Fix double extension in llms.txt URLs when source suffix matches sourcelink suffix

Bumps the all-github-actions group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `actions/checkout` from 5 to 6
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: all-github-actions
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
   pre-commit:
       runs-on: ubuntu-latest
       steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python 3.10
         uses: actions/setup-python@v6
         with:
@@ -23,7 +23,7 @@ jobs:
         python-version: ['3.9', '3.10', '3.11', '3.12']
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6

.readthedocs.yml

@@ -9,6 +9,8 @@ build:
     - pip install -r docs/requirements.txt
     - pip install -e .
     - cmake --workflow --preset documentation-workflow
+    # Generate llms.txt variants for demo purposes
+    - python docs/generate_llms_variants.py build/html
     # Copy built documentation to Read the Docs output directory
     - mkdir -p $READTHEDOCS_OUTPUT/html
     - cp -r build/html/* $READTHEDOCS_OUTPUT/html/

CHANGELOG.rst

@@ -1,6 +1,17 @@
 Changelog
 =========
 
+0.7.2
+-----
+
+- Fix double extension in llms.txt URLs when source suffix matches sourcelink suffix
+  `#63 <https://github.com/jdillard/sphinx-llms-txt/issues/63>`_
+
+0.7.1
+-----
+
+- Don't process includes within code blocks
+
 0.7.0
 -----
 

CMakeLists.txt

@@ -1,8 +1,15 @@
 cmake_minimum_required(VERSION 3.15)
-project(SphinxLLMsTxt VERSION 1.0.0 LANGUAGES NONE)
+project(SphinxDocs VERSION 1.0.0 LANGUAGES NONE)
 
-# Add CMake module path
+# Fetch Sphinx CMake modules
-list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+include(FetchContent)
+FetchContent_Declare(
+  sphinx_cmake_modules
+  GIT_REPOSITORY https://github.com/jdillard/sphinx-cmake-modules.git
+  GIT_TAG        main
+)
+FetchContent_MakeAvailable(sphinx_cmake_modules)
+list(APPEND CMAKE_MODULE_PATH "${sphinx_cmake_modules_SOURCE_DIR}/cmake/modules")
 
 # Add documentation
 add_subdirectory(docs)

CMakePresets.json

@@ -29,7 +29,7 @@
     },
     {
       "name": "docs-parallel",
-      "displayName": "Build HTML and Markdown in parallel",
+      "displayName": "Build all output formats in parallel",
       "configurePreset": "documentation",
       "targets": ["html", "markdown", "rst"]
     }

cmake/SphinxUtils.cmake

@@ -1,28 +0,0 @@
-# Sphinx related utilities
-
-set(SPHINX_SOURCE ${CMAKE_CURRENT_SOURCE_DIR}/source)
-set(SPHINX_BUILD ${CMAKE_BINARY_DIR})
-
-# Function to find Sphinx in the system
-function(setup_sphinx_environment)
-    # Find sphinx-build executable in system
-    find_program(SPHINX_EXECUTABLE
-        NAMES sphinx-build
-        DOC "Sphinx documentation generator"
-    )
-
-    if(NOT SPHINX_EXECUTABLE)
-        message(FATAL_ERROR "sphinx-build not found. Please install Sphinx.")
-    endif()
-
-    # Export to parent scope
-    set(SPHINX_EXECUTABLE "${SPHINX_EXECUTABLE}" PARENT_SCOPE)
-endfunction()
-
-# Function to add a Sphinx builder target
-function(add_sphinx_builder builder_name)
-    add_custom_target(${builder_name}
-        COMMAND ${SPHINX_EXECUTABLE} -b ${builder_name} ${SPHINX_SOURCE} ${SPHINX_BUILD}/${builder_name}
-        VERBATIM
-    )
-endfunction()

