diff --git a/MANIFEST.in b/MANIFEST.in
index aa3ab2b92..d15e2cccb 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -5,6 +5,7 @@
 # installed wheel silently omitted them while source-tree CI stayed green); graft
 # removes that failure mode at the root.
 graft solstone
+include build_hooks.py
 
 # Exclude only compiled/editor cruft.
 global-exclude *.py[cod]
diff --git a/build_hooks.py b/build_hooks.py
new file mode 100644
index 000000000..4c9ed40c7
--- /dev/null
+++ b/build_hooks.py
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: AGPL-3.0-only
+# Copyright (c) 2026 sol pbc
+
+"""Setuptools build hooks for solstone packaging."""
+
+from __future__ import annotations
+
+import shutil
+from pathlib import Path
+
+from setuptools.command.build_py import build_py
+
+
+class BuildPyWithoutTests(build_py):
+    """Build the base wheel without in-package test directories."""
+
+    def run(self) -> None:
+        super().run()
+        solstone_root = Path(self.build_lib) / "solstone"
+        if not solstone_root.exists():
+            return
+        for tests_dir in sorted(solstone_root.rglob("tests"), reverse=True):
+            if tests_dir.is_dir():
+                shutil.rmtree(tests_dir)
diff --git a/pyproject.toml b/pyproject.toml
index a29a8f057..91d3ad57c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -202,6 +202,10 @@ include-package-data = true
 
 [tool.setuptools.packages.find]
 include = ["solstone*"]
+exclude = ["*.tests", "*.tests.*"]
+
+[tool.setuptools.cmdclass]
+build_py = "build_hooks.BuildPyWithoutTests"
 
 [tool.uv]
 # The [journal]/[journal-cuda] tombstones pin solstone-journal-host==0.7.0, a
diff --git a/scripts/check_wheel_contents.py b/scripts/check_wheel_contents.py
index 9adb6c4a1..72a438f80 100644
--- a/scripts/check_wheel_contents.py
+++ b/scripts/check_wheel_contents.py
@@ -106,6 +106,10 @@ def check_base_wheel(path: Path, max_bytes: int) -> list[str]:
     onnx_members = _onnx_members(path)
     if onnx_members:
         errors.append(f"{path.name}: base wheel contains ONNX members: {onnx_members}")
+    with zipfile.ZipFile(path) as wheel:
+        for member in wheel.namelist():
+            if "tests" in member.split("/"):
+                errors.append(f"{path.name}: base wheel ships test path {member}")
     return errors
 
 
diff --git a/tests/test_check_wheel_contents.py b/tests/test_check_wheel_contents.py
index 37a227d27..c97db35a8 100644
--- a/tests/test_check_wheel_contents.py
+++ b/tests/test_check_wheel_contents.py
@@ -117,6 +117,25 @@ def test_core_wheel_validator_rejects_record_drift(tmp_path: Path) -> None:
     assert any("RECORD hash mismatch" in error for error in errors)
 
 
+def test_base_wheel_validator_rejects_tests_path_segment(tmp_path: Path) -> None:
+    clean = _write_minimal_wheel(tmp_path, "solstone")
+
+    clean_errors = checker.check_base_wheel(clean, checker.MAX_BASE_WHEEL_BYTES)
+    assert not [
+        error for error in clean_errors if "base wheel ships test path" in error
+    ]
+
+    dirty = _write_minimal_wheel(tmp_path, "solstone_dirty")
+    test_member = "solstone/apps/search/tests/test_routes.py"
+    with zipfile.ZipFile(dirty, "a") as wheel:
+        _write_member(wheel, test_member, b"")
+
+    dirty_errors = checker.check_base_wheel(dirty, checker.MAX_BASE_WHEEL_BYTES)
+    assert any(
+        f"base wheel ships test path {test_member}" in error for error in dirty_errors
+    )
+
+
 def _add_tar_member(archive: tarfile.TarFile, name: str) -> None:
     content = b"x"
     info = tarfile.TarInfo(name)