diff --git a/AGENTS.md b/AGENTS.md
index 02b41c1..3847ebe 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -20,7 +20,8 @@ studio/
 ├── src/
 │   ├── main.zig             # Model, Msg, update, app wiring
 │   ├── app.native           # the view (declarative markup)
-│   ├── ocpp/                # pure, headless OCPP engine (types, parser, …)
+│   ├── ocpp/                # pure, headless OCPP engine (types, parser, detection, …)
+│   │   └── conformance/     # vendored shared-contract fixtures + goldens + harness
 │   └── tests.zig            # headless view/model tests
 ├── scripts/smoke.sh         # portable automation smoke test (Xvfb in CI)
 ├── docs/adr/                # architecture decision records
diff --git a/CURRENT_STATE.md b/CURRENT_STATE.md
index a63749f..fba8db9 100644
--- a/CURRENT_STATE.md
+++ b/CURRENT_STATE.md
@@ -8,8 +8,8 @@
 
 ## Active milestone
 
-**S2 — Detection + conformance (0.1.0): in progress.** S1 — Engine core is
-complete (see [ROADMAP.md](ROADMAP.md)).
+**S2 — Detection + conformance (0.1.0): complete.** Next up: **S3 — Inspector UI**
+(see [ROADMAP.md](ROADMAP.md)).
 
 ## What's done
 
@@ -53,22 +53,26 @@ conformance contract (behavior, not source) and tested via
 correlates end to end (one completed session, transactionId 100001); engine
 tests green headlessly on macOS + Linux.
 
+### S2 — Detection + conformance ✅
+
+The full 16-rule OCPP 1.6J failure taxonomy in `src/ocpp/detection.zig`, mirroring
+the toolkit's `detection.ts`, plus a harness that locks Studio's output to the
+toolkit's:
+
+- **Failure model + foundational rules** (#19) — the `Failure` / `FailureCode` /
+  `FailureSeverity` model and rules 1–3.
+- **Protocol & transaction rules** (#20) — rules 4–10.
+- **Timing & anomaly rules** (#21) — rules 11–16.
+- **Conformance harness** (#22) — 15 vendored scenario traces + goldens
+  (`src/ocpp/conformance/`, `contract-v1`, generated from the toolkit) and a
+  `native test` gate asserting Studio's de-duplicated, sorted `FailureCode` set
+  matches each golden.
+
+**Exit criteria met:** 15/15 scenarios match the locked goldens.
+
 ## What's in progress
 
-**S2 — Detection + conformance (0.1.0).** Building the 16-rule failure taxonomy
-in Zig, mirroring the toolkit's `detection.ts`:
-
-- **Failure model + foundational rules** (#19) — the `Failure` / `FailureCode`
-  (16-code taxonomy) / `FailureSeverity` model, the `detection.zig` orchestrator
-  with per-code severity + remediation metadata, and rules 1–3
-  (FAILED_AUTHORIZATION, CONNECTOR_FAULT, STATION_OFFLINE_DURING_SESSION).
-- **Protocol & transaction rules** (#20) — rules 4–10: TIMEOUT_NO_HEARTBEAT,
-  METER_VALUE_GAP, INVALID_STOP_REASON, UNEXPECTED_START,
-  STATUS_TRANSITION_VIOLATION, DIAGNOSTICS_FAILURE, FIRMWARE_UPDATE_FAILURE.
-- **Timing & anomaly rules** (#21) — rules 11–16: SUSPICIOUS_SESSION_DURATION,
-  SLOW_RESPONSE, HEARTBEAT_INTERVAL_VIOLATION, METER_VALUE_ANOMALY,
-  UNRESPONSIVE_CSMS, REPEATED_BOOT_NOTIFICATION. All 16 rules now run.
-- Next: the conformance harness over the 15 shared scenarios (#22).
+- Nothing in flight — S2 is closed; S3 is next.
 
 ## What's next
 
@@ -86,8 +90,8 @@ search / filter, handling traces far larger than a browser tab can hold.
 | --- | --- |
 | `repo` (tooling, CI) | ✅ done for S0 |
 | `docs` (docs, ADRs) | ✅ done for S0 |
-| `ocpp` (engine) | 🚧 detection in progress (S2) |
+| `ocpp` (engine) | ✅ done for S2 |
 | `ui` (native views) | ⬜ placeholder (S3) |
 | `capture` (live proxy) | ⬜ not started (S5) |
 | `cli` (headless) | ⬜ not started (S4) |
-| `conformance` | ⬜ not started (S2) |
+| `conformance` | ✅ done for S2 (15/15, `contract-v1`) |
diff --git a/ROADMAP.md b/ROADMAP.md
index 438bf2b..c80289c 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -10,8 +10,8 @@ the stable part.
