diff --git a/tools/server/webui/src/lib/components/app/dialogs/DialogChatError.svelte b/tools/server/webui/src/lib/components/app/dialogs/DialogChatError.svelte
index 4e0e11317a..54a3c90d3c 100644
--- a/tools/server/webui/src/lib/components/app/dialogs/DialogChatError.svelte
+++ b/tools/server/webui/src/lib/components/app/dialogs/DialogChatError.svelte
@@ -59,7 +59,12 @@
 						<span class="font-medium">Prompt tokens:</span>
 						{contextInfo.n_prompt_tokens.toLocaleString()}
 					</p>
-					<p><span class="font-medium">Context size:</span> {contextInfo.n_ctx.toLocaleString()}</p>
+					{#if contextInfo.n_ctx}
+						<p>
+							<span class="font-medium">Context size:</span>
+							{contextInfo.n_ctx.toLocaleString()}
+						</p>
+					{/if}
 				</div>
 			{/if}
 		</div>
diff --git a/tools/server/webui/src/lib/components/app/dialogs/DialogModelInformation.svelte b/tools/server/webui/src/lib/components/app/dialogs/DialogModelInformation.svelte
index fdf02ed1c2..25d8a55748 100644
--- a/tools/server/webui/src/lib/components/app/dialogs/DialogModelInformation.svelte
+++ b/tools/server/webui/src/lib/components/app/dialogs/DialogModelInformation.svelte
@@ -105,12 +105,21 @@
 							</Table.Row>
 
 							<!-- Context Size -->
-							<Table.Row>
-								<Table.Cell class="h-10 align-middle font-medium">Context Size</Table.Cell>
-								<Table.Cell
-									>{formatNumber(serverProps.default_generation_settings.n_ctx)} tokens</Table.Cell
-								>
-							</Table.Row>
+							{#if serverProps?.default_generation_settings?.n_ctx}
+								<Table.Row>
+									<Table.Cell class="h-10 align-middle font-medium">Context Size</Table.Cell>
+									<Table.Cell
+										>{formatNumber(serverProps.default_generation_settings.n_ctx)} tokens</Table.Cell
+									>
+								</Table.Row>
+							{:else}
+								<Table.Row>
+									<Table.Cell class="h-10 align-middle font-medium text-red-500"
+										>Context Size</Table.Cell
+									>
+									<Table.Cell class="text-red-500">Not available</Table.Cell>
+								</Table.Row>
+							{/if}
 
 							<!-- Training Context -->
 							{#if modelMeta?.n_ctx_train}
diff --git a/tools/server/webui/src/lib/components/app/server/ServerStatus.svelte b/tools/server/webui/src/lib/components/app/server/ServerStatus.svelte
index d9f6d4a32a..86a962de12 100644
--- a/tools/server/webui/src/lib/components/app/server/ServerStatus.svelte
+++ b/tools/server/webui/src/lib/components/app/server/ServerStatus.svelte
@@ -48,7 +48,7 @@
 			{model || 'Unknown Model'}
 		</Badge>
 
-		{#if serverData.default_generation_settings.n_ctx}
+		{#if serverData?.default_generation_settings?.n_ctx}
 			<Badge variant="secondary" class="text-xs">
 				ctx: {serverData.default_generation_settings.n_ctx.toLocaleString()}
 			</Badge>
diff --git a/tools/server/webui/src/lib/constants/default-context.ts b/tools/server/webui/src/lib/constants/default-context.ts
deleted file mode 100644
index 78f31116e3..0000000000
--- a/tools/server/webui/src/lib/constants/default-context.ts
+++ /dev/null
@@ -1 +0,0 @@
-export const DEFAULT_CONTEXT = 4096;
diff --git a/tools/server/webui/src/lib/hooks/use-processing-state.svelte.ts b/tools/server/webui/src/lib/hooks/use-processing-state.svelte.ts
index b8d4616d0e..1205d9b973 100644
--- a/tools/server/webui/src/lib/hooks/use-processing-state.svelte.ts
+++ b/tools/server/webui/src/lib/hooks/use-processing-state.svelte.ts
@@ -147,7 +147,11 @@ export function useProcessingState(): UseProcessingStateReturn {
 		}
 
 		// Always show context info when we have valid data
-		if (stateToUse.contextUsed >= 0 && stateToUse.contextTotal > 0) {
+		if (
+			typeof stateToUse.contextTotal === 'number' &&
+			stateToUse.contextUsed >= 0 &&
+			stateToUse.contextTotal > 0
+		) {
 			const contextPercent = Math.round((stateToUse.contextUsed / stateToUse.contextTotal) * 100);
 
 			details.push(
@@ -193,7 +197,11 @@ export function useProcessingState(): UseProcessingStateReturn {
 		const details: string[] = [];
 
