diff --git a/isaaclab_arena_examples/agentic_environment_generation/gui_runner.py b/isaaclab_arena_examples/agentic_environment_generation/gui_runner.py
new file mode 100644
index 000000000..8bf2ae3c5
--- /dev/null
+++ b/isaaclab_arena_examples/agentic_environment_generation/gui_runner.py
@@ -0,0 +1,91 @@
+# Copyright (c) 2026, The Isaac Lab Arena Project Developers (https://github.com/isaac-sim/IsaacLab-Arena/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+"""CLI launcher for the ArenaEnvInitialGraphSpec live editor.
+
+Spawns Streamlit with :mod:`~isaaclab_arena_examples.agentic_environment_generation.review_gui.streamlit_ui`.
+
+Usage:
+    # Default — prompt-only (empty editor until you generate or paste YAML):
+    /isaac-sim/python.sh -m isaaclab_arena_examples.agentic_environment_generation.gui_runner
+
+    # Open an existing spec:
+    /isaac-sim/python.sh -m isaaclab_arena_examples.agentic_environment_generation.gui_runner \\
+        --yaml isaaclab_arena/tests/test_data/pick_and_place_maple_table_init_env_graph.yaml
+
+    # Custom port:
+    /isaac-sim/python.sh -m isaaclab_arena_examples.agentic_environment_generation.gui_runner \\
+        --yaml <path> --port 8600
+"""
+
+from __future__ import annotations
+
+import argparse
+import os
+import subprocess
+import sys
+from pathlib import Path
+
+_REVIEW_GUI_DIR = Path(__file__).resolve().parent / "review_gui"
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description=__doc__,
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+    parser.add_argument(
+        "--yaml",
+        type=Path,
+        default=None,
+        help="Optional ArenaEnvInitialGraphSpec YAML to open in the editor.",
+    )
+    parser.add_argument(
+        "--port",
+        type=int,
+        default=8501,
+        help="Streamlit server port (default: 8501).",
+    )
+    args = parser.parse_args()
+    serve_live_editor(args.yaml, port=args.port)
+
+
+def serve_live_editor(yaml_path: Path | None, port: int = 8501) -> None:
+    """Spawn ``streamlit run streamlit_ui.py`` and wait."""
+    app_path = _REVIEW_GUI_DIR / "streamlit_ui.py"
+    if not app_path.exists():
+        raise FileNotFoundError(f"Streamlit app not found at {app_path} — installation is incomplete.")
+
+    cmd = [
+        sys.executable,
+        "-m",
+        "streamlit",
+        "run",
+        str(app_path),
+        "--server.port",
+        str(port),
+        "--browser.gatherUsageStats",
+        "false",
+        "--server.fileWatcherType",
+        "none",
+        "--",
+    ]
+    if yaml_path is not None:
+        cmd.extend(["--yaml", str(yaml_path.resolve())])
+
+    print(f"[review_gui] launching Streamlit live editor: {' '.join(cmd)}", file=sys.stderr)
+    try:
+        subprocess.run(cmd, env=os.environ.copy(), check=True)
+    except FileNotFoundError as exc:
+        raise SystemExit(
+            "Streamlit is not installed. Inside the isaaclab_arena container run:\n"
+            "  python -m pip install --user --ignore-installed streamlit streamlit-ace"
+        ) from exc
+    except KeyboardInterrupt:
+        pass
+
+
+if __name__ == "__main__":
+    main()
diff --git a/isaaclab_arena_examples/agentic_environment_generation/review_gui/__init__.py b/isaaclab_arena_examples/agentic_environment_generation/review_gui/__init__.py
new file mode 100644
index 000000000..821e672b4
--- /dev/null
+++ b/isaaclab_arena_examples/agentic_environment_generation/review_gui/__init__.py
@@ -0,0 +1,6 @@
+# Copyright (c) 2026, The Isaac Lab Arena Project Developers (https://github.com/isaac-sim/IsaacLab-Arena/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+"""Live editor and HTML dashboard for :class:`~isaaclab_arena.environments.arena_env_graph_spec.ArenaEnvInitialGraphSpec`."""
diff --git a/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/__init__.py b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/__init__.py
new file mode 100644
index 000000000..2fd363882
--- /dev/null
+++ b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/__init__.py
@@ -0,0 +1,6 @@
+# Copyright (c) 2026, The Isaac Lab Arena Project Developers (https://github.com/isaac-sim/IsaacLab-Arena/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+"""HTML rendering backend for the initial-graph review dashboard."""
diff --git a/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/dashboard.py b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/dashboard.py
new file mode 100644
index 000000000..39a135dd0
--- /dev/null
+++ b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/dashboard.py
@@ -0,0 +1,60 @@
+# Copyright (c) 2026, The Isaac Lab Arena Project Developers (https://github.com/isaac-sim/IsaacLab-Arena/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+from __future__ import annotations
+
+import html as html_lib
+
+from isaaclab_arena.environments.arena_env_graph_spec import ArenaEnvInitialGraphSpec
+from isaaclab_arena_examples.agentic_environment_generation.review_gui.render.mermaid_graph import render_mermaid_graph
+from isaaclab_arena_examples.agentic_environment_generation.review_gui.render.panels import (
+    render_node_cards,
+    render_tasks_table,
+    render_unary_constraints,
+)
+from isaaclab_arena_examples.agentic_environment_generation.review_gui.render.styles import DASHBOARD_CSS
+
+
+def render_dashboard_html(spec: ArenaEnvInitialGraphSpec) -> str:
+    """Render the self-contained review dashboard HTML for ``spec``."""