docs/generate_llms_variants.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+"""
+Generate variant llms.txt files for demo purposes.
+
+Takes the generated llms.txt (with _sources links) and creates:
+- llms.txt - default with _sources links (unchanged)
+- llms.md.txt - .html.md links
+- llms.rst.txt - .rst links
+"""
+
+import re
+import sys
+from pathlib import Path
+
+
+def get_base_url() -> str:
+    """Import base_url from conf.py."""
+    sys.path.insert(0, str(Path(__file__).parent / "source"))
+    from conf import html_baseurl  # noqa: E402
+
+    return html_baseurl
+
+
+def generate_variants(build_dir: Path) -> None:
+    """Generate llms.txt variants from the original file."""
+    original = build_dir / "llms.txt"
+
+    if not original.exists():
+        print(f"Error: {original} not found")
+        sys.exit(1)
+
+    content = original.read_text()
+    base_url = get_base_url()
+
+    # Pattern to match links like: https://.../_sources/{docname}.rst.txt
+    link_pattern = re.compile(
+        rf"({re.escape(base_url)})_sources/([a-zA-Z0-9_/\-]+)\.rst\.txt"
+    )
+
+    # Generate .html.md variant
+    md_content = link_pattern.sub(r"\1\2.html.md", content)
+    (build_dir / "llms.md.txt").write_text(md_content)
+    print(f"Generated: {build_dir / 'llms.md.txt'} (.html.md links)")
+
+    # Generate .rst variant
+    rst_content = link_pattern.sub(r"\1\2.rst", content)
+    (build_dir / "llms.rst.txt").write_text(rst_content)
+    print(f"Generated: {build_dir / 'llms.rst.txt'} (.rst links)")
+
+    print(f"Kept: {build_dir / 'llms.txt'} (_sources links)")
+
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1:
+        build_dir = Path(sys.argv[1])
+    else:
+        build_dir = Path("build/html")
+
+    generate_variants(build_dir)

docs/requirements.txt

@@ -2,6 +2,7 @@ furo
 esbonio
 sphinx-contributors
 sphinx
+sphinx-design
 sphinx-llms-txt
 sphinx-inline-tabs
 sphinxext-opengraph

docs/source/advanced-configuration.rst

@@ -303,42 +303,121 @@ CMake Workflow
 ^^^^^^^^^^^^^^
 
 This project uses CMake to orchestrate documentation builds across multiple output formats, serving as a simple demo of the functionality.
-Building multiple formats allows you to compare what works best for your docs, as well as allows users to choose which format to feed to their LLM.
 This approach enables parallel builds and integrates well with CI/CD platforms like Read the Docs.
 