 | --- | --- | --- | --- |
 | **S0** | 0.0.x | Foundation | ✅ Complete |
 | **S1** | 0.1.0 | Engine core | ✅ Complete |
-| **S2** | 0.1.0 | Detection + conformance | Next up |
-| **S3** | 0.2.0 | Inspector UI | Planned |
+| **S2** | 0.1.0 | Detection + conformance | ✅ Complete |
+| **S3** | 0.2.0 | Inspector UI | Next up |
 | **S4** | 0.3.0 | Analysis parity+ | Planned |
 | **S5** | 0.4.0 | Live capture ⭐ | Planned |
 | **S6** | 1.0.0 | 1.0 polish | Planned |
@@ -32,11 +32,13 @@ inference), and session correlation by transaction id. **Exit criteria met:** th
 vendored `normal-session` fixture parses and correlates end to end; engine tests
 run green headlessly (`native test -Dplatform=null`) on macOS + Linux.
 
-## S2 — Detection + conformance (0.1.0)
+## S2 — Detection + conformance (0.1.0) ✅
 
-The full OCPP 1.6J failure taxonomy in Zig, plus the conformance harness that
-runs the shared scenario fixtures and checks Studio's detected failures against
-locked goldens. **Exit:** the shared scenarios match, byte for byte.
+The full OCPP 1.6J failure taxonomy in Zig — all 16 detection rules — plus the
+conformance harness that runs the 15 shared scenario fixtures and checks Studio's
+detected failures against locked goldens generated from the toolkit.
+**Exit criteria met:** 15/15 scenarios match the `contract-v1` goldens under
+`native test`.
 
 ## S3 — Inspector UI (0.2.0)
 
diff --git a/src/ocpp/conformance/README.md b/src/ocpp/conformance/README.md
new file mode 100644
index 0000000..f2627b3
--- /dev/null
+++ b/src/ocpp/conformance/README.md
@@ -0,0 +1,44 @@
+# Conformance contract (`contract-v1`)
+
+Studio and the TypeScript toolkit are **independent implementations** of the same
+OCPP analysis behavior (ADR-0001). This directory is the machine-checked contract
+between them: the shared scenarios and the failure codes each must detect.
+
+- **`fixtures/<name>.json`** — the 15 shared scenario **traces** (the input).
+- **`goldens/<name>.json`** — each scenario's expected **de-duplicated, sorted
+  `FailureCode` set** (the output to match), as a JSON array of wire codes.
+- **`harness.zig`** — runs, under `native test`, the full engine
+  (`parseTrace → buildSessionTimeline → detectFailures`) over every fixture and
+  asserts its detected code set equals the golden — the same comparison the
+  toolkit's `evaluateScenario` makes. A missing or extra code fails the scenario
+  by name.
+
+## Generated, not hand-authored
+
+Both the fixtures and the goldens are exported from the toolkit — the source of
+truth — so a golden can never drift from what the reference implementation
+actually detects. They are regenerated (not edited by hand) from the toolkit's
+`scenarios` and `evaluateScenario`:
+
+```js
+// run against a built @ocpp-debugkit/toolkit
+import { scenarios } from '@ocpp-debugkit/toolkit/scenarios';
+import { evaluateScenario } from '@ocpp-debugkit/toolkit';
+for (const s of scenarios) {
+  const detected = [...new Set(evaluateScenario(s).failures.map((f) => f.code))].sort();
+  // fixtures/<s.name>.json  <- JSON.stringify(s.trace)
+  // goldens/<s.name>.json   <- JSON.stringify(detected)
+}
+```
+
+## Why it lives under `src/`
+
+The Native SDK zero-config build (ADR-0004) embeds test data with `@embedFile`,
+which resolves within the source module root. Keeping the vendored contract here
+lets the harness embed it directly — no runtime file I/O, fully hermetic.
+
+## Versioning
+
+Tagged **`contract-v1`** (OCPP 1.6J). When the contract changes — new rules,
+new scenarios, or OCPP 2.0.1 — regenerate against the matching toolkit release
+and bump the tag.
diff --git a/src/ocpp/conformance/fixtures/connector-fault.json b/src/ocpp/conformance/fixtures/connector-fault.json
new file mode 100644
index 0000000..3d11757
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/connector-fault.json
@@ -0,0 +1,271 @@
+{
+  "traceId": "fixture-connector-fault",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-003",
+    "ocppVersion": "1.6",
+    "source": "synthetic-fixture",
+    "description": "Connector fault during active session: station boots, transaction starts, connector faults mid-charging, transaction stops with fault reason. Expects CONNECTOR_FAULT failure."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T12:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-003",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T12:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 0,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:02:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Preparing",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:02:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:02:15.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-002"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:02:15.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {
+          "idTagInfo": {
+            "status": "Accepted",
+            "expiryDate": "2024-12-31T23:59:59.000Z"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:02:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-005",
+        "StartTransaction",
+        {
+          "connectorId": 1,
+          "idTag": "SYNTHETIC-TAG-002",
+          "meterStart": 0,
+          "timestamp": "2024-01-15T12:02:30.000Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:02:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-005",
+        {
+          "transactionId": 100002,
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:02:31.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-006",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Charging",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:02:31.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-006",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:07:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-1",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:07:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-1",
+        {
+          "currentTime": "2024-01-15T12:07:30.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:15:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-007",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100002,
+          "meterValue": [
+            {
+              "timestamp": "2024-01-15T12:15:00.000Z",
+              "sampledValue": [
+                {
+                  "value": "3500",
+                  "measurand": "Energy.Active.Import.Register",
+                  "unit": "Wh"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:15:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-007",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:18:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-008",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Faulted",
+          "errorCode": "ConnectorLockFailure",
+          "info": "Connector lock mechanism failure detected"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:18:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-008",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:18:05.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-009",
+        "StopTransaction",
+        {
+          "transactionId": 100002,
+          "idTag": "SYNTHETIC-TAG-002",
+          "meterStop": 3500,
+          "timestamp": "2024-01-15T12:18:05.000Z",
+          "reason": "Other"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:18:05.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-009",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/diagnostics-failure.json b/src/ocpp/conformance/fixtures/diagnostics-failure.json
new file mode 100644
index 0000000..a4649af
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/diagnostics-failure.json
@@ -0,0 +1,104 @@
+{
+  "traceId": "scenario-diagnostics-failure",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-010",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "Station reports a diagnostics failure via DiagnosticsStatusNotification with status DiagnosisFailed."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T06:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-010",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T06:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 0,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:07:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-1",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:07:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-1",
+        {
+          "currentTime": "2024-01-15T06:07:30.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:12:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "DiagnosticsStatusNotification",
+        {
+          "status": "DiagnosisFailed"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:12:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {}
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/failed-auth.json b/src/ocpp/conformance/fixtures/failed-auth.json
new file mode 100644
index 0000000..3ca2add
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/failed-auth.json
@@ -0,0 +1,184 @@
+{
+  "traceId": "fixture-failed-auth",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-002",
+    "ocppVersion": "1.6",
+    "source": "synthetic-fixture",
+    "description": "Failed authorization: station boots, connector prepares, idTag is rejected by CSMS. StartTransaction is not attempted. Expects FAILED_AUTHORIZATION failure."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T11:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-002",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T11:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 0,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Preparing",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:15.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-INVALID"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:15.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {
+          "idTagInfo": {
+            "status": "Invalid"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:20.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-005",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-INVALID"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:20.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-005",
+        {
+          "idTagInfo": {
+            "status": "Invalid"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-006",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-INVALID"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-006",
+        {
+          "idTagInfo": {
+            "status": "Invalid"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:40.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-007",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Faulted",
+          "errorCode": "OtherError",
+          "info": "Authorization failed after 3 attempts"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T11:02:40.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-007",
+        {}
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/heartbeat-irregular.json b/src/ocpp/conformance/fixtures/heartbeat-irregular.json
new file mode 100644
index 0000000..3dc952f
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/heartbeat-irregular.json
@@ -0,0 +1,102 @@
+{
+  "traceId": "scenario-heartbeat-irregular",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-014",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "Heartbeats sent at irregular intervals — 300s expected, 600s gap observed."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T12:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-014",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T12:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:05:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-1",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:05:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-1",
+        {
+          "currentTime": "2024-01-15T12:05:00.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:15:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-2",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:15:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-2",
+        {
+          "currentTime": "2024-01-15T12:15:00.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:25:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-3",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T12:25:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-3",
+        {
+          "currentTime": "2024-01-15T12:25:00.500Z"
+        }
