diff --git a/frontend/package.json b/frontend/package.json
index 8493b97..8eb5b84 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -27,6 +27,8 @@
     "@radix-ui/react-select": "^2.2.6",
     "@radix-ui/react-separator": "^1.1.8",
     "@radix-ui/react-slot": "^1.2.4",
+    "@radix-ui/react-toggle": "^1.1.10",
+    "@radix-ui/react-toggle-group": "^1.1.11",
     "@radix-ui/react-tooltip": "^1.2.8",
     "@radix-ui/react-use-controllable-state": "^1.2.2",
     "@t3-oss/env-nextjs": "^0.12.0",
diff --git a/frontend/pnpm-lock.yaml b/frontend/pnpm-lock.yaml
index 3eae6a2..5b582ee 100644
--- a/frontend/pnpm-lock.yaml
+++ b/frontend/pnpm-lock.yaml
@@ -41,6 +41,12 @@ importers:
       '@radix-ui/react-slot':
         specifier: ^1.2.4
         version: 1.2.4(@types/react@19.2.8)(react@19.2.3)
+      '@radix-ui/react-toggle':
+        specifier: ^1.1.10
+        version: 1.1.10(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
+      '@radix-ui/react-toggle-group':
+        specifier: ^1.1.11
+        version: 1.1.11(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
       '@radix-ui/react-tooltip':
         specifier: ^1.2.8
         version: 1.2.8(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
@@ -1088,6 +1094,32 @@ packages:
       '@types/react':
         optional: true
 
+  '@radix-ui/react-toggle-group@1.1.11':
+    resolution: {integrity: sha512-5umnS0T8JQzQT6HbPyO7Hh9dgd82NmS36DQr+X/YJ9ctFNCiiQd6IJAYYZ33LUwm8M+taCz5t2ui29fHZc4Y6Q==}
+    peerDependencies:
+      '@types/react': '*'
+      '@types/react-dom': '*'
+      react: ^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc
+      react-dom: ^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc
+    peerDependenciesMeta:
+      '@types/react':
+        optional: true
+      '@types/react-dom':
+        optional: true
+
+  '@radix-ui/react-toggle@1.1.10':
+    resolution: {integrity: sha512-lS1odchhFTeZv3xwHH31YPObmJn8gOg7Lq12inrr0+BH/l3Tsq32VfjqH1oh80ARM3mlkfMic15n0kg4sD1poQ==}
+    peerDependencies:
+      '@types/react': '*'
+      '@types/react-dom': '*'
+      react: ^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc
+      react-dom: ^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc
+    peerDependenciesMeta:
+      '@types/react':
+        optional: true
+      '@types/react-dom':
+        optional: true
+
   '@radix-ui/react-tooltip@1.2.8':
     resolution: {integrity: sha512-tY7sVt1yL9ozIxvmbtN5qtmH2krXcBCfjEiCgKGLqunJHvgvZG2Pcl2oQ3kbcZARb1BGEHdkLzcYGO8ynVlieg==}
     peerDependencies:
@@ -5615,6 +5647,32 @@ snapshots:
     optionalDependencies:
       '@types/react': 19.2.8
 
