diff --git a/baseline/experiments/nanogpt_alpha_memorization/am_data.py b/baseline/experiments/nanogpt_alpha_memorization/am_data.py
index c893e95..2a7bbff 100644
--- a/baseline/experiments/nanogpt_alpha_memorization/am_data.py
+++ b/baseline/experiments/nanogpt_alpha_memorization/am_data.py
@@ -24,9 +24,10 @@ class Record:
 class Dataset:
     def __init__(self, cfg, seed, batch_size):
         self.cfg, self.seed, self.batch_size = cfg, seed, batch_size
-        self.steps, self.withdrawal = int(cfg['steps']), int(cfg['steps']) // 2
-        if self.withdrawal < 1:
-            raise ValueError('At least two updates are needed.')
+        self.steps = int(cfg['steps'])
+        self.withdrawal = int(cfg.get('withdrawal_step', self.steps // 2))
+        if self.withdrawal < 1 or self.withdrawal > self.steps:
+            raise ValueError('withdrawal_step must be within the training horizon.')
         rng = np.random.default_rng(cfg['data_seed'])
         self.train, self.audit, self.canaries = [], [], []
         p = cfg['modulus']
diff --git a/baseline/experiments/nanogpt_alpha_memorization/continue_muon_100k.py b/baseline/experiments/nanogpt_alpha_memorization/continue_muon_100k.py
new file mode 100644
index 0000000..9d330b5
--- /dev/null
+++ b/baseline/experiments/nanogpt_alpha_memorization/continue_muon_100k.py
@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+"""Continue one completed Muon run from step 10k to 100k without replaying canaries."""
+from __future__ import annotations
+import argparse, copy, json, math, time
+from collections import Counter
+from pathlib import Path
+import torch
+
+from am_data import Dataset
+from am_metrics import batches, suffix_losses
+from am_runtime import baseline, imports, make_model, environment, model_hash, atomic_json, atomic_save, safe_clip
+from am_train import audit, snapshot, restore
+
+
+def main():
+    p=argparse.ArgumentParser()
+    p.add_argument('--root',required=True,help='Completed 10-run study root')
+    p.add_argument('--seed',type=int,default=1337)
+    p.add_argument('--target-step',type=int,default=100000)
+    p.add_argument('--device',choices=['mps','cpu','cuda'],default='mps')
+    p.add_argument('--checkpoint-every',type=int,default=5000)
+    p.add_argument('--behavior-every',type=int,default=5000)
+    p.add_argument('--resume',action='store_true')
+    a=p.parse_args()
+
+    root=Path(a.root).resolve(); original_cfg=json.loads((root/'protocol.json').read_text())
+    start_run=root/'muon'/f'seed_{a.seed}'; source_checkpoint=start_run/'checkpoint_latest.pt'
+    if not source_checkpoint.exists(): raise FileNotFoundError(source_checkpoint)
+    source_saved=torch.load(source_checkpoint,map_location='cpu',weights_only=True)
+    start_step=int(source_saved['step'])
+    if start_step!=int(original_cfg['steps']): raise ValueError(f'Expected completed checkpoint at {original_cfg["steps"]}, found {start_step}')
+    if a.target_step<=start_step: raise ValueError('target-step must exceed the source checkpoint step')
+
+    # Freeze the original 0..5000 canary acquisition schedule while extending only ordinary training.
+    cfg=copy.deepcopy(original_cfg)
+    cfg['steps']=a.target_step
+    cfg['withdrawal_step']=int(original_cfg['steps'])//2
+    cfg['checkpoint_every']=a.checkpoint_every
+    cfg['behavior_every']=a.behavior_every
+    cfg['expensive_every']=max(a.behavior_every,25000)
+
+    out=root/'extensions'/f'muon_seed_{a.seed}_to_{a.target_step}'
+    out.mkdir(parents=True,exist_ok=True)
+    atomic_json(out/'continuation_protocol.json',cfg)
+    atomic_json(out/'source.json',{'source_run':str(start_run),'source_checkpoint':str(source_checkpoint),'source_step':start_step})
+
+    runtime=environment(a.device); source=baseline(original_cfg)
+    _,_,make_handles,set_lrs,zero_grad,optimizer_step=imports()
+    model=make_model(source,original_cfg,a.seed,a.device)
+    profile=copy.deepcopy(source['optimizer_profiles']['muon']); handles=make_handles(model,profile)
+    data=Dataset(cfg,a.seed,source['training']['batch_size']*source['training']['grad_accum_steps'])
+
+    original_manifest=json.loads((start_run/'manifest.json').read_text())
+    if data.fingerprint!=original_manifest['data_sha256']:
+        raise ValueError('Extended dataset changed the original canary/data schedule; refusing continuation.')
+
+    latest=out/'checkpoint_latest.pt'; completed=start_step; attempted=int(source_saved['attempted']); counts=Counter(source_saved['counts'])
+    if a.resume:
+        if not latest.exists(): raise ValueError('No continuation checkpoint exists to resume.')
+        saved=torch.load(latest,map_location='cpu',weights_only=True); completed=int(saved['step']); attempted=int(saved['attempted']); counts=Counter(saved['counts']); restore(saved,model,handles)
+    else:
+        if latest.exists(): raise ValueError('Continuation already exists; use --resume.')