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/invalid-stop-reason.json b/src/ocpp/conformance/fixtures/invalid-stop-reason.json
new file mode 100644
index 0000000..0129e2e
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/invalid-stop-reason.json
@@ -0,0 +1,247 @@
+{
+  "traceId": "scenario-invalid-stop-reason",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-007",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "StopTransaction with reason \"PowerSurge\" — not a valid OCPP 1.6 stop reason code."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T20:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-007",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T20:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 0,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:02:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-007"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:02:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {
+          "idTagInfo": {
+            "status": "Accepted",
+            "expiryDate": "2024-12-31T23:59:59.000Z"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:02:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "StartTransaction",
+        {
+          "connectorId": 1,
+          "idTag": "SYNTHETIC-TAG-007",
+          "meterStart": 0,
+          "timestamp": "2024-01-15T20:02:30.000Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:02:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {
+          "transactionId": 100007,
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:02:31.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-005",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Charging",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:02:31.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-005",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:07:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-1",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:07:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-1",
+        {
+          "currentTime": "2024-01-15T20:07:30.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:15:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-006",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100007,
+          "meterValue": [
+            {
+              "timestamp": "2024-01-15T20:15:00.000Z",
+              "sampledValue": [
+                {
+                  "value": "5000",
+                  "measurand": "Energy.Active.Import.Register",
+                  "unit": "Wh"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:15:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-006",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:30:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-007",
+        "StopTransaction",
+        {
+          "transactionId": 100007,
+          "idTag": "SYNTHETIC-TAG-007",
+          "meterStop": 5000,
+          "timestamp": "2024-01-15T20:30:00.000Z",
+          "reason": "PowerSurge"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:30:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-007",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:30:01.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-008",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T20:30:01.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-008",
+        {}
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/meter-anomaly.json b/src/ocpp/conformance/fixtures/meter-anomaly.json
new file mode 100644
index 0000000..146f18a
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/meter-anomaly.json
@@ -0,0 +1,203 @@
+{
+  "traceId": "scenario-meter-anomaly",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-012",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "Meter reading decreases from 5000 to 3000 during charging — non-monotonic anomaly."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T14:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-012",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T14:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-012"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:02:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "StartTransaction",
+        {
+          "connectorId": 1,
+          "idTag": "SYNTHETIC-TAG-012",
+          "meterStart": 0
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:02:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          },
+          "transactionId": 100012
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:05:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100012,
+          "meterValue": [
+            {
+              "sampledValue": [
+                {
+                  "value": "5000"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:05:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:06:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-005",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100012,
+          "meterValue": [
+            {
+              "sampledValue": [
+                {
+                  "value": "3000"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:06:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-005",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:10:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-006",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:10:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-006",
+        {
+          "currentTime": "2024-01-15T14:10:00.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:30:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-007",
+        "StopTransaction",
+        {
+          "transactionId": 100012,
+          "idTag": "SYNTHETIC-TAG-012",
+          "meterStop": 3000,
+          "reason": "EVDisconnected"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:30:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-007",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/meter-value-gap.json b/src/ocpp/conformance/fixtures/meter-value-gap.json
new file mode 100644
index 0000000..64bded6
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/meter-value-gap.json
@@ -0,0 +1,213 @@
+{
+  "traceId": "scenario-meter-value-gap",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-006",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "Transaction completes without any MeterValues — metering data is missing."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T18:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-006",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T18:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 0,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:02:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-006"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:02:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {
+          "idTagInfo": {
+            "status": "Accepted",
+            "expiryDate": "2024-12-31T23:59:59.000Z"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:02:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "StartTransaction",
+        {
+          "connectorId": 1,
+          "idTag": "SYNTHETIC-TAG-006",
+          "meterStart": 0,
+          "timestamp": "2024-01-15T18:02:30.000Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:02:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {
+          "transactionId": 100006,
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:02:31.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-005",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Charging",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:02:31.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-005",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:07:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-1",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:07:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-1",
+        {
+          "currentTime": "2024-01-15T18:07:30.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:30:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-006",
+        "StopTransaction",
+        {
+          "transactionId": 100006,
+          "idTag": "SYNTHETIC-TAG-006",
+          "meterStop": 0,
+          "timestamp": "2024-01-15T18:30:00.000Z",
+          "reason": "EVDisconnected"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:30:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-006",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:30:01.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-007",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T18:30:01.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-007",
+        {}
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/normal-session.json b/src/ocpp/conformance/fixtures/normal-session.json
new file mode 100644
index 0000000..f28edd6
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/normal-session.json
@@ -0,0 +1,305 @@
+{