+  '@radix-ui/react-toggle-group@1.1.11(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)':
+    dependencies:
+      '@radix-ui/primitive': 1.1.3
+      '@radix-ui/react-context': 1.1.2(@types/react@19.2.8)(react@19.2.3)
+      '@radix-ui/react-direction': 1.1.1(@types/react@19.2.8)(react@19.2.3)
+      '@radix-ui/react-primitive': 2.1.3(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
+      '@radix-ui/react-roving-focus': 1.1.11(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
+      '@radix-ui/react-toggle': 1.1.10(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
+      '@radix-ui/react-use-controllable-state': 1.2.2(@types/react@19.2.8)(react@19.2.3)
+      react: 19.2.3
+      react-dom: 19.2.3(react@19.2.3)
+    optionalDependencies:
+      '@types/react': 19.2.8
+      '@types/react-dom': 19.2.3(@types/react@19.2.8)
+
+  '@radix-ui/react-toggle@1.1.10(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)':
+    dependencies:
+      '@radix-ui/primitive': 1.1.3
+      '@radix-ui/react-primitive': 2.1.3(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
+      '@radix-ui/react-use-controllable-state': 1.2.2(@types/react@19.2.8)(react@19.2.3)
+      react: 19.2.3
+      react-dom: 19.2.3(react@19.2.3)
+    optionalDependencies:
+      '@types/react': 19.2.8
+      '@types/react-dom': 19.2.3(@types/react@19.2.8)
+
   '@radix-ui/react-tooltip@1.2.8(@types/react-dom@19.2.3(@types/react@19.2.8))(@types/react@19.2.8)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)':
     dependencies:
       '@radix-ui/primitive': 1.1.3
diff --git a/frontend/src/components/ui/toggle-group.tsx b/frontend/src/components/ui/toggle-group.tsx
new file mode 100644
index 0000000..2739e29
--- /dev/null
+++ b/frontend/src/components/ui/toggle-group.tsx
@@ -0,0 +1,83 @@
+"use client";
+
+import * as React from "react";
+import * as ToggleGroupPrimitive from "@radix-ui/react-toggle-group";
+import { type VariantProps } from "class-variance-authority";
+
+import { cn } from "@/lib/utils";
+import { toggleVariants } from "@/components/ui/toggle";
+
+const ToggleGroupContext = React.createContext<
+  VariantProps<typeof toggleVariants> & {
+    spacing?: number;
+  }
+>({
+  size: "default",
+  variant: "default",
+  spacing: 0,
+});
+
+function ToggleGroup({
+  className,
+  variant,
+  size,
+  spacing = 0,
+  children,
+  ...props
+}: React.ComponentProps<typeof ToggleGroupPrimitive.Root> &
+  VariantProps<typeof toggleVariants> & {
+    spacing?: number;
+  }) {
+  return (
+    <ToggleGroupPrimitive.Root
+      data-slot="toggle-group"
+      data-variant={variant}
+      data-size={size}
+      data-spacing={spacing}
+      style={{ "--gap": spacing } as React.CSSProperties}
+      className={cn(
+        "group/toggle-group flex w-fit items-center gap-[--spacing(var(--gap))] rounded-md data-[spacing=default]:data-[variant=outline]:shadow-xs",
+        className,
+      )}
+      {...props}
+    >
+      <ToggleGroupContext.Provider value={{ variant, size, spacing }}>
+        {children}
+      </ToggleGroupContext.Provider>
+    </ToggleGroupPrimitive.Root>
+  );
+}
+
+function ToggleGroupItem({
+  className,
+  children,
+  variant,
+  size,
+  ...props
+}: React.ComponentProps<typeof ToggleGroupPrimitive.Item> &
