diff --git a/BUILD b/BUILD
index d28698186..c2483286c 100644
--- a/BUILD
+++ b/BUILD
@@ -25,13 +25,11 @@ docs(
     external_needs = [
         "@score_process_description//:needs_json_file",
     ],
-    data = [
-        # These scenario BUILD files are used by literalinclude examples.
-        "//src/tests/docs_bzl/scenarios/nested_bundles:nested_bundle_build",
-        "//src/tests/docs_bzl/scenarios/data_files_runfiles:generated_data_build",
-        "//src/tests/docs_bzl/scenarios/external_bundle:external_bundle_build",
-    ],
     bundles = [
+        {
+            "bundle": "//src/tests/docs_bzl/scenarios:docs_literalinclude_data",
+            "mount_at": "_literalinclude_data",
+        },
         {
             "bundle": "//src/extensions/docs:extensions",
             "mount_at": "internals/extensions",
diff --git a/bzl/bundle_rules.bzl b/bzl/bundle_rules.bzl
index ab59f354c..de0951eab 100644
--- a/bzl/bundle_rules.bzl
+++ b/bzl/bundle_rules.bzl
@@ -41,11 +41,12 @@
 # Extending `sphinx_docs_library` is also not a good fit. Its provider represents
 # individual file mappings, while our provider represents complete mounted bundles. Adding
 # the required metadata would therefore not be a small extension of the existing
-# abstraction; it would change its propagated unit and its semantics. It would also couple
-# SCORE-specific composition rules to the generic `rules_sphinxdocs` implementation.
+# abstraction; it would change its propagated unit and its semantics.
 
 # We therefore reimplement the relatively small overlapping part—transitive source
-# collection—while keeping the richer bundle model explicit and independent.
+# collection—while keeping the richer bundle model explicit. The rule exposes a
+# narrow ``SphinxDocsLibraryInfo`` view only for non-document bundle data so a
+# sandboxed Sphinx action can stage those files without duplicating mounted docs.
 
 # The name `docs_bundle` reflects that relationship: it fills the same general role
 # as `sphinx_docs_library`, but uses a SCORE-specific data model for composing structured
@@ -54,6 +55,7 @@
 
 
 load("@score_docs_as_code//:bzl/basics.bzl", "join_path")
+load("@sphinxdocs//sphinxdocs/private:sphinx_docs_library_info.bzl", "SphinxDocsLibraryInfo")
 
 # Internal data passed between bundle targets and eventually consumed by an
 # adapter such as the Sphinx mounts manifest. Users configure bundles through
@@ -198,8 +200,30 @@ def _rebase_bundle_entry(entry, mount_at, attach_to):
         external = entry.external,
         repository = entry.repository,
         data = entry.data,
+        path_check = entry.path_check,
     )
 
+def _entry_with_path_check(entry, path_check):
+    """Return an entry with the requested sphinx-mounts confinement mode."""
+    return struct(
+        runtime_path = entry.runtime_path,
+        src_root = entry.src_root,
+        mount_at = entry.mount_at,
+        attach_to = entry.attach_to,
+        entry_doc = entry.entry_doc,
+        external = entry.external,
+        repository = entry.repository,
+        data = entry.data,
+        path_check = path_check,
+    )
+
+def _has_data_only_entry(entries):
+    """Return whether the entries contain a declared pure-data bundle."""
+    for entry in entries:
+        if not entry.src_root and entry.data.to_list():
+            return True
+    return False
+
 def _entries_visible_through(ctx, child):
     """Keep an external module's own docs, but not its foreign mounts."""
     entries = child[DocsBundleInfo].entries
@@ -244,11 +268,12 @@ def _docs_bundle_impl(ctx):
     own_source_files = []
     own_external_runfiles = []
     own_data = depset(direct = ctx.files.data)
+    own_source_entry = None
 
