diff --git a/docs/PresentationSubjectReplacement.md b/docs/PresentationSubjectReplacement.md
new file mode 100644
index 00000000..a9c10611
--- /dev/null
+++ b/docs/PresentationSubjectReplacement.md
@@ -0,0 +1,450 @@
+# Presentation Subject Replacement Semantics
+
+Status: implemented in Route Engine v1.46.0.
+
+## Decision Summary
+
+Presentation actions distinguish continuity from replacement by whether they
+explicitly author a render subject:
+
+- omitting a subject continues the current presentation instance
+- authoring only non-subject fields patches the current instance
+- explicitly authoring a subject creates or reapplies an instance from only the
+  fields in that action
+- subject equality is irrelevant; explicitly reauthoring the same resource or
+  content still resets every omitted instance field
+- explicitly authored fields on the replacement are applied normally
+
+This rule applies consistently to backgrounds, character items, and visual
+items.
+
+Replacement resets all omitted state owned by that background, character item,
+or visual item. This includes appearance, placement, layer, backing color,
+resource playback overrides, and animation selection. The subject and fields
+explicitly present in the replacement action are the complete new instance.
+
+This behavior does not reset other presentation channels or screen-level
+state, and it does not redefine the existing collection and removal rules for
+other item IDs.
+
+## Why
+
+An authored resource is an instruction to present an instance, not merely a
+statement about which asset ID happens to be current. Reauthoring the same
+resource can intentionally replay an entrance, restore its defaults, or start
+a new presentation of the asset.
+
+Comparing the next subject with the previous subject makes intent depend on
+value equality:
+
+```yaml
+# These would behave differently if equality controlled replacement.
+background:
+  resourceId: forest
+
+background:
+  resourceId: street
+```
+
+That is difficult to explain and prevents an author from reapplying `forest`
+as a fresh instance. Presence provides a simpler contract:
+
+> Omission means continuity. Explicit subject authoring means replacement.
+
+It also prevents state chosen for one instance from leaking accidentally onto
+the next instance. Brightness, contrast, saturation, blur, placement, layer,
+backing color, playback overrides, and animations can all be specific to one
+presentation of a subject.
+
+If a project needs settings across several subjects, it should author those
+settings on each replacement. A future whole-screen filter facility may
+provide a separate persistent scope for global scene grading; that facility is
+outside this change.
+
+## Authoring Contract
+
+Subject-bearing actions are complete declarations of the desired presentation
+instance. Authors and authoring tools must include every non-default setting
+the instance needs. An omitted optional field intentionally selects its normal
+default; it is not a request to recover that field from the previous instance.
+
+An intentional patch must omit the subject-bearing field. For example, a
+background action without `resourceId` may adjust the active background, while
+a background action with `resourceId` fully declares a new or reapplied
+background instance.
+
+The engine must not compensate for incomplete subject-bearing actions by
+merging previous state. That would make a syntactically complete action depend
+on execution history and recreate the ambiguity this contract removes.
+
+> **Deprecation note:** History-dependent subject-less continuation patches,
+> such as `background: { opacity: 0.8 }`, remain supported for compatibility in
+> v1.46.0 but are planned for removal in a future version. New content and
+> authoring tools should omit the channel when nothing changes, or emit the
+> complete subject-bearing action and every desired non-default field.
+
+## Terminology
+
+### Presentation instance
+
+The active background, character item, or visual item stored in presentation
+state.
+
+Character and visual item `id` values identify persistent item slots so later
+actions can find an existing item. Reusing an item ID does not by itself imply
+that any state from its previous instance must be inherited. The `id` remains
+on a replacement because the replacement action explicitly authors it as the
+item lookup key.
+
+### Subject
+
+The content rendered by a presentation instance:
+
+| Target                      | Subject-bearing authoring                                           |
+| --------------------------- | ------------------------------------------------------------------- |
+| Background                  | `resourceId`                                                        |
+| Character item              | a non-empty `sprites` array                                         |
+| Resource-backed visual item | `resourceId`                                                        |
+| Inline-layout visual item   | a complete `layout` value                                           |
+| Text visual item            | a complete `text` value containing both `content` and `textStyleId` |
+
+A partial text patch containing only `content` or only `textStyleId` is not a
+complete subject. It continues the existing text visual and therefore
+preserves other omitted instance fields.
+
+Changing a visual between `resourceId`, `layout`, and `text` forms is always a
+subject replacement.
+
+### Instance-owned state
+
+All fields stored on the active target belong to its presentation instance:
+
+| Target         | Instance-owned state                                                                                                                   |
+| -------------- | -------------------------------------------------------------------------------------------------------------------------------------- |
+| Background     | `resourceId`, `colorId`, transform fields, `alpha`/`opacity`, `blur`, `filters`, resource playback overrides, and `animations`         |
+| Character item | `id`, `sprites`, transform fields, `alpha`/`opacity`, `blur`, `filters`, and `animations`                                              |
+| Visual item    | `id`, its subject form, transform fields, `layer`, `alpha`/`opacity`, `blur`, `filters`, resource playback overrides, and `animations` |
+
+On replacement, Route Engine retains none of these fields from the previous
+instance. Fields explicitly authored beside the new subject form the new
+instance. Defaults for omitted fields are resolved through the existing
+resource and renderer defaults.
+
+Route Engine does not model brightness, contrast, or saturation as dedicated
+action fields. Those values are renderer shader-filter parameters and reset
+with the containing `filters` array.
+
+## Normative Rules
+
+For each target, Route Engine determines whether the current action explicitly
+authors a subject. It must not compare that subject with the previous subject.
+
+Conceptually:
+
+```text
+if action explicitly authors a subject:
+    next instance = normalized explicitly authored action only
+else:
+    next instance = previous instance patched by authored fields
+```
+
+### Omitted action
+
+When a line omits a presentation channel entirely, the existing channel state
+continues according to its current persistence rules.
+
+```yaml
+- background:
+    resourceId: forest
+    blur: { x: 6, y: 6 }
+- dialogue:
+    mode: adv
+    content:
+      - text: The forest remains blurred.
+```
+
+### Continuation patch
+
+An action without a subject patches the current instance. All omitted instance
+fields are inherited according to the existing patch rules. This is legacy
+compatibility behavior covered by the deprecation note in the authoring
+contract; new content should not rely on it.
+
+```yaml
+- background:
+    resourceId: forest
+    filters:
+      - id: grade
+        type: shader
+        parameters:
+          saturation: 0.5
+- background:
+    blur: { x: 3, y: 3 }
+```
+
+The second action keeps `forest` and its `filters`, then adds or replaces
+`blur`.
+
+### Subject replacement
+
+An explicit subject starts a fresh instance, whether the subject value is new
+or identical to the current value.
+
+```yaml
+- background:
+    resourceId: forest
+    alpha: 0.6
+    blur: { x: 6, y: 6 }
+- background:
+    resourceId: forest
+```
+
+The second action produces a background state containing only
+`resourceId: forest`. Alpha, blur, filters, transform, backing color, playback
+overrides, and animations all use their defaults because none were authored on
+the replacement.
+
+The same rule applies to a character composition:
+
+```yaml
+- character:
+    items:
+      - id: alice
+        transformId: center
+        sprites:
+          - id: body
+            resourceId: alice-happy
+            animationSpeed: 0.5
+        x: 900
+        blur: { x: 6, y: 6 }
+- character:
+    items:
+      - id: alice
+        transformId: center
+        sprites:
+          - id: body
+            resourceId: alice-happy
+```
+
+The second `alice` item contains only its explicitly authored `id`,
+`transformId`, and `sprites`. It does not inherit `x`, the sprite playback
+override, blur, filters, opacity, or animations even though its item ID and
+sprite resource are identical. Character `sprites` currently require an
+explicit `transformId`, so that authored placement remains on the replacement.
+
+It also applies to a resource-backed visual:
+
+```yaml
+- visual:
+    items:
+      - id: fog
+        resourceId: fog-heavy
+        transformId: fullscreen
+        layer: 70
+        animationSpeed: 0.5
+        filters:
+          - id: desaturate
+            type: shader
+- visual:
+    items:
+      - id: fog
+        resourceId: fog-heavy
+```
+
+The second `fog` item contains only `id` and `resourceId`. It does not inherit
+the transform, layer, resource playback override, filter, opacity, blur, or
+animations. Its layer and placement therefore resolve from their defaults.
+
+### Replacement with explicit state
+
+Explicit fields apply to the new instance:
+
+```yaml
+background:
+  resourceId: street
+  transformId: fullscreen
+  alpha: 0.8
+  filters:
+    - id: night-grade
+      type: shader
+```
+
+This produces `street` with the authored transform, alpha, and filter. Every
+other field uses its default.
+
+### Explicit clearing remains valid
+
+Existing clear forms remain useful for continuation patches:
+
+- `alpha: 1` resets alpha
+- `blur: null` clears blur
+- `filters: []` clears filters
+
+A subject replacement does not need to emit clear or default values merely to
+avoid inheritance. Absence on a replacement already means the field is absent
+from the new instance and its normal default applies.
+
+## Behavior Matrix
+
+| Authored action                           | Subject replacement | Inherit any omitted instance state |
+| ----------------------------------------- | ------------------: | ---------------------------------: |
+| Channel omitted                           |                  No |                                Yes |
+| Background patch without `resourceId`     |                  No |                                Yes |
+| Background with any defined `resourceId`  |                 Yes |                                 No |
+| Character item patch without `sprites`    |                  No |                                Yes |
+| Character item with non-empty `sprites`   |                 Yes |                                 No |
+| Visual item patch without a full subject  |                  No |                                Yes |
+| Visual item with any defined `resourceId` |                 Yes |                                 No |
+| Visual item with complete `layout`        |                 Yes |                                 No |
+| Visual item with complete `text`          |                 Yes |                                 No |
+| Visual item with partial `text` patch     |                  No |                                Yes |
+
+“Any defined `resourceId`” includes the same string already present in state.
+The engine checks authored presence, not equality.
+
+## Implemented Behavior
+
+The presentation-state reducer detects explicit subject authoring before it
+applies any previous-state merge or persistence helper. A subject replacement
+uses only the normalized fields in the current action. A continuation patch
+retains the existing field-specific patch and persistence behavior.
+
+As a result, this sequence does not transfer the first background's appearance
+to the second:
+
+```yaml
+- background:
+    resourceId: forest
+    blur: { x: 6, y: 6 }
+- background:
+    resourceId: street
+```
+
+The result is a new instance containing only `resourceId: street`.
+
+## Implementation Notes
+
+The implementation uses one shared concept of explicit subject authoring rather
+than resource-equality branches in each reducer.
+
+1. It detects background, character-item, and visual-item subject authoring using
+   the table above.
+2. For a subject replacement, it constructs the next instance solely from the
+   normalized authored action.
+3. It does not run previous-state merge, transform persistence, appearance
+   persistence, playback persistence, or persistent-animation restoration for
+   that instance.
+4. For a continuation patch, it retains the existing field-specific patch and
+   persistence behavior.
+5. It continues normalizing explicitly authored `alpha` to the internal legacy
+   `opacity` representation.
+6. The public action documentation and schema descriptions expose the same
+   contract.
+
+Renderer changes are unnecessary. The render state already consumes the
+resolved presentation state; the behavioral change belongs at the point where
+presentation actions are merged.
+
+There are no equality checks or inheritance flags. Authors who intentionally
+want state on a replacement state it explicitly.
+
+## Verification Coverage