+  VariantProps<typeof toggleVariants>) {
+  const context = React.useContext(ToggleGroupContext);
+
+  return (
+    <ToggleGroupPrimitive.Item
+      data-slot="toggle-group-item"
+      data-variant={context.variant || variant}
+      data-size={context.size || size}
+      data-spacing={context.spacing}
+      className={cn(
+        toggleVariants({
+          variant: context.variant || variant,
+          size: context.size || size,
+        }),
+        "w-auto min-w-0 shrink-0 cursor-pointer px-3 focus:z-10 focus-visible:z-10",
+        "data-[spacing=0]:rounded-none data-[spacing=0]:shadow-none data-[spacing=0]:first:rounded-l-md data-[spacing=0]:last:rounded-r-md data-[spacing=0]:data-[variant=outline]:border-l-0 data-[spacing=0]:data-[variant=outline]:first:border-l",
+        className,
+      )}
+      {...props}
+    >
+      {children}
+    </ToggleGroupPrimitive.Item>
+  );
+}
+
+export { ToggleGroup, ToggleGroupItem };
diff --git a/frontend/src/components/ui/toggle.tsx b/frontend/src/components/ui/toggle.tsx
new file mode 100644
index 0000000..94ec8f5
--- /dev/null
+++ b/frontend/src/components/ui/toggle.tsx
@@ -0,0 +1,47 @@
+"use client"
+
+import * as React from "react"
+import * as TogglePrimitive from "@radix-ui/react-toggle"
+import { cva, type VariantProps } from "class-variance-authority"
+
+import { cn } from "@/lib/utils"
+
+const toggleVariants = cva(
+  "inline-flex items-center justify-center gap-2 rounded-md text-sm font-medium hover:bg-muted hover:text-muted-foreground disabled:pointer-events-none disabled:opacity-50 data-[state=on]:bg-accent data-[state=on]:text-accent-foreground [&_svg]:pointer-events-none [&_svg:not([class*='size-'])]:size-4 [&_svg]:shrink-0 focus-visible:border-ring focus-visible:ring-ring/50 focus-visible:ring-[3px] outline-none transition-[color,box-shadow] aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive whitespace-nowrap",
+  {
+    variants: {
+      variant: {
+        default: "bg-transparent",
+        outline:
+          "border border-input bg-transparent shadow-xs hover:bg-accent hover:text-accent-foreground",
+      },
+      size: {
+        default: "h-9 px-2 min-w-9",
+        sm: "h-8 px-1.5 min-w-8",
+        lg: "h-10 px-2.5 min-w-10",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+      size: "default",
+    },
+  }
+)
+
+function Toggle({
+  className,
+  variant,
+  size,
+  ...props
+}: React.ComponentProps<typeof TogglePrimitive.Root> &
+  VariantProps<typeof toggleVariants>) {
+  return (
+    <TogglePrimitive.Root
+      data-slot="toggle"
+      className={cn(toggleVariants({ variant, size, className }))}
+      {...props}
+    />
+  )
+}
+
+export { Toggle, toggleVariants }
diff --git a/frontend/src/components/workspace/artifacts/artifact-file-detail.tsx b/frontend/src/components/workspace/artifacts/artifact-file-detail.tsx
index 03b7c0a..fea4377 100644
--- a/frontend/src/components/workspace/artifacts/artifact-file-detail.tsx
+++ b/frontend/src/components/workspace/artifacts/artifact-file-detail.tsx
@@ -4,8 +4,9 @@ import {
   SquareArrowOutUpRightIcon,
   XIcon,
 } from "lucide-react";
-import { useMemo } from "react";
+import { useEffect, useMemo, useState } from "react";
 import { toast } from "sonner";
+import { Streamdown } from "streamdown";
 
 import {
   Artifact,
@@ -22,13 +23,14 @@ import {
   SelectTrigger,
   SelectValue,
 } from "@/components/ui/select";
+import { Textarea } from "@/components/ui/textarea";
+import { ToggleGroup, ToggleGroupItem } from "@/components/ui/toggle-group";
 import { useArtifactContent } from "@/core/artifacts/hooks";
 import { urlOfArtifact } from "@/core/artifacts/utils";
 import { checkCodeFile, getFileName } from "@/core/utils/files";
 import { cn } from "@/lib/utils";
 
 import { useArtifacts } from "./context";
-import { FileViewer } from "./file-viewer";
 
 export function ArtifactFileDetail({
   className,
@@ -50,23 +52,34 @@ export function ArtifactFileDetail({
     }
     return filepathFromProps;
   }, [filepathFromProps, isWriteFile]);
-  const { isCodeFile } = useMemo(() => {
+  const { isCodeFile, language } = useMemo(() => {
     if (isWriteFile) {
       let language = checkCodeFile(filepath).language;
-      language ??= "markdown";
+      language ??= "text";
       return { isCodeFile: true, language };
     }
     return checkCodeFile(filepath);
   }, [filepath, isWriteFile]);
+  const previewable = useMemo(() => {
+    return (language === "html" && !isWriteFile) || language === "markdown";
+  }, [isWriteFile, language]);
   const { content } = useArtifactContent({
     threadId,
     filepath: filepathFromProps,
     enabled: isCodeFile && !isWriteFile,
   });
+  const [viewMode, setViewMode] = useState<"code" | "preview">("code");
+  useEffect(() => {
+    if (previewable) {
+      setViewMode("preview");
+    } else {
+      setViewMode("code");
+    }
+  }, [previewable]);
   return (
     <Artifact className={cn("rounded-none", className)}>
       <ArtifactHeader className="px-2">
-        <div>
+        <div className="flex items-center gap-2">
           <ArtifactTitle>
             {isWriteFile ? (
               <div className="px-2">{getFileName(filepath)}</div>
@@ -88,6 +101,23 @@ export function ArtifactFileDetail({
             )}
           </ArtifactTitle>
         </div>
+        <div className="flex min-w-0 grow items-center justify-center">
+          {previewable && (
+            <ToggleGroup
+              className="mx-auto"
+              type="single"
+              variant="outline"
+              size="sm"
+              value={viewMode}
+              onValueChange={(value) =>
+                setViewMode(value as "code" | "preview")
+              }
+            >
+              <ToggleGroupItem value="code">Code</ToggleGroupItem>
+              <ToggleGroupItem value="preview">Preview</ToggleGroupItem>
+            </ToggleGroup>
+          )}
+        </div>
         <div className="flex items-center gap-2">
           <ArtifactActions>
             {!isWriteFile && (
@@ -139,12 +169,57 @@ export function ArtifactFileDetail({
         </div>
       </ArtifactHeader>
       <ArtifactContent className="p-0">
-        <FileViewer
-          className="size-full"
-          threadId={threadId}
-          filepath={filepathFromProps}
-        />
+        {previewable && viewMode === "preview" && (
+          <ArtifactFilePreview
+            filepath={filepath}
+            threadId={threadId}
+            content={content}
+            language={language ?? "text"}
+          />
+        )}
+        {isCodeFile && viewMode === "code" && (
+          <Textarea
+            className="size-full resize-none rounded-none border-none"
+            readOnly
+            value={content ?? ""}
+          />
+        )}
+        {!isCodeFile && (
+          <iframe
+            className="size-full"
+            src={urlOfArtifact({ filepath, threadId })}
+          />
+        )}
       </ArtifactContent>
     </Artifact>
   );
 }
+
+export function ArtifactFilePreview({
+  filepath,
+  threadId,
+  content,
+  language,
+}: {
+  filepath: string;
+  threadId: string;
+  content: string;
+  language: string;
+}) {
+  if (language === "markdown") {
+    return (
+      <div className="size-full px-4">
+        <Streamdown className="size-full">{content ?? ""}</Streamdown>
+      </div>
+    );
+  }
+  if (language === "html") {
+    return (
+      <iframe
+        className="size-full"
+        src={urlOfArtifact({ filepath, threadId })}
+      />
+    );
+  }
+  return null;
+}
diff --git a/frontend/src/components/workspace/artifacts/file-viewer.tsx b/frontend/src/components/workspace/artifacts/file-viewer.tsx
deleted file mode 100644
index f1ae8a1..0000000
--- a/frontend/src/components/workspace/artifacts/file-viewer.tsx
+++ /dev/null
@@ -1,71 +0,0 @@
-import { useMemo } from "react";
-import type { BundledLanguage } from "shiki";
-
-import { CodeBlock } from "@/components/ai-elements/code-block";
-import { useArtifactContent } from "@/core/artifacts/hooks";
-import { urlOfArtifact } from "@/core/artifacts/utils";
-import { checkCodeFile } from "@/core/utils/files";
-import { cn } from "@/lib/utils";
-
-export function FileViewer({
-  className,
-  filepath,
-  threadId,
-}: {
-  className?: string;
-  filepath: string;
-  threadId: string;
-}) {
-  const isWriteFile = useMemo(() => {
-    return filepath.startsWith("write-file:");
-  }, [filepath]);
-  const { isCodeFile, language } = useMemo(() => {
-    if (isWriteFile) {
-      const url = new URL(filepath);
-      const path = decodeURIComponent(url.pathname);
-      return checkCodeFile(path);
-    }
-    return checkCodeFile(filepath);
-  }, [filepath, isWriteFile]);
-  if (isWriteFile || (isCodeFile && language !== "html")) {
-    return (
-      <CodeFileView
-        language={language ?? "markdown"}
-        filepath={filepath}
-        threadId={threadId}
-      />
-    );
-  }
-  return (
-    <div className={cn("size-full border-none", className)}>
-      <iframe
-        className={cn("size-full border-none", className)}
-        src={urlOfArtifact({ filepath, threadId })}
-      ></iframe>
-    </div>
-  );
-}
-
-function CodeFileView({
-  language,
-  filepath,
-  threadId,
-}: {
-  language: BundledLanguage;
-  filepath: string;
-  threadId: string;
-}) {
-  const { content: code } = useArtifactContent({
-    filepath,
-    threadId,
-  });
-  if (code) {
-    return (
-      <CodeBlock
-        className="size-full rounded-none border-none"
-        language={language}
-        code={code}
-      />
-    );
-  }
-}
diff --git a/frontend/src/core/artifacts/hooks.ts b/frontend/src/core/artifacts/hooks.ts
index 3e01521..20261aa 100644
--- a/frontend/src/core/artifacts/hooks.ts
+++ b/frontend/src/core/artifacts/hooks.ts
@@ -3,7 +3,7 @@ import { useMemo } from "react";
 
 import { useThread } from "@/components/workspace/messages/context";
 