+    initial_state = spec.initial_state_spec
+    return f"""<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<title>{html_lib.escape(spec.env_name)} — graph review</title>
+<script src="https://cdn.jsdelivr.net/npm/mermaid@10/dist/mermaid.min.js"></script>
+<style>{DASHBOARD_CSS}</style>
+</head>
+<body>
+<header>
+  <h1>{html_lib.escape(spec.env_name)}</h1>
+  <p class="sub">{len(spec.nodes)} nodes · {len(spec.tasks)} tasks · initial state: <code>{html_lib.escape(initial_state.id)}</code></p>
+</header>
+<main>
+  <section class="panel nodes-panel">
+    <h2>Nodes</h2>
+    <div class="node-grid">{render_node_cards(spec)}</div>
+  </section>
+  <section class="panel graph-panel">
+    <h2>Spatial graph <span class="muted">(initial state: <code>{html_lib.escape(initial_state.id)}</code>)</span></h2>
+    <div class="graph-row">
+      <div class="graph-mermaid">
+        <pre class="mermaid">{render_mermaid_graph(spec, initial_state)}</pre>
+      </div>
+      <aside class="graph-unary">
+        {render_unary_constraints(initial_state)}
+      </aside>
+    </div>
+  </section>
+  <section class="panel tasks-panel">
+    <h2>Tasks</h2>
+    {render_tasks_table(spec)}
+  </section>
+</main>
+<script>mermaid.initialize({{ startOnLoad: true, theme: 'dark', themeVariables: {{ fontFamily: 'ui-monospace, monospace' }} }});</script>
+</body>
+</html>
+"""
diff --git a/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/mermaid_graph.py b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/mermaid_graph.py
new file mode 100644
index 000000000..7ec9c3fb0
--- /dev/null
+++ b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/mermaid_graph.py
@@ -0,0 +1,96 @@
+# Copyright (c) 2026, The Isaac Lab Arena Project Developers (https://github.com/isaac-sim/IsaacLab-Arena/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+from __future__ import annotations
+
+import re
+
+from isaaclab_arena.environments.arena_env_graph_spec import ArenaEnvInitialGraphSpec
+from isaaclab_arena.environments.arena_env_graph_types import ArenaEnvGraphStateSpec
+
+_MERMAID_ID_SAFE = re.compile(r"[^A-Za-z0-9_]")
+
+
+def render_mermaid_graph(spec: ArenaEnvInitialGraphSpec, state: ArenaEnvGraphStateSpec) -> str:
+    """Emit a left-to-right mermaid graph of spatial and task constraints.
+
+    Binary spatial constraints (reference is set) are drawn as solid edges:
+        subject -->|kind| reference
+
+    Unary spatial constraints (no reference) are omitted from the graph and
+    listed to its right by :func:`render_unary_constraints` so their params are
+    visible.
+
+    Task constraints with a child are drawn as dashed edges:
+        parent -.->|type| child
+
+    object_reference nodes are drawn with a dotted edge to their parent node:
+        ref_node -. ref .-> parent_node
+    """
+    lines = ["graph LR"]
+
+    anchor_ids: set[str] = set()
+    edge_nodes: set[str] = set()
+
+    for constraint in state.spatial_constraints:
+        kind = constraint.kind
+        if kind == "is_anchor":
+            anchor_ids.add(constraint.subject)
+        if constraint.reference is not None:
+            lines.append(
+                f"  {_mermaid_id(constraint.subject)}[{_mermaid_label(constraint.subject)}]"
+                f" -->|{kind}| "
+                f"{_mermaid_id(constraint.reference)}[{_mermaid_label(constraint.reference)}]"
+            )
+            edge_nodes.add(constraint.subject)
+            edge_nodes.add(constraint.reference)
+
+    for task_constraint in state.task_constraints:
+        if task_constraint.child is not None:
+            lines.append(
+                f"  {_mermaid_id(task_constraint.parent)}[{_mermaid_label(task_constraint.parent)}]"
+                f" -.->|{_mermaid_label(task_constraint.type.value)}| "
+                f"{_mermaid_id(task_constraint.child)}[{_mermaid_label(task_constraint.child)}]"
+            )
+            edge_nodes.add(task_constraint.parent)
+            edge_nodes.add(task_constraint.child)
+
+    for node in spec.nodes:
+        if node.id not in edge_nodes:
+            lines.append(f"  {_mermaid_id(node.id)}[{_mermaid_label(node.id)}]")
+
+    nodes_by_id = spec.nodes_by_id
+    for node in spec.nodes:
+        if node.type.value == "object_reference" and node.parent is not None:
+            if node.parent in nodes_by_id:
+                lines.append(f"  {_mermaid_id(node.id)} -.->|ref| {_mermaid_id(node.parent)}")
+
+    for anchor_id in anchor_ids:
+        lines.append(f"  style {_mermaid_id(anchor_id)} fill:#3a7d44,color:#fff,stroke:#7fd17f,stroke-width:2px")
+
+    type_palette = {
+        "background": ("#3a4f7a", "#7aa0d8"),
+        "embodiment": ("#7a3a3a", "#d87a7a"),
+        "object": ("#7a6b3a", "#d8c47a"),
+        "object_reference": ("#6b3a7a", "#c47ad8"),
+        "lighting": ("#3a7a7a", "#7ad8d8"),
+    }
+    for node in spec.nodes:
+        if node.id in anchor_ids:
+            continue
+        fill, stroke = type_palette.get(node.type.value, ("#3a3d44", "#888"))
+        lines.append(f"  style {_mermaid_id(node.id)} fill:{fill},color:#fff,stroke:{stroke}")
+
+    return "\n".join(lines)
+
+
+def _mermaid_id(value: str) -> str:
+    """Mermaid node identifiers must be alphanumeric / underscore."""