+        restore(source_saved,model,handles)
+        if model_hash(model)!=source_saved['model_sha256']: raise ValueError('Source checkpoint tensor hash mismatch.')
+        state=snapshot(model,handles,counts,completed,attempted); state.update(model_sha256=model_hash(model),source_step=start_step)
+        atomic_save(latest,state); atomic_save(out/f'model_{completed:08d}.pt',{'model':state['model'],'step':completed,'source_step':start_step})
+
+    # Preserve the original Muon LR schedule. At 10k it has reached its configured minimum,
+    # so the continuation remains at that minimum rather than stretching/restarting the schedule.
+    schedule_steps=math.ceil(source['dataset']['train_tokens']*profile['lr_schedule_epochs']/(data.batch_size*source['model']['block_size']))
+    warmup=math.ceil(schedule_steps*profile['warmup_fraction'])
+    print(f'Continuing Muon seed={a.seed}: {completed} -> {a.target_step} on {a.device}',flush=True)
+    print(f'Canary withdrawal remains frozen at step {data.withdrawal}; no new canary presentations occur.',flush=True)
+    print(f'Original LR schedule length={schedule_steps}; continuation uses the configured minimum LR after schedule end.',flush=True)
+    print(f'Output: {out}',flush=True)
+    started=time.monotonic()
+
+    while completed<a.target_step:
+        step=completed; attempted+=1; zero_grad(handles); model.train(); set_lrs(handles,update_index=step,total_steps=schedule_steps,warmup_steps=warmup)
+        records=data.batch(step); last_loss=0.0
+        for chunk in batches(records,source['training']['batch_size']):
+            loss=suffix_losses(model,chunk)[0].mean(1).sum()/data.batch_size
+            if not torch.isfinite(loss): raise FloatingPointError(f'Nonfinite forward loss at step {step}')
+            loss.backward(); last_loss+=float(loss.detach())
+        norm,overflow=safe_clip(model,source['training']['grad_clip']); optimizer_step(handles)
+        if not all(bool(torch.isfinite(p).all()) for p in model.parameters()): raise FloatingPointError(f'Nonfinite parameter after step {step}')
+        counts.update(r.id for r in records); completed=step+1
+        if completed%100==0: print(f'muon seed={a.seed} step={completed}/{a.target_step} loss={last_loss:.6f} grad_norm={norm:.3g} norm_fallback={overflow}',flush=True)
+        if completed%a.checkpoint_every==0 or completed==a.target_step:
+            planned=data.planned_counts(completed)
+            for r in data.canaries:
+                if counts[r.id]!=planned[r.id]: raise RuntimeError(f'Canary presentation count changed for {r.id}.')
+            state=snapshot(model,handles,counts,completed,attempted); state.update(model_sha256=model_hash(model),source_step=start_step)
+            atomic_save(latest,state); atomic_save(out/f'model_{completed:08d}.pt',{'model':state['model'],'step':completed,'source_step':start_step})
+        if completed%a.behavior_every==0 or completed==a.target_step:
+            audit(model,data,cfg,source,out,completed,counts)
+
+    result={'state':'complete','seed':a.seed,'source_step':start_step,'step':completed,'elapsed_seconds':time.monotonic()-started,'runtime':runtime}
+    atomic_json(out/'complete.json',result); print(json.dumps(result),flush=True); print(out,flush=True)
+
+if __name__=='__main__': main()
diff --git a/baseline/experiments/nanogpt_alpha_memorization/tests/test_continuation.py b/baseline/experiments/nanogpt_alpha_memorization/tests/test_continuation.py
new file mode 100644
index 0000000..0c6e7ee
--- /dev/null
+++ b/baseline/experiments/nanogpt_alpha_memorization/tests/test_continuation.py
@@ -0,0 +1,33 @@
+from __future__ import annotations
+import copy, json
+from pathlib import Path
+import sys
+
+HERE=Path(__file__).resolve().parents[1]
+sys.path.insert(0,str(HERE))
+from am_data import Dataset
+
+CFG=json.loads((HERE/'protocol.json').read_text())
+
+
+def test_extended_horizon_preserves_original_canary_schedule_and_fingerprint():
+    batch_size=32
+    original=Dataset(CFG,1337,batch_size)
+    extended_cfg=copy.deepcopy(CFG)
+    extended_cfg['steps']=100000
+    extended_cfg['withdrawal_step']=CFG['steps']//2
+    extended=Dataset(extended_cfg,1337,batch_size)
+    assert original.withdrawal==extended.withdrawal==5000
+    assert original.fingerprint==extended.fingerprint
+    assert {k:v.id for k,v in original.schedule.items()}=={k:v.id for k,v in extended.schedule.items()}
+    assert extended.planned_counts(100000)==original.planned_counts(10000)
+
+
+def test_extended_batches_after_10k_contain_no_canaries():
+    extended_cfg=copy.deepcopy(CFG)
+    extended_cfg['steps']=100000
+    extended_cfg['withdrawal_step']=5000
+    data=Dataset(extended_cfg,1337,32)
+    canary_ids={r.id for r in data.canaries}
+    for step in (10000,25000,50000,99999):
+        assert not any(r.id in canary_ids for r in data.batch(step))