     if ctx.files.srcs:
         runtime_path = _bundle_runtime_path(ctx)
         external = runtime_path.startswith("../")
-        entries.append(struct(
+        own_source_entry = struct(
             runtime_path = runtime_path,
             # The execution root and runfiles tree spell external repositories
             # differently. Keep both locations so every public docs() target can
@@ -260,7 +285,9 @@ def _docs_bundle_impl(ctx):
             external = external,
             repository = ctx.label.workspace_name,
             data = own_data,
-        ))
+            path_check = "off" if own_data.to_list() else "error",
+        )
+        entries.append(own_source_entry)
         own_source_files.extend(ctx.files.srcs)
         # Local sources are read directly from the workspace by ``bazel run``.
         # Only sources from external repositories must be staged in runfiles.
@@ -277,6 +304,7 @@ def _docs_bundle_impl(ctx):
             external = False,
             repository = ctx.label.workspace_name,
             data = own_data,
+            path_check = "error",
         ))
 
     child_source_files = []
@@ -286,13 +314,20 @@ def _docs_bundle_impl(ctx):
         for source_link in ctx.files.sourcelinks
     ]
     for index, child in enumerate(ctx.attr.bundles):
+        child_entries = _entries_visible_through(ctx, child)
+        if own_source_entry != None and _has_data_only_entry(child_entries):
+            # Supporting files composed through a data-only child are available
+            # to this source tree. sphinx-mounts 0.1.x has no per-file allowlist,
+            # so the source entry uses its documented non-confining mode.
+            own_source_entry = _entry_with_path_check(own_source_entry, "off")
+            entries[0] = own_source_entry
         entries.extend([
             _rebase_bundle_entry(
                 entry,
                 ctx.attr.bundle_mount_ats[index],
                 ctx.attr.bundle_attach_tos[index],
             )
-            for entry in _entries_visible_through(ctx, child)
+            for entry in child_entries
         ])
         child_source_files.append(child[DefaultInfo].files)
         child_external_runfiles.append(child[DocsBundleInfo].external_runfiles)
@@ -313,6 +348,16 @@ def _docs_bundle_impl(ctx):
             for child in ctx.attr.bundles
         ],
     )
+    non_document_data = tuple([
+        file
+        for file in all_data.to_list()
+        if not _is_sphinx_source_file(file)
+    ])
+    sphinx_data_entry = struct(
+        strip_prefix = "/",
+        prefix = "",
+        files = non_document_data,
+    )
     return [
         DefaultInfo(files = depset(transitive = [all_source_files, all_data])),
         DocsBundleInfo(
@@ -322,6 +367,12 @@ def _docs_bundle_impl(ctx):
             external_runfiles = external_runfiles,
             data = all_data,
         ),
+        SphinxDocsLibraryInfo(
+            files = depset(direct = non_document_data),
+            strip_prefix = "/",
+            prefix = "",
+            transitive = depset(direct = [sphinx_data_entry]) if non_document_data else depset(),
+        ),
     ]
 
 _docs_bundle = rule(
@@ -378,6 +429,10 @@ def bundle_source_files(name, bundle, visibility = None):
     )
     return ":" + name
 
+def _is_sphinx_source_file(file):
+    """Return whether ``file`` is discovered as a normal Sphinx document."""
+    return file.basename.endswith(".rst") or file.basename.endswith(".md")
+
 def _external_docs_runfiles_impl(ctx):
     """Expose external documentation sources needed under ``bazel run``."""
     bundle = ctx.attr.bundle[DocsBundleInfo]
diff --git a/bzl/mount_rules.bzl b/bzl/mount_rules.bzl
index dd42571eb..2b5fcc28f 100644
--- a/bzl/mount_rules.bzl
+++ b/bzl/mount_rules.bzl
@@ -32,6 +32,7 @@ def _mounts_manifest_impl(ctx):
             "external": entry.external,
             "repository": entry.repository,
             "data": [f.path for f in entry.data.to_list()],
+            "path_check": entry.path_check,
         })
 
     out = ctx.actions.declare_file(ctx.label.name + ".json")
diff --git a/docs.bzl b/docs.bzl
index 56eaa297a..30c78c4f2 100644
--- a/docs.bzl
+++ b/docs.bzl
@@ -253,7 +253,8 @@ def docs(
     use a bundle for anything that should travel as one portable mount. A
     bundle may be data-only when its deliverable is generated/supporting data
     rather than source RST. Use ``docs(data = [...])`` only for project-level
-    inputs that do not belong to a bundle mount.
+    inputs that do not belong to a bundle mount. Compose a data-only
+    ``docs_bundle`` when those files must travel with the public bundle as well.
     """
     # HINT: keep documentation sync docs/reference/bazel_macros.rst
 
@@ -284,13 +285,12 @@ def docs(
 
     data_library_label_for_sphinx_docs = []
     if data:
-        # ``docs_bundle`` can carry data, including as a pure-data bundle. That
-        # data belongs to the bundle payload and is resolved at its eventual
-        # mount. These ``docs(data = [...])`` inputs are intentionally
-        # project-level instead: they support the project build or its
-        # literalinclude examples and are not assigned to a bundle mount. Both
-        # kinds of data are build inputs; without the staging below, project-
-        # level inputs would
+        # ``docs(data = [...])`` inputs support the project build and are not
+        # assigned to a bundle mount. They must also be staged below the
+        # Sphinx source root for the sandboxed ``needs`` action; without this,
+        # standard literalinclude resolution cannot find them.
+        #
+        # Without the staging below, project-level inputs would
         # remain only execution inputs for Sphinx's tools rather than files
         # below Sphinx's source directory, where standard ``literalinclude``
         # looks for them.
@@ -304,10 +304,13 @@ def docs(
         sphinx_docs_library(
             name = "_docs_data",
             srcs = data,
-            strip_prefix = "",
+            # ``sphinx_docs_library`` otherwise defaults to this package and
+            # would change the path seen by a relative literalinclude.
+            strip_prefix = "/",
         )
         data_library_label_for_sphinx_docs = [":_docs_data"]
 
+    bundle_data_library_label_for_sphinx_docs = []
     mounts_manifest_label = []
     if bundles:
         mounts_bundle = create_bundle(
@@ -316,6 +319,8 @@ def docs(
             visibility = ["//visibility:private"],
         )
 
+        bundle_data_library_label_for_sphinx_docs = [mounts_bundle]
+
         mounts_manifest_label = [
             create_mounts_manifest(
                 name = "_mounts_manifest",
@@ -472,7 +477,10 @@ def docs(
         # complete bundle as srcs would also expose those files as raw Sphinx
         # sources and make every nested need appear twice.
         srcs = [sphinx_sources],
-        deps = data_library_label_for_sphinx_docs,
+        deps = (
+            data_library_label_for_sphinx_docs +
+            bundle_data_library_label_for_sphinx_docs
+        ),
         config = sphinx_config,
         extra_opts = [
             "-W",
diff --git a/docs/reference/bazel_macros.rst b/docs/reference/bazel_macros.rst
index d6f2ffc43..bcf26a878 100644
--- a/docs/reference/bazel_macros.rst
+++ b/docs/reference/bazel_macros.rst
@@ -28,22 +28,25 @@ The macro must be called from the repository root package.
 Supporting files: project inputs and bundle payloads
 ----------------------------------------------------
 
-There are two ``data`` attributes, and they belong to different documentation
-trees:
+The macros expose project inputs and bundle payloads separately:
 