+    return _MERMAID_ID_SAFE.sub("_", value)
+
+
+def _mermaid_label(value: str) -> str:
+    """Escape mermaid-significant characters inside node labels."""
+    return value.replace('"', "&quot;").replace("|", "&#124;")
diff --git a/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/panels.py b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/panels.py
new file mode 100644
index 000000000..6ab00637d
--- /dev/null
+++ b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/panels.py
@@ -0,0 +1,83 @@
+# Copyright (c) 2026, The Isaac Lab Arena Project Developers (https://github.com/isaac-sim/IsaacLab-Arena/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+from __future__ import annotations
+
+import html as html_lib
+import yaml
+
+from isaaclab_arena.environments.arena_env_graph_spec import ArenaEnvInitialGraphSpec
+from isaaclab_arena.environments.arena_env_graph_types import ArenaEnvGraphNodeSpec, ArenaEnvGraphStateSpec
+from isaaclab_arena_examples.agentic_environment_generation.review_gui.render.thumbnails import (
+    render_placeholder_thumbnail,
+)
+
+
+def render_unary_constraints(state: ArenaEnvGraphStateSpec) -> str:
+    """List constraints without a reference beside the spatial graph."""
+    rows = []
+    for constraint in state.spatial_constraints:
+        if constraint.reference is not None:
+            continue
+        params = (
+            " <code"
+            f' class="muted">{html_lib.escape(yaml.safe_dump(constraint.params, default_flow_style=True).rstrip())}</code>'
+            if constraint.params
+            else ""
+        )
+        rows.append(
+            f'<li><span class="badge type-{html_lib.escape(constraint.kind)}">{html_lib.escape(constraint.kind)}</span>'
+            f" on <code>{html_lib.escape(constraint.subject)}</code>{params}</li>"
+        )
+    if not rows:
+        return '<p class="muted unary-empty"><em>No unary constraints.</em></p>'
+    return (
+        f'<h3 class="unary-heading">Unary constraints <span class="muted">({len(rows)})</span></h3>'
+        f'<ul class="unary-list">{"".join(rows)}</ul>'
+    )
+
+
+def render_tasks_table(spec: ArenaEnvInitialGraphSpec) -> str:
+    """Render task rows as an HTML table for the dashboard tasks panel."""
+    if not spec.tasks:
+        return "<p class='muted'><em>No tasks defined.</em></p>"
+    rows = []
+    for index, task in enumerate(spec.tasks):
+        params_str = yaml.safe_dump(task.params, sort_keys=False).rstrip() if task.params else "(empty)"
+        description = html_lib.escape(task.description or "")
+        rows.append(
+            "<tr>"
+            f"<td><code>{index}</code></td>"
+            f'<td><span class="badge type-task">{html_lib.escape(task.kind)}</span></td>'
+            f"<td>{description}</td>"
+            f"<td><pre>{html_lib.escape(params_str)}</pre></td>"
+            "</tr>"
+        )
+    return (
+        "<table class='tasks'>"
+        "<thead><tr><th>#</th><th>kind</th><th>description</th><th>params</th></tr></thead>"
+        f"<tbody>{''.join(rows)}</tbody>"
+        "</table>"
+    )
+
+
+def render_node_cards(spec: ArenaEnvInitialGraphSpec) -> str:
+    """Render one card per graph node for the dashboard nodes panel."""
+    return "\n".join(render_node_card(node) for node in spec.nodes)
+
+
+def render_node_card(node: ArenaEnvGraphNodeSpec) -> str:
+    """Render a single node card with placeholder thumbnail and YAML dump."""
