Add Documentation for Experimental Codebase Indexing Feature (#204)

* Add complete documentation for the new experimental Codebase Indexing feature that enables semantic code search using AI embeddings.

## New Documentation
- **docs/features/experimental/codebase-indexing.mdx**: Comprehensive feature documentation covering:
  - Semantic search capabilities using Tree-sitter parsing and AI embeddings
  - Setup requirements for OpenAI/Ollama embedding providers and Qdrant vector database
  - Configuration steps and status indicators
  - File processing with smart code parsing and automatic filtering
  - Best practices for model selection and security considerations
  - Current limitations and future enhancements
  - Privacy and security considerations

## Updated Navigation & Cross-references
- **sidebars.ts**: Added Codebase Indexing to Features > Experimental navigation menu
- **docs/features/experimental/experimental-features.md**:
  - Added Codebase Indexing to experimental features list
  - Added screenshot showing the experimental features settings panel
- **docs/faq.md**: Added FAQ entries explaining:
  - What Codebase Indexing is and its semantic search capabilities
  - Cost considerations for embedding generation and vector storage

## Assets
- **static/img/experimental-features/experimental-features.png**: Screenshot of experimental features settings panel

## Technical Details Covered
- Tree-sitter integration for AST-based code parsing
- Support for both OpenAI and Ollama embedding providers
- Qdrant vector database integration with local and cloud deployment options
- Incremental indexing with file watching and hash-based caching
- Smart file filtering excluding binaries, large files, and common ignore patterns
- codebase_search tool integration for AI-powered code discovery

The documentation is targeted at a semi-technical audience and provides practical setup guidance while explaining the underlying semantic search technology.

* Add comprehensive documentation for the experimental codebase_search tool and reorganize the tool category structure to better distinguish between read and search functionality.

## New Documentation
- **docs/advanced-usage/available-tools/codebase-search.md**: Complete tool documentation covering:
  - Semantic search capabilities using AI embeddings and vector similarity
  - Integration with experimental Codebase Indexing feature with proper warning
  - Parameters, requirements, and configuration dependencies (OpenAI/Ollama + Qdrant)
  - Detailed workflow explanation from query processing to result formatting
  - Best practices for effective semantic queries vs. traditional text search
  - Directory scoping capabilities and result interpretation guidelines
  - Usage examples demonstrating authentication, database, error handling, and testing searches
  - Similarity scoring explanation and result structure details

## Updated Navigation & Organization
- **sidebars.ts**: Added codebase_search to Available Tools navigation menu
- **docs/advanced-usage/available-tools/tool-use-overview.md**: Reorganized tool categories:
  - Split "Read Group" into separate "Read Group" and "Search Group" categories
  - **Read Group**: File system reading and exploration (read_file, list_files, list_code_definition_names)
  - **Search Group**: Pattern and semantic searching (search_files, codebase_search)
  - Updated tool group table to reflect the new logical separation
  - Updated common patterns example to showcase semantic search with codebase_search
  - Improved categorization aligns with actual tool usage patterns

## Technical Coverage
The documentation accurately reflects the tool's implementation including:
- CodeIndexManager integration and availability validation
- Dual output format for AI and UI consumption
- Vector similarity search with cosine similarity and 0.4 threshold
- Performance optimizations (50 result limit, Tree-sitter language support)
- Path filtering and workspace-relative result formatting
- Integration with experimental indexing infrastructure

This provides users with clear guidance on semantic code search capabilities while maintaining appropriate warnings about the experimental nature of the feature.

