From e7cc8c430f3449ab084b02785c2c11685ae360c4 Mon Sep 17 00:00:00 2001
From: Marcus <139352735+sucrammal@users.noreply.github.com>
Date: Mon, 15 Jun 2026 12:35:44 -0400
Subject: [PATCH 1/9] Move frame builder backend deps into dev deps

---
 package.json   | 12 +++++-------
 pnpm-lock.yaml | 30 +++++++++++++++---------------
 2 files changed, 20 insertions(+), 22 deletions(-)

diff --git a/package.json b/package.json
index d8a7b022c..291be12e0 100644
--- a/package.json
+++ b/package.json
@@ -45,6 +45,7 @@
 		"@changesets/cli": "2.29.6",
 		"@connectrpc/connect": "1.7.0",
 		"@connectrpc/connect-web": "1.7.0",
+		"@langchain/anthropic": "^1.4.0",
 		"@dimforge/rapier3d-compat": "0.18.2",
 		"@eslint/compat": "2.0.2",
 		"@eslint/js": "10.0.1",
@@ -115,11 +116,13 @@
 		"type-fest": "^5.0.1",
 		"typescript": "5.9.2",
 		"typescript-eslint": "8.56.1",
+		"uuid-tool": "^2.0.3",
 		"vite": "7.3.2",
 		"vite-plugin-devtools-json": "1.0.0",
 		"vite-plugin-glsl": "^1.5.5",
 		"vite-plugin-mkcert": "1.17.9",
-		"vitest": "3.2.6"
+		"vitest": "3.2.6",
+		"zod": "^4.4.3"
 	},
 	"peerDependencies": {
 		"@ag-grid-community/client-side-row-model": ">=32.3.0",
@@ -209,16 +212,11 @@
 	],
 	"dependencies": {
 		"@bufbuild/protobuf": "1.10.1",
-		"@connectrpc/connect": "1.7.0",
-		"@connectrpc/connect-web": "1.7.0",
-		"@langchain/anthropic": "^1.4.0",
 		"@neodrag/svelte": "^2.3.3",
 		"d3-force": "^3.0.0",
 		"filtrex": "^3.1.0",
 		"koota": "0.6.5",
 		"lodash-es": "4.18.1",
-		"three-mesh-bvh": "^0.9.8",
-		"uuid-tool": "^2.0.3",
-		"zod": "^4.4.3"
+		"three-mesh-bvh": "^0.9.8"
 	}
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index ea9be5e92..be9b2501d 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -15,15 +15,6 @@ importers:
       '@bufbuild/protobuf':
         specifier: 1.10.1
         version: 1.10.1
-      '@connectrpc/connect':
-        specifier: 1.7.0
-        version: 1.7.0(@bufbuild/protobuf@1.10.1)
-      '@connectrpc/connect-web':
-        specifier: 1.7.0
-        version: 1.7.0(@bufbuild/protobuf@1.10.1)(@connectrpc/connect@1.7.0(@bufbuild/protobuf@1.10.1))
-      '@langchain/anthropic':
-        specifier: ^1.4.0
-        version: 1.4.0(@langchain/core@1.1.48(@opentelemetry/api@1.9.0)(@opentelemetry/sdk-trace-base@2.2.0(@opentelemetry/api@1.9.0))(ws@8.21.0))
       '@neodrag/svelte':
         specifier: ^2.3.3
         version: 2.3.3(svelte@5.55.7)
@@ -45,12 +36,6 @@ importers:
       three-mesh-bvh:
         specifier: ^0.9.8
         version: 0.9.8(three@0.183.2)
-      uuid-tool:
-        specifier: ^2.0.3
-        version: 2.0.3
-      zod:
-        specifier: ^4.4.3
-        version: 4.4.3
     devDependencies:
       '@ag-grid-community/client-side-row-model':
         specifier: 32.3.9
@@ -64,6 +49,12 @@ importers:
       '@changesets/cli':
         specifier: 2.29.6
         version: 2.29.6(@types/node@25.6.0)
+      '@connectrpc/connect':
+        specifier: 1.7.0
+        version: 1.7.0(@bufbuild/protobuf@1.10.1)
+      '@connectrpc/connect-web':
+        specifier: 1.7.0
+        version: 1.7.0(@bufbuild/protobuf@1.10.1)(@connectrpc/connect@1.7.0(@bufbuild/protobuf@1.10.1))
       '@dimforge/rapier3d-compat':
         specifier: 0.18.2
         version: 0.18.2
@@ -73,6 +64,9 @@ importers:
       '@eslint/js':
         specifier: 10.0.1
         version: 10.0.1(eslint@10.0.2(jiti@2.6.1))
+      '@langchain/anthropic':
+        specifier: ^1.4.0
+        version: 1.4.0(@langchain/core@1.1.48(@opentelemetry/api@1.9.0)(@opentelemetry/sdk-trace-base@2.2.0(@opentelemetry/api@1.9.0))(ws@8.21.0))
       '@playwright/test':
         specifier: 1.55.1
         version: 1.55.1
@@ -274,6 +268,9 @@ importers:
       typescript-eslint:
         specifier: 8.56.1
         version: 8.56.1(eslint@10.0.2(jiti@2.6.1))(typescript@5.9.2)
+      uuid-tool:
+        specifier: ^2.0.3
+        version: 2.0.3
       vite:
         specifier: 7.3.2
         version: 7.3.2(@types/node@25.6.0)(jiti@2.6.1)(lightningcss@1.30.1)(tsx@4.20.5)(yaml@2.8.1)
@@ -289,6 +286,9 @@ importers:
       vitest:
         specifier: 3.2.6
         version: 3.2.6(@types/node@25.6.0)(@vitest/browser@3.2.4)(jiti@2.6.1)(jsdom@26.1.0)(lightningcss@1.30.1)(tsx@4.20.5)(yaml@2.8.1)
+      zod:
+        specifier: ^4.4.3
+        version: 4.4.3
 
