diff --git a/opencollab/adapters/git_patch.py b/opencollab/adapters/git_patch.py
index d55e3665..081402f5 100644
--- a/opencollab/adapters/git_patch.py
+++ b/opencollab/adapters/git_patch.py
@@ -36,16 +36,18 @@ def _git_command_and_config_guard(*, allow_core_worktree: bool = False) -> tuple
         "for config_scope in $config_scopes; do "
         f"unsafe_config=$({git_command} config \"$config_scope\" --includes --name-only --get-regexp "
         "'^(diff\\..*\\.(command|textconv)|filter\\..*|"
-        f"core\\.(excludesfile|sparsecheckout|sparsecheckoutcone{worktree_setting}))$' "
+        f"core\\.(excludesfile{worktree_setting}))$' "
         "2>/dev/null); "
         'config_rc=$?; if [ "$config_rc" -eq 0 ]; then '
         "echo \"unsafe repository Git configuration: $unsafe_config\" >&2; exit 125; "
         'elif [ "$config_rc" -ne 1 ]; then exit "$config_rc"; fi; '
-        f'fsmonitor=$({git_command} config "$config_scope" --includes --type=bool '
-        "--get core.fsmonitor 2>/dev/null); fsmonitor_rc=$?; "
-        'if [ "$fsmonitor_rc" -eq 0 ] && [ "$fsmonitor" = false ]; then :; '
-        'elif [ "$fsmonitor_rc" -ne 1 ]; then '
-        "echo 'unsafe repository Git configuration: core.fsmonitor' >&2; exit 125; fi; "
+        "for boolean_key in core.fsmonitor core.sparsecheckout core.sparsecheckoutcone; do "
+        f'config_value=$({git_command} config "$config_scope" --includes --type=bool '
+        '--get "$boolean_key" 2>/dev/null); config_rc=$?; '
+        'if [ "$config_rc" -eq 0 ] && [ "$config_value" = false ]; then :; '
+        'elif [ "$config_rc" -ne 1 ]; then '
+        'echo "unsafe repository Git configuration: $boolean_key" >&2; exit 125; fi; '
+        "done; "
         "done; "
         f'info_attributes=$({git_command} rev-parse --git-path info/attributes) || exit 125; '
         'if [ -L "$info_attributes" ] || { [ -e "$info_attributes" ] && [ ! -f "$info_attributes" ]; }; then '
@@ -164,13 +166,11 @@ def guarded_staged_diff_command(
     ``core.attributesFile`` and ``diff.ignoreSubmodules`` are pinned by an
     explicit ``-c``, which outranks any repository-local value, so a repository
     that marks a file undiffable or hides a gitlink change cannot do either
-    here. ``core.fsmonitor`` is judged by its value: a repository that turns a
-    monitor off is hardening itself and is allowed through, while one that turns
-    a monitor on is refused, because a monitor that lies about what changed can
-    only be trusted or refused, never overridden. Everything else that could
-    bend the reading -- a redirected working tree, a sparse checkout, an
-    excludes file, and the clean/smudge filters and external diff drivers a
-    tracked ``.gitattributes`` can still reach -- is refused outright.
+    here. ``core.fsmonitor``, ``core.sparsecheckout``, and
+    ``core.sparsecheckoutcone`` accept Git boolean false values or an absent
+    setting. Enabled or malformed values are refused. Redirected working trees,
+    excludes files, clean/smudge filters, and external diff drivers reachable
+    through tracked ``.gitattributes`` are refused outright.
 
     A refusal exits 125 rather than reporting a patch this command cannot vouch
     for.
diff --git a/tests/runtime/test_disabled_sparse_checkout.py b/tests/runtime/test_disabled_sparse_checkout.py
new file mode 100644
index 00000000..8c18e02b
--- /dev/null
+++ b/tests/runtime/test_disabled_sparse_checkout.py
@@ -0,0 +1,75 @@
+from __future__ import annotations
+
+import subprocess
+from pathlib import Path
+
+import pytest
+
+from opencollab.adapters.env import LocalEnvironment, WorktreeEnvironment
+from opencollab.adapters.tools.git_diff import GitDiffTool
+from opencollab.adapters.worktree_pool import WorktreePool
+from opencollab.application.tool_execution import ToolRuntime
+
+
+def _git(repo: Path, *args: str) -> str:
+    return subprocess.run(
+        ["git", "-C", str(repo), *args], check=True, text=True, capture_output=True,
+    ).stdout
+
+
+@pytest.mark.parametrize("disabled_sparse", [False, True])
+async def test_full_checkout_exports_after_sparse_checkout_disable(tmp_path, monkeypatch, disabled_sparse):
+    monkeypatch.setenv("GIT_CONFIG_NOSYSTEM", "1")
+    monkeypatch.setenv("GIT_CONFIG_GLOBAL", "/dev/null")
+    source = tmp_path / "source"
+    source.mkdir()
+    for name, content in (("src/app.py", "value = 1\n"), ("docs/guide.txt", "guide\n")):
+        path = source / name
+        path.parent.mkdir(exist_ok=True)
+        path.write_text(content, encoding="utf-8")
+    _git(source, "init", "-q")
+    _git(source, "add", ".")
