diff --git a/justfile b/justfile
index e7deee8..fceb756 100644
--- a/justfile
+++ b/justfile
@@ -181,6 +181,11 @@ plot-deploy GLOB='out/runs/*sub4*/per_mode_deploy.json' OUT='out/figs/deploy_ove
 regen-dynamics GLOB='logs/*_cell_*.log':
     uv run python scripts/plot_dynamics.py {{ GLOB }} --out out/figs/dynamics.png
 
+# Auto dynamics plot: newest full-length (>=MIN steps) log PER ARM, no hand-globbing.
+# Run after any sweep finishes -> always plots the freshest 60-step run of each arm.
+dyn MIN='60' OUT='out/figs/dyn_sub4.png':
+    uv run python scripts/plot_dynamics.py logs/ --latest-per-arm --min-steps {{ MIN }} --out {{ OUT }}
+
 # Phase-1 emergence overlay: one line per env_mode (hack=exploited, solve=gt_correct).
 regen-emergence GLOB='logs/*_emerge_*.log':
     uv run python scripts/plot_emergence.py {{ GLOB }} --out out/figs/emergence.png
diff --git a/scripts/plot_dynamics.py b/scripts/plot_dynamics.py
index 4c2329f..673b3d5 100644
--- a/scripts/plot_dynamics.py
+++ b/scripts/plot_dynamics.py
@@ -87,10 +87,13 @@ def parse_log(path: Path) -> dict | None:
     vhack = grab(r"v-hack-path=out/(?:vhack/)?(\S+?)\.safetensors", argv, "-")
 
     # header line: the one containing both "step" and "hack_s"
-    hdr = next((l for l in txt.splitlines() if "ref_eq" in l and "hack_s" in l), None)
+    hdr = next((l for l in txt.splitlines()
+                if "| INFO |" in l and "ref_eq" in l and "hack_s" in l), None)
     if hdr is None:
         return None
-    names = [_HDR_TOK.match(t).group(0) for t in hdr.split("| INFO |", 1)[1].split()]
+    # real column headers always start with a letter/underscore; drop pure-symbol
+    # tokens (decoration) so a stray glyph in an old log's header doesn't crash parse
+    names = [m.group(0) for t in hdr.split("| INFO |", 1)[1].split() if (m := _HDR_TOK.match(t))]
     idx = {n: i for i, n in enumerate(names)}
 
     series: dict[str, list[float]] = defaultdict(list)
@@ -330,13 +333,33 @@ def _gather(paths: list[str]) -> list[Path]:
     return out
 
 
+def _latest_per_arm(files: list[Path], min_steps: int) -> list[Path]:
+    """One log per arm: the most recent (by filename timestamp) with >= min_steps
+    rows. Lets `just dyn` auto-pick the freshest full-length run for each arm
+    instead of hand-globbing. Newest filename wins -- timestamp-prefixed names
+    sort lexicographically, no mtime races."""
+    by_arm: dict[str, tuple[Path, dict]] = {}
+    for f in sorted(files):  # ascending ts; later overwrites -> keeps newest
+        r = parse_log(f)
+        if r is None or len(r["steps"]) < min_steps:
+            continue
+        by_arm[classify(r)] = (f, r)
+    return [f for f, _ in by_arm.values()]
+
+
 def main() -> None:
     ap = argparse.ArgumentParser(description=__doc__)
     ap.add_argument("logs", nargs="+", help="log files, globs, or dirs")
     ap.add_argument("--out", type=Path, default=Path("out/figs/dynamics.png"))
+    ap.add_argument("--latest-per-arm", action="store_true",
+                    help="keep only the newest log per arm (with >= --min-steps rows)")
+    ap.add_argument("--min-steps", type=int, default=0,
+                    help="drop runs shorter than this many logged steps")
     args = ap.parse_args()
     files = _gather(args.logs)
-    runs = [r for f in files if (r := parse_log(f))]
+    if args.latest_per_arm:
+        files = _latest_per_arm(files, args.min_steps)
+    runs = [r for f in files if (r := parse_log(f)) and len(r["steps"]) >= args.min_steps]
     if not runs:
         raise SystemExit(f"no parseable runs in {len(files)} files")
     for r in runs: