diff --git a/apps/electron-backend-e2e/src/stalker-discovery.e2e.ts b/apps/electron-backend-e2e/src/stalker-discovery.e2e.ts
new file mode 100644
index 000000000..6caf03578
--- /dev/null
+++ b/apps/electron-backend-e2e/src/stalker-discovery.e2e.ts
@@ -0,0 +1,124 @@
+import {
+    closeElectronApp,
+    expect,
+    launchElectronApp,
+    test,
+} from './electron-test-fixtures';
+import {
+    StalkerReplayRun,
+    withStalkerReplayRun,
+} from './support/stalker-replay';
+
+test.describe('Electron Stalker endpoint discovery', () => {
+    test('@stalker @electron discovers a full session from a custom-prefix source without a learned endpoint', async ({
+        dataDir,
+    }) => {
+        const replay = await withStalkerReplayRun(
+            'resolver/custom-prefix-full',
+            async (run) => {
+                const app = await launchElectronApp(dataDir);
+
+                try {
+                    const ready = await app.mainWindow.evaluate(
+                        async ({ macAddress, sourceUrl }) => {
+                            const open = window.electron?.stalkerSessionOpen;
+                            if (!open) {
+                                throw new Error(
+                                    'stalker-session-open-unavailable'
+                                );
+                            }
+                            return open({
+                                descriptor: {
+                                    connectionMode: 'provisional',
+                                    macAddress,
+                                    playlistRef: 'e2e-custom-prefix-discovery',
+                                    profilePreset: {
+                                        id: 'mag250-public-5_1-minimal-v1',
+                                        version: 1,
+                                    },
+                                    provisionalReason: 'migration',
+                                    sourceUrl,
+                                },
+                            });
+                        },
+                        {
+                            macAddress: requiredInput(run, 'mac'),
+                            sourceUrl: run.entryUrl,
+                        }
+                    );
+
+                    expect(ready.kind, JSON.stringify(ready)).toBe('ready');
+                    expect(ready).toMatchObject({
+                        connectionMode: 'provisional',
+                        endpoint: `${requiredOrigin(
+                            run,
+                            'portal'
+                        )}/tenant/server/load.php`,
+                        kind: 'ready',
+                        recipe: 'full-session',
+                    });
+                    if (
+                        ready.kind !== 'ready' ||
+                        ready.connectionMode !== 'provisional'
+                    ) {
+                        throw new Error(
+                            `expected-provisional-ready:${JSON.stringify(ready)}`
+                        );
+                    }
+
+                    const committed = await app.mainWindow.evaluate(
+                        async (attemptRef) => {
+                            const control =
+                                window.electron?.stalkerSessionControl;
+                            if (!control) {
+                                throw new Error(
+                                    'stalker-session-control-unavailable'
+                                );
+                            }
+                            return control({
+                                action: 'commit',
+                                attemptRef,
+                            });
+                        },
+                        ready.attemptRef
+                    );
+                    expect(committed).toMatchObject({
+                        action: 'commit',
+                        kind: 'success',
+                    });
+                } finally {
+                    await closeElectronApp(app);
+                }
+            }
+        );
+
+        expect(replay.finalization).toMatchObject({
+            ledger: {
+                mismatchCounts: {},
+                operationCounts: {
+                    'custom-handshake': 1,
+                    'custom-landing': 1,
+                    'custom-profile': 1,
+                },
+                terminalState: 'complete',
+            },
+            ok: true,
+        });
+    });
+});
+
+function requiredInput(run: StalkerReplayRun, name: string): string {
+    const value = run.inputs[name];
+    if (!value) {
+        throw new Error(`stalker-replay-input-missing:${name}`);
+    }
+    return value;
+}
+
+function requiredOrigin(run: StalkerReplayRun, name: string): string {
+    const value = run.origins[name];
+    if (!value) {
+        throw new Error(`stalker-replay-origin-missing:${name}`);
+    }
+    return value;
+}
diff --git a/apps/stalker-mock-server/fixtures/replay/resolver/custom-prefix-full.json b/apps/stalker-mock-server/fixtures/replay/resolver/custom-prefix-full.json
new file mode 100644
index 000000000..bbeed993f
--- /dev/null
+++ b/apps/stalker-mock-server/fixtures/replay/resolver/custom-prefix-full.json
@@ -0,0 +1,244 @@
+{
+    "description": "Synthetic /tenant/c/ source discovers and authenticates its sibling custom-prefix full-session endpoint without a learned hint.",
+    "entry": {
+        "origin": "portal",
+        "path": "/tenant/c/"
+    },
+    "expectedEndpoint": {
+        "origin": "portal",
+        "path": "/tenant/server/load.php"
+    },
+    "failOnUnexpectedRequest": true,
+    "initialState": "start",
+    "origins": {
+        "portal": {}
+    },
+    "phases": [
+        {
+            "expectations": [
+                {
+                    "cardinality": {
+                        "max": 1,
+                        "min": 1
+                    },
+                    "id": "custom-landing",
+                    "method": "GET",
+                    "operation": "custom-landing",
+                    "origin": "portal",
+                    "path": "/tenant/c/",
+                    "request": {
+                        "body": {
+                            "kind": "absent"
+                        },
+                        "cookies": {
+                            "absent": [
+                                "mac",
+                                "session"
+                            ],
+                            "attributes": {},
+                            "exact": {},
+                            "present": []
+                        },
+                        "headers": {
+                            "absent": [
+                                "authorization",
+                                "cookie"
+                            ],
+                            "exact": {},
+                            "present": []
+                        },
+                        "query": {
+                            "absent": [
+                                "device_id",
+                                "device_id2",
+                                "mac",
+                                "password",
+                                "signature",
+                                "signature2",
+                                "sn",
+                                "token",
+                                "username"