+    node_dict = node.model_dump(mode="json", exclude_none=True)
+    node_yaml = yaml.safe_dump(node_dict, sort_keys=False).rstrip()
+    thumb = render_placeholder_thumbnail(node)
+    return f"""<article class="node-card type-{html_lib.escape(node.type.value)}">
+  {thumb}
+  <div class="node-meta">
+    <div class="node-id">{html_lib.escape(node.id)}</div>
+    <span class="badge type-{html_lib.escape(node.type.value)}">{html_lib.escape(node.type.value)}</span>
+  </div>
+  <pre class="node-yaml">{html_lib.escape(node_yaml)}</pre>
+</article>"""
diff --git a/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/styles.py b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/styles.py
new file mode 100644
index 000000000..ece136de4
--- /dev/null
+++ b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/styles.py
@@ -0,0 +1,77 @@
+# Copyright (c) 2026, The Isaac Lab Arena Project Developers (https://github.com/isaac-sim/IsaacLab-Arena/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+"""Dark-theme CSS for the review GUI embedded HTML dashboard."""
+
+DASHBOARD_CSS = """
+:root {
+  --bg: #15181d;
+  --bg-elev: #1d2128;
+  --bg-elev2: #262b34;
+  --border: #2f343d;
+  --fg: #e4e6eb;
+  --fg-muted: #8a9099;
+  --accent: #7fd17f;
+}
+* { box-sizing: border-box; }
+body { margin: 0; padding: 24px; font: 14px/1.5 -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
+       background: var(--bg); color: var(--fg); }
+header { margin-bottom: 16px; }
+header h1 { margin: 0; font-size: 28px; font-weight: 700; }
+header .sub { margin: 4px 0 0; color: var(--fg-muted); font-size: 13px; }
+main { display: flex; flex-direction: column; gap: 16px; }
+.panel { background: var(--bg-elev); border: 1px solid var(--border); border-radius: 8px; padding: 16px; }
+.panel h2 { margin: 0 0 12px; font-size: 16px; font-weight: 600; letter-spacing: 0.02em; }
+.panel h2 .muted { color: var(--fg-muted); font-weight: 400; font-size: 13px; }
+.graph-row { display: grid; grid-template-columns: minmax(0, 1fr) minmax(220px, 300px); gap: 16px; align-items: start; }
+.graph-mermaid { min-width: 0; }
+.graph-unary { background: var(--bg-elev2); border: 1px solid var(--border); border-radius: 6px; padding: 12px; }
+.unary-heading { margin: 0 0 10px; font-size: 13px; font-weight: 600; letter-spacing: 0.02em; }
+.unary-heading .muted { font-weight: 400; }
+.unary-list { margin: 0; padding-left: 18px; list-style: disc; color: var(--fg); }
+.unary-list li { padding: 4px 0; font-size: 12px; }
+.unary-empty { margin: 0; font-size: 12px; }
+code { font-family: ui-monospace, 'SF Mono', Menlo, monospace; font-size: 12px;
+       background: var(--bg-elev2); padding: 1px 6px; border-radius: 4px; }
+pre { font-family: ui-monospace, 'SF Mono', Menlo, monospace; font-size: 12px;
+      background: var(--bg-elev2); padding: 10px 12px; border-radius: 6px; margin: 0;
+      white-space: pre-wrap; word-break: break-word; }
+.muted { color: var(--fg-muted); }
+.badge { display: inline-block; padding: 2px 8px; border-radius: 999px; font-size: 11px;
+         font-weight: 600; letter-spacing: 0.03em; background: var(--bg-elev2); color: var(--fg); }
+.badge.type-background { background: #3a4f7a; }
+.badge.type-embodiment { background: #7a3a3a; }
+.badge.type-object { background: #7a6b3a; }
+.badge.type-object_reference { background: #6b3a7a; }
+.badge.type-lighting { background: #3a7a7a; }
+.badge.type-is_anchor { background: #3a7d44; }
+.badge.type-position_limits, .badge.type-at_pose, .badge.type-at_position { background: #6b3a7a; }
+.badge.type-task { background: #2f343d; border: 1px solid #4a5; color: var(--accent); }
+.mermaid { background: var(--bg-elev2); padding: 8px; border-radius: 6px; min-height: 220px;
+           display: flex; align-items: center; justify-content: center; margin: 0; }
+table.tasks { width: 100%; border-collapse: collapse; }
+table.tasks th, table.tasks td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--border);
+                                  vertical-align: top; font-size: 12px; }
+table.tasks th { color: var(--fg-muted); font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; }
+table.tasks pre { padding: 6px 8px; font-size: 11px; }
+.node-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; }
+.node-card { background: var(--bg-elev2); border: 1px solid var(--border); border-radius: 8px;
+             padding: 12px; display: flex; flex-direction: column; gap: 10px; }
+.node-card .thumb { aspect-ratio: 1 / 1; background: linear-gradient(135deg, #2a2f37, #1c2026);
+                    border-radius: 6px; display: flex; flex-direction: column;
+                    align-items: center; justify-content: center; color: var(--fg-muted);
+                    position: relative; overflow: hidden; }
+.node-card .thumb-rendered { background: #0e1115; }
+.node-card .thumb-rendered img { width: 100%; height: 100%; object-fit: contain; display: block; }
+.node-card .thumb-rendered .thumb-name { position: absolute; bottom: 0; left: 0; right: 0;
+                                         padding: 4px 6px; background: rgba(15, 17, 21, 0.78);
+                                         color: var(--fg); margin: 0; }
+.thumb-initial { font-size: 36px; font-weight: 700; color: var(--fg); opacity: 0.6;
+                 font-family: ui-monospace, monospace; }
+.thumb-name { font-size: 10px; margin-top: 6px; padding: 0 8px; text-align: center; word-break: break-word; }
+.node-meta { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
+.node-id { font-family: ui-monospace, monospace; font-size: 13px; font-weight: 600; word-break: break-all; }
+.node-yaml { font-size: 11px; }
+"""
diff --git a/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/thumbnails.py b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/thumbnails.py
new file mode 100644
index 000000000..f2742ee8f
--- /dev/null
+++ b/isaaclab_arena_examples/agentic_environment_generation/review_gui/render/thumbnails.py
@@ -0,0 +1,20 @@
+# Copyright (c) 2026, The Isaac Lab Arena Project Developers (https://github.com/isaac-sim/IsaacLab-Arena/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+from __future__ import annotations
+
+import html as html_lib
+
+from isaaclab_arena.environments.arena_env_graph_types import ArenaEnvGraphNodeSpec
+
+
+# TODO(qianl): Replace placeholder thumbnails with sim-rendered snapshots .