 packages:
 

From 288948676229bd33aa56f8c688d1ca5dd1963af9 Mon Sep 17 00:00:00 2001
From: Marcus <139352735+sucrammal@users.noreply.github.com>
Date: Mon, 15 Jun 2026 12:36:43 -0400
Subject: [PATCH 2/9] Changeset

---
 .changeset/flat-hats-serve.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/flat-hats-serve.md

diff --git a/.changeset/flat-hats-serve.md b/.changeset/flat-hats-serve.md
new file mode 100644
index 000000000..1d58eff42
--- /dev/null
+++ b/.changeset/flat-hats-serve.md
@@ -0,0 +1,5 @@
+---
+'@viamrobotics/motion-tools': patch
+---
+
+Reorg frame builder deps

From 9bd489658ff7149aab8b756e4eda8830ef0627a6 Mon Sep 17 00:00:00 2001
From: Marcus <139352735+sucrammal@users.noreply.github.com>
Date: Mon, 15 Jun 2026 12:52:38 -0400
Subject: [PATCH 3/9] Move uuid back into dep

---
 package.json   | 4 ++--
 pnpm-lock.yaml | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/package.json b/package.json
index 291be12e0..da5c3dd1a 100644
--- a/package.json
+++ b/package.json
@@ -116,7 +116,6 @@
 		"type-fest": "^5.0.1",
 		"typescript": "5.9.2",
 		"typescript-eslint": "8.56.1",
-		"uuid-tool": "^2.0.3",
 		"vite": "7.3.2",
 		"vite-plugin-devtools-json": "1.0.0",
 		"vite-plugin-glsl": "^1.5.5",
@@ -217,6 +216,7 @@
 		"filtrex": "^3.1.0",
 		"koota": "0.6.5",
 		"lodash-es": "4.18.1",
-		"three-mesh-bvh": "^0.9.8"
+		"three-mesh-bvh": "^0.9.8",
+		"uuid-tool": "^2.0.3"
 	}
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index be9b2501d..f5f996235 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -36,6 +36,9 @@ importers:
       three-mesh-bvh:
         specifier: ^0.9.8
         version: 0.9.8(three@0.183.2)
+      uuid-tool:
+        specifier: ^2.0.3
+        version: 2.0.3
     devDependencies:
       '@ag-grid-community/client-side-row-model':
         specifier: 32.3.9
@@ -268,9 +271,6 @@ importers:
       typescript-eslint:
         specifier: 8.56.1
         version: 8.56.1(eslint@10.0.2(jiti@2.6.1))(typescript@5.9.2)
-      uuid-tool:
-        specifier: ^2.0.3
-        version: 2.0.3
       vite:
         specifier: 7.3.2
         version: 7.3.2(@types/node@25.6.0)(jiti@2.6.1)(lightningcss@1.30.1)(tsx@4.20.5)(yaml@2.8.1)