+Building multiple formats allows you to compare what works best for your docs, as well as allows users to choose which format to feed to their LLM.
+Use :confval:`llms_txt_uri_template` to configure links to point to your preferred format.
+
 Key Files
 ~~~~~~~~~
 
+These configuration files serve as a simple example of a Sphinx site hosted on Read The Docs, some modification may be needed.
+
 .. code-block:: text
 
    .
    ├── .readthedocs.yml
    ├── CMakeLists.txt
    ├── CMakePresets.json
-   ├── cmake/
-   │   └── SphinxUtils.cmake
    └── docs/
        └── CMakeLists.txt
 
-:ghfile:`.readthedocs.yml`
+Each section below contains a summary of the file's purpose, the full contents of the file, and a table describing key lines that may need modification.
+
+.. dropdown:: .readthedocs.yml
+   :chevron: down-up
+
    A Read The Docs config file that installs dependencies, then runs the full documentation workflow which builds all output formats in parallel, and copies them into a single deploy location.
 
-:ghfile:`CMakeLists.txt`
+   .. literalinclude:: ../../.readthedocs.yml
-   A CMake config file that sets up the project and includes the ``cmake/`` module path.
+      :language: yaml
+      :lines: 1-9,11,14-
+      :linenos:
+      :emphasize-lines: 9, 14-15
 
-:ghfile:`docs/CMakeLists.txt`
+   .. list-table::
-   A CMake config file that includes the Sphinx utilities and defines the documentation-specific build targets.
+      :header-rows: 1
+      :width: 100%
+      :widths: 15 85
 
-:ghfile:`cmake/SphinxUtils.cmake`
+      * - Line
-   A CMake module that provides Sphinx related utilities.
+        - Description
+      * - **9**
+        - Update the path if your requirements file is in a different location
+      * - **13-14**
+        - Modify the copy commands for the output formats you deploy
+
+.. dropdown:: CMakeLists.txt
+   :chevron: down-up
+
+   A CMake config file that sets up the project, fetches the shared `sphinx-cmake-modules <https://github.com/jdillard/sphinx-cmake-modules>`_, and includes the docs subdirectory.
+
+   .. literalinclude:: ../../CMakeLists.txt
+      :language: cmake
+      :linenos:
+      :emphasize-lines: 9, 15
+
+   .. list-table::
+      :header-rows: 1
+      :width: 100%
+      :widths: 15 85
+
+      * - Line
+        - Description
+      * - **9**
+        - Update the ``GIT_TAG`` to use a different version or commit hash
+      * - **15**
+        - Change if your docs subdirectory has a different location
+
+.. dropdown:: docs/CMakeLists.txt
+   :chevron: down-up
+
+   A CMake config file that includes the `SphinxUtils <https://github.com/jdillard/sphinx-cmake-modules/blob/v0.1.0/SphinxUtils.cmake>`_ module from FetchContent and defines the documentation-specific build targets.
+
+   .. literalinclude:: ../CMakeLists.txt
+      :language: cmake
+      :linenos:
+      :emphasize-lines: 5-7
+
+   .. list-table::
+      :header-rows: 1
+      :width: 100%
+      :widths: 15 85
+
+      * - Line
+        - Description
+      * - **5-7**
+        - Add or remove calls based on which output formats you need
+
+
+.. dropdown:: CMakePresets.json
+   :chevron: down-up
 
-:ghfile:`CMakePresets.json`
    Defines presets for configuring and building documentation:
 
    - **Configure Presets:** Sets up the build directory.
-   - **Build Presets:** Defines Build formats individually and all in parallel.
+   - **Build Presets:** Defines build formats individually and all in parallel.
    - **Workflow Presets:** Runs the configure preset followed by the parallel build preset.
 
+   .. literalinclude:: ../../CMakePresets.json
+      :language: json
+      :linenos:
+      :emphasize-lines: 18-23, 24-29, 34
+
+   .. list-table::
+      :header-rows: 1
+      :width: 100%
+      :widths: 15 85
+
+      * - Line
+        - Description
+      * - **18-23**
+        - Remove this preset to disable Markdown documentation builds
+      * - **24-29**
+        - Remove this preset to disable reStructuredText documentation builds
+      * - **34**
+        - Modify the targets list to build only the output formats you need in parallel
+
 Usage
 ~~~~~
 

docs/source/conf.py

@@ -16,7 +16,6 @@ project = "sphinx-llms-txt"
 copyright = "Jared Dillard"
 author = "Jared Dillard"
 
-llms_txt_uri_template = "{base_url}{docname}.md"
 llms_txt_code_files = ["+:../../sphinx_llms_txt/*.py"]
 llms_txt_summary = """
 A Sphinx extension that generates a summary llms.txt file,written in Markdown,
@@ -25,10 +24,7 @@ and a single combined documentation llms-full.txt file, written in reStructuredT
 
 # This doesn't seem to be supported
 # rst_file_suffix = ".html.rst"
-
+markdown_file_suffix = ".html.md"
-extlinks = {
-    "ghfile": ("https://github.com/jdillard/sphinx-llms-txt/blob/main/%s", "%s")
-}
 
 # check if the current commit is tagged as a release (vX.Y.Z)
 try:
@@ -61,6 +57,7 @@ extensions = [
     "sphinxcontrib.restbuilder",
     "sphinx_inline_tabs",
     "sphinx.ext.extlinks",
+    "sphinx_design",
 ]
 
 # The language for content autogenerated by Sphinx. Refer to documentation

docs/source/getting-started.rst

@@ -34,24 +34,34 @@ After the HTML finishes building, **sphinx-llms-txt** will output the location o
     sphinx-llms-txt: Created /path/to/_build/html/llms-full.txt with 45 sources and 6879 lines
     sphinx-llms-txt: created /path/to/_build/html/llms.txt
 
+.. _choosing-output-format:
+
 Choosing an Output Format
 -------------------------
 
-By default, **sphinx-llms-txt** requires no additional configuration and links to raw reStructuredText source files in :confval:`_sources/ <sphinx:html_copy_source>`.
+By default, **sphinx-llms-txt** requires no additional configuration and links to raw reStructuredText source files created by the HTML builder.
-For optimal LLM support, you can use `sphinx-markdown-builder`_ and/or `sphinxcontrib-restbuilder`_, set up in parallel builds using :ref:`CMake <cmake_workflow>`.
+For optimal LLM support, see the alternative builders below and the :ref:`CMake workflow <cmake_workflow>` for setup.
 
