diff --git a/src/vtk_prompt/client.py b/src/vtk_prompt/client.py
index 2c6ee86..1f9b9d2 100644
--- a/src/vtk_prompt/client.py
+++ b/src/vtk_prompt/client.py
@@ -397,6 +397,7 @@ def query(
                     request=message,
                     ui_mode=ui_mode,
                     context_snippets=context_snippets,
+                    mcp_active=bool(mcp_client),
                     VTK_VERSION=VTK_VERSION,
                     PYTHON_VERSION=PYTHON_VERSION,
                 )
diff --git a/src/vtk_prompt/controllers/configuration.py b/src/vtk_prompt/controllers/configuration.py
index 20bab0e..601841b 100644
--- a/src/vtk_prompt/controllers/configuration.py
+++ b/src/vtk_prompt/controllers/configuration.py
@@ -44,6 +44,7 @@ def save_config(app: Any) -> str:
     max_tokens = int(getattr(app.state, "max_tokens", 1000))
     retries = int(getattr(app.state, "retry_attempts", 1))
     mcp_url = getattr(app.state, "mcp_url", "").strip()
+    data_root = getattr(app.state, "data_root", "").strip()
     top_k = int(getattr(app.state, "top_k", 5))
     base_url = getattr(app.state, "local_base_url", "").strip() if not use_cloud else ""
 
@@ -53,6 +54,7 @@ def save_config(app: Any) -> str:
         "model": provider_model,
         "base_url": base_url,
         "mcp_url": mcp_url,
+        "data_root": data_root,
         "top_k": top_k,
         "retries": retries,
         "modelParameters": {
diff --git a/src/vtk_prompt/controllers/conversation.py b/src/vtk_prompt/controllers/conversation.py
index d2f9b33..153820b 100644
--- a/src/vtk_prompt/controllers/conversation.py
+++ b/src/vtk_prompt/controllers/conversation.py
@@ -200,9 +200,7 @@ def toggle_favorite_conversation(app: Any, conversation_index: int) -> None:
 
 def save_conversation(app: Any) -> str:
     """Save current conversation history as JSON string."""
-    if hasattr(app, "prompt_client") and app.prompt_client is not None:
-        return json.dumps(app.prompt_client.conversation, indent=2)
-    return ""
+    return json.dumps(getattr(app.state, "conversation", None) or [], indent=2)
 
 
 def _parse_assistant_content(content: str) -> tuple[str | None, str | None]:
@@ -350,8 +348,7 @@ def _update_navigation_state(app: Any) -> None:
 
 def sync_with_prompt_client(app: Any) -> None:
     """Sync conversation navigation with prompt client conversation."""
-    if app.prompt_client and app.prompt_client.conversation:
-        app.state.conversation = app.prompt_client.conversation
+    if app.state.conversation:
         build_conversation_navigation(app)
 
 
diff --git a/src/vtk_prompt/controllers/generation.py b/src/vtk_prompt/controllers/generation.py
index f0569ad..576f0ed 100644
--- a/src/vtk_prompt/controllers/generation.py
+++ b/src/vtk_prompt/controllers/generation.py
@@ -82,6 +82,10 @@ async def generate_and_execute_code(app: Any) -> None:
             app._init_prompt_client()
             if hasattr(app.state, "error_message") and app.state.error_message:
                 return
+            # Tie this generation to the active conversation. A reset or session
+            # switch during the offloaded query bumps the epoch, so a stale result
+            # is discarded rather than written back over the new conversation.
+            epoch = getattr(app, "_conversation_epoch", 0)
 
             # Refine the CURRENT editor code (including manual edits), not the
             # model's previous output, so generation mutates what is on screen.
@@ -103,6 +107,8 @@ async def generate_and_execute_code(app: Any) -> None:
                 custom_prompt=app.custom_prompt_data,
                 ui_mode=True,  # This tells the client to use UI-specific components
             )
+            if getattr(app, "_conversation_epoch", 0) != epoch:
+                return  # conversation was reset/switched while the query ran
             # Keep UI in sync with conversation
             app.state.conversation = app.prompt_client.conversation
 
@@ -205,12 +211,42 @@ async def generate_and_execute_code(app: Any) -> None:
         app.state.flush()  # push final state (result/error, spinner off) to client
 
 
+def _editor_line_for(displayed_code: str, line_text: str | None) -> int:
+    """Find the 1-based line of ``line_text`` in the code shown in the editor."""
+    if not line_text:
+        return 0
+    target = line_text.strip()
+    for i, line in enumerate(displayed_code.splitlines(), start=1):
+        if line.strip() == target:
+            return i
+    return 0
+
+
+def _format_exec_error(displayed_code: str, error_message: str, line_text: str | None) -> str:
+    """Prefix a run error with the editor line and the offending source text."""
+    if not line_text:
+        return error_message
+    editor_line = _editor_line_for(displayed_code, line_text)
+    where = f"Line {editor_line}: {line_text}" if editor_line else f"At: {line_text}"
+    return f"{where}\n{error_message}"
+
+
 def execute_with_renderer(app: Any, code_string: str) -> tuple[bool, str | None]:
     """Execute VTK code with our renderer. Returns (success, error_message)."""
-    success, error_message = execute_vtk_code(code_string, app.renderer, app.render_window)
+    # Resolve bare data-file references (e.g. 'cow.g') to fetched local paths so
+    # example-style code runs. No-op unless a VTK data tree is configured. Only
+    # the executed copy is rewritten; the stored/displayed code keeps bare names.
+    from ..data.resolver import stage_code
+
+    exec_code = stage_code(code_string)
+    success, error_message, error_line_text = execute_vtk_code(
+        exec_code, app.renderer, app.render_window
+    )
 
     if not success and error_message:
-        app.state.error_message = error_message
+        app.state.error_message = _format_exec_error(
+            code_string, error_message, error_line_text
+        )
 