+
+Both state transitions and rendered output are covered.
+
+### Targeted state coverage
+
+System and unit cases for background, character, and visual targets prove:
+
+1. an omitted channel preserves existing instance state
+2. a continuation patch preserves the subject and every unmentioned field
+3. reauthoring the same subject resets every omitted instance field
+4. authoring a different subject resets every omitted instance field
+5. replacement with explicit instance fields uses only the explicit values
+6. `blur: null` and `filters: []` still clear appearance on patches
+7. a partial visual-text patch preserves other instance state
+8. a complete visual-text or inline-layout subject resets other instance state
+9. screen state and unrelated item IDs are unaffected
+
+Each target must cover representative appearance, transform, playback, and
+animation fields. Visual coverage must also include `layer`, and background
+coverage must include `colorId`. At least one case per target must cover a
+filter with brightness, contrast, or saturation parameters so the test
+protects the entire opaque filter object, not only blur.
+
+### Render and VT coverage
+
+The actual visual path is validated with isolated background, character, and
+visual VT scenarios. Each scenario shows:
+
+1. a subject rendered with unmistakable non-default appearance and placement
+2. a continuation patch retaining the unmentioned instance state
+3. an explicit reassertion rendering with default appearance, placement, and
+   layer where applicable
+
+Keep the three targets isolated rather than combining them on one page. This
+makes a failure attributable to one state transition and follows the VT
+isolation requirements in `docs/vt-guidelines.md`.
+
+The implementation PR runs the targeted automated tests and compares the
+relevant VT screenshots before review.
+
+## Compatibility and Rollout
+
+This is an intentional behavior change. Existing projects may repeat a subject
+while relying on any inherited instance field, including transform, layer,
+backing color, playback, animation, opacity, blur, or filters. Those actions
+will render differently under these semantics.
+
+The affected persistence behavior is not limited to the latest release:
+
+| Existing behavior                                                     | Present since |
+| --------------------------------------------------------------------- | ------------- |
+| Background `colorId` persists across resource updates                 | v1.15.0       |
+| Background opacity and blur persist across updates                    | v1.16.0       |
+| Character and visual opacity and blur persist by item ID              | v1.19.0       |
+| Character and visual transform overrides persist by item ID           | v1.20.0       |
+| Inline background transform overrides persist                         | v1.22.0       |
+| Full text-visual updates preserve placement and appearance            | v1.23.0       |
+| Persistent character and visual animations survive compatible updates | v1.39.1       |
+| Background, character, and visual filters persist                     | v1.42.0       |
+
+Presentation subject merging is materially the same in v1.42.0, v1.43.0, and
+v1.45.0. A project upgrading from any of those recent versions can therefore
+observe this change.
+
+The break is silent rather than structural: existing YAML remains valid, but a
+subject-bearing action that relies on omitted instance fields renders
+differently. Actions that omit the subject for continuation, and replacements
+that explicitly author every required setting, are unaffected.
+
+The supported authoring contract expects complete subject-bearing actions, so
+the practical risk for conforming projects is low. The migration risk is
+concentrated in hand-authored content and older or third-party tools that used
+subject-bearing actions as partial patches.
+
+Route Engine has no project-level presentation-semantics version from which to
+select old versus new merging behavior. Under the complete-action authoring
+contract, the change ships as a feature release in Route Engine v1.46.0, with
+the migration risk for partial subject-bearing actions documented here.
+
+There is no universal authored clear form for every instance field, so having
+authoring tools emit `alpha: 1`, `blur: null`, and `filters: []` cannot fully
+reproduce fresh-instance behavior. A compatibility mode would first require a
+versioned project or engine option and is not included here.
+
+For an engine-level rollout, migration tooling should identify subject-bearing
+actions that omit instance fields after prior state was established for the
+same channel or item ID. Authors who intended inheritance can copy the intended
+fields onto the replacement action. Authors who intended a fresh instance need
+no additional fields after migration.
+
+## Out of Scope
+
+- changing screen-level opacity or blur persistence
+- adding screen-level shader filters
+- changing renderer or resource default values
+- changing continuation-patch inheritance
+- adding per-sprite-part character appearance
+- comparing previous and next resource values
+- changing item removal or array replacement behavior
diff --git a/docs/RouteEngine.md b/docs/RouteEngine.md
index 2d3dbd62..f21e6659 100644
--- a/docs/RouteEngine.md
+++ b/docs/RouteEngine.md
@@ -411,11 +411,15 @@ visual:
                 # WGSL source with mainVertex and mainFragment
 ```
 
-Action filters are persistent appearance. A filters-only action updates the
-existing target without repeating its resource, transform, or character sprite
-parts. Omission preserves the current filters; `filters: []` clears them. For a
-background with a renderable resource and a backing `colorId`, filters apply to
-the resource target. A color-only background applies filters to its color rect.
+Action filters are instance appearance. A filters-only continuation action
+updates the existing target without repeating its resource, transform, or
+character sprite parts. Omission on a continuation patch preserves the current
+filters; `filters: []` clears them. Explicitly reauthoring a background
+`resourceId`, a non-empty character `sprites` array, or a complete visual
+subject creates a fresh instance and resets omitted filters along with all other
+omitted instance state. For a background with a renderable resource and a
+backing `colorId`, filters apply to the resource target. A color-only background
+applies filters to its color rect.
 
 #### Layout Text Styles
 
@@ -1510,8 +1514,9 @@ transform fields remain supported as overrides for compatibility.
 
 #### Updating an inline layout
 
-Later lines can replace the inline layout by visual `id` while retaining its
-transform, layer, alpha, and blur. Inline transform patches merge by field:
+A complete inline `layout` reauthors the visual subject and creates a fresh
+instance. Include every non-default transform, layer, appearance, and animation
+field required by that instance:
 
