diff --git a/docs/research/rayforge-lightburn-device-import-spike.md b/docs/research/rayforge-lightburn-device-import-spike.md
new file mode 100644
index 0000000..b258401
--- /dev/null
+++ b/docs/research/rayforge-lightburn-device-import-spike.md
@@ -0,0 +1,53 @@
+# Rayforge synthetic LightBurn JCZ device-import spike
+
+- Date: 2026-10-19
+- Rayforge commit: `c28918c87f8273dd1d244f5a057addc192807fa5`
+- Fixture: synthetic public `.lbdev`; no machine identifiers
+- Scope: device-profile importer only, with no discovery or transport
+
+## Result
+
+Pinned Rayforge parses the synthetic `JCZFiber` profile and preserves its
+display name, 110 x 110 mm work area and generic home-on-start value. It does
+not select a driver because its LightBurn driver map has no `JCZFiber` entry.
+
+The imported `DeviceProfile` also has no representation of the observed
+`RequireFrameBeforeStart` setting or the synthetic cut-list `frequency` and
+`QPulseWidth` fields. The import is therefore explicitly classified as unsafe
+for JCZ use rather than receiving guessed defaults.
+
+The checked result is
+`tests/fixtures/rayforge-lightburn-device-import.json`. Two runs produced the
+same SHA-256 digest,
+`3c26f43be6b06e9b17a5decbe4ba7bb633eb1b8ac7bb0361449d7498a3b9279c`.
+
+## Evidence boundary
+
+The fixture uses field names already recorded by the sanitized LightBurn
+device-export analysis. Its values are synthetic examples inside observed
+ranges, not a copy of a private export and not certified machine limits or
+material settings. It deliberately omits private GUIDs, source paths and
+unpublished connection serialization.
+
+This spike characterizes the current importer; it does not implement a driver
+mapping. A future `JCZFiber` mapping must target the separately tested
+no-transport addon driver and require an exact compatible profile. It must not
+silently map `JCZFiber` to a G-code or Ruida driver.
+
+## Reproduce
+
+Run against the pinned Rayforge checkout:
+
+```powershell
+python scripts/spike_rayforge_lightburn_device_import.py C:\path\to\rayforge
+```
+
+## Next seam
+
+The smallest evidence-backed extension is to recognize `JCZFiber` as a
+distinct, fail-closed profile kind, preserve its raw settings with explicit
+units/provenance, and associate it only with the external no-device JCZ driver.
+Cut-list recipes and project-layer `QPulseWidth` mapping remain gated until a
+known-working `.lbrn2` fixture establishes project serialization.
+
+No USB enumeration, controller command, motion, framing or emission occurred.
diff --git a/docs/roadmap.md b/docs/roadmap.md
index e4771e3..c1b94af 100644
--- a/docs/roadmap.md
+++ b/docs/roadmap.md
@@ -276,6 +276,12 @@ The next work package should be small enough to review in a few commits:
 Hardware work cannot proceed until item 6 is reviewed and the physical setup
 is ready.
 
+Item 2 is now covered by the
+[synthetic LightBurn JCZ device-import spike](research/rayforge-lightburn-device-import-spike.md):
+Rayforge preserves the common name and work-area fields, but maps no
+`JCZFiber` driver and drops the JCZ-specific safety and MOPA fields from its
+profile model. The fixture and regression test remain transport-free.
+
 ## Decision rules
 
 - A simulator test precedes every equivalent hardware behavior.
diff --git a/scripts/spike_rayforge_lightburn_device_import.py b/scripts/spike_rayforge_lightburn_device_import.py
new file mode 100644
index 0000000..5348606
--- /dev/null
+++ b/scripts/spike_rayforge_lightburn_device_import.py
@@ -0,0 +1,111 @@
+"""Characterize a synthetic JCZ LightBurn device import in pinned Rayforge.
+
+The fixture contains only public, synthetic values.  This spike performs no
+device discovery or transport and deliberately does not add a JCZ driver.