     if success:
         app.state.rendered_code = code_string
diff --git a/src/vtk_prompt/controllers/sessions.py b/src/vtk_prompt/controllers/sessions.py
index de764a0..5c44985 100644
--- a/src/vtk_prompt/controllers/sessions.py
+++ b/src/vtk_prompt/controllers/sessions.py
@@ -91,8 +91,7 @@ def _maybe_title(app: Any, sess: dict) -> None:
 def capture_current_session(app: Any) -> None:
     """Snapshot the live app state into the current session object."""
     sess = current_session(app)
-    client = getattr(app, "prompt_client", None)
-    messages = list(getattr(client, "conversation", None) or app.state.conversation or [])
+    messages = list(app.state.conversation or [])
     sess["messages"] = messages
     sess["code_history"] = list(app.state.code_history or [])
     sess["code_history_labels"] = list(app.state.code_history_labels or [])
@@ -126,6 +125,8 @@ def _key(s: dict):
 
 def _reset_live(app: Any) -> None:
     """Clear all live conversation/code state (the fresh-conversation hinge)."""
+    # Invalidate any in-flight generation so its result is not written back here.
+    app._conversation_epoch = getattr(app, "_conversation_epoch", 0) + 1
     client = getattr(app, "prompt_client", None)
     if client:
         client.conversation = []
@@ -155,6 +156,7 @@ def load_session(app: Any, session_id: str, execute: bool = True) -> None:
         return
     sess = sessions[session_id]
     app.state.current_session_id = session_id
+    app._conversation_epoch = getattr(app, "_conversation_epoch", 0) + 1
 
     client = getattr(app, "prompt_client", None)
     if client:
@@ -242,6 +244,17 @@ def toggle_pin_session(app: Any, session_id: str) -> None:
         refresh_sessions_list(app)
 
