fix: get_symbol_info returns wrong data for every small symbol

Parser used a 5000-char heuristic slice per symbol; any symbol block
shorter than 5000 chars bled into the next one, and last-write-wins in
the properties dict ensured the neighbor's data clobbered the target.
Reported as Simulation_SPICE:OPAMP returning PJFET data.

Switch to parenthesis-depth tracking to find the true end of each
(symbol ...) block. Also surface Sim.Pins so agents can read opamp pin
numbering without inferring it from schematic placement.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

python/commands/library_symbol.py

@@ -33,6 +33,7 @@ class SymbolInfo:
     stock: str = ""  # Stock (from JLCPCB libs)
     price: str = ""  # Price (from JLCPCB libs)
     lib_class: str = ""  # Basic/Preferred/Extended
+    sim_pins: str = ""  # Sim.Pins pin mapping (e.g. "1=in+ 2=in- 3=vcc 4=vee 5=out")
 
 
 class SymbolLibraryManager:
@@ -268,11 +269,28 @@ class SymbolLibraryManager:
                 # Find the start position of this symbol
                 start_pos = match.start()
 
-                # Extract properties from this symbol block
+                # Walk forward tracking parenthesis depth to find the true end of the block
-                # We need to find the matching closing paren - use a simple heuristic
+                depth = 0
-                # Look for the next 2000 characters for properties
+                i = start_pos
-                block_end = min(start_pos + 5000, len(content))
+                end_pos = start_pos
-                symbol_block = content[start_pos:block_end]
+                while i < len(content):
+                    ch = content[i]
+                    if ch == "(":
+                        depth += 1
+                    elif ch == ")":
+                        depth -= 1
+                        if depth == 0:
+                            end_pos = i + 1
+                            break
+                    i += 1
+
+                if end_pos == start_pos:
+                    logger.warning(
+                        f"Malformed symbol block for '{symbol_name}' in {library_path}; skipping"
+                    )
+                    continue
+
+                symbol_block = content[start_pos:end_pos]
 
                 # Extract properties
                 properties = self._extract_properties(symbol_block)
@@ -292,6 +310,7 @@ class SymbolLibraryManager:
                     stock=properties.get("Stock", ""),
                     price=properties.get("Price", ""),
                     lib_class=properties.get("Class", ""),
+                    sim_pins=properties.get("Sim.Pins", ""),
                 )
 
                 symbols.append(symbol_info)

src/tools/library-symbol.ts

@@ -158,6 +158,7 @@ Returns symbol references that can be used directly in schematics.`,
           info.category ? `Category: ${info.category}` : "",
           info.lib_class ? `Class: ${info.lib_class}` : "",
           info.datasheet ? `Datasheet: ${info.datasheet}` : "",
+          info.sim_pins ? `Sim.Pins: ${info.sim_pins}` : "",
         ]
           .filter((line) => line)
           .join("\n");