 * ``docs_bundle(data = [...])`` puts files in a bundle payload. The files
   travel with that bundle and are resolved below the bundle's eventual
   ``mount_at`` path. Use this for generated documentation, images, and other
   assets needed by a mounted bundle.
 * ``docs(data = [...])`` puts files in the project-level ``docs()`` build,
-  outside any bundle. These files have no bundle mount path. Use this only for
-  inputs needed by the project-level build itself. ``bazel run`` does not copy
-  generated data into the workspace source tree; generated documentation or
-  assets must use ``docs_bundle(data = [...])``.
-
-If a file belongs to a mounted bundle, use ``docs_bundle(data = [...])``.
-Both attributes make files available to a build; they differ in which
-documentation tree carries the files and where they are resolved.
+  outside any bundle. These files have no bundle mount path and do not travel
+  with the public bundle.
+* A data-only ``docs_bundle(data = [...])`` is a separate child bundle. Compose
+  it through ``bundles`` when the files must travel with the project's public
+  bundle or with another mounted bundle. ``docs()`` stages non-document payloads
+  from such children below the sandboxed Sphinx source root, so a project's
+  original ``literalinclude`` path works without repeating the label in
+  ``docs(data = [...])``. This keeps the original files in the bundle payload;
+  no snapshot is copied into ``docs/``.
+
+If a file belongs to a nested or generated bundle, use
+``docs_bundle(data = [...])`` and compose that bundle through ``bundles``.
 
 Minimal example (root ``BUILD``)
 --------------------------------
@@ -87,7 +90,8 @@ Minimal example (root ``BUILD``)
   The items in ``data`` are added to the py_binaries and to the Sphinx tooling so they are
   available at build time. These are project-level inputs; they are not part of
   a bundle and do not receive a bundle mount path. Use ``docs_bundle(data = [...])``
-  for files that belong to mounted documentation.
+  for files that belong to mounted documentation or must travel with the public
+  bundle.
 
   .. note::
 
@@ -97,6 +101,9 @@ Minimal example (root ``BUILD``)
 - ``bundles`` (list of placement dicts)
   Documentation bundles to overlay into this project's documentation tree, each with its
   placement (``mount_at``). See :ref:`howto_mount_external_sources` for the full reference.
+  A data-only child contributes supporting files without adding a documentation
+  page; use a private-looking mount path when it exists only to carry data for
+  the public bundle.
 
 - ``deps`` (list of bazel labels)
   Additional Bazel dependencies to add to the Python binaries and the virtual environment
@@ -187,7 +194,10 @@ Signature: ``docs_bundle(name, source_dir = None, data = [], entry_doc = "index"
   ``index.rst``. If ``source_dir`` is omitted and ``data`` contains the
   bundle's deliverable, the result is a data-only bundle. Use this attribute
   for any file that belongs with the mounted bundle. Use
-  ``docs(data = [...])`` only for project-level inputs outside a bundle.
+  ``docs(data = [...])`` only for project-level inputs outside a bundle. If a
+  source page references a file outside its ``source_dir``, use a data-only
+  child bundle and compose it through ``bundles``. Its non-document payload is
+  staged for the host's sandboxed build automatically.
 
 - ``entry_doc`` (string, optional)
   Bundle-relative docname used as the canonical navigation entry. It defaults to
diff --git a/src/extensions/docs/mounts_internals.rst b/src/extensions/docs/mounts_internals.rst
index 2fbf7c3d5..638d8cae3 100644
--- a/src/extensions/docs/mounts_internals.rst
+++ b/src/extensions/docs/mounts_internals.rst
@@ -38,12 +38,22 @@ Each manifest entry contains:
 * ``mount_at`` and ``attach_to`` — the already-composed Sphinx placement; and
 * ``entry_doc`` — the canonical entry document declared by the source bundle.
 * ``external`` — whether the directory belongs to another Bazel module.
+* ``data`` — explicitly declared supporting files carried by that entry. For
+  a source-bearing entry these are bundle-owned references (for example a test
+  fixture shown with ``literalinclude``); for a data-only entry they identify
+  the generated files that form the mount.
+* ``path_check`` — the ``sphinx-mounts`` confinement mode selected by the
+  bundle graph. It is normally ``error``; a source entry composed with a
+  data-only child uses ``off`` because sphinx-mounts 0.1.x has no per-file
+  allowlist for references outside the source directory.
 