* Refactor code structure for improved readability and maintainability

Author: hannesrudolph

docs/advanced-usage/available-tools/codebase-search.md

@@ -0,0 +1,221 @@
+# codebase_search
+
+:::warning Experimental Feature
+The `codebase_search` tool is part of the experimental [Codebase Indexing](/features/experimental/codebase-indexing) feature. This feature is under active development and may change significantly in future releases. It requires additional setup including an embedding provider and vector database.
+:::
+
+The `codebase_search` tool performs semantic searches across your entire codebase using AI embeddings. Unlike traditional text-based search, it understands the meaning of your queries and finds relevant code even when exact keywords don't match.
+
+## Parameters
+
+The tool accepts these parameters:
+
+- `query` (required): Natural language search query describing what you're looking for
+- `path` (optional): Directory path to limit search scope to a specific part of your codebase
+
+## What It Does
+
+This tool searches through your indexed codebase using semantic similarity rather than exact text matching. It finds code blocks that are conceptually related to your query, even if they don't contain the exact words you searched for. Results include relevant code snippets with file paths, line numbers, and similarity scores.
+
+## When is it used?
+
+- When Roo needs to find code related to specific functionality across your project
+- When looking for implementation patterns or similar code structures
+- When searching for error handling, authentication, or other conceptual code patterns
+- When exploring unfamiliar codebases to understand how features are implemented
+- When finding related code that might be affected by changes or refactoring
+
+## Key Features
+
+- **Semantic Understanding**: Finds code by meaning rather than exact keyword matches
+- **Cross-Project Search**: Searches across your entire indexed codebase, not just open files
+- **Contextual Results**: Returns code snippets with file paths and line numbers for easy navigation
+- **Similarity Scoring**: Results ranked by relevance with similarity scores (0-1 scale)
+- **Scope Filtering**: Optional path parameter to limit searches to specific directories
+- **Intelligent Ranking**: Results sorted by semantic relevance to your query
+- **UI Integration**: Results displayed with syntax highlighting and navigation links
+- **Performance Optimized**: Fast vector-based search with configurable result limits
+
+## Requirements
+
+This tool is only available when the experimental Codebase Indexing feature is properly configured:
+
+- **Feature Enabled**: Codebase Indexing must be enabled in experimental settings
+- **Embedding Provider**: OpenAI API key or Ollama configuration required
+- **Vector Database**: Qdrant instance running and accessible
+- **Index Status**: Codebase must be indexed (status: "Indexed" or "Indexing")
+
+## Limitations
+
+- **Experimental Feature**: Part of the experimental codebase indexing system
+- **Requires Configuration**: Depends on external services (embedding provider + Qdrant)
+- **Index Dependency**: Only searches through indexed code blocks
+- **Result Limits**: Maximum of 50 results per search to maintain performance
+- **Similarity Threshold**: Only returns results above 0.4 similarity score
+- **File Size Limits**: Limited to files under 1MB that were successfully indexed
+- **Language Support**: Effectiveness depends on Tree-sitter language support
+
+## How It Works
+
+When the `codebase_search` tool is invoked, it follows this process:
+
+1. **Availability Validation**:
+   - Verifies that the CodeIndexManager is available and initialized
+   - Confirms codebase indexing is enabled in settings
+   - Checks that indexing is properly configured (API keys, Qdrant URL)
+   - Validates the current index state allows searching
+
+2. **Query Processing**:
+   - Takes your natural language query and generates an embedding vector
+   - Uses the same embedding provider configured for indexing (OpenAI or Ollama)
+   - Converts the semantic meaning of your query into a mathematical representation
+
+3. **Vector Search Execution**:
+   - Searches the Qdrant vector database for similar code embeddings
+   - Uses cosine similarity to find the most relevant code blocks
+   - Applies the minimum similarity threshold (0.4) to filter results