 ```yaml
 visual:
@@ -1524,15 +1529,26 @@ visual:
             content: "Chapter 2"
             textStyleId: title
       transform:
+        x: 960
         y: 220
+        anchorX: 0.5
+        anchorY: 0.5
+        scaleX: 1
+        scaleY: 1
+        rotation: 0
+      layer: 70
 ```
 
-Appearance-only and animation-only updates do not need to repeat the layout:
+To patch the current inline-layout instance, omit `layout`. Inline transform
+patches then merge by field, and appearance-only or animation-only updates do
+not need to repeat the subject:
 
 ```yaml
 visual:
   items:
     - id: chapterTitle
+      transform:
+        y: 240
       alpha: 0.5
       animations:
         resourceId: titleFadeOut
@@ -1543,7 +1559,9 @@ visual:
 The existing `text` form remains supported for compatibility. New projects
 should prefer an inline layout so the visual can grow beyond one text element.
 For a new legacy text visual, both `text.content` and `text.textStyleId` are
-required; later patches can supply either field alone.
+required. A later action containing both fields reauthors the subject and
+creates a fresh instance; a partial text patch can supply either field alone
+and preserves the other instance fields.
 
 ```yaml
 visual:
@@ -1716,6 +1734,20 @@ sprite part is faded, blurred, or filtered together. Visual item appearance
 applies to the single visual item container, sprite, video, animated sprite,
 particle system, layout, or text element.
 
+Appearance persists when its presentation channel is omitted or when a later
+item action omits the subject. Explicitly authoring a background `resourceId`,
+a non-empty character `sprites` array, a visual `resourceId`, a complete visual
+`layout`, or complete visual `text` creates a fresh instance from that action
+alone. Omitted appearance, placement, layer, playback, and animation fields
+then use their defaults, even if the subject value is unchanged. See
+[Presentation Subject Replacement Semantics](PresentationSubjectReplacement.md)
+for the complete contract and migration notes.
+
+> **Deprecation note:** Subject-less continuation patches such as a background
+> action containing only `opacity` remain supported for compatibility in
+> v1.46.0, but support is planned for removal. New content should omit an
+> unchanged presentation channel or emit its complete subject-bearing action.
+
 ```yaml
 character:
   items:
diff --git a/package.json b/package.json
index 8c6f155f..03b58419 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "route-engine-js",
-  "version": "1.45.2",
+  "version": "1.46.0",
   "description": "A lightweight Visual Novel engine built in JavaScript for creating interactive narrative games with branching storylines",
   "repository": {
     "type": "git",
diff --git a/spec/constructPresentationState.subjectReplacement.test.js b/spec/constructPresentationState.subjectReplacement.test.js
new file mode 100644
index 00000000..3113c6e5
--- /dev/null
+++ b/spec/constructPresentationState.subjectReplacement.test.js
@@ -0,0 +1,328 @@
+import { describe, expect, it } from "vitest";
+import { constructPresentationState } from "../src/stores/constructPresentationState.js";
+
+const blur = {
+  x: 6,
+  y: 9,
+  quality: 3,
+  kernelSize: 9,
+  repeatEdgePixels: true,
+};
+
+const grade = {
+  id: "grade",
+  type: "shader",
+  parameters: {
+    brightness: 1.2,
+    contrast: 0.8,
+    saturation: 0.5,
+  },
+};
+
+const persistentAnimation = {
+  resourceId: "persistent-motion",
+  playback: {
+    continuity: "persistent",
+    loop: true,
+  },
+};
+
+const createBackground = () => ({
+  resourceId: "forest",
+  animationName: "idle",
+  animationSpeed: 0.5,
+  loop: false,
+  colorId: "backdrop",
+  transformId: "fullscreen",
+  x: 120,
+  y: 80,
+  anchorX: 0.5,
+  anchorY: 0.5,
+  scaleX: 1.2,
+  scaleY: 1.1,
+  rotation: 4,
+  originX: 960,
+  originY: 540,
+  opacity: 0.6,
+  blur,
+  filters: [grade],
+  animations: persistentAnimation,
+});
+
+const createCharacter = () => ({
+  id: "lead",
+  transformId: "center",
+  x: 120,
+  y: 980,
+  anchorX: 0.5,
+  anchorY: 1,
+  scaleX: 0.9,
+  scaleY: 0.9,
+  rotation: 4,
+  originX: 20,
+  originY: 40,
+  opacity: 0.6,
+  blur,
+  filters: [grade],
+  animations: persistentAnimation,
+  sprites: [
+    {
+      id: "body",
+      resourceId: "lead-body",
+      animationName: "idle",
+      animationSpeed: 0.5,
+      loop: false,
+    },
+  ],
+});
+
+const createVisual = () => ({
+  id: "fog",
+  resourceId: "fog-heavy",
+  animationName: "idle",
+  animationSpeed: 0.5,
+  transformId: "fullscreen",
+  x: 120,
+  y: 80,
+  anchorX: 0.5,
+  anchorY: 0.5,
+  scaleX: 1.2,
+  scaleY: 1.1,
+  rotation: 4,
+  originX: 20,
+  originY: 40,
+  layer: 70,
+  opacity: 0.6,
+  blur,
+  filters: [grade],
+  animations: persistentAnimation,
+});
+
+describe("presentation subject replacement", () => {
+  describe("background", () => {
+    it.each([
+      ["same", "forest"],
+      ["different", "street"],
+    ])(
+      "resets every omitted field when the %s resource is authored",
+      (_, resourceId) => {
+        const state = constructPresentationState([
+          {
+            screen: { opacity: 0.9 },
+            background: createBackground(),
+          },
+          { background: { resourceId } },
+        ]);
+
+        expect(state.background).toEqual({ resourceId });
+        expect(state.screen).toEqual({ opacity: 0.9 });
+      },
+    );
+
+    it("preserves omitted fields for a continuation patch", () => {
+      const initialBackground = createBackground();
+      const state = constructPresentationState([
+        { background: initialBackground },
+        { background: { blur: null } },
+      ]);
+
+      expect(state.background).toEqual({
+        ...initialBackground,
+        blur: null,
+      });
+    });
+
+    it("uses only fields explicitly authored on a replacement", () => {
+      const state = constructPresentationState([
+        { background: createBackground() },
+        {
+          background: {
+            resourceId: "street",
+            transformId: "street-fit",
+            alpha: 0.8,
+          },
+        },
+      ]);
+
+      expect(state.background).toEqual({
+        resourceId: "street",
+        transformId: "street-fit",
+        opacity: 0.8,
+      });
+    });
+  });
+
+  describe("character items", () => {
+    it.each([
+      ["same", "lead-body"],
+      ["different", "lead-alt"],
+    ])(
+      "resets every omitted field when the %s sprite composition is authored",
+      (_, resourceId) => {
+        const sprites = [{ id: "body", resourceId }];
+        const state = constructPresentationState([
+          { character: { items: [createCharacter()] } },
+          {
+            character: {
+              items: [{ id: "lead", transformId: "right", sprites }],
+            },
+          },
+        ]);
+
+        expect(state.character.items[0]).toEqual({
+          id: "lead",
+          transformId: "right",
+          sprites,
+        });
+      },
+    );
+
+    it("preserves the current composition and omitted fields for a continuation patch", () => {
+      const initialCharacter = createCharacter();
+      const state = constructPresentationState([
+        { character: { items: [initialCharacter] } },
+        {
+          character: {
+            items: [{ id: "lead", transformId: "right", opacity: 0.75 }],
+          },
+        },
+      ]);
+
+      expect(state.character.items[0]).toEqual({
+        ...initialCharacter,
+        transformId: "right",
+        opacity: 0.75,
+      });
+    });
+  });
+
+  describe("visual items", () => {
+    it.each([
+      ["same", "fog-heavy"],
+      ["different", "fog-light"],
+    ])(
+      "resets every omitted field when the %s resource is authored",
+      (_, resourceId) => {
+        const state = constructPresentationState([
+          { visual: { items: [createVisual()] } },
+          { visual: { items: [{ id: "fog", resourceId }] } },
+        ]);
+
+        expect(state.visual.items[0]).toEqual({ id: "fog", resourceId });
+      },
+    );
+
+    it("preserves omitted fields for a continuation patch", () => {
+      const initialVisual = createVisual();
+      const state = constructPresentationState([
+        { visual: { items: [initialVisual] } },
+        { visual: { items: [{ id: "fog", opacity: 0.75 }] } },
+      ]);
+
+      expect(state.visual.items[0]).toEqual({
+        ...initialVisual,
+        opacity: 0.75,