 The rule rejects conflicting final placements before Sphinx starts. A mount
 without ``attach_to`` is attached to the ``index`` document beside its
-``mount_at``; ``attach_to`` overrides that target. The Python
-extension may therefore preserve declaration order and only translates each
-manifest entry into the ``sphinx_mounts`` configuration format.
+``mount_at``; ``attach_to`` overrides that target. The Python extension may
+therefore preserve declaration order and only translates each manifest entry
+into the ``sphinx_mounts`` configuration format. Data-only entries containing
+non-document payloads do not create a directory mount; otherwise their parent
+directory could expose unrelated documentation files to Sphinx.
 
 Directory resolution
 --------------------
diff --git a/src/extensions/score_mounts/__init__.py b/src/extensions/score_mounts/__init__.py
index b03ca6d38..2a85a6d1f 100644
--- a/src/extensions/score_mounts/__init__.py
+++ b/src/extensions/score_mounts/__init__.py
@@ -77,7 +77,18 @@ def _resolve_data_mounts(
     """
     data_mounts: dict[str, MountSpec] = {}
     for spec in manifest.mounts:
+        # Data on a source-bearing entry is supporting input for that source
+        # tree (for example a BUILD file shown by literalinclude), not a
+        # separate documentation tree. Only pure-data bundle entries need a
+        # directory mount for their generated source files.
+        if spec.src_root:
+            continue
         for data_file in spec.data:
+            # Non-document payloads remain available as bundle inputs; mounting
+            # their parent would make sphinx-mounts walk unrelated neighboring
+            # documentation files as part of a data-only bundle.
+            if Path(data_file).suffix not in {".md", ".rst"}:
+                continue
             if ws_root is not None and runfiles_dir is not None:
                 runfiles_str = str(runfiles_dir)
                 if "/bazel-out/" in runfiles_str:
@@ -168,6 +179,7 @@ def _make_mount_entry(walk_dir: Path, spec: MountSpec) -> dict[str, object]:
         "mount_at": spec.mount_at,
         "attach_to": spec.attach_to,
         "entry_doc": spec.entry_doc,
+        "path_check": spec.path_check,
     }
 
 
diff --git a/src/extensions/score_mounts/_resolver.py b/src/extensions/score_mounts/_resolver.py
index e820d8bac..f925cc05b 100644
--- a/src/extensions/score_mounts/_resolver.py
+++ b/src/extensions/score_mounts/_resolver.py
@@ -37,6 +37,7 @@ class MountSpec:
     external: bool = False
     repository: str = ""
     data: list[str] = field(default_factory=list)
+    path_check: str = "error"
 
 
 @dataclass(frozen=True)
@@ -87,6 +88,7 @@ def load_mounts_manifest(manifest_path: str | Path) -> MountsManifest:
                 external=bool(entry.get("external", False)),
                 repository=str(entry.get("repository", "")),
                 data=[str(f) for f in cast("list[object]", raw_data)],
+                path_check=str(entry.get("path_check", "error")),
             )
         )
     return MountsManifest(mounts=mounts)
diff --git a/src/extensions/score_mounts/tests/test_data_mounts.py b/src/extensions/score_mounts/tests/test_data_mounts.py
index a8144e343..0d99c9d07 100644
--- a/src/extensions/score_mounts/tests/test_data_mounts.py
+++ b/src/extensions/score_mounts/tests/test_data_mounts.py
@@ -59,6 +59,53 @@ def test_existing_data_file_resolved(tmp_path: Path) -> None:
     assert str(tmp_path / "bazel-bin") in mounts
 
