findings and findings[0].rule_id == "PE-PI-001"
+    complete_finding(findings[0])
+    assert findings[0].status == "WARNING"
+    assert findings[0].finding_class == "RISK"
+
+
+def test_esd_without_part_is_review_not_error():
+    graph = DesignGraph(
+        components={
+            "J1": Component(
+                reference="J1", value="USB", footprint="",
+                component_type=ComponentType.CONNECTOR, mpn="",
+                pins={"1": "USB_DP"},
+            ),
+            "U2": Component(
+                reference="U2", value="UART", footprint="",
+                component_type=ComponentType.IC, mpn="CH",
+                pins={"1": "USB_DP"},
+            ),
+        },
+        nets={
+            "USB_DP": Net(
+                name="USB_DP", net_type=NetType.SIGNAL,
+                pins=[
+                    PinConnection(component_ref="J1", pin_number="1"),
+                    PinConnection(component_ref="U2", pin_number="1"),
+                ],
+            ),
+        },
+    )
+    cons = ComponentConstraints(
+        mpn="CH",
+        pintable=[Pin(number="1", name="UD+")],
+        absolute_maximum_ratings=[],
+        rules=[],
+        internal_features=InternalFeatures(esd_clamp_pins=["UD+"]),
+    )
+    findings = check_esd(graph, {"CH": cons})
+    assert findings and findings[0].rule_id == "PE-ESD-001"
+    complete_finding(findings[0])
+    assert findings[0].finding_class == "REVIEW"
+    assert findings[0].status != "ERROR"
+
+
+def test_return_path_hs_is_review():
+    graph = DesignGraph(
+        components={
+            "U1": Component(
+                reference="U1", value="", footprint="",
+                component_type=ComponentType.IC, mpn="X",
+                pins={"1": "USB_DP"},
+            ),
+        },
+        nets={
+            "USB_DP": Net(
+                name="USB_DP", net_type=NetType.SIGNAL,
+                pins=[PinConnection(component_ref="U1", pin_number="1")],
+            ),
+        },
+    )
+    layout = LayoutGraph(
+        footprints={"U1": LayoutFootprint(reference="U1", x=0, y=0, layer="F.Cu")},
+        segments=[
+            LayoutSegment(start=(0, 0), end=(20, 8), width=0.2, layer="F.Cu", net="USB_DP"),
+        ],
+        zones=[
+            LayoutZone(net="GND", layer="B.Cu", outlines=[[(0, -5), (20, -5), (20, 10), (0, 10)]]),
+        ],
+        vias=[],
+    )
+    findings = check_return_path(graph, layout)
+    assert findings and findings[0].rule_id == "PE-RET-001"
+    complete_finding(findings[0])
+    assert findings[0].finding_class == "REVIEW"
+    assert findings[0].status != "ERROR"
+    layout.vias = [LayoutVia(x=10, y=4, net="GND", drill=0.3)]
+    assert check_return_path(graph, layout) == []
+
+
+def test_llm_error_review_clamped_in_complete_finding():
+    f = Finding(
+        designator="U1",
+        finding="no vias",
+        why="PowerPAD",
+        status="ERROR",
+        source="pcb_review",
+        facts="0 vias",
+        requirement="must have vias",
+        source_quote="Use thermal vias in the exposed pad.",
+        evidence_status="SUFFICIENT",
+    )
+    complete_finding(f)
+    assert f.finding_class == "REVIEW"
+    assert f.status == "WARNING"
diff --git a/tests/test_finding_engine.py b/tests/test_finding_engine.py
index 2f7fc09..e310453 100644
--- a/tests/test_finding_engine.py
+++ b/tests/test_finding_engine.py
@@ -52,6 +52,56 @@ def test_llm_review_is_never_rule():
     assert f.finding_class == "REVIEW"
     assert f.facts
     assert f.requirement
+    assert f.status == "WARNING"
+
+
+def test_review_and_risk_cannot_stay_error():
+    review = Finding(
+        designator="U1",
+        finding="PowerPAD vias",
+        why="layout note",
+        status="ERROR",
+        source="pcb_review",
+        facts="0 vias under U1",
+        requirement="datasheet PowerPAD",
+        source_quote="Connect the thermal pad with vias to GND.",
+        evidence_status="SUFFICIENT",
+    )
+    complete_finding(review)
+    assert review.finding_class == "REVIEW"
+    assert review.status == "WARNING"
+
+    risk = Finding(
+        designator="C1",
+        finding="high utilization",
+        why="Vop near Vr",
+        status="ERROR",
+        rule_id="PE-DRT-002",
+        source="pcb_derating",
+        evidence_status="SUFFICIENT",
+        facts="3.0 / 3.3 V",
+        requirement="utilization band",
+    )
+    complete_finding(risk)
+    assert risk.finding_class == "RISK"
+    assert risk.status == "WARNING"
+
+
+def test_mandatory_rule_stays_error():
+    f = Finding(
+        designator="U1",
+        finding="NC tied",
+        why="NC must float",
+        status="ERROR",
+        rule_id="PE-NC-001",
+        source="nc_pin_check",
+        facts="NC on GND",
+        requirement="NC pins must not be connected.",
+        evidence_status="SUFFICIENT",
+    )
+    complete_finding(f)
+    assert f.finding_class == "RULE"
+    assert f.provenance == "MANDATORY"
     assert f.status == "ERROR"