diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index 1a70378..a9a7678 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -82,7 +82,7 @@ jobs:
         os: [ ubuntu-latest, macos-latest ]
         python-version: [ "3.10", "3.13" ]
         # Oldest najaeda the package declares support for, and the newest.
-        najaeda: [ "==0.7.25", "" ]
+        najaeda: [ "==0.7.27", "" ]
     steps:
       - name: Checkout code
         uses: actions/checkout@v5
diff --git a/.gitignore b/.gitignore
index 71ff588..f31cee7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,3 +18,4 @@ python/dist/
 python/LICENSE
 .pytest_cache/
 __pycache__/
+dist/
diff --git a/python/naja_schematic/__init__.py b/python/naja_schematic/__init__.py
index a9b4699..bacb2d1 100644
--- a/python/naja_schematic/__init__.py
+++ b/python/naja_schematic/__init__.py
@@ -9,7 +9,7 @@
 """
 # Single version for the whole project: CMakeLists.txt reads this line into the
 # C++ app too (NAJA_SCHEMATIC_VERSION_STRING), so keep it a plain literal.
-__version__ = "0.1.8"
+__version__ = "0.1.9"
 
 from .protocol import diagnosis_response, handle_request
 from .server import ViewerServer
diff --git a/python/naja_schematic/protocol.py b/python/naja_schematic/protocol.py
index d35a78f..971ca40 100644
--- a/python/naja_schematic/protocol.py
+++ b/python/naja_schematic/protocol.py
@@ -60,8 +60,11 @@ def has_visible_primitive_instances(design):
 # sequential model) -- never from its name. A cell naja has no model for is
 # "unknown" and draws as the generic box. LocalSNLProvider.cpp's
 # getPrimitiveType() mirrors this, same as the rest of the wire protocol.
+# The truth-table checks are only asked of a cell with exactly one output
+# bit: on a multi-output cell (NLDB0's full adder, a multi-output Liberty
+# cell) naja's getTruthTable() throws, and najaeda doesn't translate that
+# exception -- it aborts the process.
 _PRIMITIVE_TYPE_CHECKS = (
-    ("isSequential", "dff"),
     ("isConst0", "tie0"),
     ("isConst1", "tie1"),
     ("isInv", "inv"),
@@ -79,11 +82,19 @@ def get_primitive_type(model):
         return "unknown"
     if model.isAssign():
         return "assign"
+    if model.isSequential():
+        return "dff"
+    if output_bit_count(model) != 1:
+        return "unknown"
     for check, ptype in _PRIMITIVE_TYPE_CHECKS:
         if getattr(model, check)():
             return ptype
     return "unknown"
 
+def output_bit_count(model):
+    return sum(1 for term in model.getBitTerms()
+               if term.getDirection() != naja.SNLTerm.Direction.Input)
+
 def with_clock(entry, term):
     # Only sent when set: marks a flip-flop's clock pin (see drawDffInstance).
     if term.is_clock():
diff --git a/python/pyproject.toml b/python/pyproject.toml
index 1361810..52b051d 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -11,7 +11,7 @@ license = "Apache-2.0"
 authors = [{name = "Naja Authors", email = "contact@keplertech.io"}]
 requires-python = ">=3.10"
 dependencies = [
-  "najaeda>=0.7.25",
+  "najaeda>=0.7.27",
   "websockets>=13",
   "anywidget>=0.9",
 ]
diff --git a/python/tests/test_protocol.py b/python/tests/test_protocol.py
index b8d1aea..6b0b859 100644
--- a/python/tests/test_protocol.py
+++ b/python/tests/test_protocol.py
@@ -1,6 +1,10 @@
 import json
+import subprocess
+import sys
 from types import SimpleNamespace
 
+from najaeda import naja
+
 from naja_schematic import protocol
 from naja_schematic.protocol import handle_message, handle_request
 
@@ -163,8 +167,11 @@ def test_get_primitive_type_uses_naja_modeling_not_names():
     checks = ("isAssign", "isSequential", "isInv", "isBuf", "isAnd", "isNand",
               "isOr", "isNor", "isXor", "isXnor", "isConst0", "isConst1")
 