+      });
+    });
+
+    it("treats a complete text value as a fresh subject", () => {
+      const state = constructPresentationState([
+        {
+          visual: {
+            items: [
+              {
+                id: "fog",
+                text: { content: "Chapter 1", textStyleId: "title" },
+                transformId: "title-top",
+                layer: 70,
+                opacity: 0.6,
+                filters: [grade],
+                animations: persistentAnimation,
+              },
+            ],
+          },
+        },
+        {
+          visual: {
+            items: [
+              {
+                id: "fog",
+                text: { content: "Chapter 2", textStyleId: "accent" },
+              },
+            ],
+          },
+        },
+      ]);
+
+      expect(state.visual.items[0]).toEqual({
+        id: "fog",
+        text: { content: "Chapter 2", textStyleId: "accent" },
+      });
+    });
+
+    it("preserves omitted fields for a partial text patch", () => {
+      const state = constructPresentationState([
+        {
+          visual: {
+            items: [
+              {
+                id: "title",
+                text: { content: "Chapter 1", textStyleId: "title" },
+                transformId: "title-top",
+                layer: 70,
+                opacity: 0.6,
+                filters: [grade],
+              },
+            ],
+          },
+        },
+        {
+          visual: {
+            items: [{ id: "title", text: { content: "Chapter 2" } }],
+          },
+        },
+      ]);
+
+      expect(state.visual.items[0]).toEqual({
+        id: "title",
+        text: { content: "Chapter 2", textStyleId: "title" },
+        transformId: "title-top",
+        layer: 70,
+        opacity: 0.6,
+        filters: [grade],
+      });
+    });
+
+    it("treats a complete inline layout as a fresh subject", () => {
+      const nextLayout = {
+        elements: [{ id: "title", type: "text", content: "Chapter 2" }],
+      };
+      const state = constructPresentationState([
+        {
+          visual: {
+            items: [
+              {
+                id: "title",
+                layout: {
+                  elements: [
+                    { id: "title", type: "text", content: "Chapter 1" },
+                  ],
+                },
+                transformId: "title-top",
+                layer: 70,
+                opacity: 0.6,
+                filters: [grade],
+              },
+            ],
+          },
+        },
+        { visual: { items: [{ id: "title", layout: nextLayout }] } },
+      ]);
+
+      expect(state.visual.items[0]).toEqual({
+        id: "title",
+        layout: nextLayout,
+      });
+    });
+  });
+});
diff --git a/spec/system/constructPresentationState.spec.yaml b/spec/system/constructPresentationState.spec.yaml
index cec42a27..2bfb0c37 100644
--- a/spec/system/constructPresentationState.spec.yaml
+++ b/spec/system/constructPresentationState.spec.yaml
@@ -94,7 +94,7 @@ out:
     content:
       - text: "Next line"
 ---
-case: background colorId persists across resource updates
+case: background resource replacement resets colorId
 in:
   - - background:
         resourceId: "mainBackground"
@@ -104,7 +104,6 @@ in:
 out:
   background:
     resourceId: "altBackground"
-    colorId: "backdrop"
 ---
 case: background colorId update keeps the current background resource
 in:
@@ -242,7 +241,7 @@ out:
     content:
       - text: "Next line"
 ---
-case: persistent background animation survives same-background reassertion without animations
+case: same-background reassertion resets persistent animation
 in:
   - - background:
         resourceId: "mainBackground"
@@ -255,10 +254,6 @@ in:
 out:
   background:
     resourceId: "mainBackground"
-    animations:
-      resourceId: "bgFade"
-      playback:
-        continuity: "persistent"
 ---
 case: persistent background animation clears when background is modified
 in:
@@ -1477,7 +1472,7 @@ out:
           textStyleId: "accentTitle"
         transformId: "titleTop"
 ---
-case: visual text full update keeps previous transform, appearance, and layer
+case: visual text full update resets omitted transform, appearance, and layer
 in:
   - - visual:
         items:
@@ -1501,9 +1496,6 @@ out:
         text:
           content: "Chapter 2"
           textStyleId: "accentTitle"
-        transformId: "titleTop"
-        layer: 70
-        opacity: 0.8
 ---
 case: new visual text item requires content and textStyleId
 in:
@@ -1525,7 +1517,7 @@ in:
               textStyleId: "title"
 throws: 'Visual item "title" cannot define both resourceId and text'
 ---
-case: item transform overrides persist across later item updates
+case: visual resource replacement resets previous transform overrides
 in:
   - - visual:
         items:
@@ -1554,15 +1546,6 @@ out:
         resourceId: "effect-fog"
         transformId: "fullscreen"
         opacity: 0.45
-        x: 100
-        y: 120
-        anchorX: 0
-        anchorY: 0
-        scaleX: 1.2
-        scaleY: 1.3
-        rotation: -8
-        originX: 20
-        originY: 40
 ---
 case: preserve background without animations (no empty animations added)
 in:
@@ -2008,7 +1991,7 @@ out:
     content:
       - text: "Second ADV line"
 ---
-case: inline visual layout replacement preserves item state and merges inline transform
+case: inline visual layout replacement resets omitted item state
 in:
   - - visual:
         items:
@@ -2051,15 +2034,7 @@ out:
               content: "Chapter 2"
               textStyleId: "title"
         transform:
-          x: 100
           y: 180
-          anchorX: 0.5
-          anchorY: 0.5
-          rotation: 0
-          scaleX: 1
-          scaleY: 1
-        layer: 70
-        opacity: 0.8
 ---
 case: inline visual layout cannot be combined with resourceId
 in:
diff --git a/spec/system/selectors/selectPresentationChanges.spec.yaml b/spec/system/selectors/selectPresentationChanges.spec.yaml
index fb6264b1..7bef6446 100644
--- a/spec/system/selectors/selectPresentationChanges.spec.yaml
+++ b/spec/system/selectors/selectPresentationChanges.spec.yaml
@@ -161,7 +161,7 @@ out:
       data:
         colorId: "night"
 ---
-case: "Detect updated background resource without color change"
+case: "Detect updated background resource and cleared color"
 in:
   - state:
       projectData:
@@ -192,6 +192,10 @@ out:
       changeType: "update"
       data:
         resourceId: "bg-home"
+    color:
+      changeType: "delete"
+      data:
+        colorId: "night"
 ---
 case: "Detect updated background color without resource change"
 in:
@@ -259,6 +263,10 @@ out:
       data:
         resourceId: "bg-school"
         transformId: "wide"
+    color:
+      changeType: "delete"
+      data:
+        colorId: "night"
 ---
 case: "Detect updated background inline transform as resource change"
 in:
diff --git a/spec/system/selectors/selectPresentationState.spec.yaml b/spec/system/selectors/selectPresentationState.spec.yaml
index 201db378..d35034fe 100644
--- a/spec/system/selectors/selectPresentationState.spec.yaml
+++ b/spec/system/selectors/selectPresentationState.spec.yaml
@@ -36,7 +36,7 @@ out:
   background:
     resourceId: abcd
 ---
-case: background colorId persists across later lines
+case: background resource replacement resets colorId across later lines
 in:
   - state:
       global:
@@ -75,7 +75,6 @@ in:
 out:
   background:
     resourceId: xyz
-    colorId: night
   dialogue:
     mode: adv
     content:
diff --git a/spec/system/selectors/selectSectionChanges.spec.yaml b/spec/system/selectors/selectSectionChanges.spec.yaml
index ce3147ec..73fdff41 100644
--- a/spec/system/selectors/selectSectionChanges.spec.yaml
+++ b/spec/system/selectors/selectSectionChanges.spec.yaml
@@ -168,11 +168,15 @@ out:
             changeType: "update"
             data:
               resourceId: "bg2"
+          color:
+            changeType: "delete"
+            data:
+              colorId: "night"
     - id: "3"
       changes:
         background:
           color:
-            changeType: "update"
+            changeType: "add"
             data:
               colorId: "day"
     - id: "4"
diff --git a/spec/visualInlineLayout.test.js b/spec/visualInlineLayout.test.js
index 57f7ec35..2f47c175 100644
--- a/spec/visualInlineLayout.test.js
+++ b/spec/visualInlineLayout.test.js
@@ -170,7 +170,7 @@ describe("inline visual layouts", () => {
     });
   });
 
