diff --git a/CHANGELOG.md b/CHANGELOG.md
index e6e3f60..0f15547 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 ## [Unreleased]
 
+### ✨ Features
+
+- `bonchi init` / `bonchi setup` resolve to the git/worktree root (`git rev-parse --show-toplevel`), so they work from any subdirectory — enabling monorepo layouts with a single root `.worktree.yml`. `init` outside a git repo now errors cleanly.
+
 ### 🐛 Fixes
 
 - Port allocation now skips browser-unsafe ports (Chromium's `kRestrictedPorts`, e.g. `4045`/`4190` in the default `4000..5000` range). Previously an allocated port could land on one of these, leaving the dev server reachable on the socket but blocked by the browser with `ERR_UNSAFE_PORT`.
diff --git a/README.md b/README.md
index eba066e..39e0854 100644
--- a/README.md
+++ b/README.md
@@ -114,6 +114,23 @@ copy:
 
 Default is to leave it out, so edits to main's `.worktree.yml` automatically apply to every subsequent `bonchi setup` run.
 
+`bonchi init` and `bonchi setup` resolve to the **git/worktree root** (`git rev-parse --show-toplevel`), so they work from any subdirectory. `init` writes `.worktree.yml` at the root and `setup` anchors all steps there — no need to `cd` to the top first. (`init` outside a git repo errors cleanly.)
+
+### Monorepos
+
+git cannot make a worktree of a subfolder, so a monorepo (e.g. root folders `server/` and `extension/`) becomes a **single** worktree containing all apps, with **one** `.worktree.yml` at the root. Because commands resolve to the git root, `bonchi setup` works the same from `foo/`, `foo/server/`, or anywhere below. Configure per-app concerns with prefixed paths and distinct port names:
+
+```yaml
+copy:
+  - server/.env
+  - extension/.env
+ports:
+  - SERVER_PORT
+  - EXTENSION_PORT
+# fan out per-app dev/setup from your own orchestrator
+setup: bin/worktree-dev
+```
+
 ### Edit
 
 Use `edit` to modify files during setup. Three actions are available; entries run in order, so you can interleave them. Env vars (`$VAR`) are expanded in replacement values.
diff --git a/lib/bonchi/cli.rb b/lib/bonchi/cli.rb
index 41323ba..6306a75 100644
--- a/lib/bonchi/cli.rb
+++ b/lib/bonchi/cli.rb
@@ -115,7 +115,9 @@ def pr(input)
       which ports to allocate, and what setup command to run.
     DESC
     def init
-      path = File.join(Dir.pwd, ".worktree.yml")
+      root = Git.toplevel
+      abort "Error: not inside a git repository" unless root
+      path = File.join(root, ".worktree.yml")
       if File.exist?(path)
         abort "Error: .worktree.yml already exists"
       end
diff --git a/lib/bonchi/git.rb b/lib/bonchi/git.rb
index 92522e3..513cf14 100644
--- a/lib/bonchi/git.rb
+++ b/lib/bonchi/git.rb
@@ -24,6 +24,11 @@ def main_worktree
       `git worktree list --porcelain`.lines.first.sub("worktree ", "").strip
     end
 
+    def toplevel
+      root = `git rev-parse --show-toplevel 2>/dev/null`.strip
+      root.empty? ? nil : root
+    end
+
     def worktree_list
       `git worktree list`.lines.map(&:strip).reject(&:empty?)
     end
diff --git a/lib/bonchi/setup.rb b/lib/bonchi/setup.rb
index 36561c5..ed549e3 100644
--- a/lib/bonchi/setup.rb
+++ b/lib/bonchi/setup.rb
@@ -6,7 +6,7 @@ class Setup
     include Colors
 
     def initialize(worktree: nil)
-      @worktree = worktree || Dir.pwd
+      @worktree = worktree || Git.toplevel || Dir.pwd
       @main_worktree = Git.main_worktree
     end
 
diff --git a/test/test_setup.rb b/test/test_setup.rb
index 990316d..8272e88 100644
--- a/test/test_setup.rb
+++ b/test/test_setup.rb
@@ -223,3 +223,72 @@ def test_aborts_when_neither_worktree_has_config
     end
   end
 end
+
+class TestSetupAnchoring < Minitest::Test
+  def test_anchors_worktree_to_git_toplevel_when_no_arg
+    Bonchi::Git.stub(:toplevel, "/repo/root") do
+      Bonchi::Git.stub(:main_worktree, "/repo/main") do
+        setup = Bonchi::Setup.new
+        assert_equal "/repo/root", setup.instance_variable_get(:@worktree)
+      end
+    end
+  end
+
+  def test_falls_back_to_pwd_when_not_in_git_repo
+    Bonchi::Git.stub(:toplevel, nil) do
+      Bonchi::Git.stub(:main_worktree, "/repo/main") do
+        setup = Bonchi::Setup.new
+        assert_equal Dir.pwd, setup.instance_variable_get(:@worktree)
+      end
+    end
+  end
+
+  def test_explicit_worktree_arg_overrides_toplevel
+    Bonchi::Git.stub(:toplevel, "/repo/root") do
+      Bonchi::Git.stub(:main_worktree, "/repo/main") do
+        setup = Bonchi::Setup.new(worktree: "/explicit/path")
+        assert_equal "/explicit/path", setup.instance_variable_get(:@worktree)
+      end
+    end
+  end
+end
+
+class TestInitAnchoring < Minitest::Test
+  def setup
+    @tmpdir = Dir.mktmpdir
+    @subdir = File.join(@tmpdir, "server")
+    FileUtils.mkdir_p(@subdir)
+    @cli = Bonchi::CLI.new
+  end
+
+  def teardown
+    FileUtils.remove_entry(@tmpdir)
+  end
+
+  def silenced
+    out = $stdout
+    $stdout = StringIO.new
+    yield
+  ensure
+    $stdout = out
+  end
+
+  def test_init_writes_config_at_git_toplevel_from_subdir
+    Bonchi::Git.stub(:toplevel, @tmpdir) do
+      Dir.chdir(@subdir) do
+        silenced { @cli.init }
+      end
+    end
+
+    assert File.exist?(File.join(@tmpdir, ".worktree.yml"))
+    refute File.exist?(File.join(@subdir, ".worktree.yml"))
+  end
+
+  def test_init_aborts_outside_git_repo
+    Bonchi::Git.stub(:toplevel, nil) do
+      assert_raises(SystemExit) do
+        silenced { @cli.init }
+      end
+    end
+  end
+end