tests/fixtures/Simulation_SPICE_minimal.kicad_sym

@@ -0,0 +1,421 @@
+(kicad_symbol_lib
+	(version 20241209)
+	(generator "kicad_symbol_editor")
+	(generator_version "9.0")
+	(symbol "OPAMP"
+		(pin_names
+			(offset 0.254)
+		)
+		(exclude_from_sim no)
+		(in_bom yes)
+		(on_board yes)
+		(property "Reference" "U"
+			(at 3.81 3.175 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(justify left)
+			)
+		)
+		(property "Value" "${SIM.PARAMS}"
+			(at 3.81 -3.175 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(justify left)
+			)
+		)
+		(property "Footprint" ""
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Datasheet" "https://ngspice.sourceforge.io/docs/ngspice-html-manual/manual.xhtml#sec__SUBCKT_Subcircuits"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Description" "Operational amplifier, single"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Sim.Pins" "1=in+ 2=in- 3=vcc 4=vee 5=out"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Sim.Device" "SUBCKT"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(justify left)
+				(hide yes)
+			)
+		)
+		(property "Sim.Library" "${KICAD9_SYMBOL_DIR}/Simulation_SPICE.sp"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Sim.Name" "kicad_builtin_opamp"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "ki_keywords" "simulation"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(symbol "OPAMP_0_1"
+			(polyline
+				(pts
+					(xy 5.08 0) (xy -5.08 5.08) (xy -5.08 -5.08) (xy 5.08 0)
+				)
+				(stroke
+					(width 0.254)
+					(type default)
+				)
+				(fill
+					(type background)
+				)
+			)
+		)
+		(symbol "OPAMP_1_1"
+			(pin input line
+				(at -7.62 2.54 0)
+				(length 2.54)
+				(name "+"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+				(number "1"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+			)
+			(pin input line
+				(at -7.62 -2.54 0)
+				(length 2.54)
+				(name "-"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+				(number "2"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+			)
+			(pin power_in line
+				(at -2.54 7.62 270)
+				(length 3.81)
+				(name "V+"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+				(number "3"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+			)
+			(pin power_in line
+				(at -2.54 -7.62 90)
+				(length 3.81)
+				(name "V-"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+				(number "4"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+			)
+			(pin output line
+				(at 7.62 0 180)
+				(length 2.54)
+				(name "~"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+				(number "5"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+			)
+		)
+		(embedded_fonts no)
+	)
+	(symbol "PJFET"
+		(pin_numbers
+			(hide yes)
+		)
+		(pin_names
+			(offset 0)
+		)
+		(exclude_from_sim no)
+		(in_bom yes)
+		(on_board yes)
+		(property "Reference" "Q"
+			(at 5.08 1.27 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(justify left)
+			)
+		)
+		(property "Value" "PJFET"
+			(at 5.08 -1.27 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(justify left)
+			)
+		)
+		(property "Footprint" ""
+			(at 5.08 2.54 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Datasheet" "https://ngspice.sourceforge.io/docs/ngspice-html-manual/manual.xhtml#cha_JFETs"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Description" "P-JFET transistor, for simulation only"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Sim.Device" "PJFET"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Sim.Type" "SHICHMANHODGES"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "Sim.Pins" "1=D 2=G 3=S"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(property "ki_keywords" "transistor PJFET P-JFET"
+			(at 0 0 0)
+			(effects
+				(font
+					(size 1.27 1.27)
+				)
+				(hide yes)
+			)
+		)
+		(symbol "PJFET_0_1"
+			(polyline
+				(pts
+					(xy -1.143 0) (xy -0.127 0.381) (xy -0.127 -0.381) (xy -1.143 0)
+				)
+				(stroke
+					(width 0)
+					(type default)
+				)
+				(fill
+					(type outline)
+				)
+			)
+			(polyline
+				(pts
+					(xy 0.254 1.905) (xy 0.254 -1.905) (xy 0.254 -1.905)
+				)
+				(stroke
+					(width 0.254)
+					(type default)
+				)
+				(fill
+					(type none)
+				)
+			)
+			(circle
+				(center 1.27 0)
+				(radius 2.8194)
+				(stroke
+					(width 0.254)
+					(type default)
+				)
+				(fill
+					(type none)
+				)
+			)
+			(polyline
+				(pts
+					(xy 2.54 2.54) (xy 2.54 1.397) (xy 0.254 1.397)
+				)
+				(stroke
+					(width 0)
+					(type default)
+				)
+				(fill
+					(type none)
+				)
+			)
+			(polyline
+				(pts
+					(xy 2.54 -2.54) (xy 2.54 -1.27) (xy 0.254 -1.27)
+				)
+				(stroke
+					(width 0)
+					(type default)
+				)
+				(fill
+					(type none)
+				)
+			)
+		)
+		(symbol "PJFET_1_1"
+			(pin input line
+				(at -5.08 0 0)
+				(length 5.334)
+				(name "G"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+				(number "2"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+			)
+			(pin passive line
+				(at 2.54 5.08 270)
+				(length 2.54)
+				(name "D"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+				(number "1"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+			)
+			(pin passive line
+				(at 2.54 -5.08 90)
+				(length 2.54)
+				(name "S"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+				(number "3"
+					(effects
+						(font
+							(size 1.27 1.27)
+						)
+					)
+				)
+			)
+		)
+		(embedded_fonts no)
+	)
+)