-  it("replaces inline layout content by id while preserving visual state", () => {
+  it("replaces inline layout content by id with only explicitly authored state", () => {
     const presentationState = constructPresentationState([
       {
         visual: {
@@ -226,22 +226,21 @@ describe("inline visual layouts", () => {
       },
     ]);
 
-    expect(presentationState.visual.items[0]).toMatchObject({
+    expect(presentationState.visual.items[0]).toEqual({
       id: "title",
       layout: {
-        elements: [{ content: "Chapter 2" }],
+        elements: [
+          {
+            id: "text",
+            type: "text",
+            content: "Chapter 2",
+            textStyleId: "title",
+          },
+        ],
       },
       transform: {
-        x: 100,
         y: 180,
-        anchorX: 0.5,
-        anchorY: 0.5,
-        scaleX: 1,
-        scaleY: 1,
-        rotation: 0,
       },
-      layer: 70,
-      opacity: 0.8,
     });
   });
 
diff --git a/src/schemas/presentationActions.yaml b/src/schemas/presentationActions.yaml
index ef476876..07ef165a 100644
--- a/src/schemas/presentationActions.yaml
+++ b/src/schemas/presentationActions.yaml
@@ -238,7 +238,7 @@ definitions:
 
   visualText:
     type: object
-    description: Text-backed visual configuration. Placement, layer, alpha, blur, filters, and animations stay on the visual item.
+    description: Text-backed visual configuration. A value with both content and textStyleId defines a fresh visual subject and resets omitted item state; a partial value patches the active text subject. Placement, layer, alpha, blur, filters, and animations stay on the visual item.
     properties:
       content:
         $ref: "#/definitions/visualTextContent"
@@ -283,7 +283,7 @@ definitions:
 
   visualInlineLayout:
     type: object
-    description: Inline RouteGraphics layout rendered as one visual item. The visual item owns placement, layer, appearance, and animations.
+    description: Inline RouteGraphics layout rendered as one visual item. A complete layout defines a fresh visual subject and resets omitted item state. The visual item owns placement, layer, appearance, and animations.
     properties:
       elements:
         type: array
@@ -361,7 +361,7 @@ properties:
     properties:
       resourceId:
         type: string
-        description: ID of the background resource to display
+        description: ID of the background resource to display. Authoring this field creates a fresh background instance and resets omitted color, placement, appearance, playback, and animation state, even when the ID is unchanged. Omit resourceId for a continuation patch.
       animationName:
         type: string
         description: Optional spritesheet animation name. If omitted for a spritesheet resource, the first defined animation is used.
@@ -373,7 +373,7 @@ properties:
         description: Optional video or spritesheet playback loop override
       colorId:
         type: string
-        description: Optional resources.colors ID for the solid color rendered behind the background resource. Persists until changed or cleared with cleanAll
+        description: Optional resources.colors ID for the solid color rendered behind the background resource. Persists through omitted background actions and subject-less patches, but resets when resourceId is authored without colorId.
       transformId:
         type: string
         description: Optional transform resource to position the background
@@ -586,7 +586,7 @@ properties:
               $ref: "#/definitions/shaderFilters"
             sprites:
               type: array
-              description: Array of sprite parts that make up the character
+              description: Array of sprite parts that make up the character. Authoring a non-empty array creates a fresh character item and resets every omitted item field, even when the composition is unchanged. Omit sprites for a continuation patch.
               items:
                 type: object
                 properties:
@@ -638,7 +638,7 @@ properties:
               description: Override the animation speed
             resourceId:
               type: string
-              description: ID of an image, video, spritesheet, particle, or layout resource
+              description: ID of an image, video, spritesheet, particle, or layout resource. Authoring this field creates a fresh visual item and resets every omitted item field, even when the ID is unchanged. Omit all complete visual subjects for a continuation patch.
             text:
               $ref: "#/definitions/visualText"
             layout:
diff --git a/src/stores/constructPresentationState.js b/src/stores/constructPresentationState.js
index 4247aa56..8786dd87 100644
--- a/src/stores/constructPresentationState.js
+++ b/src/stores/constructPresentationState.js
@@ -144,11 +144,22 @@ const hasVisualSubject = (item, previousItem) => {
   return !previousItem?.text;
 };
 
+const hasExplicitVisualSubject = (item) =>
+  hasDefinedProperty(item, "resourceId") ||
+  hasCompleteVisualText(item) ||
+  hasCompleteVisualLayout(item);
+
 const hasCharacterSubject = (item) =>
   (item?.sprites && item.sprites.length > 0) ||
   item?.transformId ||
   item?.resourceId;
 
+const hasExplicitCharacterSubject = (item) =>
+  hasDefinedProperty(item, "resourceId") ||
+  (hasDefinedProperty(item, "sprites") &&
+    Array.isArray(item.sprites) &&
+    item.sprites.length > 0);
+
 const mergeVisualItemPatch = (previousItem, item) => {
   const mergedItem = {
     ...clonePresentationValue(previousItem),
@@ -340,7 +351,11 @@ const processItemsWithAnimations = (
   items,
   hasResourceFn,
   previousItems = [],
-  { hasPatchFn = () => false, mergeItemFn } = {},
+  {
+    hasPatchFn = () => false,
+    hasSubjectFn = (item, previousItem) => hasResourceFn(item, previousItem),
+    mergeItemFn,
+  } = {},
 ) => {
   if (!items || items.length === 0) {
     return { hasValidItems: false, processedItems: [] };
@@ -349,7 +364,7 @@ const processItemsWithAnimations = (
   const processedItems = items
     .map((item, index) => {
       const previousItem = findPreviousItem(previousItems, item, index);
-      const hasResource = hasResourceFn(item, previousItem);
+      const hasSubject = hasSubjectFn(item, previousItem);
       const hasAppearance = hasItemAppearance(item);
       const hasTransform = hasItemTransform(item);
       const hasPatch = hasPatchFn(item);
@@ -357,7 +372,7 @@ const processItemsWithAnimations = (
       let processedItem = normalizeAlphaAlias(clonePresentationValue(item));
 
       if (
-        !hasResource &&
+        !hasSubject &&
         (hasAppearance || hasTransform || hasPatch) &&
         previousItem
       ) {
@@ -376,6 +391,7 @@ const processItemsWithAnimations = (
         const nextHasResource = hasResourceFn(processedItem);
 
         if (
+          !hasSubject &&
           previousHasResource &&
           nextHasResource &&
           hasPersistentAnimationSelection(previousItem)
@@ -388,6 +404,10 @@ const processItemsWithAnimations = (
         }
       }
 
