diff --git a/src/agent_tools/subprocess_tools.py b/src/agent_tools/subprocess_tools.py
index 5b620cf5f..27ae30886 100644
--- a/src/agent_tools/subprocess_tools.py
+++ b/src/agent_tools/subprocess_tools.py
@@ -231,6 +231,7 @@ def _wrap_workspace_namespace(
     cwd: str,
     *,
     chdir: str = "/workspace",
+    interpreter_prefix: str | None = None,
 ) -> str | None:
     """Run a shell command with the active workspace mounted at /workspace.
 
@@ -254,8 +255,27 @@ def _wrap_workspace_namespace(
         "--dir", "/tmp", "--tmpfs", "/tmp",
         "--dev-bind", "/dev", "/dev", "--proc", "/proc",
         "--dir", "/workspace", "--bind", cwd, "/workspace",
-        "--chdir", chdir, "/bin/bash", "-lc", content,
     ]
+    # setup-python installs interpreters under /opt, and local CI virtualenvs
+    # can live under /tmp. Those paths are hidden by the private root/tmpfs.
+    # Expose only the active interpreter environment, read-only, so Python
+    # tools keep their installed packages without exposing the host /tmp.
+    if interpreter_prefix:
+        prefix = os.path.abspath(interpreter_prefix)
+        mounted_roots = ("/usr", "/home", "/mnt")
+        if os.path.isdir(prefix) and not any(
+            prefix == root or prefix.startswith(root + os.sep)
+            for root in mounted_roots
+        ):
+            parents = []
+            parent = os.path.dirname(prefix)
+            while parent not in ("/", "/tmp", "/etc", "/workspace", *mounted_roots):
+                parents.append(parent)
+                parent = os.path.dirname(parent)
+            for directory in reversed(parents):
+                args.extend(("--dir", directory))
+            args.extend(("--ro-bind", prefix, prefix))
+    args.extend(("--chdir", chdir, "/bin/bash", "-lc", content))
     return shlex.join(args)
 
 
@@ -940,6 +960,7 @@ class PythonTool:
                 python_command,
                 agent_cwd(),
                 chdir="/workspace",
+                interpreter_prefix=sys.prefix,
             )
             if needs_virtual_namespace
             else None
diff --git a/tests/test_tool_path_confinement.py b/tests/test_tool_path_confinement.py
index be4a75162..d8e1400fc 100644
--- a/tests/test_tool_path_confinement.py
+++ b/tests/test_tool_path_confinement.py
@@ -304,7 +304,7 @@ async def test_write_file_dispatch_rejects_empty_directory_like_workspace_path(m
         security_context=NO_TOOL_SECURITY_CONTEXT,
     )
     assert desc == "write_file: /workspace/papers"
-    assert "refusing to create an empty file at a directory-like path" in (
+    assert "content required; refusing to create an empty file" in (
         result.get("error") or ""
     )
     assert result.get("exit_code") == 1
diff --git a/tests/test_workspace_artifact_tool_floor.py b/tests/test_workspace_artifact_tool_floor.py
index 20a5295e2..1d65ea9e3 100644
--- a/tests/test_workspace_artifact_tool_floor.py
+++ b/tests/test_workspace_artifact_tool_floor.py
@@ -1037,14 +1037,14 @@ def test_visual_text_extraction_is_distinct_from_speech_transcription():
 
 
 def test_local_media_routes_select_dedicated_ocr_for_visual_text():
+    import re
+
     source = (Path(__file__).parents[1] / "src" / "agent_loop.py").read_text()
 
     assert source.count(
         "_ocr_requested = _visual_text_extraction_requested(_last_user)"
     ) == 3
-    assert source.count(
-        '{"extract_text"}\n                if _ocr_requested'
-    ) == 3
+    assert len(re.findall(r'\{"extract_text"\}\s*\n\s*if _ocr_requested', source)) == 3
 
 
 def test_workspace_paths_split_on_chinese_list_punctuation():
@@ -1656,7 +1656,8 @@ def test_local_media_is_exempt_from_pure_web_schema_and_round_clamps():
     pure_web_start = source.index("    _local_media_turn = bool(")
     pure_web_end = source.index("\n    if (\n        _pure_web_turn", pure_web_start)
     assert "and not _local_media_turn" in source[pure_web_start:pure_web_end]
-    assert source.count("if _pure_web_turn:") >= 3
+    assert source.count("if _pure_web_turn:") == 2
+    assert 'if _pure_web_turn and tool_surface != "full":' in source
 
 
 def test_empty_local_media_round_nudges_export_instead_of_ending():
@@ -2189,7 +2190,7 @@ def test_python_emits_one_final_bare_expression_without_duplicating_print():
     assert explicit["output"] == "once"
 
 
-def test_python_loaded_code_sees_virtual_workspace_alias(monkeypatch):
+def test_python_loaded_code_sees_virtual_workspace_alias(monkeypatch, tmp_path):
     """Absolute /workspace paths must work inside generated Python scripts."""
     import asyncio
     import shutil
@@ -2201,7 +2202,7 @@ def test_python_loaded_code_sees_virtual_workspace_alias(monkeypatch):
 
     from src.agent_tools import subprocess_tools
     from src import tool_execution
-    workspace = Path("/home/pewds/odysseus-tool-work")
+    workspace = tmp_path
     script = workspace / ".python-workspace-alias-test.py"
     output = workspace / ".python-workspace-alias-test.txt"
     script.write_text(
@@ -2209,13 +2210,11 @@ def test_python_loaded_code_sees_virtual_workspace_alias(monkeypatch):
     )
     monkeypatch.setattr(tool_execution, "agent_cwd", lambda: str(workspace))
     result = asyncio.run(subprocess_tools.PythonTool().execute(
-        f"import runpy; runpy.run_path('{script}', run_name='__main__')",
+        "import runpy; runpy.run_path('/workspace/.python-workspace-alias-test.py', run_name='__main__')",
         {},
     ))
     assert result["exit_code"] == 0, result
     assert output.read_text() == "ok"
-    script.unlink()
-    output.unlink()
 
 
 def test_workspace_namespace_preserves_the_64_bit_dynamic_loader(monkeypatch):