+  "traceId": "fixture-normal-session",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-001",
+    "ocppVersion": "1.6",
+    "source": "synthetic-fixture",
+    "description": "Normal charging session: boot → authorize → start transaction → meter values → stop transaction. No failures expected."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T10:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-001",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T10:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 0,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:02:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Preparing",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:02:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:02:15.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-001"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:02:15.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {
+          "idTagInfo": {
+            "status": "Accepted",
+            "expiryDate": "2024-12-31T23:59:59.000Z",
+            "parentIdTag": "SYNTHETIC-PARENT-001"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:02:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-005",
+        "StartTransaction",
+        {
+          "connectorId": 1,
+          "idTag": "SYNTHETIC-TAG-001",
+          "meterStart": 0,
+          "timestamp": "2024-01-15T10:02:30.000Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:02:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-005",
+        {
+          "transactionId": 100001,
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:02:31.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-006",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Charging",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:02:31.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-006",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:07:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-1",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:07:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-1",
+        {
+          "currentTime": "2024-01-15T10:07:30.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:15:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-007",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100001,
+          "meterValue": [
+            {
+              "timestamp": "2024-01-15T10:15:00.000Z",
+              "sampledValue": [
+                {
+                  "value": "5000",
+                  "measurand": "Energy.Active.Import.Register",
+                  "unit": "Wh"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:15:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-007",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:30:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-008",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100001,
+          "meterValue": [
+            {
+              "timestamp": "2024-01-15T10:30:00.000Z",
+              "sampledValue": [
+                {
+                  "value": "10000",
+                  "measurand": "Energy.Active.Import.Register",
+                  "unit": "Wh"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:30:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-008",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:35:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-009",
+        "StopTransaction",
+        {
+          "transactionId": 100001,
+          "idTag": "SYNTHETIC-TAG-001",
+          "meterStop": 10000,
+          "timestamp": "2024-01-15T10:35:00.000Z",
+          "reason": "EVDisconnected"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:35:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-009",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:35:01.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-010",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T10:35:01.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-010",
+        {}
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/short-session.json b/src/ocpp/conformance/fixtures/short-session.json
new file mode 100644
index 0000000..7ec2375
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/short-session.json
@@ -0,0 +1,172 @@
+{
+  "traceId": "scenario-short-session",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-013",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "Transaction starts and stops within 10 seconds — suspiciously short."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T09:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-013",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T09:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:01.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-013"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:01.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:02.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "StartTransaction",
+        {
+          "connectorId": 1,
+          "idTag": "SYNTHETIC-TAG-013",
+          "meterStart": 0
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:02.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          },
+          "transactionId": 100013
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:03.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100013,
+          "meterValue": [
+            {
+              "sampledValue": [
+                {
+                  "value": "100"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:03.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:04.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-005",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:04.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-005",
+        {
+          "currentTime": "2024-01-15T09:00:04.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:10.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-006",
+        "StopTransaction",
+        {
+          "transactionId": 100013,
+          "idTag": "SYNTHETIC-TAG-013",
+          "meterStop": 100,
+          "reason": "EVDisconnected"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T09:00:10.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-006",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/slow-csms-response.json b/src/ocpp/conformance/fixtures/slow-csms-response.json
new file mode 100644
index 0000000..dafdda1
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/slow-csms-response.json
@@ -0,0 +1,60 @@
+{
+  "traceId": "scenario-slow-csms-response",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-011",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "CSMS responds slowly to BootNotification — 15s response gap."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T06:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-011",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:00:15.000Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T06:00:15.000Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:00:16.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T06:00:16.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {
+          "currentTime": "2024-01-15T06:00:16.500Z"
+        }
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/station-offline.json b/src/ocpp/conformance/fixtures/station-offline.json
new file mode 100644
index 0000000..923b193
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/station-offline.json
@@ -0,0 +1,195 @@
+{
+  "traceId": "scenario-station-offline",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-004",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "Station offline during active session — StartTransaction with no StopTransaction."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T14:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-004",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T14:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 0,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:02:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-004"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:02:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {
+          "idTagInfo": {
+            "status": "Accepted",
+            "expiryDate": "2024-12-31T23:59:59.000Z"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:02:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "StartTransaction",
+        {
+          "connectorId": 1,
+          "idTag": "SYNTHETIC-TAG-004",
+          "meterStart": 0,
+          "timestamp": "2024-01-15T14:02:30.000Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:02:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {
+          "transactionId": 100004,
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:02:31.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-005",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Charging",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:02:31.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-005",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:07:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-1",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:07:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-1",