+      if (hasSubject) {
+        return processedItem;
+      }
+
       return applyPersistentItemAppearance(
         applyPersistentItemTransform(processedItem, previousItem),
         previousItem,
@@ -677,23 +697,37 @@ export const background = (state, presentation) => {
       }
     }
 
-    applyPersistentBackgroundTransform(nextBackground, previousBackground, {
-      hasAuthoredTransformId: hasTransformId,
-    });
+    if (!hasResourceId) {
+      applyPersistentBackgroundTransform(nextBackground, previousBackground, {
+        hasAuthoredTransformId: hasTransformId,
+      });
+    }
 
-    if (!hasColorId && previousBackground?.colorId) {
+    if (!hasResourceId && !hasColorId && previousBackground?.colorId) {
       nextBackground.colorId = previousBackground.colorId;
     }
 
-    if (!hasOpacity && hasDefinedProperty(previousBackground, "opacity")) {
+    if (
+      !hasResourceId &&
+      !hasOpacity &&
+      hasDefinedProperty(previousBackground, "opacity")
+    ) {
       nextBackground.opacity = previousBackground.opacity;
     }
 
-    if (!hasBlur && hasDefinedProperty(previousBackground, "blur")) {
+    if (
+      !hasResourceId &&
+      !hasBlur &&
+      hasDefinedProperty(previousBackground, "blur")
+    ) {
       nextBackground.blur = clonePresentationValue(previousBackground.blur);
     }
 
-    if (!hasFilters && hasDefinedProperty(previousBackground, "filters")) {
+    if (
+      !hasResourceId &&
+      !hasFilters &&
+      hasDefinedProperty(previousBackground, "filters")
+    ) {
       nextBackground.filters = clonePresentationValue(
         previousBackground.filters,
       );
@@ -763,6 +797,7 @@ export const background = (state, presentation) => {
     }
 
     if (
+      !hasResourceId &&
       previousBackground?.resourceId === nextBackground.resourceId &&
       previousBackground?.transformId === nextBackground.transformId &&
       !hasOwnProperty(nextBackground, "animations") &&
@@ -1104,6 +1139,7 @@ export const visual = (state, presentation) => {
       previousItems,
       {
         hasPatchFn: hasVisualSubjectPatch,
+        hasSubjectFn: hasExplicitVisualSubject,
         mergeItemFn: mergeVisualItemPatch,
       },
     );
@@ -1157,6 +1193,7 @@ export const character = (state, presentation) => {
     presentation.character.items,
     hasCharacterSubject,
     state.character?.items || [],
+    { hasSubjectFn: hasExplicitCharacterSubject },
   );
 