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import subprocess
+import sys
+from pathlib import Path
+
+
+RAYFORGE_COMMIT = "c28918c87f8273dd1d244f5a057addc192807fa5"
+
+
+def _commit_of(source: Path) -> str:
+    result = subprocess.run(
+        ["git", "-C", str(source), "rev-parse", "HEAD"],
+        check=True,
+        capture_output=True,
+        text=True,
+    )
+    return result.stdout.strip()
+
+
+def run(source: Path, fixture: Path) -> dict[str, object]:
+    commit = _commit_of(source)
+    if commit != RAYFORGE_COMMIT:
+        raise RuntimeError(f"expected Rayforge {RAYFORGE_COMMIT}, found {commit}")
+    sys.path.insert(0, str(source))
+
+    from rayforge.machine.device.lightburn_importer import (
+        convert_to_profile,
+        parse_lbdev,
+    )
+
+    raw = parse_lbdev(fixture)
+    profile, summary = convert_to_profile(fixture)
+    settings = raw["Settings"]
+    cut_entry = raw["CutList"][0]
+
+    if raw["Type"] != "JCZFiber":
+        raise AssertionError("synthetic fixture is not a JCZFiber profile")
+    if profile.machine_config.axis_extents != (110.0, 110.0):
+        raise AssertionError("work area did not survive import")
+    if profile.machine_config.driver is not None or summary.driver is not None:
+        raise AssertionError("pinned Rayforge unexpectedly mapped a JCZ driver")
+
+    return {
+        "rayforge_commit": commit,
+        "transport": None,
+        "fixture": fixture.name,
+        "fixture_provenance": "synthetic public data",
+        "raw_profile": {
+            "name": raw["DisplayName"],
+            "type": raw["Type"],
+            "work_area_mm": [raw["Width"], raw["Height"]],
+            "require_frame_before_start": settings[
+                "RequireFrameBeforeStart"
+            ],
+            "cut_entry": {
+                "frequency": cut_entry["frequency"],
+                "QPulseWidth": cut_entry["QPulseWidth"],
+            },
+        },
+        "mapped_profile": {
+            "name": profile.meta.name,
+            "driver": profile.machine_config.driver,
+            "work_area_mm": list(profile.machine_config.axis_extents),
+            "home_on_start": profile.machine_config.home_on_start,
+        },
+        "gap_matrix": {
+            "jczfiber_driver_mapped": profile.machine_config.driver is not None,
+            "require_frame_before_start_mapped": False,
+            "cut_list_mapped": False,
+            "frequency_mapped": False,
+            "q_pulse_width_mapped": False,
+            "safe_for_jcz_use": False,
+        },
+        "conclusion": (
+            "name and work area survive, but JCZFiber has no driver mapping; "
+            "RequireFrameBeforeStart, CutList, frequency and QPulseWidth are "
+            "not represented in the imported Rayforge profile"
+        ),
+    }
+
+
+def main() -> None:
+    root = Path(__file__).parents[1]
+    parser = argparse.ArgumentParser()
+    parser.add_argument("source", type=Path, help="pinned Rayforge checkout")
+    parser.add_argument(
+        "--fixture",
+        type=Path,
+        default=root / "tests" / "fixtures" / "synthetic-jcz-device.lbdev",
+    )
+    parser.add_argument("--output", type=Path)
+    args = parser.parse_args()
+    result = run(args.source.resolve(), args.fixture.resolve())
+    rendered = json.dumps(result, indent=2, sort_keys=True) + "\n"
+    if args.output:
+        args.output.write_text(rendered, encoding="utf-8", newline="\n")
+    else:
+        print(rendered, end="")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tests/fixtures/rayforge-lightburn-device-import.json b/tests/fixtures/rayforge-lightburn-device-import.json
new file mode 100644
index 0000000..e78087f
--- /dev/null
+++ b/tests/fixtures/rayforge-lightburn-device-import.json
@@ -0,0 +1,37 @@
+{
