diff --git a/README.md b/README.md
index f5112ea..169ad4c 100644
--- a/README.md
+++ b/README.md
@@ -36,47 +36,49 @@ cargo install --path .
 ## Usage
 
 ```text
-worktree-link [OPTIONS] <SOURCE> [TARGET]
-wtl [OPTIONS] <SOURCE> [TARGET]
+worktree-link [OPTIONS]
+wtl [OPTIONS]
 ```
 
-### Arguments
-
-| Argument | Description | Default |
-|----------|-------------|---------|
-| `SOURCE` | Source directory (main worktree) | Required |
-| `TARGET` | Target directory (new worktree) | `.` (current directory) |
-
 ### Options
 
 | Option | Description | Default |
 |--------|-------------|---------|
+| `-s, --source <DIR>` | Source directory (main worktree) | Auto-detected via `git worktree list` |
+| `-t, --target <DIR>` | Target directory (new worktree) | `.` (current directory) |
 | `-c, --config <FILE>` | Path to config file | `<SOURCE>/.worktreelinks` |
 | `-n, --dry-run` | Show what would be done without making changes | `false` |
 | `-f, --force` | Overwrite existing files/symlinks | `false` |
 | `-v, --verbose` | Enable verbose logging | `false` |
 | `--unlink` | Remove symlinks previously created by worktree-link | `false` |
+| `--no-ignore` | Do not respect .gitignore rules | `false` |
 
 ### Examples
 
 ```bash
-# Create symlinks from main worktree to the current directory
-wtl /path/to/main
+# Create symlinks (auto-detect source from git, target is current directory)
+wtl
+
+# Specify the source directory explicitly
+wtl -s /path/to/main
 
 # Specify the target directory explicitly
-wtl /path/to/main ./feature-branch
+wtl -t /path/to/feature-branch
 
-# Preview with dry-run before creating links
-wtl --dry-run /path/to/main
+# Specify both source and target
+wtl -s /path/to/main -t ./feature-branch
 
-# Then actually create the links
-wtl /path/to/main
+# Preview with dry-run before creating links
+wtl --dry-run
 
 # Overwrite existing files/symlinks
-wtl --force /path/to/main
+wtl --force
 
 # Remove previously created symlinks
-wtl --unlink /path/to/main
+wtl --unlink
+
+# Disable .gitignore filtering
+wtl --no-ignore
 ```
 