+                            ],
+                            "exact": {},
+                            "present": []
+                        }
+                    },
+                    "response": {
+                        "body": {
+                            "kind": "empty"
+                        },
+                        "headers": {},
+                        "status": 204
+                    }
+                }
+            ],
+            "mode": "ordered",
+            "name": "custom-landing",
+            "nextState": "full-session",
+            "state": "start"
+        },
+        {
+            "expectations": [
+                {
+                    "cardinality": {
+                        "max": 1,
+                        "min": 1
+                    },
+                    "id": "custom-handshake",
+                    "method": "GET",
+                    "operation": "custom-handshake",
+                    "origin": "portal",
+                    "path": "/tenant/server/load.php",
+                    "request": {
+                        "body": {
+                            "kind": "absent"
+                        },
+                        "cookies": {
+                            "absent": [
+                                "session"
+                            ],
+                            "attributes": {},
+                            "exact": {
+                                "mac": {
+                                    "kind": "ref",
+                                    "symbol": "mac"
+                                }
+                            },
+                            "present": []
+                        },
+                        "headers": {
+                            "absent": [
+                                "authorization"
+                            ],
+                            "exact": {},
+                            "present": []
+                        },
+                        "query": {
+                            "absent": [
+                                "password",
+                                "token",
+                                "username"
+                            ],
+                            "exact": {
+                                "action": "handshake",
+                                "type": "stb"
+                            },
+                            "present": []
+                        }
+                    },
+                    "response": {
+                        "body": {
+                            "kind": "json",
+                            "value": {
+                                "js": {
+                                    "token": {
+                                        "kind": "generate",
+                                        "symbol": "custom-token",
+                                        "valueKind": "token"
+                                    }
+                                }
+                            }
+                        },
+                        "headers": {
+                            "content-type": [
+                                "application/json"
+                            ]
+                        },
+                        "status": 200
+                    }
+                },
+                {
+                    "cardinality": {
+                        "max": 1,
+                        "min": 1
+                    },
+                    "id": "custom-profile",
+                    "method": "GET",
+                    "operation": "custom-profile",
+                    "origin": "portal",
+                    "path": "/tenant/server/load.php",
+                    "request": {
+                        "body": {
+                            "kind": "absent"
+                        },
+                        "cookies": {
+                            "absent": [
+                                "session"
+                            ],
+                            "attributes": {},
+                            "exact": {
+                                "mac": {
+                                    "kind": "ref",
+                                    "symbol": "mac"
+                                }
+                            },
+                            "present": []
+                        },
+                        "headers": {
+                            "absent": [],
+                            "exact": {
+                                "authorization": {
+                                    "kind": "parts",
+                                    "parts": [
+                                        {
+                                            "kind": "literal",
+                                            "value": "Bearer "
+                                        },
+                                        {
+                                            "kind": "ref",
+                                            "symbol": "custom-token"
+                                        }
+                                    ]
+                                }
+                            },
+                            "present": []
+                        },
+                        "query": {
+                            "absent": [
+                                "password",
+                                "username"
+                            ],
+                            "exact": {
+                                "action": "get_profile",
+                                "auth_second_step": "0",
+                                "type": "stb"
+                            },
+                            "present": []
+                        }
+                    },
+                    "response": {
+                        "body": {
+                            "kind": "json",
+                            "value": {
+                                "js": {
+                                    "id": 1,
+                                    "status": 0
+                                }
+                            }
+                        },
+                        "headers": {
+                            "content-type": [
+                                "application/json"
+                            ]
+                        },
+                        "status": 200
+                    }
+                }
+            ],
+            "mode": "ordered",
+            "name": "full-session",
+            "nextState": "complete",
+            "state": "full-session"
+        }
+    ],
+    "scenarioId": "resolver-custom-prefix-full",
+    "schemaVersion": 1,
+    "symbols": [
+        {
+            "kind": "generate",
+            "symbol": "mac",
+            "valueKind": "mac"
+        }
+    ],
+    "terminalState": "complete"
+}
diff --git a/apps/stalker-mock-server/src/app/replay/replay-fixture-corpus.spec.ts b/apps/stalker-mock-server/src/app/replay/replay-fixture-corpus.spec.ts
index 7fd8c07ca..62a98a64a 100644
--- a/apps/stalker-mock-server/src/app/replay/replay-fixture-corpus.spec.ts
+++ b/apps/stalker-mock-server/src/app/replay/replay-fixture-corpus.spec.ts
@@ -47,6 +47,7 @@ const EXPECTED_SCENARIOS = [
     'redirect-repeated-loop',
     'refresh-concurrent-rejections',
     'refresh-exhausted-retry',
+    'resolver-custom-prefix-full',
     'resolver-direct-load-jsonp',
     'resolver-direct-portal-statusless',
     'resolver-learned-rediscovery',