+    _git(source, "-c", "user.name=Test User", "-c", "user.email=test@example.invalid",
+         "-c", "commit.gpgsign=false", "commit", "-qm", "base")
+    if disabled_sparse:
+        _git(source, "sparse-checkout", "init", "--cone")
+        _git(source, "sparse-checkout", "set", "src")
+        assert not (source / "docs/guide.txt").exists()
+        _git(source, "sparse-checkout", "disable")
+        for key in ("core.sparsecheckout", "core.sparsecheckoutcone"):
+            assert _git(source, "config", "--type=bool", "--get", key) == "false\n"
+    assert (source / "docs/guide.txt").read_text(encoding="utf-8") == "guide\n"
+    assert _git(source, "status", "--porcelain") == ""
+    assert all(line.startswith("H ") for line in _git(source, "ls-files", "-t").splitlines())
+
+    local = LocalEnvironment(str(source))
+    try:
+        result = await GitDiffTool().execute_with_runtime({}, ToolRuntime(local, None, None))
+        assert result == "Status: working tree clean.\n\ndiff vs HEAD: (no changes)"
+    finally:
+        await local.cleanup()
+
+    env = WorktreeEnvironment(str(source))
+    candidate = Path(await env.setup())
+    try:
+        await env.write_file("src/app.py", "value = 2\n")
+        expected = _git(candidate, "diff", "--binary", "--full-index", "--no-color",
+                        "--unified=3", "--src-prefix=a/", "--dst-prefix=b/", "HEAD")
+        assert "+value = 2\n" in expected
+        assert await env.get_diff() == expected
+        assert _git(candidate, "diff", "--cached") == ""
+    finally:
+        await env.cleanup()
+    assert not candidate.exists()
+
+    pool = WorktreePool(str(source), use_worktrees=True, enable_adoption=True)
+    try:
+        worker = await pool.acquire("coder")
+        pooled_candidate = Path(worker.workspace)
+        await worker.write_file("src/app.py", "value = 2\n")
+        assert await worker.get_diff() == expected
+    finally:
+        await pool.release()
+    assert not pooled_candidate.exists()
+    assert _git(source, "status", "--porcelain") == ""
+    assert (source / "src/app.py").read_text(encoding="utf-8") == "value = 1\n"
diff --git a/tests/tools/test_git_patch.py b/tests/tools/test_git_patch.py
index b9e13aef..dc59339a 100644
--- a/tests/tools/test_git_patch.py
+++ b/tests/tools/test_git_patch.py
@@ -205,6 +205,59 @@ def test_patch_rejects_worktree_scoped_sparse_checkout(tmp_path):
     assert result.returncode == 125
     assert "core.sparsecheckout" in result.stderr
 
+@pytest.mark.parametrize("scope", ["--local", "--worktree"])
+@pytest.mark.parametrize("value", ["false", "FaLsE", "no", "off", "0", ""])
+def test_patch_allows_disabled_sparse_boolean_values(tmp_path, scope, value):
+    repo = _repo(tmp_path)
+    (repo / "tracked.txt").write_text("new\n", encoding="utf-8")
+    expected = _extract(repo)
+    assert expected.returncode == 0, expected.stderr
+    _git(repo, "config", "extensions.worktreeConfig", "true")
+    for key in ("core.sparsecheckout", "core.sparsecheckoutcone"):
+        _git(repo, "config", scope, key, value)
+
+    result = _extract(repo)
+
+    assert result.returncode == 0, result.stderr
+    assert result.stdout == expected.stdout
+
+@pytest.mark.parametrize("scope", ["--local", "--worktree"])
+@pytest.mark.parametrize("key", ["core.sparsecheckout", "core.sparsecheckoutcone"])
+@pytest.mark.parametrize("value", ["true", "yes", "on", "1", "-1", "2", "invalid", None])
+def test_patch_rejects_enabled_or_invalid_sparse_values(tmp_path, scope, key, value):
+    repo = _repo(tmp_path)
+    _git(repo, "config", "extensions.worktreeConfig", "true")
+    if value is None:
+        config = Path(_git(repo, "rev-parse", "--git-path", "config.worktree" if scope == "--worktree"
+                           else "config").stdout.strip())
+        with (repo / config).open("a", encoding="utf-8") as stream:
+            stream.write(f"[core]\n\t{key.split('.')[1]}\n")
+    else:
+        _git(repo, "config", scope, key, value)
+
+    result = _extract(repo)
+
+    assert result.returncode == 125
+    assert f"unsafe repository Git configuration: {key}" in result.stderr
+
+@pytest.mark.parametrize("sparse_index", [False, True])
+def test_patch_rejects_active_sparse_checkout(tmp_path, sparse_index):
+    repo = _repo(tmp_path)
+    for directory in ("visible", "hidden"):
+        (repo / directory).mkdir()
+        (repo / directory / "file.txt").write_text("tracked\n", encoding="utf-8")
+    _git(repo, "add", ".")
+    _git(repo, "commit", "-qm", "add directories")
+    _git(repo, "sparse-checkout", "init", "--cone", "--sparse-index" if sparse_index else "--no-sparse-index")
+    _git(repo, "sparse-checkout", "set", "visible")
+    assert not (repo / "hidden" / "file.txt").exists()
+    assert "S hidden/" in _git(repo, "ls-files", "--sparse", "-t").stdout
+
+    result = _extract(repo)
+
+    assert result.returncode == 125
+    assert "core.sparsecheckout" in result.stderr
+
 def test_patch_rejects_transform_config_loaded_through_include(tmp_path):
     repo = _repo(tmp_path)
     (repo / "payload.txt").write_text("candidate\n", encoding="utf-8")