diff --git a/Partner-Core/src/main/java/work/slhaf/partner/module/impression/ImpressionUpdatePlan.kt b/Partner-Core/src/main/java/work/slhaf/partner/module/impression/ImpressionUpdatePlan.kt
new file mode 100644
index 00000000..54acb5ea
--- /dev/null
+++ b/Partner-Core/src/main/java/work/slhaf/partner/module/impression/ImpressionUpdatePlan.kt
@@ -0,0 +1,66 @@
+package work.slhaf.partner.module.impression
+
+/**
+ * A conservative, auditable plan produced after message rolling.
+ *
+ * The updater should treat this model as intent only: validation decides whether
+ * a step is safe to execute, and the applier performs mutations through
+ * CognitionCapability / ImpressionCore so indexes stay consistent.
+ */
+data class ImpressionUpdatePlan @JvmOverloads constructor(
+    val steps: List<ImpressionUpdateStep>,
+    val status: PlanStatus = PlanStatus.PREPARED,
+    val reason: String? = null,
+)
+
+enum class PlanStatus {
+    PREPARED,
+    CONFIRMED,
+    REJECTED,
+}
+
+sealed class ImpressionUpdateStep
+
+data class UpdateExistingStep(
+    val entityUuid: String,
+    val updatePatch: UpdatePatch,
+) : ImpressionUpdateStep()
+
+
+data class CreateEntityStep(
+    val subject: String,
+    val impressions: List<ImpressionPatch> = emptyList(),
+    val features: List<FeaturePatch> = emptyList(),
+    val aliases: List<AliasPatch> = emptyList(),
+    val relations: List<RelationPatch> = emptyList(),
+) : ImpressionUpdateStep()
+
+sealed class UpdatePatch
+
+data class ImpressionPatch @JvmOverloads constructor(
+    val impression: String,
+    val newImpression: String? = null,
+    val confidence: Double = 1.0,
+) : UpdatePatch()
+
+data class FeaturePatch @JvmOverloads constructor(
+    val feature: String,
+    val newFeature: String? = null,
+    val confidence: Double = 1.0,
+) : UpdatePatch()
+
+data class AliasPatch @JvmOverloads constructor(
+    val alias: String,
+    val deprecated: Boolean = false,
+) : UpdatePatch()
+
+data class SubjectPatch @JvmOverloads constructor(
+    val subject: String,
+    val keepOldSubjectAsAlias: Boolean = true,
+) : UpdatePatch()
+
+data class RelationPatch @JvmOverloads constructor(
+    val target: String,
+    val relation: String,
+    val strength: Double = 1.0,
+) : UpdatePatch()