 
+def test_source_supporting_file_is_not_mounted_as_a_second_source_tree(
+    tmp_path: Path,
+) -> None:
+    """Supporting files on a source bundle do not create a duplicate mount."""
+    source_dir = tmp_path / "docs"
+    source_dir.mkdir()
+    (source_dir / "index.rst").write_text("Index", encoding="utf-8")
+    fixture = tmp_path / "src" / "tests" / "scenario" / "BUILD"
+    fixture.parent.mkdir(parents=True)
+    fixture.write_text("filegroup(name = 'fixture')", encoding="utf-8")
+
+    spec = MountSpec(
+        src_root="docs",
+        runtime_path="docs",
+        mount_at="docs",
+        data=["src/tests/scenario/BUILD"],
+        path_check="off",
+    )
+    manifest = MountsManifest(mounts=[spec])
+
+    assert _resolve_data_mounts(manifest, tmp_path, tmp_path / "runfiles") == {}
+    assert _make_mount_entry(source_dir, spec)["path_check"] == "off"
+
+
+def test_non_document_payload_does_not_mount_its_parent_directory(
+    tmp_path: Path,
+) -> None:
+    """A data-only BUILD payload must not turn neighboring docs into mounts."""
+    data_file = tmp_path / "bazel-bin" / "scenario" / "BUILD"
+    data_file.parent.mkdir(parents=True)
+    data_file.write_text("filegroup(name = 'fixture')", encoding="utf-8")
+    (data_file.parent / "index.rst").write_text("not a bundle page", encoding="utf-8")
+
+    manifest = MountsManifest(
+        mounts=[
+            MountSpec(
+                src_root="",
+                runtime_path="",
+                mount_at="data",
+                data=["bazel-out/k8-fastbuild/bin/scenario/BUILD"],
+            )
+        ]
+    )
+
+    assert _resolve_data_mounts(manifest, tmp_path, tmp_path / "runfiles") == {}
+
+
 def test_mount_entry_uses_canonical_directory_for_symlinked_bundle(
     tmp_path: Path,
 ) -> None:
diff --git a/src/extensions/score_mounts/tests/test_resolver.py b/src/extensions/score_mounts/tests/test_resolver.py
index b9fe60e5b..64e40ab63 100644
--- a/src/extensions/score_mounts/tests/test_resolver.py
+++ b/src/extensions/score_mounts/tests/test_resolver.py
@@ -71,6 +71,7 @@ def test_load_entry_with_attach_to_and_entry_doc(tmp_path: Path) -> None:
                     "mount_at": "x",
                     "attach_to": "internals/index",
                     "entry_doc": "start",
+                    "path_check": "off",
                 }
             ],
         },
@@ -78,6 +79,7 @@ def test_load_entry_with_attach_to_and_entry_doc(tmp_path: Path) -> None:
     spec = load_mounts_manifest(str(manifest)).mounts[0]
     assert spec.attach_to == "internals/index"
     assert spec.entry_doc == "start"
+    assert spec.path_check == "off"
 
 
 def test_external_mount_keeps_execroot_and_runfiles_locations(tmp_path: Path) -> None:
diff --git a/src/extensions/score_sync_toml/_mounts.py b/src/extensions/score_sync_toml/_mounts.py
index d84cf3412..65a809be5 100644
--- a/src/extensions/score_sync_toml/_mounts.py
+++ b/src/extensions/score_sync_toml/_mounts.py
@@ -56,6 +56,8 @@ def materialize_mounts(entries: list[dict[str, Any]]) -> Path | None:
             lines.append(f"attach_to = {_toml_string(entry['attach_to'])}")
         if entry.get("entry_doc", "index") != "index":
             lines.append(f"entry_doc = {_toml_string(entry['entry_doc'])}")
+        if entry.get("path_check", "error") != "error":
+            lines.append(f"path_check = {_toml_string(entry['path_check'])}")
         lines.append("")
     outdir = Path(tempfile.mkdtemp(prefix="score_sync_toml_"))
     fragment = outdir / "score_mounts.toml"
diff --git a/src/extensions/score_sync_toml/test_mounts.py b/src/extensions/score_sync_toml/test_mounts.py
index 52a299af6..4b2b65fd1 100644
--- a/src/extensions/score_sync_toml/test_mounts.py
+++ b/src/extensions/score_sync_toml/test_mounts.py
@@ -48,6 +48,17 @@ def test_materialize_mounts_omits_default_fields():
     )
 