+   - Limits results to 50 matches for optimal performance
+
+4. **Path Filtering** (if specified):
+   - Filters results to only include files within the specified directory path
+   - Uses normalized path comparison for accurate filtering
+   - Maintains relevance ranking within the filtered scope
+
+5. **Result Processing and Formatting**:
+   - Converts absolute file paths to workspace-relative paths
+   - Structures results with file paths, line ranges, similarity scores, and code content
+   - Formats for both AI consumption and UI display with syntax highlighting
+
+6. **Dual Output Format**:
+   - **AI Output**: Structured text format with query, file paths, scores, and code chunks
+   - **UI Output**: JSON format with syntax highlighting and navigation capabilities
+
+## Search Query Best Practices
+
+### Effective Query Patterns
+
+**Good: Conceptual and specific**
+```xml
+<codebase_search>
+<query>user authentication and password validation</query>
+</codebase_search>
+```
+
+**Good: Feature-focused**
+```xml
+<codebase_search>
+<query>database connection pool setup</query>
+</codebase_search>
+```
+
+**Good: Problem-oriented**
+```xml
+<codebase_search>
+<query>error handling for API requests</query>
+</codebase_search>
+```
+
+**Less effective: Too generic**
+```xml
+<codebase_search>
+<query>function</query>
+</codebase_search>
+```
+
+### Query Types That Work Well
+
+- **Functional Descriptions**: "file upload processing", "email validation logic"
+- **Technical Patterns**: "singleton pattern implementation", "factory method usage"
+- **Domain Concepts**: "user profile management", "payment processing workflow"
+- **Architecture Components**: "middleware configuration", "database migration scripts"
+
+## Directory Scoping
+
+Use the optional `path` parameter to focus searches on specific parts of your codebase:
+
+**Search within API modules:**
+```xml
+<codebase_search>
+<query>endpoint validation middleware</query>
+<path>src/api</path>
+</codebase_search>
+```
+
+**Search in test files:**
+```xml
+<codebase_search>
+<query>mock data setup patterns</query>
+<path>tests</path>
+</codebase_search>
+```
+
+**Search specific feature directories:**
+```xml
+<codebase_search>
+<query>component state management</query>
+<path>src/components/auth</path>
+</codebase_search>
+```
+
+## Result Interpretation
+
+### Similarity Scores
+
+- **0.8-1.0**: Highly relevant matches, likely exactly what you're looking for
+- **0.6-0.8**: Good matches with strong conceptual similarity
+- **0.4-0.6**: Potentially relevant but may require review
+- **Below 0.4**: Filtered out as too dissimilar
+
+### Result Structure
+
+Each search result includes:
+- **File Path**: Workspace-relative path to the file containing the match
+- **Score**: Similarity score indicating relevance (0.4-1.0)
+- **Line Range**: Start and end line numbers for the code block
+- **Code Chunk**: The actual code content that matched your query
+
+## Examples When Used
+
+- When implementing a new feature, Roo searches for "authentication middleware" to understand existing patterns before writing new code.
+- When debugging an issue, Roo searches for "error handling in API calls" to find related error patterns across the codebase.
+- When refactoring code, Roo searches for "database transaction patterns" to ensure consistency across all database operations.
+- When onboarding to a new codebase, Roo searches for "configuration loading" to understand how the application bootstraps.
+
+## Usage Examples
+
+Searching for authentication-related code across the entire project:
+```xml
+<codebase_search>
+<query>user login and authentication logic</query>
+</codebase_search>
+```
+
+Finding database-related code in a specific directory:
+```xml
+<codebase_search>
+<query>database connection and query execution</query>
+<path>src/data</path>
+</codebase_search>
+```
+
+Looking for error handling patterns in API code:
+```xml
+<codebase_search>
+<query>HTTP error responses and exception handling</query>
+<path>src/api</path>
+</codebase_search>
+```
+
+Searching for testing utilities and mock setups:
+```xml
+<codebase_search>
+<query>test setup and mock data creation</query>
+<path>tests</path>
+</codebase_search>
+```
+
+Finding configuration and environment setup code:
+```xml
+<codebase_search>
+<query>environment variables and application configuration</query>
+</codebase_search>

