diff --git a/harness/mix.py b/harness/mix.py
index 5d9a5d7..f9434de 100644
--- a/harness/mix.py
+++ b/harness/mix.py
@@ -77,3 +77,11 @@ def accepted_task_counts(logs_dir=None):
             if k:
                 out[k] = out.get(k, 0) + 1
     return out
+
+
+def below_target(counts, share=TYPE_SHARE):
+    """Kinds whose share of `counts` is below the target for the next item (deficit > 0).
+    Since 2026-10-05 (Kral + Opus): only these kinds are generated and run; CLAS and FUNC wait until they are at or
+    below their target share."""
+    total, ss = sum(counts.values()) + 1, sum(share.values())
+    return {k for k, v in share.items() if total * v / ss - counts.get(k, 0) > 0}
diff --git a/harness/pipeline.py b/harness/pipeline.py
index 5781a48..9ae9148 100644
--- a/harness/pipeline.py
+++ b/harness/pipeline.py
@@ -129,16 +129,18 @@ class Pipeline:
             done = {(r["task"], r["attempt"]) for r in rows}
             ev0 = {r["task"]: self.evaluate(r) for r in rows if r["attempt"] == 0}
             tasks = trajectories.accepted_tasks()
-            cands = [t for t in tasks if (t, 0) not in done and (t, 0) not in self.inflight]
-            if cands:    # first attempts: the kind with the biggest deficit against the target mix goes first
-                counts = {}
-                for r in rows:
-                    if self.evaluate(r)["accepted"]:
-                        k = mix.kind_of_task_dir(r["task"])
-                        counts[k] = counts.get(k, 0) + 1
-                for (t, _a) in self.inflight:
-                    k = mix.kind_of_task_dir(t)
+            counts = {}      # accepted trajectories (and runs in flight) per kind
+            for r in rows:
+                if self.evaluate(r)["accepted"]:
+                    k = mix.kind_of_task_dir(r["task"])
                     counts[k] = counts.get(k, 0) + 1
+            for (t, _a) in self.inflight:
+                k = mix.kind_of_task_dir(t)
+                counts[k] = counts.get(k, 0) + 1
+            below = mix.below_target(counts)     # only kinds below their target share run (Kral + Opus 2026-10-05)
+            cands = [t for t in tasks if (t, 0) not in done and (t, 0) not in self.inflight
+                     and mix.kind_of_task_dir(t) in below]
+            if cands:    # first attempts: the kind with the biggest deficit against the target mix goes first
                 total, tot_share = sum(counts.values()) + 1, sum(mix.TYPE_SHARE.values())
                 best = max(cands, key=lambda t: (total * mix.TYPE_SHARE.get(mix.kind_of_task_dir(t), 0) / tot_share
                                                  - counts.get(mix.kind_of_task_dir(t), 0), -int(t[1:])))
@@ -146,7 +148,8 @@ class Pipeline:
                 return best, 0
             for t in tasks:                      # second attempt: first failed, or accepted without a repair
                 e = ev0.get(t)
-                if e and (t, 1) not in done and (t, 1) not in self.inflight and (not e["accepted"] or not e["repair"]):
+                if e and (t, 1) not in done and (t, 1) not in self.inflight and (not e["accepted"] or not e["repair"]) \
+                        and mix.kind_of_task_dir(t) in below:
                     self.inflight.add((t, 1))
                     return t, 1
         return None
@@ -358,6 +361,26 @@ trajectory runs {len(rows)}, accepted trajectories {len(accepted)} (acceptance {
         log("pipeline ended:", text.replace("\n", " | "))
 
 
+def acquire_controller_lock():
+    """One controller only. An exclusive flock on runs/pipeline/controller.lock lives as long as the process (the
+    kernel drops it when the process dies, so a crash never leaves a stale lock); the pid is written for people."""
+    import fcntl
+    os.makedirs(PIPE, exist_ok=True)
+    path = os.path.join(PIPE, "controller.lock")
+    f = open(path, "a+")
+    try:
+        fcntl.flock(f, fcntl.LOCK_EX | fcntl.LOCK_NB)
+    except OSError:
+        f.seek(0)
+        sys.exit("a controller is already running (pid %s, %s); not starting a second one" % (
+            f.read().strip() or "?", path))
+    f.seek(0)
+    f.truncate()
+    f.write("%d\n" % os.getpid())
+    f.flush()
+    return f
+
+
 def main():
     load_env(os.path.join(ROOT, ".env"))
     ap = argparse.ArgumentParser()
@@ -379,7 +402,9 @@ def main():
                 break
             time.sleep(30)
     os.makedirs(OUT, exist_ok=True)
+    guard = acquire_controller_lock()
     Pipeline(a).run()
+    guard.close()
 
 
 if __name__ == "__main__":
diff --git a/harness/trainset.py b/harness/trainset.py
index 005d693..1e14476 100644
--- a/harness/trainset.py
+++ b/harness/trainset.py
@@ -279,7 +279,7 @@ def run_balanced(part, parts, deadline):
         if blocked:
             print("kinds skipped (low acceptance):", sorted(blocked), flush=True)
         waiting = {k for k, n in backlog_by_kind().items() if n > BAL_KIND_BACKLOG}
-        allowed = set(mix.TYPE_SHARE) - blocked - waiting
+        allowed = (set(mix.TYPE_SHARE) - blocked - waiting) & mix.below_target(counts)   # only kinds below their share
         if not allowed:
             time.sleep(120)     # every kind has a backlog: the trajectories are the slower side
             continue