 
+def export_session(app: Any, session_id: str) -> str:
+    """Return a session's persisted JSON for download (empty string if unknown)."""
+    if session_id == (getattr(app.state, "current_session_id", "") or ""):
+        capture_current_session(app)  # fold in any unsaved live messages first
+    sess = _sessions(app).get(session_id)
+    if not sess:
+        return ""
+    data = {key: sess.get(key) for key in _PERSIST_KEYS}
+    return json.dumps(data, indent=2)
+
+
 def _sessions_dir() -> Path:
     """Directory holding one JSON file per persisted session."""
     directory = _config_home() / "sessions"
diff --git a/src/vtk_prompt/data/__init__.py b/src/vtk_prompt/data/__init__.py
new file mode 100644
index 0000000..dec1cba
--- /dev/null
+++ b/src/vtk_prompt/data/__init__.py
@@ -0,0 +1,5 @@
+"""Sample-data resolution for example-style prompts that read files."""
+
+from .resolver import artifacts, available_names, has_data_root, referenced, resolve
+
+__all__ = ["artifacts", "available_names", "has_data_root", "referenced", "resolve"]
diff --git a/src/vtk_prompt/data/resolver.py b/src/vtk_prompt/data/resolver.py
new file mode 100644
index 0000000..ac8c696
--- /dev/null
+++ b/src/vtk_prompt/data/resolver.py
@@ -0,0 +1,198 @@
+"""Resolve named VTK example datasets to local file paths.
+
+VTK examples reference data files by bare name (for example ``cow.g``). The bytes
+live in VTK's content-addressed ExternalData store; each file has a
+``<path>.sha512`` pointer somewhere in a VTK data tree. This module builds a
+``basename -> sha512`` index from a local VTK data tree (pointed at by the
+``VTK_PROMPT_DATA_ROOT`` environment variable), then resolves a name by fetching
+the blob from the ExternalData store, caching it locally and verifying its
+checksum. That lets generated example-style code which reads such files run.
+"""
+
+import hashlib
+import logging
+import os
+import re
+import shutil
+import urllib.request
+from pathlib import Path
+from urllib.error import URLError
+
+logger = logging.getLogger(__name__)
+
+_STORE_URL = "https://data.kitware.com/api/v1/file/hashsum/sha512/{digest}/download"
+_DATA_ROOT_ENV = "VTK_PROMPT_DATA_ROOT"
+_POINTER_SUFFIX = ".sha512"
+
+_index_cache: dict[str, str] | None = None
+_data_root_override: Path | None = None
+
+
+def set_data_root(path: str | None) -> None:
+    """Point the resolver at a VTK data tree at runtime (the Settings field).
+
+    A falsy value clears the override and falls back to the VTK_PROMPT_DATA_ROOT
+    environment variable. Always invalidates the cached index so the next lookup
+    rebuilds against the new root.
+    """
+    global _data_root_override, _index_cache
+    cleaned = (path or "").strip()
+    _data_root_override = Path(cleaned) if cleaned else None
+    _index_cache = None
+
+
+def _cache_dir() -> Path:
+    base = os.environ.get("XDG_CACHE_HOME")
+    root = Path(base) if base else Path.home() / ".cache"
+    directory = root / "vtk-prompt" / "data"
+    directory.mkdir(parents=True, exist_ok=True)
+    return directory
+
+
+def _data_root() -> Path | None:
+    if _data_root_override is not None and _data_root_override.is_dir():
+        return _data_root_override
+    root = os.environ.get(_DATA_ROOT_ENV)
+    if root and Path(root).is_dir():
+        return Path(root)
+    return None
+
+
+def _build_index(root: Path) -> dict[str, str]:
+    index: dict[str, str] = {}
+    for dirpath, _dirs, files in os.walk(root):
+        for filename in files:
+            if not filename.endswith(_POINTER_SUFFIX):
+                continue
+            name = filename[: -len(_POINTER_SUFFIX)]
+            if name in index:
+                continue  # first occurrence wins on duplicate basenames
+            try:
+                digest = (Path(dirpath) / filename).read_text().strip()
+            except OSError:
+                continue
+            if digest:
+                index[name] = digest
+    return index
+
+
+def _load_index() -> dict[str, str]:
+    global _index_cache
+    if _index_cache is None:
+        root = _data_root()
+        _index_cache = _build_index(root) if root else {}
+    return _index_cache
+
+
+def _sha512(path: Path) -> str:
+    digest = hashlib.sha512()
+    with open(path, "rb") as handle:
+        for chunk in iter(lambda: handle.read(65536), b""):
+            digest.update(chunk)
+    return digest.hexdigest()
+
+
+def _download(digest: str, dest: Path) -> bool:
+    url = _STORE_URL.format(digest=digest)
+    try:
+        with urllib.request.urlopen(url, timeout=60) as response, open(dest, "wb") as out:
+            shutil.copyfileobj(response, out)
+        return True
+    except (OSError, URLError) as exc:
+        logger.warning("Could not download %s: %s", dest.name, exc)
+        dest.unlink(missing_ok=True)
+        return False
+
+
+def resolve(name: str) -> str | None:
+    """Return a local path for a named dataset, downloading and caching as needed.
+
+    Returns None if the name is unknown (not in the data index) or the download
+    or checksum verification fails.
+    """
+    name = os.path.basename((name or "").strip())
+    if not name:
+        return None
+    digest = _load_index().get(name)
+    cached = _cache_dir() / name
+
+    if cached.exists() and (not digest or _sha512(cached) == digest):
+        return str(cached)
+    if not digest:
+        return None
+
+    if not _download(digest, cached):
+        return None
+    if _sha512(cached) != digest:
+        logger.warning("Checksum mismatch for %s; discarding", name)
+        cached.unlink(missing_ok=True)
+        return None
+    return str(cached)
+
+
+def available_names() -> list[str]:
+    """Return the sorted list of dataset names known to the resolver."""
+    return sorted(_load_index().keys())
+
+
+def has_data_root() -> bool:
+    """Whether a local VTK data tree is configured (enables name resolution)."""
+    return _data_root() is not None
+
+
+# Match single- or double-quoted string literals with no embedded quote/newline.
+_LITERAL_RE = re.compile(r"([\'\"])([^\'\"\n]+?)\1")
+
+
+def stage_code(code: str) -> str:
+    """Rewrite bare data-file references in code to resolved local paths.
+
+    Only string literals that are a bare filename (no directory separator) whose
+    basename is a known dataset are rewritten, so example code like
+    ``reader.SetFileName('cow.g')`` runs against the fetched file. Explicit paths
+    and unrelated strings are left untouched.
+    """
+    index = _load_index()
+    if not index or not code:
+        return code
+
+    def _replace(match: "re.Match[str]") -> str:
+        quote, value = match.group(1), match.group(2)
+        if ("/" in value) or ("\\" in value):
+            return match.group(0)
+        if value in index:
+            path = resolve(value)
+            if path:
+                return f"{quote}{path}{quote}"
+        return match.group(0)
+
+    return _LITERAL_RE.sub(_replace, code)
+
+
+def referenced(code: str) -> list[str]:
+    """Return dataset names referenced as bare string literals in code (no fetch)."""
+    index = _load_index()
+    if not index or not code:
+        return []
+    found: list[str] = []
+    for match in _LITERAL_RE.finditer(code):
+        value = match.group(2)
+        if ("/" in value) or ("\\" in value):
+            continue
+        if value in index and value not in found:
+            found.append(value)
+    return found
+
+
+def artifacts(code: str) -> list[dict]:
+    """Return data artifacts referenced by code (name, cache path, fetched flag).
+
+    Pure lookup (no download); used to surface what files the current code pulls
+    in and where they live.
+    """
+    cache = _cache_dir()
+    result: list[dict] = []
+    for name in referenced(code):
+        path = cache / name
+        result.append({"name": name, "path": str(path), "cached": path.exists()})
+    return result
diff --git a/src/vtk_prompt/prompts/components/tool_use.yml b/src/vtk_prompt/prompts/components/tool_use.yml
new file mode 100644
index 0000000..96182e8
--- /dev/null
+++ b/src/vtk_prompt/prompts/components/tool_use.yml
@@ -0,0 +1,15 @@
+role: assistant
+content: |
+  You have access to VTK reference tools provided by a vtk-mcp server. Use them to
+  ground your code rather than relying on memory for uncommon or uncertain APIs:
+  - Find and confirm classes: search for the right class when unsure which to use,
+    and verify exact class names, method names, and signatures for anything you are
+    not fully certain about.
+  - Check data flow: confirm a filter's expected input and output types before
+    wiring it into a pipeline.
+  - Validate before finalizing: validate the generated code and fix any reported
+    invalid class names, methods, or imports.
+  - Adapt examples: when helpful, retrieve a relevant VTK example and base your code
+    on it.
+  For simple, well-known operations you are confident about, answer directly without
+  tools. Prefer tool-verified facts over assumptions for anything uncommon.
diff --git a/src/vtk_prompt/prompts/prompt_component_assembler.py b/src/vtk_prompt/prompts/prompt_component_assembler.py
index 6cde261..f024f88 100644
--- a/src/vtk_prompt/prompts/prompt_component_assembler.py
+++ b/src/vtk_prompt/prompts/prompt_component_assembler.py
@@ -197,6 +197,7 @@ def assemble_vtk_prompt(
     request: str,
     ui_mode: bool = False,
     context_snippets: str | None = None,
+    mcp_active: bool = False,
     **variables: Any,
 ) -> PromptData:
     """Assemble VTK prompt from file-based components.
@@ -205,6 +206,7 @@ def assemble_vtk_prompt(
         request: User's request text
         ui_mode: Whether to include UI-specific instructions
         context_snippets: Optional context snippets from vtk-mcp (enables rag_context component)
+        mcp_active: Whether a vtk-mcp server is reachable (enables tool_use guidance)
         **variables: Additional variables for substitution
 
     Returns:
@@ -218,6 +220,7 @@ def assemble_vtk_prompt(
     assembler.add_component("vtk_instructions")
 
     # Conditional components (order matters for message composition)
+    assembler.add_if(mcp_active, "tool_use")
     assembler.add_if(bool(context_snippets), "rag_context")
     assembler.add_if(ui_mode, "ui_renderer")
 
diff --git a/src/vtk_prompt/rendering/code_executor.py b/src/vtk_prompt/rendering/code_executor.py
index 95738bb..2be9aaa 100644
--- a/src/vtk_prompt/rendering/code_executor.py
+++ b/src/vtk_prompt/rendering/code_executor.py
@@ -1,5 +1,7 @@
 """VTK Code Execution Module."""
 