 		// Always show context info when we have valid data
-		if (stateToUse.contextUsed >= 0 && stateToUse.contextTotal > 0) {
+		if (
+			typeof stateToUse.contextTotal === 'number' &&
+			stateToUse.contextUsed >= 0 &&
+			stateToUse.contextTotal > 0
+		) {
 			const contextPercent = Math.round((stateToUse.contextUsed / stateToUse.contextTotal) * 100);
 
 			details.push(
diff --git a/tools/server/webui/src/lib/stores/chat.svelte.ts b/tools/server/webui/src/lib/stores/chat.svelte.ts
index 7bb5e3b5f4..dc21d9444b 100644
--- a/tools/server/webui/src/lib/stores/chat.svelte.ts
+++ b/tools/server/webui/src/lib/stores/chat.svelte.ts
@@ -30,7 +30,6 @@ import {
 	findLeafNode,
 	isAbortError
 } from '$lib/utils';
-import { DEFAULT_CONTEXT } from '$lib/constants/default-context';
 import { SYSTEM_MESSAGE_PLACEHOLDER } from '$lib/constants/ui';
 import { REASONING_TAGS } from '$lib/constants/agentic';
 import {
@@ -1252,17 +1251,22 @@ class ChatStore {
 		}
 	}
 
-	private getContextTotal(): number {
+	private getContextTotal(): number | null {
 		const activeConvId = this.activeConversationId;
 		const activeState = activeConvId ? this.getProcessingState(activeConvId) : null;
-		if (activeState && activeState.contextTotal > 0) return activeState.contextTotal;
+
+		if (activeState && typeof activeState.contextTotal === 'number' && activeState.contextTotal > 0)
+			return activeState.contextTotal;
+
 		if (isRouterMode()) {
 			const modelContextSize = selectedModelContextSize();
-			if (modelContextSize && modelContextSize > 0) return modelContextSize;
+			if (typeof modelContextSize === 'number' && modelContextSize > 0) return modelContextSize;
+		} else {
+			const propsContextSize = contextSize();
+			if (typeof propsContextSize === 'number' && propsContextSize > 0) return propsContextSize;
 		}
-		const propsContextSize = contextSize();
-		if (propsContextSize && propsContextSize > 0) return propsContextSize;
-		return DEFAULT_CONTEXT;
+
+		return null;
 	}
 
 	updateProcessingStateFromTimings(
diff --git a/tools/server/webui/src/lib/stores/models.svelte.ts b/tools/server/webui/src/lib/stores/models.svelte.ts
index 6451f6df84..4cb6167220 100644
--- a/tools/server/webui/src/lib/stores/models.svelte.ts
+++ b/tools/server/webui/src/lib/stores/models.svelte.ts
@@ -178,7 +178,9 @@ class ModelsStore {
 	 */
 	getModelContextSize(modelId: string): number | null {
 		const props = this.getModelProps(modelId);
-		return props?.default_generation_settings?.n_ctx ?? null;
+		const nCtx = props?.default_generation_settings?.n_ctx;
+
+		return typeof nCtx === 'number' ? nCtx : null;
 	}
 
 	/**
diff --git a/tools/server/webui/src/lib/stores/server.svelte.ts b/tools/server/webui/src/lib/stores/server.svelte.ts
index 47328a0adc..48874bf1b7 100644
--- a/tools/server/webui/src/lib/stores/server.svelte.ts
+++ b/tools/server/webui/src/lib/stores/server.svelte.ts
@@ -45,7 +45,9 @@ class ServerStore {
 	}
 
 	get contextSize(): number | null {
-		return this.props?.default_generation_settings?.n_ctx ?? null;
+		const nCtx = this.props?.default_generation_settings?.n_ctx;
+
+		return typeof nCtx === 'number' ? nCtx : null;
 	}
 
 	get webuiSettings(): Record<string, string | number | boolean> | undefined {
diff --git a/tools/server/webui/src/lib/types/api.d.ts b/tools/server/webui/src/lib/types/api.d.ts
index b73fe4acb9..307e3b71d9 100644
--- a/tools/server/webui/src/lib/types/api.d.ts
+++ b/tools/server/webui/src/lib/types/api.d.ts
@@ -351,7 +351,7 @@ export interface ApiProcessingState {
 	tokensDecoded: number;
 	tokensRemaining: number;
 	contextUsed: number;
-	contextTotal: number;
+	contextTotal: number | null;
 	outputTokensUsed: number; // Total output tokens (thinking + regular content)
 	outputTokensMax: number; // Max output tokens allowed
 	temperature: number;