 
+def test_materialize_mounts_preserves_non_default_path_check():
+    fragment = materialize_mounts(
+        [{"dir": "docs", "mount_at": "guide", "path_check": "off"}]
+    )
+
+    assert fragment is not None
+    assert fragment.read_text(encoding="utf-8") == (
+        '[[mounts]]\ndir = "docs"\nmount_at = "guide"\npath_check = "off"\n'
+    )
+
+
 def test_materialize_mounts_maps_external_runfiles_path_to_bazel_bin(
     tmp_path: Path, monkeypatch: pytest.MonkeyPatch
 ) -> None:
diff --git a/src/tests/docs_bzl/scenarios/BUILD b/src/tests/docs_bzl/scenarios/BUILD
new file mode 100644
index 000000000..74645a286
--- /dev/null
+++ b/src/tests/docs_bzl/scenarios/BUILD
@@ -0,0 +1,26 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+
+load("//:docs.bzl", "docs_bundle")
+
+# These scenario BUILD files are used by literalinclude examples in the root
+# documentation. Keep the payload with the scenarios that own the fixtures.
+docs_bundle(
+    name = "docs_literalinclude_data",
+    data = [
+        "//src/tests/docs_bzl/scenarios/data_files_runfiles:generated_data_build",
+        "//src/tests/docs_bzl/scenarios/external_bundle:external_bundle_build",
+        "//src/tests/docs_bzl/scenarios/nested_bundles:nested_bundle_build",
+    ],
+    visibility = ["//visibility:public"],
+)
diff --git a/src/tests/docs_bzl/scenarios/bundle_data_provider/BUILD b/src/tests/docs_bzl/scenarios/bundle_data_provider/BUILD
new file mode 100644
index 000000000..8ffb6f652
--- /dev/null
+++ b/src/tests/docs_bzl/scenarios/bundle_data_provider/BUILD
@@ -0,0 +1,36 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License, Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+
+load("//:docs.bzl", "docs", "docs_bundle")
+
+filegroup(
+    name = "fixture_build",
+    srcs = ["BUILD"],
+    visibility = ["//visibility:public"],
+)
+
+docs_bundle(
+    name = "literalinclude_data",
+    data = [":fixture_build"],
+    visibility = ["//visibility:public"],
+)
+
+docs(
+    source_dir = "docs",
+    project = "Bundle Data Provider",
+    project_url = "https://example.invalid/bundle-data-provider",
+    bundles = [{
+        "bundle": ":literalinclude_data",
+        "mount_at": "_literalinclude_data",
+    }],
+)
diff --git a/src/tests/docs_bzl/scenarios/bundle_data_provider/docs/index.rst b/src/tests/docs_bzl/scenarios/bundle_data_provider/docs/index.rst
new file mode 100644
index 000000000..db961a335
--- /dev/null
+++ b/src/tests/docs_bzl/scenarios/bundle_data_provider/docs/index.rst
@@ -0,0 +1,21 @@
+..
+   # *******************************************************************************
+   # Copyright (c) 2026 Contributors to the Eclipse Foundation
+   #
+   # See the NOTICE file(s) distributed with this work for additional
+   # information regarding copyright ownership.
+   #
+   # This program and the accompanying materials are made available under the
+   # terms of the Apache License, Version 2.0 which is available at
+   # https://www.apache.org/licenses/LICENSE-2.0
+   #
+   # SPDX-License-Identifier: Apache-2.0
+   # *******************************************************************************
+
+Bundle Data Provider
+====================
+
+The provider deliberately documents its BUILD file as-is:
+
+.. literalinclude:: ../BUILD
+   :language: starlark
