diff --git a/Dockerfile.sandbox b/Dockerfile.sandbox
index 6fb7e2e..10df4dd 100644
--- a/Dockerfile.sandbox
+++ b/Dockerfile.sandbox
@@ -62,6 +62,7 @@ COPY eval/ /app/eval/
 COPY calibration/ /app/calibration/
 COPY proof/ /app/proof/
 COPY validator/ /app/validator/
+COPY miner/ /app/miner/
 COPY configs/ /app/configs/
 COPY restricted_files.yaml /app/restricted_files.yaml
 COPY ralph_bootstrap.py /app/ralph_bootstrap.py
diff --git a/validator/sandbox.py b/validator/sandbox.py
index b86d8b3..d094bc1 100644
--- a/validator/sandbox.py
+++ b/validator/sandbox.py
@@ -108,7 +108,7 @@ def build_container_env(env_extra: dict[str, str] | None) -> dict[str, str]:
         "PYTHONUNBUFFERED": "1",
         "PYTHONDONTWRITEBYTECODE": "1",
         "HOME": "/scratch",
-        "TMPDIR": "/scratch/tmp",
+        "TMPDIR": "/scratch",
     }
     for k, v in (env_extra or {}).items():
         if k in _TRAINING_ENV_BLOCKLIST:
diff --git a/validator/service.py b/validator/service.py
index 969f433..96fe2bb 100644
--- a/validator/service.py
+++ b/validator/service.py
@@ -143,12 +143,29 @@ def _safe_current_block(chain) -> int:
 
 
 def archive_bundle(bundle_dir: Path, queue_dir: Path, dest: str) -> None:
-    """Move a processed bundle to scored/ or rejected/."""
+    """Move a processed bundle to scored/ or rejected/.
+
+    Rejected bundles are terminal — their hash is recorded in hf_state.json so
+    they are never re-downloaded or re-evaluated — so the heavy training/
+    checkpoint (~0.5 GB each) is GC'd on archive to keep queue/rejected/ from
+    filling the disk. The lightweight manifests are kept as an audit trail.
+    Opt out with RALPH_QUEUE_GC_REJECTED=0.
+    """
     target = queue_dir / dest / bundle_dir.name
     target.parent.mkdir(parents=True, exist_ok=True)
     if target.exists():
         shutil.rmtree(target)
     shutil.move(str(bundle_dir), str(target))
+    if dest == "rejected" and os.environ.get(
+        "RALPH_QUEUE_GC_REJECTED", "1"
+    ).strip().lower() not in {"0", "false", "no", "off"}:
+        ckpt_dir = target / "training"
+        if ckpt_dir.exists():
+            try:
+                shutil.rmtree(ckpt_dir)
+                log_info(f"  queue GC: removed rejected checkpoint {target.name}/training")
+            except OSError as e:
+                log_warn(f"queue GC: could not remove {ckpt_dir}: {e}")
 
 
 def _close_losing_prs(bundle_dir: Path, reason: str) -> None:
diff --git a/validator/validator.py b/validator/validator.py
index 83a2ed4..42bc593 100644
--- a/validator/validator.py
+++ b/validator/validator.py
@@ -686,8 +686,8 @@ def _sandboxed_hidden_eval(
             Mount(proof_dir, "/in", ro=True),
             Mount(eval_dir, "/eval-private", ro=True),
         ]
+        # ENTRYPOINT already runs `python -m validator.sandbox_eval`; pass args only.
         container_argv = [
-            "python", "-m", "validator.sandbox_eval",
             "/canon", "/in/patch.diff", "/in/training/checkpoint.pt", "/eval-private", "/out",
         ]
         try:
@@ -945,6 +945,11 @@ def _hosb_sandbox_nlls(ralph_root: Path, proof_dir: Path, idx_grid, tgt_grid, se
 
     grid_dir = Path(tempfile.mkdtemp(prefix="ralph_hosb_grid_"))
     out_dir = Path(tempfile.mkdtemp(prefix="ralph_hosb_out_"))
+    # userns-remap maps the container --user to an unprivileged host uid that
+    # cannot touch root-owned 0700 mkdtemp dirs; open the dir bits so the (ro)
+    # grid is readable and the (rw) out is writable from the remapped namespace.
+    os.chmod(grid_dir, 0o755)
+    os.chmod(out_dir, 0o777)
     try:
         np.save(grid_dir / "idx_grid.npy", idx_grid)
         np.save(grid_dir / "scored_idx.npy", scored_idx)  # positions, NOT the answer
@@ -966,8 +971,9 @@ def _hosb_sandbox_nlls(ralph_root: Path, proof_dir: Path, idx_grid, tgt_grid, se
             Mount(proof_dir, "/in", ro=True),
             Mount(grid_dir, "/grid", ro=True),  # idx_grid + scored_idx — NO targets, NO raw shard
         ]
+        # ENTRYPOINT already runs `python -m validator.sandbox_eval`; pass args only.
         container_argv = [
-            "python", "-m", "validator.sandbox_eval", "--grid",
+            "--grid",
             "/canon", "/in/patch.diff", "/in/training/checkpoint.pt", "/grid", "/out",
         ]
         res = run_in_sandbox(