+def render_placeholder_thumbnail(node: ArenaEnvGraphNodeSpec) -> str:
+    """Per-node placeholder thumbnail — two-letter initial."""
+    initial = (node.name[:2] if node.name else "?").upper()
+    return f"""<div class="thumb">
+    <span class="thumb-initial">{html_lib.escape(initial)}</span>
+    <span class="thumb-name">{html_lib.escape(node.name)}</span>
+  </div>"""
diff --git a/isaaclab_arena_examples/agentic_environment_generation/review_gui/streamlit_ui.py b/isaaclab_arena_examples/agentic_environment_generation/review_gui/streamlit_ui.py
new file mode 100644
index 000000000..c3b5b0a59
--- /dev/null
+++ b/isaaclab_arena_examples/agentic_environment_generation/review_gui/streamlit_ui.py
@@ -0,0 +1,454 @@
+# Copyright (c) 2026, The Isaac Lab Arena Project Developers (https://github.com/isaac-sim/IsaacLab-Arena/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+"""Streamlit UI for the initial-graph live editor.
+
+Launch via :mod:`~isaaclab_arena_examples.agentic_environment_generation.gui_runner`:
+
+    # Default — prompt-only (empty editor until you generate or paste YAML):
+    /isaac-sim/python.sh -m isaaclab_arena_examples.agentic_environment_generation.gui_runner
+
+    # Open an existing spec:
+    /isaac-sim/python.sh -m isaaclab_arena_examples.agentic_environment_generation.gui_runner \\
+        --yaml isaaclab_arena/tests/test_data/pick_and_place_maple_table_init_env_graph.yaml
+
+Natural-language generation calls the LLM from Streamlit (``NV_API_KEY``) and
+compiles the returned intent in-process with :class:`IntentCompiler`.
+"""
+
+from __future__ import annotations
+
+import argparse
+import traceback
+import yaml
+from dataclasses import asdict, dataclass
+from pathlib import Path
+from typing import Any
+
+import streamlit as st
+
+from isaaclab_arena.agentic_environment_generation.asset_matcher import ASSET_ERROR_STAGES
+from isaaclab_arena.agentic_environment_generation.environment_generation_agent import (
+    AssetCatalogue,
+    EnvironmentGenerationAgent,
+    RelationCatalogue,
+    TaskCatalogue,
+    build_asset_catalogue,
+    build_relation_catalogue,
+    build_task_catalogue,
+)
+from isaaclab_arena.agentic_environment_generation.intent_compiler import IntentCompiler
+from isaaclab_arena.environments.arena_env_graph_spec import ArenaEnvInitialGraphSpec
+from isaaclab_arena_examples.agentic_environment_generation.review_gui.render.dashboard import render_dashboard_html
+
+_IFRAME_HEIGHT_PX = 1100
+
+_DEFAULT_GENERATION_PROMPT = (
+    "franka pick up avocado from the maple table and place it into a bowl on the table. "
+    "there are other veggies on the table as distractor"
+)
+
+_BROKEN_PLACEHOLDER_HTML = """<!DOCTYPE html><html><body style="
+    font-family: ui-monospace, monospace;
+    background:#15181d; color:#e4e6eb; padding:24px; margin:0;">
+<p>No visualization yet — fix the YAML errors to auto-render.</p>
+</body></html>"""
+
+_DEFAULT_SAVE_PATH = "isaaclab_arena_environments/llm_generated/generated_spec.yaml"
+
+
+@dataclass
+class ValidationResult:
+    """Outcome of parsing and validating YAML text as an initial graph spec."""