From e92c050b86c114cac1bb66949b163876fb384c3f Mon Sep 17 00:00:00 2001
From: Marcus <139352735+sucrammal@users.noreply.github.com>
Date: Mon, 15 Jun 2026 16:31:31 -0400
Subject: [PATCH 4/9] Validation for duplicate entries under same component

---
 server/routes/scene-builder.ts                |  3 +-
 .../LLMSceneBuilder/SceneBuilder.svelte       |  6 +---
 .../LLMSceneBuilder/frameDeltaAdapter.ts      | 32 +++++++++++++++++++
 3 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/server/routes/scene-builder.ts b/server/routes/scene-builder.ts
index cc5de363a..99fe3e078 100644
--- a/server/routes/scene-builder.ts
+++ b/server/routes/scene-builder.ts
@@ -47,7 +47,7 @@ const ResponseSchema = z.object({
 	updates: z
 		.array(FrameDeltaSchema)
 		.describe(
-			'One entry per component that needs to change. Always populate for any requested change — empty only if truly nothing needs to change.'
+			'One entry per component that needs to change. If a component needs both translation and orientation changes, put ALL of them in the same entry — never create two entries with the same componentName. Empty only if truly nothing needs to change.'
 		),
 	explanation: z
 		.string()
@@ -61,6 +61,7 @@ const SYSTEM_PROMPT = `You are a robot spatial configuration assistant. The user
 Rules:
 - Only modify components listed in the context below. Each component has a "name" field — use that exact string as "componentName" in your response.
 - Return only components that actually need to change.
+- CRITICAL: Each component may appear at most once in the updates array. If a component needs both a translation change and an orientation change, combine them into a single entry with both fields set. Never create two separate entries for the same componentName.
 - For translation, return only the changed axes (x, y, z are each optional). All translation values are in millimeters.
 - For orientation, current values are shown as { roll, pitch, yaw } in degrees. Return only the axes that are changing with their new absolute values.
   - Coordinate system: X is forward, Y is left, Z is up (right-handed).
diff --git a/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte b/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte
index 3168b493b..22f46473d 100644
--- a/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte
+++ b/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte
@@ -37,7 +37,7 @@
 			<div class="flex gap-2">
 				<textarea
 					class="flex-1 resize-none rounded border border-gray-300 p-2 text-xs focus:ring-1 focus:ring-gray-400 focus:outline-none disabled:bg-gray-50 disabled:text-gray-400"
-					placeholder="Describe the frame change, e.g. 'Move the arm 200mm forward along X'"
+					placeholder="Describe a frame change — translation, rotation, or parent. e.g. 'Move arm-1 200mm forward and rotate 90° left'"
 					rows={3}
 					disabled={sceneBuilder.uiState === 'loading' || sceneBuilder.uiState === 'diff'}
 					bind:value={prompt}
@@ -69,10 +69,6 @@
 
 			<!-- diff ready -->
 			{#if sceneBuilder.uiState === 'diff'}
-				{#if sceneBuilder.explanation}
-					<p class="text-gray-6 italic">{sceneBuilder.explanation}</p>
-				{/if}
-
 				{#if sceneBuilder.diffGroups.length > 0}
 					<div class="flex flex-col gap-2 overflow-auto">
 						{#each sceneBuilder.diffGroups as group (group.componentName)}
diff --git a/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts b/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts
index c371169f2..60371acaa 100644
--- a/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts
+++ b/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts
@@ -41,7 +41,39 @@ export function validateProposedFrameDeltas(
 	const prepared: PreparedUpdate[] = []
 	const knownNames = new Set(config.components.map((c) => c.name))
 