docs/advanced-usage/available-tools/tool-use-overview.md

@@ -10,7 +10,8 @@ Tools are organized into logical groups based on their functionality:
 
 | Category | Purpose | Tools | Common Use |
 |----------|---------|-------|------------|
-| **Read Group** | File system reading and searching | [read_file](/advanced-usage/available-tools/read-file), [search_files](/advanced-usage/available-tools/search-files), [list_files](/advanced-usage/available-tools/list-files), [list_code_definition_names](/advanced-usage/available-tools/list-code-definition-names) | Code exploration and analysis |
+| **Read Group** | File system reading and exploration | [read_file](/advanced-usage/available-tools/read-file), [list_files](/advanced-usage/available-tools/list-files), [list_code_definition_names](/advanced-usage/available-tools/list-code-definition-names) | Code exploration and analysis |
+| **Search Group** | Pattern and semantic searching | [search_files](/advanced-usage/available-tools/search-files), [codebase_search](/advanced-usage/available-tools/codebase-search) | Finding code patterns and functionality |
 | **Edit Group** | File system modifications | [apply_diff](/advanced-usage/available-tools/apply-diff), [insert_content](/advanced-usage/available-tools/insert-content), [search_and_replace](/advanced-usage/available-tools/search-and-replace), [write_to_file](/advanced-usage/available-tools/write-to-file) | Code changes and file manipulation |
 | **Browser Group** | Web automation | [browser_action](/advanced-usage/available-tools/browser-action) | Web testing and interaction |
 | **Command Group** | System command execution | [execute_command](/advanced-usage/available-tools/execute-command) | Running scripts, building projects |
@@ -32,10 +33,15 @@ Certain tools are accessible regardless of the current mode:
 These tools help Roo understand your code and project:
 
 - [read_file](/advanced-usage/available-tools/read-file) - Examines the contents of files
-- [search_files](/advanced-usage/available-tools/search-files) - Finds patterns across multiple files
 - [list_files](/advanced-usage/available-tools/list-files) - Maps your project's file structure
 - [list_code_definition_names](/advanced-usage/available-tools/list-code-definition-names) - Creates a structural map of your code
 
+### Search Tools
+These tools help Roo find patterns and functionality across your codebase:
+
+- [search_files](/advanced-usage/available-tools/search-files) - Finds patterns across multiple files using regex
+- [codebase_search](/advanced-usage/available-tools/codebase-search) - Performs semantic searches across your indexed codebase
+
 ### Edit Tools
 These tools help Roo make changes to your code:
 
@@ -211,7 +217,7 @@ Tools are made available based on the current mode:
 
 1. **Information Gathering**
    ```
-   [ask_followup_question](/advanced-usage/available-tools/ask-followup-question) → [read_file](/advanced-usage/available-tools/read-file) → [search_files](/advanced-usage/available-tools/search-files)
+   [ask_followup_question](/advanced-usage/available-tools/ask-followup-question) → [read_file](/advanced-usage/available-tools/read-file) → [codebase_search](/advanced-usage/available-tools/codebase-search)
    ```
 
 2. **Code Modification**

docs/faq.md

@@ -136,6 +136,14 @@ Yes, if you use a [local model](/advanced-usage/local-models).
 
 Yes, you can create your own MCP servers to add custom functionality to Roo Code. See the [MCP documentation](https://github.com/modelcontextprotocol) for details.
 
+### What is Codebase Indexing?
+
+[Codebase Indexing](/features/experimental/codebase-indexing) is an experimental feature that creates a semantic search index of your project using AI embeddings. This enables Roo Code to better understand and navigate large codebases by finding relevant code based on meaning rather than just keywords.
+
+### How much does Codebase Indexing cost?
+
+Codebase Indexing requires an OpenAI API key for generating embeddings and a Qdrant vector database for storage. Costs depend on your project size and the embedding model used. Initial indexing is the most expensive part; subsequent updates are incremental and much cheaper.
+
 ## Troubleshooting
 
 ### Roo Code isn't responding. What should I do?
@@ -148,7 +156,7 @@ Yes, you can create your own MCP servers to add custom functionality to Roo Code
 
 ### I'm seeing an error message. What does it mean?
 
-The error message should provide some information about the problem. If you're unsure how to resolve it, seek help in the community forums.
+The error message should provide some information about the problem. If you're unsure how to resolve it, seek help in [Discord](https://discord.gg/roocode).
 
 ### Roo Code made changes I didn't want. How do I undo them?