diff --git a/src/resources/extensions/sf/preferences-validation.ts b/src/resources/extensions/sf/preferences-validation.ts
index c7c4c253b..111eb105e 100644
--- a/src/resources/extensions/sf/preferences-validation.ts
+++ b/src/resources/extensions/sf/preferences-validation.ts
@@ -309,6 +309,79 @@ export function validatePreferences(preferences: SFPreferences): {
     }
   }
 
+  // ─── forensics_dedup ────────────────────────────────────────────────
+  if (preferences.forensics_dedup !== undefined) {
+    validated.forensics_dedup = !!preferences.forensics_dedup;
+  }
+
+  // ─── stale_commit_threshold_minutes ─────────────────────────────────
+  if (preferences.stale_commit_threshold_minutes !== undefined) {
+    const raw = Number(preferences.stale_commit_threshold_minutes);
+    if (Number.isFinite(raw) && raw >= 0) {
+      validated.stale_commit_threshold_minutes = Math.floor(raw);
+    } else {
+      errors.push("stale_commit_threshold_minutes must be a non-negative number (minutes; 0 = disabled)");
+    }
+  }
+
+  // ─── widget_mode ────────────────────────────────────────────────────
+  if (preferences.widget_mode !== undefined) {
+    const valid = new Set(["full", "small", "min", "off"]);
+    if (typeof preferences.widget_mode === "string" && valid.has(preferences.widget_mode)) {
+      validated.widget_mode = preferences.widget_mode as SFPreferences["widget_mode"];
+    } else {
+      errors.push("widget_mode must be one of: full, small, min, off");
+    }
+  }
+
+  // ─── slice_parallel ─────────────────────────────────────────────────
+  // Shallow validation: object-shape check + primitive field coercion.
+  // Deeper structural checks can come later; the goal here is to stop
+  // silently dropping the preference.
+  if (preferences.slice_parallel !== undefined) {
+    const sp = preferences.slice_parallel;
+    if (typeof sp === "object" && sp !== null && !Array.isArray(sp)) {
+      const v: SFPreferences["slice_parallel"] = {};
+      const anySp = sp as Record<string, unknown>;
+      if (anySp.enabled !== undefined) v.enabled = !!anySp.enabled;
+      if (anySp.max_workers !== undefined) {
+        const n = Number(anySp.max_workers);
+        if (Number.isFinite(n) && n >= 1) {
+          v.max_workers = Math.floor(n);
+        } else {
+          errors.push("slice_parallel.max_workers must be a positive integer");
+        }
+      }
+      validated.slice_parallel = v;
+    } else {
+      errors.push("slice_parallel must be an object");
+    }
+  }
+
+  // ─── modelOverrides ─────────────────────────────────────────────────
+  // Per-model capability overrides. Deep-merged into built-in profiles at
+  // consumer sites — here we just confirm the shape and pass through.
+  if (preferences.modelOverrides !== undefined) {
+    const mo = preferences.modelOverrides;
+    if (typeof mo === "object" && mo !== null && !Array.isArray(mo)) {
+      validated.modelOverrides = mo as SFPreferences["modelOverrides"];
+    } else {
+      errors.push("modelOverrides must be an object keyed by model ID");
+    }
+  }
+
+  // ─── safety_harness ─────────────────────────────────────────────────
+  // Rich nested config. Pass-through with an object-shape guard; field-level
+  // validation can land alongside the features that consume them.
+  if (preferences.safety_harness !== undefined) {
+    const sh = preferences.safety_harness;
+    if (typeof sh === "object" && sh !== null && !Array.isArray(sh)) {
+      validated.safety_harness = sh as SFPreferences["safety_harness"];
+    } else {
+      errors.push("safety_harness must be an object");
+    }
+  }
+
   // ─── Search Provider ─────────────────────────────────────────────
   if (preferences.search_provider !== undefined) {
     const validSearchProviders = new Set(["brave", "tavily", "ollama", "combosearch", "native", "auto"]);