diff --git a/graphify/exporters/html.py b/graphify/exporters/html.py
index e4be7f1a3..14f781249 100644
--- a/graphify/exporters/html.py
+++ b/graphify/exporters/html.py
@@ -157,8 +157,9 @@ const nodesDS = new vis.DataSet(RAW_NODES.map((n, i) => ({{
   // graphs. `i` is the map index — physics still settles small graphs identically.
   x: 30 * Math.sqrt(i) * Math.cos(i * 2.4),
   y: 30 * Math.sqrt(i) * Math.sin(i * 2.4),
-  _community: n.community, _community_name: n.community_name,
-  _source_file: n.source_file, _file_type: n.file_type, _degree: n.degree,
+  community: n.community, community_name: n.community_name,
+  source_file: n.source_file, file_type: n.file_type, degree: n.degree,
+  member_count: n.member_count,
 }})));
 
 const edgesDS = new vis.DataSet(RAW_EDGES.map((e, i) => ({{
@@ -210,14 +211,22 @@ function showInfo(nodeId) {{
     const color = nb ? nb.color.background : '#555';
     return `<span class="neighbor-link" style="border-left-color:${{esc(color)}}" data-nid="${{esc(nid)}}">${{esc(nb ? nb.label : nid)}}</span>`;
   }}).join('');
-  document.getElementById('info-content').innerHTML = `
-    <div class="field"><b>${{esc(n.label)}}</b></div>
-    <div class="field">Type: ${{esc(n._file_type || 'unknown')}}</div>
-    <div class="field">Community: ${{esc(n._community_name)}}</div>
-    <div class="field">Source: ${{esc(n._source_file || '-')}}</div>
-    <div class="field">Degree: ${{n._degree}}</div>
-    ${{neighborIds.length ? `<div class="field" style="margin-top:8px;color:#aaa;font-size:11px">Neighbors (${{neighborIds.length}})</div><div id="neighbors-list">${{neighborItems}}</div>` : ''}}
-  `;
+  const isMetaNode = !n.file_type && !n.source_file;
+  let html = `<div class="field"><b>${{esc(n.label)}}</b></div>`;
+  if (!isMetaNode) {{
+    html += `<div class="field">Type: ${{esc(n.file_type || 'unknown')}}</div>`;
+  }}
+  html += `<div class="field">Community: ${{esc(n.community_name || '')}}</div>`;
+  if (!isMetaNode) {{
+    html += `<div class="field">Source: ${{esc(n.source_file || '-')}}</div>`;
+  }} else if (n.member_count !== undefined && n.member_count !== null) {{
+    html += `<div class="field">Members: ${{esc(n.member_count)}}</div>`;
+  }}
+  html += `<div class="field">Degree: ${{n.degree}}</div>`;
+  if (neighborIds.length) {{
+    html += `<div class="field" style="margin-top:8px;color:#aaa;font-size:11px">Neighbors (${{neighborIds.length}})</div><div id="neighbors-list">${{neighborItems}}</div>`;
+  }}
+  document.getElementById('info-content').innerHTML = html;
 }}
 
 function focusNode(nodeId) {{
@@ -541,6 +550,8 @@ def to_html(
             "file_type": data.get("file_type", ""),
             "degree": deg,
         }
+        if member_counts:
+            node["member_count"] = member_counts.get(cid, len(communities.get(cid, [])))
         # Conditional learning fields — only present for annotated nodes, so
         # un-annotated output keeps the exact pre-feature node dict shape.
         entry = learning_overlay.get(str(node_id)) if learning_overlay else None
diff --git a/tests/test_export.py b/tests/test_export.py
index 725f45843..d05bdbb28 100644
--- a/tests/test_export.py
+++ b/tests/test_export.py
@@ -1197,3 +1197,179 @@ def test_to_html_spiral_seed_uses_a_real_map_index():
                 "spiral seed references `i` but the node map has no index param "
                 "-> ReferenceError: i is not defined (#3699)"
             )
+
+
+def test_to_html_canonical_node_schema_mapping(tmp_path):
+    """#3914: nodesDS and showInfo must use canonical un-prefixed field names
+    matching RAW_NODES and Graphify's node schema (file_type, source_file,
+    community_name, degree), eliminating the underscore-prefixed mapping."""
+    import networkx as nx
+    G = nx.Graph()
+    G.add_node("n_sample", label="SampleNode", file_type="code", source_file="src/sample.py")
+    out = tmp_path / "graph.html"
+    to_html(G, {0: ["n_sample"]}, str(out), community_labels={0: "Core"})
+    content = out.read_text(encoding="utf-8")
+
+    # RAW_NODES carries canonical un-prefixed fields
+    nodes = {n["id"]: n for n in _vis_nodes_from_html(content)}
+    assert nodes["n_sample"]["file_type"] == "code"
+    assert nodes["n_sample"]["source_file"] == "src/sample.py"
+    assert nodes["n_sample"]["community_name"] == "Core"
+    assert "degree" in nodes["n_sample"]
+
+    # nodesDS dataset mapping must preserve canonical field names
+    assert "file_type: n.file_type" in content
+    assert "source_file: n.source_file" in content
+    assert "community_name: n.community_name" in content
+    assert "degree: n.degree" in content
+
+    # nodesDS must not contain old underscore-prefixed mappings
+    assert "_file_type: n.file_type" not in content
+    assert "_source_file: n.source_file" not in content
+    assert "_community_name: n.community_name" not in content
+    assert "_degree: n.degree" not in content
+    assert "_community: n.community" not in content
+
+    # showInfo must consume canonical fields directly
+    assert "n.file_type" in content
+    assert "n.source_file" in content
+    assert "n.community_name" in content
+    assert "n.degree" in content
+    assert "n._file_type" not in content
+    assert "n._source_file" not in content
+    assert "n._community_name" not in content
+    assert "n._degree" not in content
+
+
+def _run_node_info_harness(html_content: str, target_node_id: str) -> str:
+    """Helper to execute graph.html's client script in Node.js and return #info-content innerHTML."""