 ## Configuration (`.worktreelinks`)
@@ -145,7 +147,7 @@ cargo build
 cargo test
 
 # Debug run
-cargo run -- --dry-run /path/to/source /path/to/target
+cargo run -- --dry-run -s /path/to/source -t /path/to/target
 ```
 
 ## License
diff --git a/src/cli.rs b/src/cli.rs
index d473637..1a60338 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -5,11 +5,13 @@ use std::path::PathBuf;
 #[derive(Parser, Debug)]
 #[command(name = "worktree-link", version, about)]
 pub struct Cli {
-    /// Source directory (main worktree)
-    pub source: PathBuf,
+    /// Source directory (main worktree).
+    /// Auto-detected via `git worktree list` if omitted.
+    #[arg(short, long)]
+    pub source: Option<PathBuf>,
 
     /// Target directory (new worktree)
-    #[arg(default_value = ".")]
+    #[arg(short, long, default_value = ".")]
     pub target: PathBuf,
 
     /// Path to config file [default: <SOURCE>/.worktreelinks]
diff --git a/src/git.rs b/src/git.rs
new file mode 100644
index 0000000..323f83c
--- /dev/null
+++ b/src/git.rs
@@ -0,0 +1,171 @@
+use anyhow::{bail, Context, Result};
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+
+/// Detect the main worktree from a specific directory by running `git worktree list --porcelain`.
+///
+/// The first entry in porcelain output is always the main worktree.
+/// Returns the canonicalized path of the main worktree.
+pub(crate) fn detect_main_worktree_in(dir: &Path) -> Result<PathBuf> {
+    let output = Command::new("git")
+        .args(["worktree", "list", "--porcelain"])
+        .current_dir(dir)
+        .output()
+        .context("Failed to run git. Use --source to specify the main worktree path.")?;
+
+    if !output.status.success() {
+        let stderr = String::from_utf8_lossy(&output.stderr);
+        bail!(
+            "Failed to detect main worktree: `git worktree list --porcelain` exited with {}.\nstderr:\n{}\nUse --source to specify the main worktree path.",
+            output.status,
+            stderr.trim_end(),
+        );
+    }
+
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    parse_main_worktree(&stdout)
+}
+
+/// Parse the first worktree path from `git worktree list --porcelain` output.
+fn parse_main_worktree(porcelain_output: &str) -> Result<PathBuf> {
+    for line in porcelain_output.lines() {
+        if let Some(path_str) = line.strip_prefix("worktree ") {
+            let path = PathBuf::from(path_str);
+            return fs::canonicalize(&path).with_context(|| {
+                format!(
+                    "Main worktree not found at: {path_str}. Use --source to specify it manually."
+                )
+            });
+        }
+    }
+
+    bail!("Failed to detect main worktree from git output. Use --source to specify it manually.")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs;
+
+    #[test]
+    fn detect_main_worktree_returns_main_path() {
+        let main_dir = git_tempdir("detect_main");
+
+        // Create an initial commit so `git worktree add` works
+        fs::write(main_dir.join("README.md"), "# test").unwrap();
+        let status = Command::new("git")
+            .args(["add", "."])
+            .current_dir(&main_dir)
+            .status()
+            .unwrap();
+        assert!(status.success());
+        let status = Command::new("git")
+            .args(["commit", "-m", "init", "--quiet"])
+            .current_dir(&main_dir)
+            .status()
+            .unwrap();
+        assert!(status.success());
+
+        // Add a linked worktree
+        let wt_dir = std::env::temp_dir().join("worktree-link-test-detect_main_wt");
+        let _ = fs::remove_dir_all(&wt_dir);
+        let status = Command::new("git")
+            .args(["worktree", "add", wt_dir.to_str().unwrap(), "-b", "test-wt"])
+            .current_dir(&main_dir)
+            .status()
+            .unwrap();
+        assert!(status.success());
+
+        // Detect from the linked worktree should return the main worktree path
+        let detected = detect_main_worktree_in(&wt_dir).unwrap();
+        assert_eq!(detected, main_dir);
+
+        // Cleanup
+        let _ = Command::new("git")
+            .args(["worktree", "remove", "--force", wt_dir.to_str().unwrap()])
+            .current_dir(&main_dir)
+            .status();
+        let _ = fs::remove_dir_all(&wt_dir);
+    }
+
+    #[test]
+    fn detect_main_worktree_from_main_returns_self() {
+        let main_dir = git_tempdir("detect_self");
+
+        let detected = detect_main_worktree_in(&main_dir).unwrap();
+        assert_eq!(detected, main_dir);
+    }
+
+    #[test]
+    fn detect_main_worktree_outside_git_repo_fails() {
+        let dir = tempdir("detect_nogit");
+
+        let result = detect_main_worktree_in(&dir);
+        assert!(result.is_err());
+        let err_msg = result.unwrap_err().to_string();
+        assert!(
+            err_msg.contains("--source"),
+            "Error message should mention --source, got: {err_msg}"
+        );
+    }
+
+    #[test]
+    fn parse_main_worktree_extracts_first_entry() {
+        let dir = git_tempdir("parse_first");
+        let commit = Command::new("git")
+            .args(["commit", "--allow-empty", "-m", "init"])
+            .current_dir(&dir)
+            .output()
+            .unwrap();
+        assert!(commit.status.success(), "git commit failed");
+
+        // Get raw porcelain output
+        let output = Command::new("git")
+            .args(["worktree", "list", "--porcelain"])
+            .current_dir(&dir)
+            .output()
+            .unwrap();
+        let stdout = String::from_utf8_lossy(&output.stdout);
+
+        // Delegate to the function under test
+        let parsed = parse_main_worktree(&stdout).unwrap();
+        assert_eq!(parsed, dir);
+
+        let _ = fs::remove_dir_all(&dir);
+    }
+
+    fn git_tempdir(name: &str) -> PathBuf {
+        let dir = std::env::temp_dir().join(format!("worktree-link-test-{name}"));
+        let _ = fs::remove_dir_all(&dir);
+        fs::create_dir_all(&dir).unwrap();
+        let status = Command::new("git")
+            .args(["init", "--quiet"])
+            .current_dir(&dir)
+            .status()
+            .expect("git init failed");
+        assert!(status.success(), "git init exited with {status}");
+        // Set user config for commits
+        let status = Command::new("git")
+            .args(["config", "user.email", "test@test.com"])
+            .current_dir(&dir)
+            .status()
+            .unwrap();
+        assert!(status.success());
+        let status = Command::new("git")
+            .args(["config", "user.name", "Test"])
+            .current_dir(&dir)
+            .status()
+            .unwrap();
+        assert!(status.success());
+        // Return canonical path so comparisons work
+        fs::canonicalize(&dir).unwrap()
+    }
+
+    fn tempdir(name: &str) -> PathBuf {
+        let dir = std::env::temp_dir().join(format!("worktree-link-test-{name}"));
+        let _ = fs::remove_dir_all(&dir);
+        fs::create_dir_all(&dir).unwrap();
+        fs::canonicalize(&dir).unwrap()
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 49f372b..2f045d1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,6 @@
 mod cli;
 mod config;
+mod git;
 mod linker;
 mod walker;
 
@@ -24,14 +25,6 @@ fn main() -> Result<()> {
         .without_time()
         .init();
 
-    // Resolve source directory
-    let source = fs::canonicalize(&cli.source)
-        .with_context(|| format!("Source directory does not exist: {}", cli.source.display()))?;
-
-    if !source.is_dir() {
-        bail!("Source is not a directory: {}", source.display());
-    }
-
     // Resolve target directory
     let target = fs::canonicalize(&cli.target)
         .with_context(|| format!("Target directory does not exist: {}", cli.target.display()))?;
@@ -40,6 +33,19 @@ fn main() -> Result<()> {
         bail!("Target is not a directory: {}", target.display());
     }
 
+    // Resolve source directory
+    let source = match cli.source {
+        Some(s) => {
+            let resolved = fs::canonicalize(&s)
+                .with_context(|| format!("Source directory does not exist: {}", s.display()))?;
+            if !resolved.is_dir() {
+                bail!("Source is not a directory: {}", resolved.display());
+            }
+            resolved
+        }
+        None => git::detect_main_worktree_in(&target)?,
+    };
+
     if source == target {
         bail!("Source and target cannot be the same directory");
     }