+import traceback
+
 import vtk
 
 from .. import get_logger
@@ -10,7 +12,7 @@
 
 def execute_vtk_code(
     code_string: str, renderer: vtk.vtkRenderer, render_window: vtk.vtkRenderWindow
-) -> tuple[bool, str | None]:
+) -> tuple[bool, str | None, str | None]:
     """Execute VTK code with renderer context.
 
     Clears previous actors, cleans the code string, executes it with the renderer
@@ -49,9 +51,39 @@ def execute_vtk_code(
         except Exception as render_error:
             logger.warning("Render error: %s", render_error)
 
-        return True, None
+        return True, None, None
 
-    except Exception as e:
-        error_message = f"Error executing code: {str(e)}"
+    except (Exception, SystemExit) as e:
+        # SystemExit is NOT an Exception subclass: generated code that calls
+        # sys.exit() or argparse.parse_args() (common in VTK example scripts that
+        # read command-line data files) would otherwise propagate out and kill the
+        # whole trame app. Trap it here and report it as a normal code error.
+        if isinstance(e, SystemExit):
+            error_message = (
+                "Error executing code: the generated code runs as a standalone "
+                "script (it uses argparse/sys.exit and expects command-line "
+                "arguments), so it cannot run inside the app as written."
+            )
+        else:
+            error_message = f"Error executing code: {str(e)}"
         logger.error(error_message)
-        return False, error_message
+        # Identify the offending line *within the executed code* and return its
+        # text (not its number). The executed code differs from what the editor
+        # shows: an explanation banner is prepended, a markdown fence may be
+        # stripped, an import may be added, and data literals may be rewritten.
+        # The caller matches on text to locate the editor line robustly.
+        line_text = None
+        segment = locals().get("code_segment")
+        if isinstance(segment, str):
+            lineno = None
+            if isinstance(e, SyntaxError) and e.lineno:
+                lineno = e.lineno
+            else:
+                for frame, frame_line in traceback.walk_tb(e.__traceback__):
+                    if frame.f_code.co_filename == "<string>":
+                        lineno = frame_line
+            if lineno is not None:
+                lines = segment.splitlines()
+                if 1 <= lineno <= len(lines):
+                    line_text = lines[lineno - 1].strip()
+        return False, error_message, line_text
diff --git a/src/vtk_prompt/state/initializer.py b/src/vtk_prompt/state/initializer.py
index 63a198c..4f8c5ae 100644
--- a/src/vtk_prompt/state/initializer.py
+++ b/src/vtk_prompt/state/initializer.py
@@ -27,6 +27,13 @@ def initialize_state(app: Any) -> None:
     app.state.generated_code = ""
     app.state.generated_explanation = ""
     app.state.current_prompt = ""  # the sent prompt shown inline with the explanation
+    app.state.data_artifacts = []  # datasets referenced by the current code
+    # Sample-data resolver root: defaults to the env var, overridable in Settings.
+    import os as _os
+    from ..data.resolver import set_data_root as _set_data_root
+
+    app.state.data_root = _os.environ.get("VTK_PROMPT_DATA_ROOT", "")
+    _set_data_root(app.state.data_root)
     # Code currently shown in the 3D view (last successful render); used to
     # disable Run when the editor already matches what is rendered.
     app.state.rendered_code = ""
@@ -154,7 +161,7 @@ def init_prompt_client(app: Any) -> None:
         mcp_url = getattr(app.state, "mcp_url", "").strip() or None
         app.prompt_client = VTKPromptClient(
             verbose=False,
-            conversation=app.state.conversation,
+            conversation=list(app.state.conversation or []),
             mcp_url=mcp_url,
         )
     except ValueError as e:
diff --git a/src/vtk_prompt/ui/layout/content.py b/src/vtk_prompt/ui/layout/content.py
index be73b70..58feb13 100644
--- a/src/vtk_prompt/ui/layout/content.py
+++ b/src/vtk_prompt/ui/layout/content.py
@@ -29,6 +29,41 @@ def build_content(layout: Any, app: Any) -> None:
                         with vuetify.VCardTitle(
                             "Generated Code", classes="d-flex align-center"
                         ):
+                            # Data files this code references, with where they live.
+                            with html.Div(
+                                classes="d-flex align-center ml-3",
+                                v_show="data_artifacts.length > 0",
+                            ):
+                                with vuetify.VTooltip(
+                                    v_for="a in data_artifacts",
+                                    key="a.name",
+                                    location="bottom",
+                                ):
+                                    with vuetify.Template(v_slot_activator="{ props }"):
+                                        vuetify.VChip(
+                                            "{{ a.name }}",
+                                            v_bind="props",
+                                            size="small",
+                                            variant="tonal",
+                                            classes="mr-1",
+                                            color=("a.cached ? 'success' : 'primary'", "primary"),
+                                            prepend_icon=(
+                                                "a.cached ? 'mdi-file-check'"
+                                                + " : 'mdi-cloud-download-outline'",
+                                                "mdi-file-outline",
+                                            ),
+                                        )
+                                    with html.Div():
+                                        html.Div(
+                                            "{{ a.cached ? 'Fetched' :"
+                                            + " 'Will download on run' }}",
+                                            classes="font-weight-medium",
+                                        )
+                                        html.Div("{{ a.path }}", classes="text-caption")
+                                        html.Div(
+                                            "Source: VTK data store",
+                                            classes="text-caption text-medium-emphasis",
+                                        )
                             vuetify.VSpacer()
                             # Undo across code versions (generations, runs, edits)
                             with vuetify.VTooltip(text="Undo code change", location="bottom"):
diff --git a/src/vtk_prompt/ui/layout/conversation_history.py b/src/vtk_prompt/ui/layout/conversation_history.py
index 0a30be2..41980e9 100644
--- a/src/vtk_prompt/ui/layout/conversation_history.py
+++ b/src/vtk_prompt/ui/layout/conversation_history.py
@@ -20,6 +20,16 @@ def _header(app: Any) -> None:
                     disabled=("conversation_navigation.length === 0", True),
                     v_bind="props",
                 )
+        with vuetify.VTooltip(text="Import conversation", location="bottom"):
+            with vuetify.Template(v_slot_activator="{ props }"):
+                vuetify.VBtn(
+                    icon="mdi-tray-arrow-up",
+                    click="import_dialog = true",
+                    variant="text",
+                    density="compact",
+                    color="primary",
+                    v_bind="props",
+                )
         with vuetify.VTooltip(text="Toggle sort order", location="bottom"):
             with vuetify.Template(v_slot_activator="{ props }"):
                 vuetify.VBtn(
@@ -57,6 +67,10 @@ def _row_menu(app: Any) -> None:
                 click="rename_target_id = s.id; rename_text = s.title; rename_dialog = true"
             ):
                 vuetify.VListItemTitle("Rename")
+            with vuetify.VListItem(
+                click="window.trame.utils.vtk_prompt.exportSession(s.id, s.title)"
+            ):
+                vuetify.VListItemTitle("Export")
             with vuetify.VListItem(
                 click=(
                     "delete_target_id = s.id; delete_target_title = s.title;"
@@ -88,6 +102,23 @@ def _dialogs(app: Any) -> None:
                     color="primary",
                     variant="text",
                 )
+    # Import
+    with vuetify.VDialog(v_model=("import_dialog", False), max_width="480"):
+        with vuetify.VCard():
+            vuetify.VCardTitle("Import conversation")
+            with vuetify.VCardText():
+                vuetify.VFileUpload(
+                    label="Choose a .json conversation file",
+                    v_model=("uploaded_files", None),
+                    accept=".json",
+                    multiple=True,
+                    hide_details="auto",
+                    density="compact",
+                    color="teal-lighten-5",
+                )
+            with vuetify.VCardActions():
+                vuetify.VSpacer()
+                vuetify.VBtn("Close", click="import_dialog = false", variant="text")
     # Delete
     with vuetify.VDialog(v_model=("delete_dialog", False), max_width="420"):
         with vuetify.VCard():
diff --git a/src/vtk_prompt/ui/layout/settings_dialog.py b/src/vtk_prompt/ui/layout/settings_dialog.py
index 71c6742..a51bc21 100644
--- a/src/vtk_prompt/ui/layout/settings_dialog.py
+++ b/src/vtk_prompt/ui/layout/settings_dialog.py
@@ -7,238 +7,239 @@
 