tests/test_symbol_library.py

@@ -0,0 +1,117 @@
+"""
+Regression tests for symbol library parsing.
+
+Covers:
+- The 5000-char heuristic bug where PJFET properties bled into the OPAMP block.
+- The sim_pins field exposed from Sim.Pins properties.
+"""
+
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "python"))
+
+from commands.library_symbol import SymbolLibraryCommands, SymbolLibraryManager
+
+FIXTURE = Path(__file__).parent / "fixtures" / "Simulation_SPICE_minimal.kicad_sym"
+SPICE_LIB = Path("/usr/share/kicad/symbols/Simulation_SPICE.kicad_sym")
+
+
+def _manager_for_fixture() -> SymbolLibraryManager:
+    manager = SymbolLibraryManager.__new__(SymbolLibraryManager)
+    manager.project_path = None
+    manager.libraries = {"Simulation_SPICE": str(FIXTURE)}
+    manager.symbol_cache = {}
+    return manager
+
+
+@pytest.mark.unit
+class TestSymbolLibraryManagerParsing:
+    """Unit tests using the minimal fixture file (no disk I/O to system libs)."""
+
+    def test_both_symbols_present(self):
+        manager = _manager_for_fixture()
+        symbols = manager.list_symbols("Simulation_SPICE")
+        names = [s.name for s in symbols]
+        assert "OPAMP" in names
+        assert "PJFET" in names
+        assert len(symbols) == 2
+
+    def test_opamp_description_is_not_pjfet(self):
+        manager = _manager_for_fixture()
+        symbols = manager.list_symbols("Simulation_SPICE")
+        opamp = next(s for s in symbols if s.name == "OPAMP")
+        assert "JFET" not in opamp.description
+
+    def test_opamp_description_correct(self):
+        manager = _manager_for_fixture()
+        symbols = manager.list_symbols("Simulation_SPICE")
+        opamp = next(s for s in symbols if s.name == "OPAMP")
+        assert opamp.description == "Operational amplifier, single"
+
+    def test_opamp_value_correct(self):
+        manager = _manager_for_fixture()
+        symbols = manager.list_symbols("Simulation_SPICE")
+        opamp = next(s for s in symbols if s.name == "OPAMP")
+        assert opamp.value == "${SIM.PARAMS}"
+
+    def test_opamp_sim_pins_exposed(self):
+        manager = _manager_for_fixture()
+        symbols = manager.list_symbols("Simulation_SPICE")
+        opamp = next(s for s in symbols if s.name == "OPAMP")
+        assert opamp.sim_pins == "1=in+ 2=in- 3=vcc 4=vee 5=out"
+
+    def test_pjfet_description_correct(self):
+        manager = _manager_for_fixture()
+        symbols = manager.list_symbols("Simulation_SPICE")
+        pjfet = next(s for s in symbols if s.name == "PJFET")
+        assert pjfet.description == "P-JFET transistor, for simulation only"
+
+    def test_pjfet_value_correct(self):
+        manager = _manager_for_fixture()
+        symbols = manager.list_symbols("Simulation_SPICE")
+        pjfet = next(s for s in symbols if s.name == "PJFET")
+        assert pjfet.value == "PJFET"
+
+    def test_pjfet_sim_pins_exposed(self):
+        manager = _manager_for_fixture()
+        symbols = manager.list_symbols("Simulation_SPICE")
+        pjfet = next(s for s in symbols if s.name == "PJFET")
+        assert pjfet.sim_pins == "1=D 2=G 3=S"
+
+
+@pytest.mark.integration
+class TestGetSymbolInfoHandler:
+    """Integration tests against the real system Simulation_SPICE library."""
+
+    def test_opamp_via_commands_handler(self):
+        if not SPICE_LIB.exists():
+            pytest.skip(f"System library not found: {SPICE_LIB}")
+        manager = SymbolLibraryManager.__new__(SymbolLibraryManager)
+        manager.project_path = None
+        manager.libraries = {"Simulation_SPICE": str(SPICE_LIB)}
+        manager.symbol_cache = {}
+        commands = SymbolLibraryCommands(library_manager=manager)
+        result = commands.get_symbol_info({"symbol": "Simulation_SPICE:OPAMP"})
+        assert result["success"] is True
+        info = result["symbol_info"]
+        assert info["description"] == "Operational amplifier, single"
+        assert "JFET" not in info["description"]
+        assert info["value"] == "${SIM.PARAMS}"
+        assert info["sim_pins"] == "1=in+ 2=in- 3=vcc 4=vee 5=out"
+
+    def test_pjfet_via_commands_handler(self):
+        if not SPICE_LIB.exists():
+            pytest.skip(f"System library not found: {SPICE_LIB}")
+        manager = SymbolLibraryManager.__new__(SymbolLibraryManager)
+        manager.project_path = None
+        manager.libraries = {"Simulation_SPICE": str(SPICE_LIB)}
+        manager.symbol_cache = {}
+        commands = SymbolLibraryCommands(library_manager=manager)
+        result = commands.get_symbol_info({"symbol": "Simulation_SPICE:PJFET"})
+        assert result["success"] is True
+        info = result["symbol_info"]
+        assert info["description"] == "P-JFET transistor, for simulation only"
+        assert info["value"] == "PJFET"