   if (hasValidItems) {
diff --git a/vt/reference/background/subject-replacement-01.webp b/vt/reference/background/subject-replacement-01.webp
new file mode 100644
index 00000000..8c3d94c4
--- /dev/null
+++ b/vt/reference/background/subject-replacement-01.webp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:4ca7de9aa32ec33c31cc4f6c4d624670032a3fa96ec14e7b916303ae24dc8477
+size 1956
diff --git a/vt/reference/background/subject-replacement-02.webp b/vt/reference/background/subject-replacement-02.webp
new file mode 100644
index 00000000..b55a5573
--- /dev/null
+++ b/vt/reference/background/subject-replacement-02.webp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:587c6726d6441fe9d4eedd0ee0b256b700b15bc18e85c3da9248f3dae5c03bf1
+size 2378
diff --git a/vt/reference/background/subject-replacement-03.webp b/vt/reference/background/subject-replacement-03.webp
new file mode 100644
index 00000000..5207f05d
--- /dev/null
+++ b/vt/reference/background/subject-replacement-03.webp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:492076e4ced59a7faf8324016f6d2fdbb0228e8ab083ca9daddc01886df56d18
+size 10860
diff --git a/vt/reference/character/subject-replacement-01.webp b/vt/reference/character/subject-replacement-01.webp
new file mode 100644
index 00000000..366fbf5f
--- /dev/null
+++ b/vt/reference/character/subject-replacement-01.webp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:863bd2550a16415e61620eb30e80fbcd857e20ab11dcd4a87adda9e47e85472e
+size 2372
diff --git a/vt/reference/character/subject-replacement-02.webp b/vt/reference/character/subject-replacement-02.webp
new file mode 100644
index 00000000..d3357098
--- /dev/null
+++ b/vt/reference/character/subject-replacement-02.webp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:5a2ac8623a320ed1a2ce43dd38a774f3d74b932fa26d1a43f9bccce683ed9847
+size 2706
diff --git a/vt/reference/character/subject-replacement-03.webp b/vt/reference/character/subject-replacement-03.webp
new file mode 100644
index 00000000..92d2e04a
--- /dev/null
+++ b/vt/reference/character/subject-replacement-03.webp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:2876a1651b2151433b646bccd8cbb26d1426c8e6cb0a7958e1204b002f0c4488
+size 5490
diff --git a/vt/reference/visual/subject-replacement-01.webp b/vt/reference/visual/subject-replacement-01.webp
new file mode 100644
index 00000000..bf4fc9ce
--- /dev/null
+++ b/vt/reference/visual/subject-replacement-01.webp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:1f4bce9e32ae5269ae6a2ab9189cbe49bf3553f480b83d4573025fbbf69acddf
+size 2376
diff --git a/vt/reference/visual/subject-replacement-02.webp b/vt/reference/visual/subject-replacement-02.webp
new file mode 100644
index 00000000..b3c95534
--- /dev/null
+++ b/vt/reference/visual/subject-replacement-02.webp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:043884c17441d6763d95bba660988a22de62b04ff3b3b82a60e3ec5716b65bea
+size 2708
diff --git a/vt/reference/visual/subject-replacement-03.webp b/vt/reference/visual/subject-replacement-03.webp
new file mode 100644
index 00000000..9da1c85d
--- /dev/null
+++ b/vt/reference/visual/subject-replacement-03.webp
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:38453297a855f36a4727ce98449f253d1eaebfc901318523fca026591b6f9193
+size 5496
diff --git a/vt/specs/background/subject-replacement.yaml b/vt/specs/background/subject-replacement.yaml
new file mode 100644
index 00000000..38f171f7
--- /dev/null
+++ b/vt/specs/background/subject-replacement.yaml
@@ -0,0 +1,63 @@
+---
+title: Background Subject Replacement
+description: |
+  A subject-less background action should patch the active instance, while
+  explicitly reauthoring the same resourceId should create a fresh instance.
+
+  - the first screenshot should show the forest inset, faded, and blurred
+  - the second screenshot should increase opacity while preserving placement and blur
+  - the third screenshot should show the same forest at default placement and appearance
+skipInitialScreenshot: true
+steps:
+  - action: screenshot
+  - action: customEvent
+    name: vt:nextLine
+  - action: screenshot
+  - action: customEvent
+    name: vt:nextLine
+  - action: screenshot
+---
+screen:
+  width: 1920
+  height: 1080
+  backgroundColor: "#FFFFFF"
+resources:
+  images:
+    forest:
+      fileId: dmni32
+      width: 1920
+      height: 1080
+story:
+  initialSceneId: backgroundSubjectScene
+  scenes:
+    backgroundSubjectScene:
+      name: Background Subject Scene
+      initialSectionId: main
+      sections:
+        main:
+          lines:
+            - id: styledBackground
+              actions:
+                background:
+                  resourceId: forest
+                  x: 280
+                  y: 180
+                  anchorX: 0
+                  anchorY: 0
+                  scaleX: 0.7
+                  scaleY: 0.7
+                  opacity: 0.5
+                  blur:
+                    x: 6
+                    y: 9
+                    quality: 3
+                    kernelSize: 9
+                    repeatEdgePixels: true
+            - id: patchedBackground
+              actions:
+                background:
+                  opacity: 0.8
+            - id: replacedBackground
+              actions:
+                background:
+                  resourceId: forest
diff --git a/vt/specs/character/subject-replacement.yaml b/vt/specs/character/subject-replacement.yaml
new file mode 100644
index 00000000..e4b6536e
--- /dev/null
+++ b/vt/specs/character/subject-replacement.yaml
@@ -0,0 +1,85 @@
+---
+title: Character Subject Replacement
+description: |
+  A subject-less character item should patch the active instance, while
+  explicitly reauthoring the same sprite composition should create a fresh
+  instance.
+
+  - the first screenshot should show the character left of center, faded, and blurred
+  - the second screenshot should increase opacity while preserving placement and blur
+  - the third screenshot should show the same sprite centered with default appearance
+skipInitialScreenshot: true
+steps:
+  - action: screenshot
+  - action: customEvent
+    name: vt:nextLine
+  - action: screenshot
+  - action: customEvent
+    name: vt:nextLine
+  - action: screenshot
+---
+screen:
+  width: 1920
+  height: 1080
+  backgroundColor: "#FFFFFF"
+resources:
+  colors:
+    stageWhite:
+      hex: "#FFFFFF"
+  images:
+    character-a:
+      fileId: char_sprite_1
+      width: 553
+      height: 865
+  transforms:
+    character-center:
+      x: 960
+      y: 1080
+      anchorX: 0.5
+      anchorY: 1
+      rotation: 0
+      scaleX: 1
+      scaleY: 1
+story:
+  initialSceneId: characterSubjectScene
+  scenes:
+    characterSubjectScene:
+      name: Character Subject Scene
+      initialSectionId: main
+      sections:
+        main:
+          lines:
+            - id: styledCharacter
+              actions:
+                background:
+                  colorId: stageWhite
+                character:
+                  items:
+                    - id: lead
+                      transformId: character-center
+                      x: 520
+                      opacity: 0.5
+                      blur:
+                        x: 6
+                        y: 9
+                        quality: 3
+                        kernelSize: 9
+                        repeatEdgePixels: true
+                      sprites:
+                        - id: body
+                          resourceId: character-a
+            - id: patchedCharacter
+              actions:
+                character:
+                  items:
+                    - id: lead
+                      opacity: 0.8
+            - id: replacedCharacter
+              actions:
+                character:
+                  items:
+                    - id: lead
+                      transformId: character-center
+                      sprites:
+                        - id: body
+                          resourceId: character-a
diff --git a/vt/specs/visual/subject-replacement.yaml b/vt/specs/visual/subject-replacement.yaml
new file mode 100644
index 00000000..c279da19
--- /dev/null
+++ b/vt/specs/visual/subject-replacement.yaml
@@ -0,0 +1,81 @@
+---
+title: Visual Subject Replacement
+description: |
+  A subject-less visual item should patch the active instance, while explicitly
+  reauthoring the same resourceId should create a fresh instance.
+
+  - the first screenshot should show the visual left of center, faded, and blurred
+  - the second screenshot should increase opacity while preserving placement and blur
+  - the third screenshot should show the same resource centered with default appearance
+skipInitialScreenshot: true
+steps:
+  - action: screenshot
+  - action: customEvent
+    name: vt:nextLine
+  - action: screenshot
+  - action: customEvent
+    name: vt:nextLine
+  - action: screenshot
+---
+screen:
+  width: 1920
+  height: 1080
+  backgroundColor: "#FFFFFF"
+resources:
+  colors:
+    stageWhite:
+      hex: "#FFFFFF"
+  images:
+    visual-sprite:
+      fileId: char_sprite_2
+      width: 553
+      height: 865
+  transforms:
+    visual-center:
+      x: 960
+      y: 1080
+      anchorX: 0.5
+      anchorY: 1
+      rotation: 0
+      scaleX: 1
+      scaleY: 1
+story:
+  initialSceneId: visualSubjectScene
+  scenes:
+    visualSubjectScene:
+      name: Visual Subject Scene
+      initialSectionId: main
+      sections:
+        main:
+          lines:
+            - id: styledVisual
+              actions:
+                background:
+                  colorId: stageWhite
+                visual:
+                  items:
+                    - id: glow
+                      resourceId: visual-sprite
+                      transformId: visual-center
+                      x: 520
+                      layer: 90
+                      opacity: 0.5
+                      blur:
+                        x: 6
+                        y: 9
+                        quality: 3
+                        kernelSize: 9
+                        repeatEdgePixels: true
+            - id: patchedVisual
+              actions:
+                visual:
+                  items:
+                    - id: glow
+                      opacity: 0.8
+            - id: replacedVisual
+              actions:
+                visual:
+                  items:
+                    - id: glow
+                      resourceId: visual-sprite
+                      transformId: visual-center