+
+    spec: ArenaEnvInitialGraphSpec | None
+    error: str | None
+
+    @property
+    def is_valid(self) -> bool:
+        """True when ``spec`` parsed successfully."""
+        return self.spec is not None
+
+
+@dataclass
+class CatalogueBundle:
+    """Asset/relation/task vocabulary for the env-generation agent."""
+
+    asset_catalogue: AssetCatalogue
+    relation_catalogue: RelationCatalogue
+    task_catalogue: TaskCatalogue
+
+
+@st.cache_resource(show_spinner="Building asset catalogues (first run)…")
+def _get_catalogue_bundle() -> CatalogueBundle:
+    """Build and cache registry-backed catalogues for LLM prompt assembly."""
+    return CatalogueBundle(
+        asset_catalogue=build_asset_catalogue(),
+        relation_catalogue=build_relation_catalogue(),
+        task_catalogue=build_task_catalogue(),
+    )
+
+
+def validate_yaml_text(text: str) -> ValidationResult:
+    """Parse ``text`` as YAML and validate it as an :class:`ArenaEnvInitialGraphSpec`."""
+    cached_text = st.session_state.get("_validation_text")
+    cached_result = st.session_state.get("_validation_result")
+    if cached_text == text and isinstance(cached_result, ValidationResult):
+        return cached_result
+
+    if not text.strip():
+        result = ValidationResult(spec=None, error=None)
+    else:
+        try:
+            raw = yaml.safe_load(text)
+            if raw is None:
+                result = ValidationResult(spec=None, error="YAML is empty")
+            elif not isinstance(raw, dict):
+                result = ValidationResult(spec=None, error=f"Expected mapping, got {type(raw).__name__}")
+            else:
+                spec = ArenaEnvInitialGraphSpec.from_dict(raw)
+                result = ValidationResult(spec=spec, error=None)
+        except Exception:
+            result = ValidationResult(spec=None, error=traceback.format_exc())
+
+    st.session_state["_validation_text"] = text
+    st.session_state["_validation_result"] = result
+    return result
+
+
+def _get_generation_agent() -> EnvironmentGenerationAgent | None:
+    """Lazy-init the LLM agent when ``NV_API_KEY`` is available."""
+    if st.session_state.get("generation_agent_error"):
+        return None
+    agent = st.session_state.get("generation_agent")
+    if agent is not None:
+        return agent
+    try:
+        agent = EnvironmentGenerationAgent()
+    except AssertionError as exc:
+        st.session_state["generation_agent_error"] = str(exc)
+        return None
+    except Exception as exc:
+        st.session_state["generation_agent_error"] = f"{type(exc).__name__}: {exc}"
+        return None
+    st.session_state["generation_agent"] = agent
+    st.session_state.pop("generation_agent_error", None)
+    return agent
+
+
+def _format_trace_lines(trace: list[dict[str, Any]], *, errors_only: bool = False) -> str:
+    """Format intent-compiler trace events as fixed-width log lines."""
+    error_stages = ASSET_ERROR_STAGES | IntentCompiler._ERROR_TRACE_STAGES
+    lines: list[str] = []
+    for event in trace:
+        stage = event.get("stage", "")
+        if errors_only and stage not in error_stages:
+            continue
+        chosen = event.get("chosen")
+        chosen_str = chosen if chosen is not None else "<none>"
+        note = event.get("note") or ""
+        note_str = f"  [{note}]" if note else ""
+        lines.append(f"{stage:34s} {event.get('query', ''):24s} -> {chosen_str}{note_str}")
+    return "\n".join(lines)
+
+
+def _apply_generated_yaml(yaml_text: str, *, spec: ArenaEnvInitialGraphSpec | None = None) -> None:
+    """Push compiled spec YAML into the editor and sync the dashboard preview."""
+    st.session_state["edited_text"] = yaml_text
+    st.session_state["editor_version"] = st.session_state.get("editor_version", 0) + 1
+    st.session_state["last_rendered_text"] = yaml_text
+    if spec is not None:
+        st.session_state["rendered_html"] = render_dashboard_html(spec)
+        st.session_state["_validation_text"] = yaml_text
+        st.session_state["_validation_result"] = ValidationResult(spec=spec, error=None)
+    else:
+        st.session_state["rendered_html"] = ""
+        st.session_state.pop("_validation_text", None)
+        st.session_state.pop("_validation_result", None)
+
+
+def run_generation_pipeline(prompt: str) -> tuple[bool, str]:
+    """Call the LLM, compile intent in-process, and load YAML into the editor."""
+    prompt = prompt.strip()
+    if not prompt:
+        return False, "Enter a prompt describing the environment."
