diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..171bc45
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,93 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+This is a Python-based tool that converts Google Devsite documentation (from bazel.build/docs) into Hugo/Docsy format for easier navigation and modification. The converter transforms Devsite frontmatter, directory layout, and styling to be compatible with the Hugo static site generator and Docsy theme.
+
+## Core Commands
+
+### Running the Converter
+```bash
+# Basic conversion
+python cli.py convert --source /path/to/devsite/source --output /path/to/hugo/output
+
+# With dry run validation
+python cli.py convert --source /path/to/devsite/source --output /path/to/hugo/output --dry-run
+
+# Incremental conversion (only changed files)
+python cli.py convert --source /path/to/devsite/source --output /path/to/hugo/output --incremental
+
+# View converter info
+python cli.py info
+```
+
+### Environment Setup
+```bash
+# Install dependencies
+pip install -r requirements.txt
+
+# Or using the project setup
+pip install -e .
+```
+
+### Docker Usage
+```bash
+# Run the Docker container
+docker run -it -p 1313:1313 alan707/bazel-docs:latest bash
+
+# Inside container: convert docs
+python /app/cli.py convert --source /app/work/bazel-source/site/en/ --output /app/docs/
+
+# Inside container: setup Hugo modules and run server
+cd /app/docs
+hugo mod init github.com/alan707/bazel-docs && \
+    hugo mod get github.com/google/docsy@v0.12.0 && \
+    hugo mod tidy
+hugo server --bind 0.0.0.0 --baseURL "http://localhost:1313"
+```
+
+## Architecture
+
+### Core Components
+
+1. **CLI Interface (`cli.py`)**: Click-based command line interface with convert and info commands
+2. **Main Converter (`devsite_to_hugo_converter.py`)**: Orchestrates the conversion process using parser and generator
+3. **Devsite Parser (`utils/devsite_parser.py`)**: Parses Google Devsite structure, including `_book.yaml` and `_index.yaml` files
+4. **Hugo Generator (`utils/hugo_generator.py`)**: Generates Hugo site structure and configuration using Jinja2 templates
+
+### Configuration System
+
+The `config.yaml` file controls all aspects of the conversion:
+
+- **Content Mapping**: Maps Devsite sections to Hugo categories (tutorials, how-to-guides, explanations, reference)
+- **External Links**: Handles redirects to legacy Bazel API documentation
+- **Code Language Detection**: Automatic language detection for code blocks using pattern matching
+- **CSS Conversion**: Transforms CSS/SCSS for Docsy theme compatibility
+- **File Patterns**: Controls which files are included/excluded during conversion
+
+### Template System
+
+Uses Jinja2 templates in the `templates/` directory:
+- `hugo_config.yaml.jinja2`: Generates Hugo site configuration
+- `section_index.jinja2`: Creates section index pages
+
+### Content Organization
+
+The converter maps Devsite sections to Hugo content types:
+- Tutorials → tutorials category (weight 1-3)
+- Install/Configure/Build guides → how-to-guides category
+- Concepts/Extending → explanations category
+- Reference materials → reference category
+
+## Development Notes
+
+### Code Language Detection
+The system automatically detects programming languages for code blocks without explicit language identifiers using pattern matching defined in `config.yaml`. Supports Starlark (Bazel), Bash, Python, C++, Java, JavaScript, TypeScript, and more.
+
+### Link Conversion
+The converter handles both internal link conversion within the Hugo site and external link redirection to maintain compatibility with existing Bazel API documentation.
+
+### CSS/SCSS Processing
+PostCSS and Autoprefixer are used for CSS processing (see package.json dependencies), though the main conversion logic is in Python.
\ No newline at end of file
diff --git a/config.yaml b/config.yaml
index c21dbe3..026b095 100644
--- a/config.yaml
+++ b/config.yaml
@@ -13,6 +13,16 @@ hugo:
   baseURL: "https://bazel-docs-68tmf.ondigitalocean.app/"
   languageCode: "en-us"
   theme: "docsy"
+
+# External links configuration
+external_links:
+  # Base URL for legacy Bazel API documentation
+  bazel_api_base: "https://bazel.build"
+  # Paths that should be redirected to external API docs
+  external_paths:
+    - "/rules/"
+    - "/reference/"
+    - "/docs/build-ref"
   
 content_mapping:
   # set 'enable_category_indices' to true to generate _index.md files for categories
diff --git a/devsite_to_hugo_converter.py b/devsite_to_hugo_converter.py
index 18eead4..f5a5504 100644
--- a/devsite_to_hugo_converter.py
+++ b/devsite_to_hugo_converter.py
@@ -233,7 +233,7 @@ def _convert_single_file(self, source_file: Path, output_file: Path, dry_run: bo
                 hugo_frontmatter['title'] = title_from_h1
 
             # Convert body content
-            hugo_body = self._convert_body_content(body)
+            hugo_body = self._convert_body_content(body, source_file)
 