 from typing import Any
 
+from trame.widgets import html
 from trame.widgets import vuetify3 as vuetify
 
 from ...provider_utils import DEFAULT_MODEL, DEFAULT_PROVIDER
 
 vuetify.enable_lab()
 
+_LABEL = "text-overline text-medium-emphasis d-block mb-1"
+_DESC = "text-caption text-medium-emphasis d-block mb-3"
+
+
+def _section(title: str) -> None:
+    html.Div(title, classes=_LABEL)
+
 
 def build_settings_dialog(layout: Any, app: Any) -> None:
     """Build the advanced settings dialog with configuration options."""
     with layout.content:
-        with vuetify.VDialog(v_model=("advanced_settings_open", False), classes="w-33"):
+        with vuetify.VDialog(v_model=("advanced_settings_open", False), max_width="560"):
             with vuetify.VCard():
                 with vuetify.VTabs(
                     v_model=("active_settings_tab", "files"),
                     color="primary",
-                    classes="pa-1",
+                    classes="px-2",
                 ):
-                    vuetify.VTab("Files", value="files")
+                    vuetify.VTab("Config", value="files")
                     vuetify.VTab("Model", value="model")
                     vuetify.VTab("Advanced", value="advanced")
+                vuetify.VDivider()
                 with vuetify.VTabsWindow(v_model=("active_settings_tab", "files")):
-                    # Files Tab
-                    with vuetify.VTabsWindowItem(value="files"):
-                        with vuetify.VCard():
-                            with vuetify.VCardTitle("Uploads"):
-                                vuetify.VCardSubtitle(
-                                    "Upload conversation files (.json) or prompt "
-                                    "config files (.yaml/.yml)"
-                                )
-                            with vuetify.VCardText():
-                                with vuetify.VTooltip(
-                                    text="Upload conversation files (.json) or prompt "
-                                    "config files (.yaml/.yml)",
-                                    location="top",
-                                ):
-                                    with vuetify.Template(v_slot_activator="{ props }"):
-                                        vuetify.VFileUpload(
-                                            label="Upload Files (.json, .yaml, .yml)",
-                                            v_model=("uploaded_files", None),
-                                            accept=".json,.yaml,.yml",
-                                            multiple=True,
-                                            hide_details="auto",
-                                            classes="py-3 pr-1 mr-1 w-100",
-                                            v_bind="props",
-                                            color="teal-lighten-5",
-                                        )
-                        with vuetify.VCard():
-                            with vuetify.VCardTitle("Settings"):
-                                vuetify.VCardSubtitle("Configure default behavior")
-                            with vuetify.VCardText():
-                                vuetify.VCheckbox(
-                                    label="Automatically run new conversation files",
-                                    v_model=("auto_run_conversation_file", True),
-                                    density="compact",
-                                    color="primary",
-                                    hide_details=True,
-                                )
-                        with vuetify.VCard():
-                            with vuetify.VCardTitle("Downloads"):
-                                vuetify.VCardSubtitle("Download conversation or prompt files")
-                            with vuetify.VCardText():
-                                with vuetify.VRow(cols=12):
-                                    with vuetify.VCol(cols=6):
-                                        vuetify.VBtn(
-                                            "Download Conversation File",
-                                            color="secondary",
-                                            classes="mr-2 mt-2 w-100",
-                                            click="download_conversation_file",
-                                            append_icon="mdi-download",
-                                        )
-                                    with vuetify.VCol(cols=6):
-                                        vuetify.VBtn(
-                                            "Download Prompt File",
-                                            color="secondary",
-                                            classes="mr-2 mt-2 w-100",
-                                            click="download_prompt_file",
-                                            append_icon="mdi-download",
-                                        )
-                    # Model Tab
-                    with vuetify.VTabsWindowItem(value="model"):
-                        # Tab Navigation - Centered
-                        with vuetify.VRow(justify="center"):
-                            with vuetify.VCol(cols="auto"):
-                                with vuetify.VTabs(
-                                    v_model=("tab_index", 0),
-                                    color="primary",
-                                    slider_color="primary",
-                                    centered=True,
-                                    grow=False,
-                                ):
-                                    vuetify.VTab("☁️ Cloud")
-                                    vuetify.VTab("🏠Local")
-
-                        # Tab Content
-                        with vuetify.VTabsWindow(v_model="tab_index"):
-                            # Cloud Providers Tab Content
-                            with vuetify.VTabsWindowItem():
-                                with vuetify.VCard(flat=True, style="mt-2"):
-                                    with vuetify.VCardText():
-                                        # Provider selection
-                                        vuetify.VSelect(
-                                            label="Provider",
-                                            v_model=("provider", DEFAULT_PROVIDER),
-                                            items=("available_providers", []),
-                                            density="compact",
-                                            variant="outlined",
-                                            prepend_icon="mdi-cloud",
-                                        )
-                                        # Model selection
-                                        vuetify.VSelect(
-                                            label="Model",
-                                            v_model=("model", DEFAULT_MODEL),
-                                            items=("available_models[provider] || []",),
-                                            density="compact",
-                                            variant="outlined",
-                                            prepend_icon="mdi-brain",
-                                        )
-                                        # API Token
-                                        vuetify.VTextField(
-                                            label="API Token",
-                                            v_model=("api_token", ""),
-                                            placeholder="Enter your API token",
-                                            type="password",
-                                            density="compact",
-                                            variant="outlined",
-                                            prepend_icon="mdi-key",
-                                            hint="Required for cloud providers",
-                                            persistent_hint=True,
-                                            error=("!api_token", False),