+
+    agent = _get_generation_agent()
+    if agent is None:
+        err = st.session_state.get(
+            "generation_agent_error",
+            "Set NV_API_KEY in the environment before generating specs.",
+        )
+        return False, err
+
+    try:
+        catalogues = _get_catalogue_bundle()
+    except Exception:
+        return False, traceback.format_exc()
+
+    try:
+        intent, _raw = agent.generate_spec(
+            prompt,
+            asset_catalog=catalogues.asset_catalogue,
+            relation_catalog=catalogues.relation_catalogue,
+            task_catalog=catalogues.task_catalogue,
+        )
+    except Exception:
+        return False, traceback.format_exc()
+
+    try:
+        compiler = IntentCompiler()
+        spec = compiler.compile(intent)
+        yaml_text = yaml.safe_dump(spec.to_dict(), sort_keys=False)
+        trace = [asdict(event) for event in compiler.trace]
+        has_resolution_errors = compiler.has_resolution_errors
+        reasoning = intent.reasoning
+    except Exception:
+        return False, traceback.format_exc()
+
+    _apply_generated_yaml(yaml_text, spec=spec)
+
+    if reasoning:
+        st.session_state["last_generation_reasoning"] = reasoning
+    if trace:
+        st.session_state["last_generation_trace"] = trace
+
+    if has_resolution_errors:
+        error_trace = _format_trace_lines(trace, errors_only=True)
+        return (
+            True,
+            (
+                "Spec generated with resolution warnings — review the trace below and edit the YAML as needed.\n\n"
+                f"{error_trace}"
+            ),
+        )
+
+    return True, "Spec generated and loaded into the YAML editor."
+
+
+def parse_args() -> argparse.Namespace:
+    """Parse Streamlit CLI args forwarded after ``--`` by :mod:`gui_runner`."""
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument(
+        "--yaml",
+        type=Path,
+        default=None,
+        help="Optional path to an ArenaEnvInitialGraphSpec YAML to open in the editor.",
+    )
+    return parser.parse_args()
+
+
+def initialize_state(yaml_path: Path | None) -> None:
+    """Seed ``st.session_state`` from disk exactly once per session."""
+    session_key = str(yaml_path.resolve()) if yaml_path is not None else ""
+    if st.session_state.get("_yaml_path") == session_key:
+        return
+
+    st.session_state["_yaml_path"] = session_key
+    st.session_state.setdefault("generation_prompt", _DEFAULT_GENERATION_PROMPT)
+    st.session_state.setdefault("editor_version", 0)
+    st.session_state.pop("_validation_text", None)
+    st.session_state.pop("_validation_result", None)
+
+    if yaml_path is None:
+        st.session_state["original_text"] = ""
+        st.session_state["edited_text"] = ""
+        st.session_state["last_rendered_text"] = ""
+        st.session_state["rendered_html"] = ""
+        st.session_state["save_path"] = _DEFAULT_SAVE_PATH
+        return
+
+    original_text = yaml_path.read_text(encoding="utf-8")
+
+    st.session_state["original_text"] = original_text
+    st.session_state["edited_text"] = original_text
+    st.session_state["last_rendered_text"] = ""
+    st.session_state["rendered_html"] = ""
+    st.session_state["save_path"] = str(yaml_path)
+
+
+def render_validation_badge(validation: ValidationResult) -> None:
+    """Show a success or error badge for the current editor YAML."""
+    if validation.spec is None and validation.error is None:
+        return
+    if validation.is_valid:
+        spec = validation.spec
+        st.success(
+            f"Valid spec — {spec.env_name} · {len(spec.nodes)} nodes · "
+            f"{len(spec.tasks)} tasks · initial state: {spec.initial_state_spec.id}",
+            icon="✅",
+        )
+    else:
+        st.error(f"Invalid YAML\n\n```\n{validation.error}\n```", icon="🛑")
+
+
+def render_save_button(validation: ValidationResult) -> None:
+    """Render save controls and optional save-path editor."""
+    can_save = validation.is_valid
+    save_path_str = st.session_state["save_path"]
+    save_label = f"Save to {Path(save_path_str).name}" if save_path_str else "Save YAML"
+
+    if st.button(
+        save_label,
+        disabled=not can_save,
+        use_container_width=True,
+        help=f"Writes the editor contents to {save_path_str}. Disabled while YAML is invalid.",
+    ):
+        try:
+            out_path = Path(save_path_str)
+            out_path.parent.mkdir(parents=True, exist_ok=True)
+            out_path.write_text(st.session_state["edited_text"], encoding="utf-8")
+            st.session_state["original_text"] = st.session_state["edited_text"]
+            st.toast(f"Saved → {save_path_str}", icon="💾")
+        except OSError as exc:
+            st.error(f"Save failed: {exc}", icon="🛑")
+
+    with st.expander("Change save location", expanded=False):
+        new_path = st.text_input(
+            "Save path",
+            value=save_path_str,
+            key="save_path_input",
+            help="Defaults to the YAML file passed via --yaml, or a generated-spec path when none was given.",
+        )
+        if new_path and new_path != save_path_str:
+            st.session_state["save_path"] = new_path
+
+
+def render_editor_panel(yaml_path: Path | None) -> ValidationResult:
+    """Render the ACE YAML editor and refresh the dashboard when text changes."""