+  "conclusion": "name and work area survive, but JCZFiber has no driver mapping; RequireFrameBeforeStart, CutList, frequency and QPulseWidth are not represented in the imported Rayforge profile",
+  "fixture": "synthetic-jcz-device.lbdev",
+  "fixture_provenance": "synthetic public data",
+  "gap_matrix": {
+    "cut_list_mapped": false,
+    "frequency_mapped": false,
+    "jczfiber_driver_mapped": false,
+    "q_pulse_width_mapped": false,
+    "require_frame_before_start_mapped": false,
+    "safe_for_jcz_use": false
+  },
+  "mapped_profile": {
+    "driver": null,
+    "home_on_start": false,
+    "name": "Synthetic JCZ MOPA",
+    "work_area_mm": [
+      110.0,
+      110.0
+    ]
+  },
+  "raw_profile": {
+    "cut_entry": {
+      "QPulseWidth": 100,
+      "frequency": 40000
+    },
+    "name": "Synthetic JCZ MOPA",
+    "require_frame_before_start": true,
+    "type": "JCZFiber",
+    "work_area_mm": [
+      110,
+      110
+    ]
+  },
+  "rayforge_commit": "c28918c87f8273dd1d244f5a057addc192807fa5",
+  "transport": null
+}
diff --git a/tests/fixtures/synthetic-jcz-device.lbdev b/tests/fixtures/synthetic-jcz-device.lbdev
new file mode 100644
index 0000000..8439dd3
--- /dev/null
+++ b/tests/fixtures/synthetic-jcz-device.lbdev
@@ -0,0 +1,23 @@
+{
+  "FixtureProvenance": "synthetic public data; not a machine export",
+  "DeviceList": [
+    {
+      "DisplayName": "Synthetic JCZ MOPA",
+      "Name": "JCZ",
+      "Type": "JCZFiber",
+      "Width": 110,
+      "Height": 110,
+      "HomeOnStartup": false,
+      "Settings": {
+        "RequireFrameBeforeStart": true
+      },
+      "CutList": [
+        {
+          "Name": "Synthetic MOPA entry",
+          "frequency": 40000,
+          "QPulseWidth": 100
+        }
+      ]
+    }
+  ]
+}
diff --git a/tests/test_rayforge_lightburn_device_import_spike.py b/tests/test_rayforge_lightburn_device_import_spike.py
new file mode 100644
index 0000000..b1497c7
--- /dev/null
+++ b/tests/test_rayforge_lightburn_device_import_spike.py
@@ -0,0 +1,44 @@
+import json
+import unittest
+from pathlib import Path
+
+
+ROOT = Path(__file__).parents[1]
+RESULT = ROOT / "tests" / "fixtures" / "rayforge-lightburn-device-import.json"
+SOURCE = ROOT / "tests" / "fixtures" / "synthetic-jcz-device.lbdev"
+
+
+class RayforgeLightBurnDeviceImportSpikeTests(unittest.TestCase):
+    def test_public_fixture_is_synthetic_and_contains_no_private_identity(self):
+        source = json.loads(SOURCE.read_text(encoding="utf-8"))
+        self.assertEqual(
+            "synthetic public data; not a machine export",
+            source["FixtureProvenance"],
+        )
+        rendered = SOURCE.read_text(encoding="utf-8").lower()
+        self.assertNotIn("serial", rendered)
+        self.assertNotIn("guid", rendered)
+
+    def test_common_profile_fields_survive(self):
+        result = json.loads(RESULT.read_text(encoding="utf-8"))
+        self.assertIsNone(result["transport"])
+        self.assertEqual("JCZFiber", result["raw_profile"]["type"])
+        self.assertEqual([110, 110], result["mapped_profile"]["work_area_mm"])
+        self.assertEqual(
+            "Synthetic JCZ MOPA", result["mapped_profile"]["name"]
+        )
+
+    def test_jcz_specific_fields_fail_closed(self):
+        result = json.loads(RESULT.read_text(encoding="utf-8"))
+        gaps = result["gap_matrix"]
+        self.assertIsNone(result["mapped_profile"]["driver"])
+        self.assertFalse(gaps["jczfiber_driver_mapped"])
+        self.assertFalse(gaps["require_frame_before_start_mapped"])
+        self.assertFalse(gaps["cut_list_mapped"])
+        self.assertFalse(gaps["frequency_mapped"])
+        self.assertFalse(gaps["q_pulse_width_mapped"])
+        self.assertFalse(gaps["safe_for_jcz_use"])
+
+
+if __name__ == "__main__":
+    unittest.main()