+        {
+          "currentTime": "2024-01-15T14:07:30.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:15:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-006",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100004,
+          "meterValue": [
+            {
+              "timestamp": "2024-01-15T14:15:00.000Z",
+              "sampledValue": [
+                {
+                  "value": "2000",
+                  "measurand": "Energy.Active.Import.Register",
+                  "unit": "Wh"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T14:15:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-006",
+        {}
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/status-transition-violation.json b/src/ocpp/conformance/fixtures/status-transition-violation.json
new file mode 100644
index 0000000..c301735
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/status-transition-violation.json
@@ -0,0 +1,129 @@
+{
+  "traceId": "scenario-status-transition-violation",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-009",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "Connector status jumps from Available to Finishing without going through Preparing/Charging — invalid OCPP 1.6 transition."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T08:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-009",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T08:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 0,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:02:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:02:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:07:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-1",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:07:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-1",
+        {
+          "currentTime": "2024-01-15T08:07:30.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:12:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Finishing",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:12:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {}
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/unexpected-start.json b/src/ocpp/conformance/fixtures/unexpected-start.json
new file mode 100644
index 0000000..59c0e5e
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/unexpected-start.json
@@ -0,0 +1,126 @@
+{
+  "traceId": "scenario-unexpected-start",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-008",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "Station sends StartTransaction without BootNotification or Authorize — transaction started without proper initialization."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T22:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "StartTransaction",
+        {
+          "connectorId": 1,
+          "idTag": "SYNTHETIC-TAG-008",
+          "meterStart": 0,
+          "timestamp": "2024-01-15T22:00:00.000Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T22:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "transactionId": 100008,
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T22:00:01.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Charging",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T22:00:01.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T22:00:10.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100008,
+          "meterValue": [
+            {
+              "timestamp": "2024-01-15T22:00:10.000Z",
+              "sampledValue": [
+                {
+                  "value": "100",
+                  "measurand": "Energy.Active.Import.Register",
+                  "unit": "Wh"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T22:00:10.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T22:01:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "StopTransaction",
+        {
+          "transactionId": 100008,
+          "idTag": "SYNTHETIC-TAG-008",
+          "meterStop": 100,
+          "timestamp": "2024-01-15T22:01:30.000Z",
+          "reason": "EVDisconnected"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T22:01:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/unexpected-stop-reason.json b/src/ocpp/conformance/fixtures/unexpected-stop-reason.json
new file mode 100644
index 0000000..b953363
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/unexpected-stop-reason.json
@@ -0,0 +1,247 @@
+{
+  "traceId": "scenario-unexpected-stop-reason",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-005",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "Stop transaction with unexpected stop reason — parser/timeline validation only."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T16:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-005",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:00:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-001",
+        {
+          "currentTime": "2024-01-15T16:00:00.500Z",
+          "interval": 300,
+          "status": "Accepted"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:01:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "StatusNotification",
+        {
+          "connectorId": 0,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:01:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:02:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-003",
+        "Authorize",
+        {
+          "idTag": "SYNTHETIC-TAG-005"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:02:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-003",
+        {
+          "idTagInfo": {
+            "status": "Accepted",
+            "expiryDate": "2024-12-31T23:59:59.000Z"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:02:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-004",
+        "StartTransaction",
+        {
+          "connectorId": 1,
+          "idTag": "SYNTHETIC-TAG-005",
+          "meterStart": 0,
+          "timestamp": "2024-01-15T16:02:30.000Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:02:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-004",
+        {
+          "transactionId": 100005,
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:02:31.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-005",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Charging",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:02:31.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-005",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:07:30.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-hb-1",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:07:30.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-hb-1",
+        {
+          "currentTime": "2024-01-15T16:07:30.500Z"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:20:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-006",
+        "MeterValues",
+        {
+          "connectorId": 1,
+          "transactionId": 100005,
+          "meterValue": [
+            {
+              "timestamp": "2024-01-15T16:20:00.000Z",
+              "sampledValue": [
+                {
+                  "value": "4000",
+                  "measurand": "Energy.Active.Import.Register",
+                  "unit": "Wh"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:20:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-006",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:25:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-007",
+        "StopTransaction",
+        {
+          "transactionId": 100005,
+          "idTag": "SYNTHETIC-TAG-005",
+          "meterStop": 4000,
+          "timestamp": "2024-01-15T16:25:00.000Z",
+          "reason": "Other"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:25:00.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-007",
+        {
+          "idTagInfo": {
+            "status": "Accepted"
+          }
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:25:01.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-008",
+        "StatusNotification",
+        {
+          "connectorId": 1,
+          "status": "Available",
+          "errorCode": "NoError"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T16:25:01.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-008",
+        {}
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/fixtures/unresponsive-csms.json b/src/ocpp/conformance/fixtures/unresponsive-csms.json
new file mode 100644
index 0000000..3e34923
--- /dev/null
+++ b/src/ocpp/conformance/fixtures/unresponsive-csms.json
@@ -0,0 +1,47 @@
+{
+  "traceId": "scenario-unresponsive-csms",
+  "metadata": {
+    "stationId": "CS-SYNTHETIC-015",
+    "ocppVersion": "1.6",
+    "source": "synthetic-scenario",
+    "description": "CSMS never responds to BootNotification — unresponsive CSMS."