             # Remove duplicate H1 title if it matches frontmatter title
             if 'title' in hugo_frontmatter:
@@ -311,7 +311,7 @@ def _convert_frontmatter(self, frontmatter: Dict) -> Dict:
 
         return hugo_frontmatter
 
-    def _convert_body_content(self, body: str) -> str:
+    def _convert_body_content(self, body: str, source_file: Path) -> str:
         """Convert Devsite-specific content to Hugo format"""
         # Remove [TOC] directive (let Docsy handle TOC automatically)
         body = re.sub(r'\[TOC\]', '', body)
@@ -342,7 +342,7 @@ def _convert_body_content(self, body: str) -> str:
         body = body.strip()  # Remove trailing whitespace
 
         # Convert internal links
-        body = self._convert_internal_links(body)
+        body = self._convert_internal_links(body, source_file)
 
         # Fix directory structure formatting
         body = self._fix_directory_structures(body)
@@ -383,7 +383,7 @@ def _remove_duplicate_h1_title(self, body: str,
 
         return body
 
-    def _convert_internal_links(self, content: str) -> str:
+    def _convert_internal_links(self, content: str, source_file: Path) -> str:
         """Convert internal links to Hugo format"""
         # Pattern for markdown links - handle multi-line links
         link_pattern = r'\[([^\]]+)\]\(([^)]+)\)'
@@ -404,19 +404,68 @@ def replace_link(match):
             if link_url.startswith('#'):
                 return match.group(0)
 
+            # Handle external API links (absolute paths to external documentation)
+            if link_url.startswith('/') and self._should_redirect_to_external(link_url):
+                external_base = self.config.get('external_links', {}).get('bazel_api_base', 'https://bazel.build')
+                return f'[{link_text}]({external_base}{link_url})'
+
             # Handle relative links to .md files
-            if link_url.endswith('.md'):
+            if link_url.endswith('.md') or '.md#' in link_url:
+                # Split URL and anchor
+                if '#' in link_url:
+                    url_part, anchor_part = link_url.split('#', 1)
+                    anchor = f'#{anchor_part}'
+                else:
+                    url_part = link_url
+                    anchor = ''
+
                 # Normalize the path
-                normalized_path = link_url.replace('.md', '')
-                # Remove leading './' if present
-                if normalized_path.startswith('./'):
-                    normalized_path = normalized_path[2:]
+                normalized_path = url_part.replace('.md', '')
+
+                # Handle relative paths by resolving against source file location
+                if not normalized_path.startswith('/'):
+                    # Get the source file's directory relative to the source root
+                    source_dir = source_file.parent
+                    # Find the source root (work/bazel-source/site/en)
+                    source_root = None
+                    for parent in source_file.parents:
+                        if parent.name == 'en' and parent.parent.name == 'site':
+                            source_root = parent
+                            break
+
+                    if source_root:
+                        # Get relative directory from source root
+                        rel_source_dir = source_dir.relative_to(source_root)
+
+                        # Remove leading './' if present
+                        if normalized_path.startswith('./'):
+                            normalized_path = normalized_path[2:]
+
+                        # Resolve relative path
+                        if str(rel_source_dir) == '.':
+                            # File is in root, just use the filename
+                            full_path = normalized_path
+                        else:
+                            # Combine source directory with relative path
+                            full_path = str(rel_source_dir / normalized_path)
+
+                        # Get category mapping for this path
+                        path_parts = full_path.split('/')
+                        if path_parts:
+                            section_name = path_parts[0]
+                            if section_name in self.config.get('content_mapping', {}):
+                                mapping = self.config['content_mapping'][section_name]
+                                category_type = mapping['type']
+                                return f'[{link_text}](/{category_type}/{full_path}/{anchor})'
+                            else:
+                                return f'[{link_text}]({full_path}/{anchor})'
+
                 # Remove leading '/' if present (absolute paths within site)
                 if normalized_path.startswith('/'):
                     normalized_path = normalized_path[1:]
 
                 # Use simple relative links to avoid shortcode issues
-                return f'[{link_text}](/{normalized_path}/)'
+                return f'[{link_text}](/{normalized_path}/{anchor})'
 
             # Handle relative links to directories (assume they have index pages)
             if '/' in link_url and not '.' in link_url.split('/')[-1]:
@@ -434,6 +483,11 @@ def replace_link(match):
 
         return re.sub(link_pattern, replace_link, content, flags=re.DOTALL)
 
+    def _should_redirect_to_external(self, link_url: str) -> bool:
+        """Check if a link should be redirected to external Bazel API docs"""
+        external_paths = self.config.get('external_links', {}).get('external_paths', [])
+        return any(link_url.startswith(path) for path in external_paths)
+
     def _fix_directory_structures(self, content: str) -> str:
         """Fix directory structure formatting to use proper code blocks"""
         # Pattern to match directory structures with Unicode tree characters