+    import re
+    import shutil
+    import subprocess
+    node = shutil.which("node")
+    if node is None:
+        import pytest
+        pytest.skip("node not available")
+
+    m = re.search(r"<script>(.*?)</script>\s*<script>", html_content, re.DOTALL)
+    assert m, "vis script block not found in html"
+    script = m.group(1)
+
+    harness = f"""
+const mockElem = () => ({{
+  innerHTML: '',
+  style: {{}},
+  appendChild: () => {{}},
+  addEventListener: () => {{}},
+  classList: {{ add: () => {{}}, remove: () => {{}} }},
+  prepend: () => {{}},
+}});
+
+const doc = {{
+  elements: {{
+    'info-content': mockElem(),
+    'graph': mockElem(),
+    'search': mockElem(),
+    'search-results': mockElem(),
+    'select-all-cb': Object.assign(mockElem(), {{ checked: true }}),
+    'legend': mockElem()
+  }},
+  getElementById(id) {{
+    return this.elements[id] || (this.elements[id] = mockElem());
+  }},
+  createElement() {{ return mockElem(); }},
+  addEventListener() {{}},
+  querySelectorAll() {{ return []; }}
+}};
+
+class MockDataSet {{
+  constructor(items) {{
+    this.map = new Map();
+    items.forEach(it => this.map.set(it.id, it));
+  }}
+  get(id) {{ return this.map.get(id); }}
+  update() {{}}
+}}
+
+const vis = {{
+  DataSet: MockDataSet,
+  Network: class {{
+    constructor() {{}}
+    once() {{}}
+    on() {{}}
+    getConnectedNodes() {{ return []; }}
+    focus() {{}}
+    selectNodes() {{}}
+  }}
+}};
+
+const document = doc;
+const window = {{}};
+
+{script}
+
+showInfo('{target_node_id}');
+console.log('OUTPUT:' + doc.getElementById('info-content').innerHTML);
+"""
+    proc = subprocess.run([node, "-e", harness], capture_output=True, text=True, timeout=30)
+    assert proc.returncode == 0, f"Node script failed ({proc.returncode}): {proc.stderr}"
+    m_out = re.search(r"OUTPUT:(.*)", proc.stdout)
+    assert m_out, f"OUTPUT not found in stdout: {proc.stdout}"
+    return m_out.group(1)
+
+
+def test_to_html_show_info_runtime_renders_node_fields(tmp_path):
+    """#3914: Execute showInfo in Node.js for a normal node.
+    Type: code and Source: src/sample.py must be rendered into info-content,
+    not Type: unknown or Source: -."""
+    import networkx as nx
+    G = nx.Graph()
+    G.add_node("n_sample", label="SampleNode", file_type="code", source_file="src/sample.py")
+    G.add_node("n_other", label="OtherNode", file_type="document", source_file="doc/readme.md")
+    G.add_edge("n_sample", "n_other", relation="references", confidence="EXTRACTED")
+
+    out = tmp_path / "graph.html"
+    to_html(G, {0: ["n_sample", "n_other"]}, str(out), community_labels={0: "Core"})
+    content = out.read_text(encoding="utf-8")
+
+    info_html = _run_node_info_harness(content, "n_sample")
+    assert '<div class="field"><b>SampleNode</b></div>' in info_html
+    assert '<div class="field">Type: code</div>' in info_html
+    assert '<div class="field">Community: Core</div>' in info_html
+    assert '<div class="field">Source: src/sample.py</div>' in info_html
+    assert '<div class="field">Degree: 1</div>' in info_html
+    assert "Type: unknown" not in info_html
+    assert "Source: -" not in info_html
+
+
+def test_to_html_aggregated_community_nodes_runtime(tmp_path):
+    """#3914: Execute showInfo in Node.js for an aggregated community node.
+    Community meta-nodes have no file_type/source_file and must not display
+    misleading Type: unknown or Source: -; they must display community name
+    and member count."""
+    import networkx as nx
+    meta = nx.Graph()
+    meta.add_node("0", label="Core Systems")
+    meta.add_node("1", label="UI Layer")
+    meta.add_edge("0", "1", relation="cross-community", confidence="AGGREGATED")
+
+    out = tmp_path / "graph.html"
+    to_html(
+        meta,
+        {0: ["0"], 1: ["1"]},
+        str(out),
+        community_labels={0: "Core Systems", 1: "UI Layer"},
+        member_counts={0: 25, 1: 10},
+    )
+    content = out.read_text(encoding="utf-8")
+
+    nodes = _vis_nodes_from_html(content)
+    assert any(n.get("member_count") == 25 for n in nodes)
+
+    info_html = _run_node_info_harness(content, "0")
+    assert '<div class="field"><b>Core Systems</b></div>' in info_html
+    assert '<div class="field">Community: Core Systems</div>' in info_html
+    assert '<div class="field">Members: 25</div>' in info_html
+    assert '<div class="field">Degree: 1</div>' in info_html
+    assert "Type: unknown" not in info_html
+    assert "Source: -" not in info_html