-    def model(name, *true_checks):
+    output = SimpleNamespace(getDirection=lambda: naja.SNLTerm.Direction.Output)
+
+    def model(name, *true_checks, outputs=1):
         return SimpleNamespace(getName=lambda: name,
+                               getBitTerms=lambda: [output] * outputs,
                                **{c: (lambda c=c: c in true_checks) for c in checks})
     assert protocol.get_primitive_type(None) == "unknown"
     assert protocol.get_primitive_type(model("x", "isAssign")) == "assign"
@@ -175,3 +182,25 @@ def model(name, *true_checks):
     assert protocol.get_primitive_type(model("TIEH", "isConst1")) == "tie1"
     # The name never matters: an unmodelled "AND2" is just a box.
     assert protocol.get_primitive_type(model("AND2_X1")) == "unknown"
+    # A multi-output cell never reaches the truth-table checks (naja throws).
+    assert protocol.get_primitive_type(model("FA", "isXor", outputs=2)) == "unknown"
+    assert protocol.get_primitive_type(model("DFF2", "isSequential", outputs=2)) == "dff"
+
+
+def test_get_primitive_type_of_full_adder(tmp_path):
+    # SystemVerilog `a + b` elaborates to NLDB0 full adders (two outputs),
+    # whose truth-table checks abort the process inside najaeda: run it in a
+    # subprocess, which also keeps this design out of the session's universe.
+    (tmp_path / "add.sv").write_text(
+        "module top(input [1:0] a, b, output [1:0] y); assign y = a + b; endmodule\n")
+    script = (
+        "from najaeda import netlist, naja\n"
+        "from naja_schematic import protocol\n"
+        "netlist.load_system_verilog(['add.sv'])\n"
+        "top = naja.NLUniverse.get().getTopDesign()\n"
+        "print(sorted({protocol.get_primitive_type(i.getModel())\n"
+        "              for i in top.getInstances()}))\n")
+    run = subprocess.run([sys.executable, "-c", script], cwd=tmp_path,
+                         capture_output=True, text=True)
+    assert run.returncode == 0, run.stderr
+    assert run.stdout.strip().splitlines()[-1] == "['unknown']"
diff --git a/src/LocalSNLProvider.cpp b/src/LocalSNLProvider.cpp
index defc163..b610adb 100644
--- a/src/LocalSNLProvider.cpp
+++ b/src/LocalSNLProvider.cpp
@@ -134,10 +134,22 @@ static std::string displayChain(const std::vector<SNLInstance*>& chain) {
 // (e.g. gate-level Verilog loaded without Liberty) is Unknown and draws as
 // the generic box. protocol.py's get_primitive_type() mirrors this, same as
 // the rest of the wire protocol (see CLAUDE.md).
+// The truth-table checks are only asked of a cell with exactly one output
+// bit: on a multi-output cell (NLDB0's full adder, a multi-output Liberty
+// cell) naja's getTruthTable() throws from isConst0()/isInv()/...
+static size_t outputBitCount(const SNLDesign* model) {
+  size_t count = 0;
+  for (auto* term : model->getBitTerms()) {
+    if (term->getDirection() != SNLTerm::Direction::Input) ++count;
+  }
+  return count;
+}
+
 static PrimitiveType getPrimitiveType(const SNLDesign* model) {
   if (!model) return PrimitiveType::Unknown;
   if (NLDB0::isAssign(model)) return PrimitiveType::Assign;
   if (SNLDesignModeling::isSequential(model)) return PrimitiveType::Dff;
+  if (outputBitCount(model) != 1) return PrimitiveType::Unknown;
   if (SNLDesignModeling::isConst0(model)) return PrimitiveType::Tie0;
   if (SNLDesignModeling::isConst1(model)) return PrimitiveType::Tie1;
   if (SNLDesignModeling::isInv(model))  return PrimitiveType::Inv;
diff --git a/thirdparty/imgui b/thirdparty/imgui
index 64944b4..0f4b927 160000
--- a/thirdparty/imgui
+++ b/thirdparty/imgui
@@ -1 +1 @@
-Subproject commit 64944b4520b30772de8dbf0b37d0311746477a32
+Subproject commit 0f4b927e819823006a878bcb7fe93be129fd8d3f