-import { loadArtifactContent } from "./loader";
+import { loadArtifactContent, loadArtifactContentFromToolCall } from "./loader";
 
 export function useArtifactContent({
   filepath,
@@ -20,25 +20,10 @@ export function useArtifactContent({
   const { thread } = useThread();
   const content = useMemo(() => {
     if (isWriteFile) {
-      const url = new URL(filepath);
-      const toolCallId = url.searchParams.get("tool_call_id");
-      const messageId = url.searchParams.get("message_id");
-      if (messageId && toolCallId) {
-        const message = thread.messages.find(
-          (message) => message.id === messageId,
-        );
-        if (message?.type === "ai" && message.tool_calls) {
-          const toolCall = message.tool_calls.find(
-            (toolCall) => toolCall.id === toolCallId,
-          );
-          if (toolCall) {
-            return toolCall.args.content;
-          }
-        }
-      }
+      return loadArtifactContentFromToolCall({ url: filepath, thread });
     }
     return null;
-  }, [filepath, isWriteFile, thread.messages]);
+  }, [filepath, isWriteFile, thread]);
   const { data, isLoading, error } = useQuery({
     queryKey: ["artifact", filepath, threadId],
     queryFn: () => {
diff --git a/frontend/src/core/artifacts/loader.ts b/frontend/src/core/artifacts/loader.ts
index d55b1b4..915b1aa 100644
--- a/frontend/src/core/artifacts/loader.ts
+++ b/frontend/src/core/artifacts/loader.ts
@@ -1,3 +1,7 @@
+import type { UseStream } from "@langchain/langgraph-sdk/react";
+
+import type { AgentThreadState } from "../threads";
+
 import { urlOfArtifact } from "./utils";
 
 export async function loadArtifactContent({
@@ -12,3 +16,26 @@ export async function loadArtifactContent({
   const text = await response.text();
   return text;
 }
+
+export function loadArtifactContentFromToolCall({
+  url: urlString,
+  thread,
+}: {
+  url: string;
+  thread: UseStream<AgentThreadState>;
+}) {
+  const url = new URL(urlString);
+  const toolCallId = url.searchParams.get("tool_call_id");
+  const messageId = url.searchParams.get("message_id");
+  if (messageId && toolCallId) {
+    const message = thread.messages.find((message) => message.id === messageId);
+    if (message?.type === "ai" && message.tool_calls) {
+      const toolCall = message.tool_calls.find(
+        (toolCall) => toolCall.id === toolCallId,
+      );
+      if (toolCall) {
+        return toolCall.args.content;
+      }
+    }
+  }
+}
diff --git a/frontend/src/core/utils/files.ts b/frontend/src/core/utils/files.ts
index f3923d0..1a37984 100644
--- a/frontend/src/core/utils/files.ts
+++ b/frontend/src/core/utils/files.ts
@@ -1,6 +1,13 @@
-import type { BundledLanguage } from "shiki";
+const extensionMap: Record<string, string> = {
+  // Text
+  txt: "text",
+  csv: "csv",
+  log: "text",
+  conf: "text",
+  config: "text",
+  properties: "text",
+  props: "text",
 
-const extensionMap: Record<string, BundledLanguage> = {
   // JavaScript/TypeScript ecosystem
   js: "javascript",
   jsx: "jsx",
@@ -137,14 +144,14 @@ export function getFileExtension(filepath: string) {
 export function checkCodeFile(
   filepath: string,
 ):
-  | { isCodeFile: true; language: BundledLanguage }
+  | { isCodeFile: true; language: string }
   | { isCodeFile: false; language: null } {
   const extension = getFileExtension(filepath);
   const isCodeFile = extension in extensionMap;
   if (isCodeFile) {
     return {
       isCodeFile: true,
-      language: extensionMap[extension] as unknown as BundledLanguage,
+      language: extensionMap[extension] ?? "text",
     };
   }
   return {