+	// Merge multiple deltas for the same component — the LLM sometimes splits
+	// translation and orientation into separate entries despite the schema saying one per component.
+	const mergedDeltas = new Map<string, FrameDelta>()
 	for (const delta of deltas) {
+		const existing = mergedDeltas.get(delta.componentName)
+		if (existing) {
+			mergedDeltas.set(delta.componentName, {
+				componentName: delta.componentName,
+				translation:
+					existing.translation || delta.translation
+						? {
+								x: delta.translation?.x ?? existing.translation?.x,
+								y: delta.translation?.y ?? existing.translation?.y,
+								z: delta.translation?.z ?? existing.translation?.z,
+							}
+						: undefined,
+				orientation:
+					existing.orientation || delta.orientation
+						? {
+								roll: delta.orientation?.roll ?? existing.orientation?.roll,
+								pitch: delta.orientation?.pitch ?? existing.orientation?.pitch,
+								yaw: delta.orientation?.yaw ?? existing.orientation?.yaw,
+							}
+						: undefined,
+				parent: delta.parent ?? existing.parent,
+				explanation: [existing.explanation, delta.explanation].filter(Boolean).join(', ') || undefined,
+			})
+		} else {
+			mergedDeltas.set(delta.componentName, delta)
+		}
+	}
+
+	for (const delta of mergedDeltas.values()) {
 		const component = config.components.find((c) => c.name === delta.componentName)
 
 		if (!component) {

From d1f74ea7e4497080b46ebfa1228cf9d360e7ba9f Mon Sep 17 00:00:00 2001
From: Marcus <139352735+sucrammal@users.noreply.github.com>
Date: Mon, 15 Jun 2026 16:39:11 -0400
Subject: [PATCH 5/9] Update placeholder explanation

User story: tried to use the frame builder tool to rotate a joint position.
---
 src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte b/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte
index 22f46473d..2305e205d 100644
--- a/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte
+++ b/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte
@@ -37,7 +37,7 @@
 			<div class="flex gap-2">
 				<textarea
 					class="flex-1 resize-none rounded border border-gray-300 p-2 text-xs focus:ring-1 focus:ring-gray-400 focus:outline-none disabled:bg-gray-50 disabled:text-gray-400"
-					placeholder="Describe a frame change — translation, rotation, or parent. e.g. 'Move arm-1 200mm forward and rotate 90° left'"
+					placeholder="Describe a frame change — translation, rotation, or parent. e.g. 'Move arm 200mm forward and rotate 90° left'"
 					rows={3}
 					disabled={sceneBuilder.uiState === 'loading' || sceneBuilder.uiState === 'diff'}
 					bind:value={prompt}

From 09ad762efc86ffc8b4797fa1f0ecb653a905f4eb Mon Sep 17 00:00:00 2001
From: Marcus <139352735+sucrammal@users.noreply.github.com>
Date: Mon, 15 Jun 2026 16:41:58 -0400
Subject: [PATCH 6/9] Create dry-papayas-heal.md

---
 .changeset/dry-papayas-heal.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/dry-papayas-heal.md

diff --git a/.changeset/dry-papayas-heal.md b/.changeset/dry-papayas-heal.md
new file mode 100644
index 000000000..674266516
--- /dev/null
+++ b/.changeset/dry-papayas-heal.md
@@ -0,0 +1,5 @@
+---
+'@viamrobotics/motion-tools': patch
+---
+
+Quick frame builder UX hits

From 44d3e002a91982bca4e5c272ac16481d10bcd4c2 Mon Sep 17 00:00:00 2001
From: Marcus <139352735+sucrammal@users.noreply.github.com>
Date: Mon, 15 Jun 2026 17:07:09 -0400
Subject: [PATCH 7/9] Clearer error state