diff --git a/src/tests/docs_bzl/test_external_consumer_bundle_data.py b/src/tests/docs_bzl/test_external_consumer_bundle_data.py
new file mode 100644
index 000000000..cd889512d
--- /dev/null
+++ b/src/tests/docs_bzl/test_external_consumer_bundle_data.py
@@ -0,0 +1,97 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License, Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+"""Black-box coverage for an external consumer mounting a data-backed bundle."""
+
+import subprocess
+from pathlib import Path
+
+from src.tests.docs_bzl.helpers import repo_root, run_scenario
+
+
+def _write_consumer(workspace: Path, source_root: Path) -> None:
+    """Create a minimal Bzlmod consumer for the public provider bundle."""
+    subprocess.run(["git", "init", "--quiet", str(workspace)], check=True)
+    (workspace / ".bazelversion").write_text(
+        (source_root / ".bazelversion").read_text(encoding="utf-8"),
+        encoding="utf-8",
+    )
+    (workspace / "MODULE.bazel").write_text(
+        f'''module(name = "literalinclude_consumer")
+bazel_dep(name = "rules_python", version = "1.8.5")
+python = use_extension("@rules_python//python/extensions:python.bzl", "python")
+python.toolchain(is_default = True, python_version = "3.12")
+bazel_dep(name = "score_docs_as_code", version = "8.1.0")
+local_path_override(module_name = "score_docs_as_code", path = "{source_root}")
+''',
+        encoding="utf-8",
+    )
+    (workspace / "BUILD").write_text(
+        """load("@score_docs_as_code//:docs.bzl", "docs")
+
+docs(
+    source_dir = "docs",
+    project = "Literalinclude Consumer",
+    project_url = "https://example.invalid/literalinclude-consumer",
+    bundles = [{
+        "bundle": "@score_docs_as_code//src/tests/docs_bzl/scenarios/bundle_data_provider:docs_bundle",
+        "mount_at": "provider",
+    }],
+)
+""",
+        encoding="utf-8",
+    )
+    docs = workspace / "docs"
+    docs.mkdir()
+    (docs / "index.rst").write_text(
+        """Literalinclude Consumer
+========================
+
+The provider bundle is mounted below this page.
+""",
+        encoding="utf-8",
+    )
+
+
+def test_external_consumer_can_render_data_backed_literalincludes(
+    tmp_path: Path,
+) -> None:
+    """A Bzlmod consumer can render a provider's original literalinclude path."""
+    source_root = repo_root()
+    _write_consumer(tmp_path, source_root)
+
+    result = subprocess.run(
+        [
+            "bazel",
+            "--batch",
+            f"--output_user_root={tmp_path / '.bazel_output'}",
+            f"--bazelrc={source_root / '.bazelrc'}",
+            "run",
+            # local_path_override cannot run the source-link helper in a
+            # sandbox in this consumer setup; keep the Sphinx action sandboxed.
+            "--strategy=MergeBundleSourcelinks=local",
+            "//:docs",
+        ],
+        cwd=tmp_path,
+        text=True,
+        capture_output=True,
+    )
+
+    assert result.returncode == 0, result.stdout + result.stderr
+    provider_page = tmp_path / "_build" / "provider" / "index.html"
+    assert provider_page.is_file()
+    assert "filegroup" in provider_page.read_text(encoding="utf-8")
+
+
+def test_sandboxed_needs_build_stages_nested_bundle_non_document_data() -> None:
+    """A nested data bundle supplies the original BUILD path to Sphinx."""
+    run_scenario("build", "bundle_data_provider", ":needs_json")