 .. list-table:: Output Format Comparison
    :header-rows: 1
    :widths: 18 27 27 27
 
    * -
-     - Default (no config)
+     - Default
-     - Markdown (CMake)
+     - Markdown
-     - RST (CMake)
+     - reStructuredText
+   * - **Setup**
+     - No config
+     - CMake [#sphinxllm]_
+     - CMake
+   * - **Builder**
+     - Native [#native]_
+     - `sphinx-markdown-builder`_
+     - `sphinxcontrib-restbuilder`_
    * - **Format**
-     - Raw RST source
+     - Raw reStructuredText source
-     - Rendered Markdown
+     - Rendered Markdown [#rendered]_
-     - Rendered RST
+     - Rendered reStructuredText [#rendered]_
    * - **LLM Readability**
      - Good - preserves structure for simple syntax
      - Excellent - native LLM format
@@ -61,18 +71,22 @@ For optimal LLM support, you can use `sphinx-markdown-builder`_ and/or `sphinxco
      - More compact (less input tokens)
      - Can preserve Sphinx semantics
    * - **Key Disadvantage**
-     - Raw directives (e.g., autodoc) won't be parsed
+     - Raw directives won't be parsed [#autodoc]_
      - Loses structure from complex directives
      - Can lose structure from complex directives
    * - **llms-full.txt support**
-     - Suported with above caveats
+     - Supported with above caveats
-     - Pending `support <https://github.com/liran-funaro/sphinx-markdown-builder/pull/37>`__
+     - Pending `support <https://github.com/liran-funaro/sphinx-markdown-builder/pull/37>`__ [#pending]_
-     - Pending `support <https://github.com/sphinx-contrib/restbuilder/pull/35>`__
+     - Pending `support <https://github.com/sphinx-contrib/restbuilder/pull/35>`__ [#pending]_
-
-
-See :ref:`cmake_workflow` for an example of building HTML, Markdown, and RST in parallel.
-Use :confval:`llms_txt_uri_template` to configure links to point to your preferred format.
 
 .. _sphinx-markdown-builder: https://pypi.org/project/sphinx-markdown-builder/
 .. _sphinxcontrib-restbuilder: https://pypi.org/project/sphinxcontrib-restbuilder/
 
+.. rubric:: Footnotes
+
+.. [#sphinxllm] See `sphinx-llm <https://github.com/NVIDIA/sphinx-llm>`_ as an alternative for CMake-free Markdown builds.
+.. [#native] Uses raw :confval:`_sources/ <sphinx:html_copy_source>` files created by Sphinx's HTML builder with some minor enhancements.
+.. [#autodoc] Directives like ``autodoc`` will appear as raw directive syntax rather than the extracted docstrings.
+.. [#pending] PRs that add ``llms-full.txt`` concatenation support have yet to be released.
+.. [#rendered] Directives are expanded and processed before output, so content like autodoc docstrings will be included.
+

docs/source/index.rst

@@ -8,7 +8,9 @@ A `Sphinx`_ extension that generates a summary ``llms.txt`` file, written in Mar
 Demo
 ----
 
-You can see this Sphinx project's `llms.txt`_ and `llms-full.txt`_ files as a simple example.
+This Sphinx project's `llms.txt`_ and `llms-full.txt`_ files as an example of the default output format.
+
+Alternative :ref:`output formats <choosing-output-format>` are also available. For example: `Markdown`_ and `reStructuredText`_.
 
 Highlights
 ----------
@@ -24,6 +26,11 @@ Highlights
    Filter content, include source code files, or integrate with alternative output formats like Markdown for even better LLM compatibility.
    See :doc:`getting-started` for output format options and :doc:`configuration-values` for all settings.
 