---
 server/routes/scene-builder.ts                |  2 +-
 .../LLMSceneBuilder/SceneBuilder.svelte       | 36 ++++++++++++-------
 .../lib/hooks/useStandaloneLLM.svelte.ts      |  2 +-
 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/server/routes/scene-builder.ts b/server/routes/scene-builder.ts
index 99fe3e078..e257217ba 100644
--- a/server/routes/scene-builder.ts
+++ b/server/routes/scene-builder.ts
@@ -121,6 +121,6 @@ export async function handleSceneBuilder(req: Request): Promise<Response> {
 		return Response.json(result, { status: 200, headers: CORS_HEADERS })
 	} catch (error) {
 		console.error('LLM error:', error)
-		return new Response('LLM call failed', { status: 502, headers: CORS_HEADERS })
+		return new Response('Something went wrong — check that ANTHROPIC_API_KEY is set correctly.', { status: 502, headers: CORS_HEADERS })
 	}
 }
diff --git a/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte b/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte
index 2305e205d..3b37d1e8f 100644
--- a/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte
+++ b/src/lib/plugins/LLMSceneBuilder/SceneBuilder.svelte
@@ -1,5 +1,6 @@
 <script lang="ts">
 	import { Portal } from '@threlte/extras'
+	import { Icon } from '@viamrobotics/prime-core'
 
 	import DashboardButton from '$lib/components/overlay/dashboard/Button.svelte'
 	import FloatingPanel from '$lib/components/overlay/FloatingPanel.svelte'
@@ -107,11 +108,13 @@
 				{/if}
 
 				{#if sceneBuilder.updateErrors.length > 0}
-					<ul class="text-red-6 space-y-0.5">
-						{#each sceneBuilder.updateErrors as err (err.componentName)}
-							<li><span class="font-mono">{err.componentName}</span>: {err.reason}</li>
-						{/each}
-					</ul>
+					<div class="border-danger-medium bg-danger-light rounded border p-2">
+						<ul class="text-danger-dark space-y-0.5">
+							{#each sceneBuilder.updateErrors as err (err.componentName)}
+								<li><span class="font-mono">{err.componentName}</span>: {err.reason}</li>
+							{/each}
+						</ul>
+					</div>
 				{/if}
 
 				<div class="mt-auto flex gap-2">
@@ -132,13 +135,22 @@
 
 			<!-- error -->
 			{#if sceneBuilder.uiState === 'error'}
-				<p class="text-red-6">{sceneBuilder.errorMessage}</p>
-				<button
-					class="self-start rounded border border-gray-300 px-3 py-1.5 hover:bg-gray-50"
-					onclick={sceneBuilder.resetError}
-				>
-					Try again
-				</button>
+				<div class="border-danger-medium bg-danger-light flex flex-col gap-2 rounded border p-2.5">
+					<div class="text-danger-dark flex items-center gap-1.5 font-medium">
+						<Icon
+							name="alert-circle-outline"
+							aria-hidden="true"
+						/>
+						Error
+					</div>
+					<p class="text-danger-dark">{sceneBuilder.errorMessage}</p>
+					<button
+						class="border-danger-medium text-danger-dark self-start rounded border px-3 py-1.5 hover:bg-[#F8E1DF]"
+						onclick={sceneBuilder.resetError}
+					>
+						Try again
+					</button>
+				</div>
 			{/if}
 		</div>
 	</FloatingPanel>
diff --git a/src/routes/lib/hooks/useStandaloneLLM.svelte.ts b/src/routes/lib/hooks/useStandaloneLLM.svelte.ts
index f3fc3cfe6..be1fb41b5 100644
--- a/src/routes/lib/hooks/useStandaloneLLM.svelte.ts
+++ b/src/routes/lib/hooks/useStandaloneLLM.svelte.ts
@@ -20,7 +20,7 @@ export const provideStandaloneLLM = (): StandaloneLLMContext => {
 			}),
 		})
 		if (!res.ok) {
-			throw new Error(`${res.status}: ${await res.text()}`)
+			throw new Error(await res.text())
 		}
 		return res.json()
 	}

From 8bccd9c9147dcf38c85e654f02a8b463577e9242 Mon Sep 17 00:00:00 2001
From: Marcus <139352735+sucrammal@users.noreply.github.com>
Date: Mon, 15 Jun 2026 17:18:45 -0400
Subject: [PATCH 8/9] Lint