-                                        )
-
-                            # Local Models Tab Content
-                            with vuetify.VTabsWindowItem():
-                                with vuetify.VCard(flat=True, style="mt-2"):
-                                    with vuetify.VCardText():
-                                        vuetify.VTextField(
-                                            label="Base URL",
-                                            v_model=(
-                                                "local_base_url",
-                                                "http://localhost:11434/v1",
-                                            ),
-                                            placeholder="http://localhost:11434/v1",
-                                            density="compact",
-                                            variant="outlined",
-                                            prepend_icon="mdi-server",
-                                            hint="Ollama, LM Studio, etc.",
-                                            persistent_hint=True,
-                                        )
-                                        vuetify.VTextField(
-                                            label="Model Name",
-                                            v_model=("local_model", "devstral"),
-                                            placeholder="devstral",
-                                            density="compact",
-                                            variant="outlined",
-                                            prepend_icon="mdi-brain",
-                                            hint="Model identifier",
-                                            persistent_hint=True,
-                                        )
-                                        # Optional API Token for local
-                                        vuetify.VTextField(
-                                            label="API Token (Optional)",
-                                            v_model=("api_token", "ollama"),
-                                            placeholder="ollama",
-                                            type="password",
-                                            density="compact",
-                                            variant="outlined",
-                                            prepend_icon="mdi-key",
-                                            hint="Optional for local servers",
-                                            persistent_hint=True,
-                                        )
-
-                    # Advanced Settings Tab
-                    with vuetify.VTabsWindowItem(value="advanced"):
-                        # vtk-mcp Settings Card
-                        with vuetify.VCard(classes="mt-2"):
-                            vuetify.VCardTitle("🔌 vtk-mcp", classes="pb-0")
-                            with vuetify.VCardText():
-                                vuetify.VTextField(
-                                    label="vtk-mcp Server URL",
-                                    v_model=("mcp_url", ""),
-                                    placeholder="http://localhost:8000",
-                                    clearable=True,
-                                    density="compact",
-                                    variant="outlined",
-                                    prepend_icon="mdi-bookshelf",
-                                    hint="Enables context retrieval and VTK API "
-                                    "validation; leave blank for baseline generation",
-                                    persistent_hint=True,
-                                )
-                                vuetify.VTextField(
-                                    label="Top K",
-                                    v_model=("top_k", 5),
-                                    type="number",
-                                    min=1,
-                                    max=15,
-                                    density="compact",
-                                    disabled=("!mcp_url",),
-                                    variant="outlined",
-                                    prepend_icon="mdi-chart-scatter-plot",
-                                )
-
-                        # Generation Settings Card
-                        with vuetify.VCard(classes="mt-2"):
-                            vuetify.VCardTitle("⚙️ Generation Settings", classes="pb-0")
-                            with vuetify.VCardText():
-                                vuetify.VSlider(
-                                    label="Temperature",
-                                    v_model=("temperature", 0.1),
-                                    min=0.0,
-                                    max=1.0,
-                                    step=0.1,
-                                    thumb_label="always",
-                                    color="orange",
-                                    prepend_icon="mdi-thermometer",
-                                    classes="mt-2",
-                                    disabled=("!temperature_supported",),
-                                )
-                                vuetify.VTextField(
-                                    label="Max Tokens",
-                                    v_model=("max_tokens", 1000),
-                                    type="number",
-                                    density="compact",
-                                    variant="outlined",
-                                    prepend_icon="mdi-format-text",
-                                )
-                                vuetify.VTextField(
-                                    label="Retry Attempts",
-                                    v_model=("retry_attempts", 3),
-                                    type="number",
-                                    min=1,
-                                    max=5,
-                                    density="compact",
-                                    variant="outlined",
-                                    prepend_icon="mdi-repeat",
-                                )
+                    _config_tab()
+                    _model_tab()
+                    _advanced_tab()
+
+
+def _config_tab() -> None:
+    with vuetify.VTabsWindowItem(value="files"):
+        with vuetify.VCardText(classes="pa-4"):
+            _section("Configuration")
+            html.Div(
+                "Import or export the model/prompt config (.yaml). To import a "
+                "conversation, use Import in Recents.",
+                classes=_DESC,
+            )
+            vuetify.VFileInput(
+                label="Import config file (.yaml, .yml)",
+                v_model=("uploaded_files", None),
+                accept=".yaml,.yml",
+                multiple=True,
+                prepend_icon="",
+                prepend_inner_icon="mdi-upload",
+                density="compact",
+                variant="outlined",
+                hide_details=True,
+                classes="mb-3",
+            )
+            vuetify.VBtn(
+                "Download config",
+                variant="outlined",
+                color="primary",
+                size="small",
+                prepend_icon="mdi-download",
+                click="window.trame.utils.vtk_prompt.exportConfig()",
+            )
+
+            vuetify.VDivider(classes="my-5")
+            _section("Behavior")
+            vuetify.VCheckbox(
+                label="Automatically run imported conversations",
+                v_model=("auto_run_conversation_file", True),
+                density="compact",
+                color="primary",
+                hide_details=True,
+            )
+
+            vuetify.VDivider(classes="my-5")
+            _section("Sample data")
+            html.Div(
+                "Local VTK data tree used to resolve example datasets by name "
+                "(e.g. cow.g).",
+                classes=_DESC,
+            )
+            vuetify.VTextField(