+.. seealso::
+
+   For better default output without configuration, see `sphinx-llm <https://github.com/NVIDIA/sphinx-llm>`_ from NVIDIA.
+   sphinx-llms-txt is best when customized with alternative output formats, content filtering, or source code inclusion.
+
 .. toctree::
    :maxdepth: 2
 
@@ -36,6 +43,8 @@ Highlights
 
 .. _llms.txt: https://sphinx-llms-txt.readthedocs.io/en/latest/llms.txt
 .. _llms-full.txt: https://sphinx-llms-txt.readthedocs.io/en/latest/llms-full.txt
+.. _Markdown: https://sphinx-llms-txt.readthedocs.io/en/latest/llms.md.txt
+.. _reStructuredText: https://sphinx-llms-txt.readthedocs.io/en/latest/llms.rst.txt
 .. _Sphinx: http://sphinx-doc.org/
 
 .. |PyPI version| image:: https://img.shields.io/pypi/v/sphinx-llms-txt.svg

sphinx_llms_txt/__init__.py

@@ -21,7 +21,7 @@ from .manager import LLMSFullManager
 from .processor import DocumentProcessor
 from .writer import FileWriter
 
-__version__ = "0.7.0"
+__version__ = "0.7.2"
 
 # Export classes needed by tests
 __all__ = [

sphinx_llms_txt/processor.py

@@ -128,8 +128,11 @@ class DocumentProcessor:
         Returns:
             Processed content with directive paths properly resolved
         """
+        # Get code block ranges to skip directives inside them
+        code_block_ranges = self._get_code_block_ranges(content)
+
         # Get the configured path directives to process
-        default_path_directives = ["image", "figure"]
+        default_path_directives = ["image", "figure", "literalinclude"]
         custom_path_directives = self.config.get("llms_txt_directives")
         path_directives = set(default_path_directives + custom_path_directives)
 
@@ -143,6 +146,11 @@ class DocumentProcessor:
         is_test = "pytest" in str(source_path) and "subdir" in str(source_path)
 
         def replace_directive_path(match, base_url=base_url, is_test=is_test):
+            # Check if this directive is within a code block
+            if self._is_in_code_block(match.start(), code_block_ranges):
+                # This directive is inside a code block, don't process it
+                return match.group(0)
+
             prefix = match.group(1)  # The entire directive prefix including whitespace
             path = match.group(3).strip()  # The path argument
 
@@ -276,6 +284,71 @@ class DocumentProcessor:
 
         return possible_paths
 
+    def _get_code_block_ranges(self, content: str) -> List[Tuple[int, int]]:
+        """Find all code block ranges in the content.
+
+        Args:
+            content: The source content to analyze
+
+        Returns:
+            List of (start, end) tuples representing code block character
+            ranges
+        """
+        code_block_ranges = []
+
+        # Match code block as well as `code` and `sourcecode` aliases
+        code_block_pattern = re.compile(
+            r"^(\s*)\.\.\s+(code-block|code|sourcecode)::\s*\S*\s*$", re.MULTILINE
+        )
+
+        for match in code_block_pattern.finditer(content):
+            start_pos = match.start()
+            indent = match.group(1)
+            indent_len = len(indent)
+
+            # Find the end of the code block by looking for the next line
+            # that is not indented more than the directive
+            block_start = match.end()
+            pos = block_start
+
+            # Skip any blank lines immediately after the directive
+            while pos < len(content) and content[pos] in "\n":
+                pos += 1
+
+            # Find where the code block ends
+            lines = content[pos:].split("\n")
+            block_end = pos
+            for line in lines:
+                if line.strip():  # Non-empty line
+                    # Check indentation level
+                    line_indent = len(line) - len(line.lstrip())
+                    if line_indent <= indent_len:
+                        # The block ends when we find a line that is indented
+                        # less than the directive itself
+                        break
+                block_end += len(line) + 1  # +1 for the newline
+
+            code_block_ranges.append((start_pos, block_end))
+
+        return code_block_ranges
+
+    def _is_in_code_block(
+        self, match_start: int, code_block_ranges: List[Tuple[int, int]]
+    ) -> bool:
+        """Check if a match position is within a code block.
+
+        Args:
+            match_start: The starting position of the match
+            code_block_ranges: List of (start, end) tuples for code blocks
+
+        Returns:
+            True if the match is within a code block, False otherwise
+        """
+        for block_start, block_end in code_block_ranges:
+            if block_start <= match_start < block_end:
+                return True
+        return False
+
     def _process_includes(self, content: str, source_path: Path) -> str:
         """Process include directives in content.
 