+  },
+  "events": [
+    {
+      "timestamp": "2024-01-15T08:00:00.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-001",
+        "BootNotification",
+        {
+          "chargePointVendor": "SyntheticVendor",
+          "chargePointModel": "SM-100",
+          "chargePointSerialNumber": "CS-SYNTHETIC-015",
+          "firmwareVersion": "1.0.0"
+        }
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:00:05.000Z",
+      "direction": "CS_TO_CSMS",
+      "message": [
+        2,
+        "msg-002",
+        "Heartbeat",
+        {}
+      ]
+    },
+    {
+      "timestamp": "2024-01-15T08:00:05.500Z",
+      "direction": "CSMS_TO_CS",
+      "message": [
+        3,
+        "msg-002",
+        {
+          "currentTime": "2024-01-15T08:00:05.500Z"
+        }
+      ]
+    }
+  ]
+}
diff --git a/src/ocpp/conformance/goldens/connector-fault.json b/src/ocpp/conformance/goldens/connector-fault.json
new file mode 100644
index 0000000..0763085
--- /dev/null
+++ b/src/ocpp/conformance/goldens/connector-fault.json
@@ -0,0 +1 @@
+["CONNECTOR_FAULT"]
diff --git a/src/ocpp/conformance/goldens/diagnostics-failure.json b/src/ocpp/conformance/goldens/diagnostics-failure.json
new file mode 100644
index 0000000..e062642
--- /dev/null
+++ b/src/ocpp/conformance/goldens/diagnostics-failure.json
@@ -0,0 +1 @@
+["DIAGNOSTICS_FAILURE"]
diff --git a/src/ocpp/conformance/goldens/failed-auth.json b/src/ocpp/conformance/goldens/failed-auth.json
new file mode 100644
index 0000000..50b085c
--- /dev/null
+++ b/src/ocpp/conformance/goldens/failed-auth.json
@@ -0,0 +1 @@
+["FAILED_AUTHORIZATION"]
diff --git a/src/ocpp/conformance/goldens/heartbeat-irregular.json b/src/ocpp/conformance/goldens/heartbeat-irregular.json
new file mode 100644
index 0000000..8908b7f
--- /dev/null
+++ b/src/ocpp/conformance/goldens/heartbeat-irregular.json
@@ -0,0 +1 @@
+["HEARTBEAT_INTERVAL_VIOLATION"]
diff --git a/src/ocpp/conformance/goldens/invalid-stop-reason.json b/src/ocpp/conformance/goldens/invalid-stop-reason.json
new file mode 100644
index 0000000..67c3fac
--- /dev/null
+++ b/src/ocpp/conformance/goldens/invalid-stop-reason.json
@@ -0,0 +1 @@
+["INVALID_STOP_REASON"]
diff --git a/src/ocpp/conformance/goldens/meter-anomaly.json b/src/ocpp/conformance/goldens/meter-anomaly.json
new file mode 100644
index 0000000..d95f1c1
--- /dev/null
+++ b/src/ocpp/conformance/goldens/meter-anomaly.json
@@ -0,0 +1 @@
+["METER_VALUE_ANOMALY"]
diff --git a/src/ocpp/conformance/goldens/meter-value-gap.json b/src/ocpp/conformance/goldens/meter-value-gap.json
new file mode 100644
index 0000000..29a3646
--- /dev/null
+++ b/src/ocpp/conformance/goldens/meter-value-gap.json
@@ -0,0 +1 @@
+["METER_VALUE_GAP"]
diff --git a/src/ocpp/conformance/goldens/normal-session.json b/src/ocpp/conformance/goldens/normal-session.json
new file mode 100644
index 0000000..fe51488
--- /dev/null
+++ b/src/ocpp/conformance/goldens/normal-session.json
@@ -0,0 +1 @@
+[]
diff --git a/src/ocpp/conformance/goldens/short-session.json b/src/ocpp/conformance/goldens/short-session.json
new file mode 100644
index 0000000..419a57e
--- /dev/null
+++ b/src/ocpp/conformance/goldens/short-session.json
@@ -0,0 +1 @@
+["SUSPICIOUS_SESSION_DURATION"]
diff --git a/src/ocpp/conformance/goldens/slow-csms-response.json b/src/ocpp/conformance/goldens/slow-csms-response.json
new file mode 100644
index 0000000..81f4181
--- /dev/null
+++ b/src/ocpp/conformance/goldens/slow-csms-response.json
@@ -0,0 +1 @@
+["SLOW_RESPONSE"]
diff --git a/src/ocpp/conformance/goldens/station-offline.json b/src/ocpp/conformance/goldens/station-offline.json
new file mode 100644
index 0000000..35efa2d
--- /dev/null
+++ b/src/ocpp/conformance/goldens/station-offline.json
@@ -0,0 +1 @@
+["STATION_OFFLINE_DURING_SESSION"]
diff --git a/src/ocpp/conformance/goldens/status-transition-violation.json b/src/ocpp/conformance/goldens/status-transition-violation.json
new file mode 100644
index 0000000..c1ffad5
--- /dev/null
+++ b/src/ocpp/conformance/goldens/status-transition-violation.json
@@ -0,0 +1 @@
+["STATUS_TRANSITION_VIOLATION"]
diff --git a/src/ocpp/conformance/goldens/unexpected-start.json b/src/ocpp/conformance/goldens/unexpected-start.json
new file mode 100644
index 0000000..23771a5
--- /dev/null
+++ b/src/ocpp/conformance/goldens/unexpected-start.json
@@ -0,0 +1 @@
+["UNEXPECTED_START"]
diff --git a/src/ocpp/conformance/goldens/unexpected-stop-reason.json b/src/ocpp/conformance/goldens/unexpected-stop-reason.json
new file mode 100644
index 0000000..fe51488
--- /dev/null
+++ b/src/ocpp/conformance/goldens/unexpected-stop-reason.json
@@ -0,0 +1 @@
+[]
diff --git a/src/ocpp/conformance/goldens/unresponsive-csms.json b/src/ocpp/conformance/goldens/unresponsive-csms.json
new file mode 100644
index 0000000..ab6935f
--- /dev/null
+++ b/src/ocpp/conformance/goldens/unresponsive-csms.json
@@ -0,0 +1 @@
+["UNRESPONSIVE_CSMS"]
diff --git a/src/ocpp/conformance/harness.zig b/src/ocpp/conformance/harness.zig
new file mode 100644
index 0000000..9e0b667
--- /dev/null
+++ b/src/ocpp/conformance/harness.zig
@@ -0,0 +1,104 @@
+//! Conformance harness — pins Studio's detection to the toolkit's.
