leaderboard: format submitted_at as `YYYY-MM-DD HH:MM UTC`; lock tables read-only

Table cells were editable (gradio_leaderboard inherits gr.Dataframe's
interactive default); add interactive=False to both Validated and
Unvalidated widgets so cell contents aren't accidentally typed over.

submitted_at column rendered as raw ISO-8601 ("2026-05-28T07:13:16Z");
apply the same _fmt_timestamp helper the detail panel already uses so
the table reads as "2026-05-28 07:13 UTC". Helper moved into
leaderboard.py (formatter module) and re-imported by app.py.

app.py

@@ -13,7 +13,6 @@ from __future__ import annotations
 import html
 import logging
 import os
-import re
 from functools import lru_cache
 from pathlib import Path
 
@@ -31,6 +30,7 @@ from leaderboard import (
     LEADERBOARD_DATATYPES,
     LEADERBOARD_HIDE_COLUMNS,
     VALIDATED_LEADERBOARD_DATATYPES,
+    _fmt_timestamp,
     build_combined_csv,
     load_leaderboard_split,
 )
@@ -92,8 +92,6 @@ Full policy: [`docs/benchmark/validation.md`]({VALIDATION_DOC_URL})."""
 
 DETAIL_PLACEHOLDER = "_Click a row above for details._"
 
-_ISO_TS_RE = re.compile(r"^(\d{4}-\d{2}-\d{2})T(\d{2}:\d{2}):\d{2}Z$")
-
 
 def _has(value) -> bool:
     """True for values that should show up in the detail panel."""
@@ -104,22 +102,6 @@ def _has(value) -> bool:
     return str(value).strip() != ""
 
 
-def _fmt_timestamp(ts) -> str:
-    """Render an ISO-8601 ``submitted_at`` as ``YYYY-MM-DD HH:MM UTC``.
-
-    The schema writes timestamps as ``YYYY-MM-DDTHH:MM:SSZ``; the
-    minute-level UTC form is plenty for the detail panel, drops the
-    ``T``/``Z`` punctuation, and renders timezone explicitly so a
-    reader doesn't have to know that "Z" means UTC.
-    """
-    if not _has(ts):
-        return ""
-    m = _ISO_TS_RE.match(str(ts))
-    if m:
-        return f"{m.group(1)} {m.group(2)} UTC"
-    return str(ts)
-
-
 def _build_report_iframe(html_bytes: bytes) -> str:
     """Wrap a fetched report's HTML bytes into a self-contained iframe.
 
@@ -301,6 +283,7 @@ with gr.Blocks(title="CADGenBench Leaderboard", theme=gr.themes.Soft()) as block
             search_columns=["submission_name", "submitter_name"],
             hide_columns=LEADERBOARD_HIDE_COLUMNS,
             label="Validated Leaderboard",
+            interactive=False,
         )
         unvalidated_view = Leaderboard(
             value=initial_unvalidated,
@@ -308,6 +291,7 @@ with gr.Blocks(title="CADGenBench Leaderboard", theme=gr.themes.Soft()) as block
             search_columns=["submission_name", "submitter_name"],
             hide_columns=LEADERBOARD_HIDE_COLUMNS,
             label="Unvalidated Leaderboard",
+            interactive=False,
         )
         with gr.Row():
             refresh_btn = gr.Button("Refresh", size="sm")

leaderboard.py

@@ -10,6 +10,7 @@ from __future__ import annotations
 import json
 import logging
 import os
+import re
 import tempfile
 import time
 import uuid
@@ -111,6 +112,27 @@ VALIDATED_LEADERBOARD_DATATYPES = _datatypes_for(VALIDATED_LEADERBOARD_COLS)
 PENDING_CELL_TAG = "⏳ evaluating..."
 FAILED_CELL_TAG = "✗ failed"
 
+_ISO_TS_RE = re.compile(r"^(\d{4}-\d{2}-\d{2})T(\d{2}:\d{2}):\d{2}Z$")
+
+
+def _fmt_timestamp(ts) -> str:
+    """Render an ISO-8601 ``submitted_at`` as ``YYYY-MM-DD HH:MM UTC``.
+
+    The schema writes timestamps as ``YYYY-MM-DDTHH:MM:SSZ``; the
+    minute-level UTC form is plenty for the table + detail panel,
+    drops the ``T``/``Z`` punctuation, and renders the timezone
+    explicitly so a reader doesn't have to know that "Z" means UTC.
+    """
+    if ts is None or (isinstance(ts, float) and pd.isna(ts)):
+        return ""
+    s = str(ts).strip()
+    if not s:
+        return ""
+    m = _ISO_TS_RE.match(s)
+    if m:
+        return f"{m.group(1)} {m.group(2)} UTC"
+    return s
+
 
 def _load_rows_from_hub() -> list[dict] | None:
     """Pull results.jsonl from the submissions dataset via raw HTTPS.
@@ -369,6 +391,8 @@ def _project_and_format(df: pd.DataFrame, columns: list[str]) -> pd.DataFrame:
         out["model details (optional)"] = out["model details (optional)"].apply(
             _agent_url_md
         )
+    if "submitted_at" in out.columns:
+        out["submitted_at"] = out["submitted_at"].apply(_fmt_timestamp)
     return out
 
 

tests/test_leaderboard.py

@@ -114,7 +114,9 @@ def test_field_passthrough(monkeypatch):
     # Use submitter_name to identify Beta (its submission_name is now
     # wrapped as a markdown link).
     beta = unvalidated[unvalidated["submitter_name"] == "team-beta"].iloc[0]
-    assert beta["submitted_at"] == "2026-05-02T10:00:00Z"
+    # submitted_at is rendered as `YYYY-MM-DD HH:MM UTC` by
+    # _fmt_timestamp; the underlying ISO-8601 string is the input.
+    assert beta["submitted_at"] == "2026-05-02 10:00 UTC"
     assert beta["cadgenbench_version"] == "0.1.0"
 
     assert list(validated.columns) == leaderboard.VALIDATED_LEADERBOARD_COLS
@@ -239,6 +241,25 @@ def test_build_combined_csv_orders_validated_first(monkeypatch):
         assert s == "validated", f"unexpected status before unvalidated tier: {s!r}"
 
 
+def test_fmt_timestamp_formats_iso_and_passes_through_garbage():
+    """ISO ``YYYY-MM-DDTHH:MM:SSZ`` -> ``YYYY-MM-DD HH:MM UTC``; garbage stays.
+
+    Empty / None / NaN render as the empty string (the cell is
+    rendered blank rather than as a literal placeholder).
+    """
+    import math
+
+    assert leaderboard._fmt_timestamp("2026-05-28T07:13:16Z") == "2026-05-28 07:13 UTC"
+    assert leaderboard._fmt_timestamp(None) == ""
+    assert leaderboard._fmt_timestamp("") == ""
+    assert leaderboard._fmt_timestamp("   ") == ""
+    assert leaderboard._fmt_timestamp(float("nan")) == ""
+    # Anything that doesn't match the canonical shape passes through
+    # unchanged (e.g., a manually-edited cell or a legacy timestamp
+    # format) so the visible cell is at least not blank-replaced.
+    assert leaderboard._fmt_timestamp("not-a-timestamp") == "not-a-timestamp"
+
+
 def test_datatypes_align_with_columns():
     """Per-column datatype lists track the column-list lengths.