# How to Exclude Specific Directories or Files from Litho's Analysis in deepwiki-rs > Exclude directories and files from Litho analysis using litho.toml, CLI flags, or Rust config. Control deepwiki-rs analysis scope efficiently. - Repository: [Sopaco/deepwiki-rs](https://github.com/sopaco/deepwiki-rs) - Tags: how-to-guide - Published: 2026-02-16 --- **You can exclude specific directories or files from Litho's analysis by configuring the `excluded_dirs`, `excluded_files`, and `excluded_extensions` fields in the `Config` struct, either through a [`litho.toml`](https://github.com/sopaco/deepwiki-rs/blob/main/litho.toml) configuration file, CLI flags, or programmatically in Rust.** The **deepwiki-rs** repository implements Litho, a documentation engine that analyzes codebases to generate structured documentation. When processing large repositories, you often need to exclude build artifacts, dependencies, or generated files to reduce token usage and focus analysis on relevant source code. Litho provides three distinct filter mechanisms to control exactly which paths get analyzed. ## Understanding Litho's Exclusion Filters Litho's filtering system centers on the **`Config`** struct defined in [`src/config.rs`](https://github.com/sopaco/deepwiki-rs/blob/main/src/config.rs). This struct maintains three collections that determine path eligibility during the file system traversal: - **`excluded_dirs`**: Skips any path containing these directory names. By default, this includes `[".litho", "litho.docs", "target", "node_modules", ".git", "build", "dist", "venv", ".svelte-kit", "__pycache__", "__tests__", "__mocks__", "__fixtures__"]`【】. - **`excluded_files`**: Skips files matching exact names or simple `*` wildcard patterns. Defaults include `["litho.toml", "*.litho", "*.log", "*.tmp", "*.cache", "bun.lock", "package-lock.json", "yarn.lock", "pnpm-lock.yaml", "Cargo.lock", ".gitignore", "*.tpl", "*.md", "*.txt", ".env"]`【】. - **`excluded_extensions`**: Skips files based solely on their extension. Default exclusions cover `["jpg", "jpeg", "png", "gif", "bmp", "ico", "mp3", "mp4", "avi", "pdf", "zip", "tar", "exe", "dll", "so", "archive"]`【】. During the analysis phase, the **`FileExplorer`** tool in [`src/llm/tools/file_explorer.rs`](https://github.com/sopaco/deepwiki-rs/blob/main/src/llm/tools/file_explorer.rs) evaluates each path against these collections through its `is_ignored` method (lines 59-73)【】. ## Method 1: Configure Exclusions via litho.toml The most persistent way to exclude specific directories or files from Litho's analysis is through the TOML configuration file. The CLI ([`src/cli.rs`](https://github.com/sopaco/deepwiki-rs/blob/main/src/cli.rs)) automatically reads this file at startup and populates the `Config` struct. Create or modify [`litho.toml`](https://github.com/sopaco/deepwiki-rs/blob/main/litho.toml) in your project root: ```toml # litho.toml excluded_dirs = [ ".litho", "target", "node_modules", "generated", # Custom generated code directory "tests" # Exclude test directories ] excluded_files = [ "*.log", "secret.env", # Sensitive configuration "README.md", "*.tmp" ] excluded_extensions = [ "png", "mp4", "sqlite" # Database files ] ``` This approach ensures that every run of Litho respects these exclusions without requiring additional command-line arguments. ## Method 2: Override with CLI Flags For temporary or one-off exclusions, you can pass overrides directly via command-line arguments. The CLI parser merges these flags into the `Config` instance before analysis begins, allowing you to exclude specific directories or files without modifying [`litho.toml`](https://github.com/sopaco/deepwiki-rs/blob/main/litho.toml). ```bash # Exclude the docs/ folder and all backup files for this run only deepwiki-rs -p . --exclude-dir docs --exclude-file *.bak --exclude-file *.old ``` This method is particularly useful when: - Testing Litho against a subset of your codebase - Running CI pipelines that need different exclusion rules than local development - Temporarily ignoring directories that would otherwise cause excessive token consumption ## Method 3: Programmatic Configuration When embedding Litho as a library in your own Rust application, you can construct a `Config` instance manually and populate the exclusion vectors directly. This provides maximum flexibility for dynamic exclusion logic. ```rust use deepwiki_rs::config::Config; use deepwiki_rs::generator::run; fn main() { let mut cfg = Config::default(); // Exclude specific