+                label="Sample data location",
+                v_model=("data_root", ""),
+                placeholder="/path/to/VTK/Testing/Data",
+                hint="Folder of .sha512 data pointers; blank uses the "
+                "VTK_PROMPT_DATA_ROOT environment variable",
+                persistent_hint=True,
+                density="compact",
+                variant="outlined",
+                clearable=True,
+            )
+
+
+def _model_tab() -> None:
+    with vuetify.VTabsWindowItem(value="model"):
+        with vuetify.VCardText(classes="pa-4"):
+            with vuetify.VTabs(
+                v_model=("tab_index", 0),
+                color="primary",
+                density="compact",
+                classes="mb-4",
+            ):
+                vuetify.VTab("Cloud", prepend_icon="mdi-cloud-outline")
+                vuetify.VTab("Local", prepend_icon="mdi-laptop")
+            with vuetify.VTabsWindow(v_model="tab_index", classes="pt-3"):
+                with vuetify.VTabsWindowItem():
+                    vuetify.VSelect(
+                        label="Provider",
+                        v_model=("provider", DEFAULT_PROVIDER),
+                        items=("available_providers", []),
+                        density="compact",
+                        variant="outlined",
+                        classes="mb-3",
+                    )
+                    vuetify.VSelect(
+                        label="Model",
+                        v_model=("model", DEFAULT_MODEL),
+                        items=("available_models[provider] || []",),
+                        density="compact",
+                        variant="outlined",
+                        classes="mb-3",
+                    )
+                    vuetify.VTextField(
+                        label="API token",
+                        v_model=("api_token", ""),
+                        placeholder="Enter your API token",
+                        type="password",
+                        density="compact",
+                        variant="outlined",
+                        hint="Required for cloud providers",
+                        persistent_hint=True,
+                        error=("!api_token", False),
+                    )
+                with vuetify.VTabsWindowItem():
+                    vuetify.VTextField(
+                        label="Base URL",
+                        v_model=("local_base_url", "http://localhost:11434/v1"),
+                        placeholder="http://localhost:11434/v1",
+                        density="compact",
+                        variant="outlined",
+                        hint="Ollama, LM Studio, and other OpenAI-compatible servers",
+                        persistent_hint=True,
+                        classes="mb-3",
+                    )
+                    vuetify.VTextField(
+                        label="Model name",
+                        v_model=("local_model", "devstral"),
+                        placeholder="devstral",
+                        density="compact",
+                        variant="outlined",
+                        hint="Model identifier as served by your endpoint",
+                        persistent_hint=True,
+                        classes="mb-3",
+                    )
+                    vuetify.VTextField(
+                        label="API token",
+                        v_model=("api_token", "ollama"),
+                        placeholder="ollama",
+                        type="password",
+                        density="compact",
+                        variant="outlined",
+                        hint="Optional for local servers",
+                        persistent_hint=True,
+                    )
+
+
+def _advanced_tab() -> None:
+    with vuetify.VTabsWindowItem(value="advanced"):
+        with vuetify.VCardText(classes="pa-4"):
+            _section("vtk-mcp")
+            html.Div(
+                "Connect a vtk-mcp server to ground generation in the real VTK API "
+                "and validate code before returning it.",
+                classes=_DESC,
+            )
+            vuetify.VTextField(
+                label="Server URL",
+                v_model=("mcp_url", ""),
+                placeholder="http://localhost:8000",
+                clearable=True,
+                density="compact",
+                variant="outlined",
+                hint="Leave blank for baseline generation without tools",
+                persistent_hint=True,
+                classes="mb-3",
+            )
+            vuetify.VTextField(
+                label="Top K",
+                v_model=("top_k", 5),
+                type="number",
+                min=1,
+                max=15,
+                density="compact",
+                variant="outlined",
+                disabled=("!mcp_url",),
+                hint="Context snippets retrieved per request",
+                persistent_hint=True,
+            )
+
+            vuetify.VDivider(classes="my-5")
+            _section("Generation")
+            with html.Div(classes="d-flex align-center justify-space-between mt-2 mb-1"):
+                html.Span("Temperature", classes="text-body-2")
+                html.Span(
+                    "{{ temperature }}", classes="text-body-2 text-medium-emphasis"
+                )
+            vuetify.VSlider(
+                v_model=("temperature", 0.1),
+                min=0.0,
+                max=1.0,
+                step=0.1,
+                thumb_label=True,
+                color="primary",
+                hide_details=True,
+                disabled=("!temperature_supported",),
+                classes="mb-4",
+            )
+            vuetify.VTextField(
+                label="Max tokens",
+                v_model=("max_tokens", 1000),
+                type="number",
+                density="compact",
+                variant="outlined",
+                classes="mb-3",
+            )
+            vuetify.VTextField(
+                label="Retry attempts",
+                v_model=("retry_attempts", 3),
+                type="number",
+                min=1,
+                max=5,
+                density="compact",
+                variant="outlined",
+            )
diff --git a/src/vtk_prompt/utils.js b/src/vtk_prompt/utils.js
index 5cbfeae..e019583 100644
--- a/src/vtk_prompt/utils.js
+++ b/src/vtk_prompt/utils.js
@@ -10,4 +10,32 @@ window.trame.utils.vtk_prompt = {
       return true;
     },
   },
+
+  download(name, text, mime) {
+    const blob = new Blob([text], { type: mime || "application/json" });
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement("a");
+    a.href = url;
+    a.download = name;
+    document.body.appendChild(a);
+    a.click();
+    a.remove();
+    URL.revokeObjectURL(url);
+  },
+
+  sanitize(name) {
+    return (name || "conversation").replace(/[^\w.-]+/g, "_").slice(0, 80);
+  },
+
+  async exportSession(id, title) {
+    const text = await window.trame.trigger("export_session", [id]);
+    if (text) {
+      this.download(this.sanitize(title) + ".json", text, "application/json");
+    }
+  },
+
+  async exportConfig() {
+    const text = await window.trame.trigger("save_config");
+    if (text) this.download("vtk-prompt-config.yaml", text, "text/yaml");
+  },
 };
diff --git a/src/vtk_prompt/utils/prompt_loader.py b/src/vtk_prompt/utils/prompt_loader.py
index d8a7627..668d89a 100644
--- a/src/vtk_prompt/utils/prompt_loader.py
+++ b/src/vtk_prompt/utils/prompt_loader.py
@@ -124,6 +124,12 @@ def _process_rag_and_generation_settings(app: Any) -> None:
         _base = app.custom_prompt_data.get("base_url")
         if isinstance(_base, str) and _base.strip():
             app.state.local_base_url = _base.strip()
+    if "data_root" in app.custom_prompt_data:
+        _dr = app.custom_prompt_data.get("data_root")
+        if isinstance(_dr, str):
+            app.state.data_root = _dr.strip()
+            from ..data.resolver import set_data_root
+            set_data_root(app.state.data_root)
 