+//!
+//! For each of the 15 shared scenarios, the vendored **trace** runs through the
+//! full engine (`parseTrace → buildSessionTimeline → detectFailures`) and its
+//! de-duplicated, sorted `FailureCode` set is compared to the locked **golden**
+//! — the same comparison semantics as the toolkit's `evaluateScenario`.
+//!
+//! Fixtures and goldens under `fixtures/` and `goldens/` are generated from the
+//! toolkit (the source of truth), tagged `contract-v1`; they are not authored by
+//! hand. See `README.md` in this directory. This layout lives under `src/` so the
+//! zero-config build can `@embedFile` it (ADR-0004).
+
+const std = @import("std");
+const parser = @import("../parser.zig");
+const timeline = @import("../timeline.zig");
+const detection = @import("../detection.zig");
+
+/// The 15 shared scenarios (the toolkit's `scenarioNames`).
+const scenario_names = [_][]const u8{
+    "normal-session",
+    "failed-auth",
+    "connector-fault",
+    "station-offline",
+    "unexpected-stop-reason",
+    "meter-value-gap",
+    "invalid-stop-reason",
+    "unexpected-start",
+    "status-transition-violation",
+    "diagnostics-failure",
+    "slow-csms-response",
+    "meter-anomaly",
+    "short-session",
+    "heartbeat-irregular",
+    "unresponsive-csms",
+};
+
+test "conformance: detected failure codes match the locked goldens" {
+    var any_failed = false;
+    inline for (scenario_names) |name| {
+        runScenario(
+            name,
+            @embedFile("fixtures/" ++ name ++ ".json"),
+            @embedFile("goldens/" ++ name ++ ".json"),
+        ) catch {
+            any_failed = true;
+        };
+    }
+    try std.testing.expect(!any_failed);
+}
+
+fn runScenario(name: []const u8, trace_json: []const u8, golden_json: []const u8) !void {
+    var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
+    defer arena.deinit();
+    const a = arena.allocator();
+
+    // Full engine pipeline over the vendored trace.
+    const parsed = try parser.parseTrace(a, trace_json);
+    const sessions = try timeline.buildSessionTimeline(a, parsed.events);
+    const failures = try detection.detectFailures(a, parsed.events, sessions);
+
+    // De-duplicate + sort the detected failure codes (evaluateScenario semantics).
+    var seen = std.StringHashMap(void).init(a);
+    var detected: std.ArrayList([]const u8) = .empty;
+    for (failures) |f| {
+        const code = f.code.toWire();
+        const gop = try seen.getOrPut(code);
+        if (!gop.found_existing) try detected.append(a, code);
+    }
+    std.mem.sort([]const u8, detected.items, {}, lessStr);
+
+    // The golden is a sorted JSON array of wire codes; sort again defensively.
+    const golden = try std.json.parseFromSliceLeaky([][]const u8, a, golden_json, .{ .allocate = .alloc_always });
+    std.mem.sort([]const u8, golden, {}, lessStr);
+
+    if (!equalCodes(golden, detected.items)) {
+        std.debug.print("conformance mismatch [{s}]\n  expected: ", .{name});
+        printCodes(golden);
+        std.debug.print("\n  detected: ", .{});
+        printCodes(detected.items);
+        std.debug.print("\n", .{});
+        return error.ConformanceMismatch;
+    }
+}
+
+fn equalCodes(a: []const []const u8, b: []const []const u8) bool {
+    if (a.len != b.len) return false;
+    for (a, b) |x, y| {
+        if (!std.mem.eql(u8, x, y)) return false;
+    }
+    return true;
+}
+
+fn lessStr(_: void, a: []const u8, b: []const u8) bool {
+    return std.mem.order(u8, a, b) == .lt;
+}
+
+fn printCodes(codes: []const []const u8) void {
+    std.debug.print("[", .{});
+    for (codes, 0..) |c, i| {
+        if (i > 0) std.debug.print(", ", .{});
+        std.debug.print("{s}", .{c});
+    }
+    std.debug.print("]", .{});
+}
diff --git a/src/ocpp/ocpp.zig b/src/ocpp/ocpp.zig
index 37cf79b..5594399 100644
--- a/src/ocpp/ocpp.zig
+++ b/src/ocpp/ocpp.zig
@@ -16,4 +16,5 @@ test {
     _ = parser;
     _ = timeline;
     _ = detection;
+    _ = @import("conformance/harness.zig");
 }