---
 server/routes/scene-builder.ts                       | 5 ++++-
 src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts | 3 ++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/server/routes/scene-builder.ts b/server/routes/scene-builder.ts
index e257217ba..d3a244ec0 100644
--- a/server/routes/scene-builder.ts
+++ b/server/routes/scene-builder.ts
@@ -121,6 +121,9 @@ export async function handleSceneBuilder(req: Request): Promise<Response> {
 		return Response.json(result, { status: 200, headers: CORS_HEADERS })
 	} catch (error) {
 		console.error('LLM error:', error)
-		return new Response('Something went wrong — check that ANTHROPIC_API_KEY is set correctly.', { status: 502, headers: CORS_HEADERS })
+		return new Response('Something went wrong — check that ANTHROPIC_API_KEY is set correctly.', {
+			status: 502,
+			headers: CORS_HEADERS,
+		})
 	}
 }
diff --git a/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts b/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts
index 60371acaa..1cc9f45f9 100644
--- a/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts
+++ b/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts
@@ -66,7 +66,8 @@ export function validateProposedFrameDeltas(
 							}
 						: undefined,
 				parent: delta.parent ?? existing.parent,
-				explanation: [existing.explanation, delta.explanation].filter(Boolean).join(', ') || undefined,
+				explanation:
+					[existing.explanation, delta.explanation].filter(Boolean).join(', ') || undefined,
 			})
 		} else {
 			mergedDeltas.set(delta.componentName, delta)

From fad627565fe833bb3b562bb8aed3b8ef22cebd91 Mon Sep 17 00:00:00 2001
From: Marcus <139352735+sucrammal@users.noreply.github.com>
Date: Tue, 16 Jun 2026 10:11:17 -0400
Subject: [PATCH 9/9] Refactor mergeDeltas code

---
 .../LLMSceneBuilder/frameDeltaAdapter.ts      | 34 ++++++++++---------
 1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts b/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts
index 1cc9f45f9..4f166f94b 100644
--- a/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts
+++ b/src/lib/plugins/LLMSceneBuilder/frameDeltaAdapter.ts
@@ -28,6 +28,22 @@ export interface UpdateError {
 	reason: string
 }
 
+function mergeTranslation(
+	a?: FrameDelta['translation'],
+	b?: FrameDelta['translation']
+): FrameDelta['translation'] {
+	return a || b ? { x: b?.x ?? a?.x, y: b?.y ?? a?.y, z: b?.z ?? a?.z } : undefined
+}
+
+function mergeOrientation(
+	a?: FrameDelta['orientation'],
+	b?: FrameDelta['orientation']
+): FrameDelta['orientation'] {
+	return a || b
+		? { roll: b?.roll ?? a?.roll, pitch: b?.pitch ?? a?.pitch, yaw: b?.yaw ?? a?.yaw }
+		: undefined
+}
+
 /**
  * Validates LLM-proposed frame deltas and computes the resulting changes without
  * applying them. Each PreparedUpdate carries old and new values so the caller
@@ -49,22 +65,8 @@ export function validateProposedFrameDeltas(
 		if (existing) {
 			mergedDeltas.set(delta.componentName, {
 				componentName: delta.componentName,
-				translation:
-					existing.translation || delta.translation
-						? {
-								x: delta.translation?.x ?? existing.translation?.x,
-								y: delta.translation?.y ?? existing.translation?.y,
-								z: delta.translation?.z ?? existing.translation?.z,
-							}
-						: undefined,
-				orientation:
-					existing.orientation || delta.orientation
-						? {
-								roll: delta.orientation?.roll ?? existing.orientation?.roll,
-								pitch: delta.orientation?.pitch ?? existing.orientation?.pitch,
-								yaw: delta.orientation?.yaw ?? existing.orientation?.yaw,
-							}
-						: undefined,
+				translation: mergeTranslation(existing.translation, delta.translation),
+				orientation: mergeOrientation(existing.orientation, delta.orientation),
 				parent: delta.parent ?? existing.parent,
 				explanation:
 					[existing.explanation, delta.explanation].filter(Boolean).join(', ') || undefined,