 
 def _process_model_parameters(app: Any) -> None:
diff --git a/src/vtk_prompt/vtk_prompt_ui.py b/src/vtk_prompt/vtk_prompt_ui.py
index 93daddf..341fdec 100644
--- a/src/vtk_prompt/vtk_prompt_ui.py
+++ b/src/vtk_prompt/vtk_prompt_ui.py
@@ -344,6 +344,11 @@ def save_conversation(self) -> str:
         """Save current conversation history as JSON string."""
         return conversation.save_conversation(self)
 
+    @trigger("export_session")
+    def export_session(self, session_id: str) -> str:
+        """Return one session's JSON for download (called from utils.js)."""
+        return sessions.export_session(self, session_id)
+
     @trigger("save_config")
     def save_config(self) -> str:
         """Save current configuration as YAML string for download."""
@@ -354,6 +359,14 @@ def _on_provider_change(self, provider, **kwargs) -> None:
         """Handle provider selection change."""
         configuration.on_provider_change(self, provider, **kwargs)
 
+    @change("data_root")
+    def _on_data_root_change(self, data_root, **_: Any) -> None:
+        """Repoint the sample-data resolver and refresh referenced-file chips."""
+        from .data.resolver import artifacts, set_data_root
+
+        set_data_root(data_root or "")
+        self.state.data_artifacts = artifacts(self.state.generated_code)
+
     @change("history_sort_order")
     def _on_sessions_sort_change(self, **_: Any) -> None:
         """Re-render the Recents list when its sort order changes."""
@@ -362,6 +375,11 @@ def _on_sessions_sort_change(self, **_: Any) -> None:
     @change("generated_code")
     def _on_generated_code_change(self, **_: Any) -> None:
         """Debounce-snapshot manual edits so undo/redo can step through them."""
+        # Surface the data files the current code references (pure index lookup).
+        from .data.resolver import artifacts
+
+        self.state.data_artifacts = artifacts(self.state.generated_code)
+
         if self._snapshot_task is not None and not self._snapshot_task.done():
             self._snapshot_task.cancel()
         try:
diff --git a/tests/test_executor_guarded_main.py b/tests/test_executor_guarded_main.py
index f58628d..517198f 100644
--- a/tests/test_executor_guarded_main.py
+++ b/tests/test_executor_guarded_main.py
@@ -46,6 +46,6 @@ def test_guarded_main_script_adds_actor_to_renderer():
     except Exception:  # pragma: no cover - no VTK rendering backend available
         pytest.skip("VTK render window unavailable in this environment")
 
-    ok, err = execute_vtk_code(GUARDED_SPHERE, renderer, render_window)
+    ok, err, _ = execute_vtk_code(GUARDED_SPHERE, renderer, render_window)
     assert ok, err
     assert renderer.GetActors().GetNumberOfItems() == 1