+    try:
+        from streamlit_ace import st_ace  # noqa: PLC0415
+    except ImportError as exc:
+        st.error(
+            "`streamlit-ace` is not installed. Inside the isaaclab_arena container run:\n"
+            "`python -m pip install --user --ignore-installed streamlit-ace`\n\n"
+            f"Underlying error: {exc}",
+            icon="🛑",
+        )
+        st.stop()
+
+    st.subheader("YAML editor")
+    if yaml_path is not None:
+        st.caption(f"Source: `{yaml_path}`")
+    else:
+        st.caption("No file loaded — generate a spec or paste YAML.")
+
+    editor_key = str(yaml_path) if yaml_path is not None else "new"
+    new_text = st_ace(
+        value=st.session_state["edited_text"],
+        language="yaml",
+        theme="monokai",
+        keybinding="vscode",
+        font_size=13,
+        tab_size=2,
+        show_gutter=True,
+        show_print_margin=False,
+        wrap=False,
+        auto_update=False,
+        min_lines=30,
+        key=f"ace_editor::{editor_key}::{st.session_state.get('editor_version', 0)}",
+    )
+    if new_text is not None:
+        st.session_state["edited_text"] = new_text
+
+    validation = validate_yaml_text(st.session_state["edited_text"])
+    render_validation_badge(validation)
+
+    edited_since_render = st.session_state["edited_text"] != st.session_state["last_rendered_text"]
+    if edited_since_render:
+        if validation.is_valid:
+            with st.spinner("Rendering visualization…"):
+                st.session_state["rendered_html"] = render_dashboard_html(validation.spec)
+        else:
+            st.session_state["rendered_html"] = _BROKEN_PLACEHOLDER_HTML
+        st.session_state["last_rendered_text"] = st.session_state["edited_text"]
+        if validation.is_valid:
+            st.toast("Visualization updated.", icon="🔄")
+
+    render_save_button(validation)
+    return validation
+
+
+def render_generation_panel() -> None:
+    """Prompt input and generate-spec controls (top of the left column)."""
+    st.subheader("Generate from prompt")
+    st.caption("Calls the env-generation agent (LLM) then compiles intent in-process.")
+
+    prompt = st.text_area(
+        "Prompt",
+        value=st.session_state.get("generation_prompt", _DEFAULT_GENERATION_PROMPT),
+        height=120,
+        placeholder="Describe the robot task, scene, objects, and distractors…",
+    )
+    st.session_state["generation_prompt"] = prompt
+
+    agent_error = st.session_state.get("generation_agent_error")
+    if agent_error:
+        st.info(f"LLM agent unavailable: {agent_error}", icon="ℹ️")
+
+    if st.button("Generate & compile", type="primary", use_container_width=True):
+        with st.spinner("Generating spec (LLM call + intent compile)…"):
+            ok, message = run_generation_pipeline(st.session_state["generation_prompt"])
+        if ok:
+            if "resolution warnings" in message:
+                st.warning(message, icon="⚠️")
+            else:
+                st.success(message, icon="✅")
+            st.rerun()
+        else:
+            st.error(f"Generation failed\n\n```\n{message}\n```", icon="🛑")
+
+    reasoning = st.session_state.get("last_generation_reasoning")
+    if reasoning:
+        with st.expander("Agent reasoning (last run)", expanded=False):
+            st.markdown(reasoning)
+
+    trace = st.session_state.get("last_generation_trace")
+    if trace:
+        with st.expander("Resolution trace (last run)", expanded=False):
+            st.code(_format_trace_lines(trace), language=None)
+
+
+def render_visualization_panel() -> None:
+    """Embed the rendered dashboard HTML in the right-hand column."""
+    st.subheader("Visualization")
+    if not st.session_state.get("last_rendered_text", "").strip():
+        st.caption("Generate or enter valid YAML to see the visualization.")
+        return
+
+    st.caption("Updates automatically when the YAML is valid.")
+    st.components.v1.html(
+        st.session_state["rendered_html"],
+        height=_IFRAME_HEIGHT_PX,
+        scrolling=True,
+    )
+
+
+def main() -> None:
+    """Build the two-column Streamlit layout for generation, editing, and preview."""
+    st.set_page_config(
+        page_title="ArenaEnvInitialGraphSpec live editor",
+        layout="wide",
+        initial_sidebar_state="collapsed",
+    )
+
+    args = parse_args()
+    yaml_path = args.yaml.resolve() if args.yaml is not None else None
+    if yaml_path is not None and not yaml_path.exists():
+        st.error(f"YAML file not found: {yaml_path}", icon="🛑")
+        st.stop()
+
+    initialize_state(yaml_path)
+
+    st.markdown("### ArenaEnvInitialGraphSpec live editor")
+    left, right = st.columns([2, 3], gap="large")
+    with left:
+        render_generation_panel()
+        render_editor_panel(yaml_path)
+    with right:
+        render_visualization_panel()
+
+
+main()
diff --git a/setup.py b/setup.py
index 582f669ec..c411f629b 100644
--- a/setup.py
+++ b/setup.py
@@ -26,6 +26,8 @@
     "jupyter",
     "debugpy",
     "tenacity",
+    "streamlit>=1.30",
+    "streamlit-ace>=0.1.1",
 ]
 
 setup(