directories cfg.excluded_dirs.push("vendor".to_string()); cfg.excluded_dirs.push("third_party".to_string()); // Exclude specific files or patterns cfg.excluded_files.push("debug.log".to_string()); cfg.excluded_files.push("local.env".to_string()); // Exclude by extension cfg.excluded_extensions.push("sqlite".to_string()); cfg.excluded_extensions.push("db".to_string()); // Run Litho with custom configuration run(cfg).expect("Litho analysis failed"); } ``` This approach allows you to build exclusion rules based on runtime conditions, user preferences, or external configuration sources. ## How Exclusion Filters Work Internally Understanding the internal mechanics helps optimize your exclusion strategy. When Litho initiates analysis, the `FileExplorer` tool traverses the project tree and evaluates each path against the exclusion criteria in [`src/llm/tools/file_explorer.rs`](https://github.com/sopaco/deepwiki-rs/blob/main/src/llm/tools/file_explorer.rs). The evaluation logic follows this priority order: 1. **Directory name check**: If the path contains any string in `excluded_dirs`, the entire subtree is skipped immediately. 2. **File name pattern matching**: The file name is compared against `excluded_files` entries, supporting simple `*` wildcards. 3. **Extension filtering**: The file extension is checked against `excluded_extensions`. 4. **Runtime flags**: Additional checks for test files (if `include_tests` is false), hidden files (if `include_hidden` is false), and file size limits. This short-circuit evaluation ensures that directory-level exclusions prevent unnecessary deep traversal of large ignored trees like `node_modules` or `target`, significantly improving performance. ## Summary - **Litho** uses three filter collections in the `Config` struct: `excluded_dirs`, `excluded_files`, and `excluded_extensions`, defined in [`src/config.rs`](https://github.com/sopaco/deepwiki-rs/blob/main/src/config.rs). - **Default exclusions** cover common build artifacts, dependency folders, and binary files, but you can customize them via [`litho.toml`](https://github.com/sopaco/deepwiki-rs/blob/main/litho.toml), CLI flags, or programmatic configuration. - **Performance optimization** occurs through early short-circuiting in [`src/llm/tools/file_explorer.rs`](https://github.com/sopaco/deepwiki-rs/blob/main/src/llm/tools/file_explorer.rs), where directory matches prevent traversal of entire subtrees. - **Flexible configuration** allows temporary exclusions via command-line arguments (`--exclude-dir`, `--exclude-file`) or permanent rules via TOML configuration. ## Frequently Asked Questions ### How do I exclude a directory that isn't in the default exclusion list? Add the directory name to the `excluded_dirs` array in your [`litho.toml`](https://github.com/sopaco/deepwiki-rs/blob/main/litho.toml) file. For example, to exclude a `generated` folder: `excluded_dirs = ["target", "generated", "node_modules"]`. You can also use the `--exclude-dir` CLI flag for temporary exclusions without modifying the configuration file. ### Can I use glob patterns or regex in the exclusion filters? Litho supports simple wildcard patterns using `*` in the `excluded_files` field (e.g., `*.log` or `debug.*`), but it does not support full regular expressions or complex glob patterns like `**`. For directory exclusions, you must specify exact directory names that match any segment of the path. ### Why are my exclusion rules not being applied during analysis? Ensure your [`litho.toml`](https://github.com/sopaco/deepwiki-rs/blob/main/litho.toml) is in the project root or the directory specified by the `-p` flag. Verify that the configuration file uses the correct field names (`excluded_dirs`, `excluded_files`, `excluded_extensions`) and TOML syntax. If using CLI flags, check that they are passed before any positional arguments. The `FileExplorer` logic in [`src/llm/tools/file_explorer.rs`](https://github.com/sopaco/deepwiki-rs/blob/main/src/llm/tools/file_explorer.rs) applies these filters at runtime, so syntax errors in the config may cause defaults to be used instead. ### Does excluding directories improve performance significantly? Yes. Litho's `FileExplorer` short-circuits directory traversal when it encounters an `excluded_dirs` match, preventing the engine from scanning large subtrees like `node_modules` or `target` directories. This reduces both file system I/O and the number of paths passed to the LLM, significantly decreasing analysis time and token consumption.