@@ -286,11 +359,18 @@ class DocumentProcessor:
         Returns:
             Processed content with include directives replaced with included content
         """
+        code_block_ranges = self._get_code_block_ranges(content)
+
         # Find all include directives using regex
         include_pattern = build_directive_pattern(["include"])
 
         # Function to replace each include with content
         def replace_include(match):
+            # Check if this include is within a code block
+            if self._is_in_code_block(match.start(), code_block_ranges):
+                # This include is inside a code block, don't process it
+                return match.group(0)
+
             include_path = match.group(3)
             directive_part = match.group(
                 1

sphinx_llms_txt/writer.py

@@ -163,11 +163,17 @@ class FileWriter:
 
                     title = page_titles.get(docname, docname)
 
+                    # Avoid duplicate extensions when suffix matches
+                    # sourcelink_suffix (e.g., both are ".txt")
+                    effective_sourcelink_suffix = sourcelink_suffix
+                    if suffix and suffix == sourcelink_suffix:
+                        effective_sourcelink_suffix = ""
+
                     uri = uri_template.format(
                         base_url=base_url,
                         docname=docname,
                         suffix=suffix or "",
-                        sourcelink_suffix=sourcelink_suffix,
+                        sourcelink_suffix=effective_sourcelink_suffix,
                     )
 
                     f.write(f"- [{title}]({uri})\n")

tests/test_llms_txt.py

@@ -198,6 +198,31 @@ def test_process_includes(tmp_path):
     assert processed_content == expected_content
 
 
+def test_process_includes_in_code_block(tmp_path):
+    """Test that an `include` within a `code-block` is not processed."""
+    # Create a processor
+    config = {"llms_txt_directives": []}
+    processor = DocumentProcessor(config)
+
+    # Create a source file that uses include syntax within a `code-block`
+    source_content = (
+        "Normal paragraph.\n\n"
+        ".. code-block:: rst\n\n"
+        "   .. include:: foo.txt\n\n"
+        "Another normal paragraph."
+    )
+    source_file = tmp_path / "source.txt"
+    with open(source_file, "w", encoding="utf-8") as f:
+        f.write(source_content)
+
+    # Run the include directive processor
+    processed_content = processor._process_includes(source_content, source_file)
+
+    # Check that the include directive was not processed
+    expected_content = source_content
+    assert processed_content == expected_content
+
+
 def test_process_includes_with_relative_paths(tmp_path):
     """Test that include directives with relative paths are processed correctly."""
     # Create a processor

tests/test_uri_template.py

@@ -132,6 +132,48 @@ def test_uri_template_custom(tmp_path):
     assert "- [Home Page](https://example.com/raw/index.rst)" in content
 
 
+def test_uri_template_no_double_extension_when_suffix_matches_sourcelink(tmp_path):
+    """Test that .txt suffix + .txt sourcelink_suffix doesn't produce .txt.txt URLs."""
+    build_dir = tmp_path / "build"
+    build_dir.mkdir()
+
+    sources_dir = build_dir / "_sources"
+    sources_dir.mkdir()
+
+    class MockApp:
+        class Config:
+            html_sourcelink_suffix = ".txt"
+
+        config = Config()
+
+    config = {
+        "llms_txt_file": True,
+        "llms_txt_filename": "llms.txt",
+        "html_baseurl": "https://example.com",
+    }
+    writer = FileWriter(config, str(build_dir), MockApp())
+
+    page_titles = {
+        "index": "Home Page",
+        "contents": "Table of Contents",
+    }
+
+    # .txt source files — suffix matches sourcelink_suffix
+    page_order = [("index", ".txt"), ("contents", ".txt")]
+
+    writer.write_verbose_info_to_file(page_order, page_titles, 0, sources_dir)
+
+    verbose_file = build_dir / "llms.txt"
+    with open(verbose_file, "r", encoding="utf-8") as f:
+        content = f.read()
+
+    # Should NOT have double .txt.txt extension
+    assert ".txt.txt" not in content
+    # Should have single .txt extension
+    assert "- [Home Page](https://example.com/_sources/index.txt)" in content
+    assert "- [Table of Contents](https://example.com/_sources/contents.txt)" in content
+
+
 def test_uri_template_invalid_fallback(tmp_path):
     """
     Test that invalid template falls back to default sources template when