diff --git a/.rubocop.yml b/.rubocop.yml
index 9ece655..6556a60 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -39,6 +39,7 @@ Layout/LineLength:
   Max: 80
 
 Bundler/GemComment: { Enabled: false }
+Layout/SingleLineBlockChain: { Enabled: false }
 Lint/ConstantResolution: { Enabled: false }
 RSpec/StubbedMock: { Enabled: false }
 Style/ConstantVisibility: { Enabled: false }
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 73fb175..e5870a9 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config --auto-gen-only-exclude --exclude-limit 400`
-# on 2024-06-12 23:47:02 UTC using RuboCop version 1.64.1.
+# on 2024-06-13 00:13:12 UTC using RuboCop version 1.64.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -28,11 +28,12 @@ Metrics/AbcSize:
   Exclude:
     - 'lib/baes/actions/bisect.rb'
 
-# Offense count: 4
+# Offense count: 5
 # Configuration parameters: CountComments, Max, CountAsOne, AllowedMethods, AllowedPatterns.
 Metrics/MethodLength:
   Exclude:
     - 'lib/baes/actions/bisect.rb'
+    - 'lib/baes/actions/build_tree.rb'
     - 'lib/baes/actions/run.rb'
 
 # Offense count: 1
@@ -43,12 +44,11 @@ RSpec/BeNil:
   Exclude:
     - 'spec/baes_spec.rb'
 
-# Offense count: 16
+# Offense count: 10
 # Configuration parameters: Max, CountAsOne.
 RSpec/ExampleLength:
   Exclude:
     - 'spec/baes/actions/bisect_spec.rb'
-    - 'spec/baes/actions/build_tree_spec.rb'
     - 'spec/baes/actions/rebase_spec.rb'
     - 'spec/baes/branch_spec.rb'
 
diff --git a/lib/baes/actions/bisect.rb b/lib/baes/actions/bisect.rb
index 9fcf11c..5267e72 100644
--- a/lib/baes/actions/bisect.rb
+++ b/lib/baes/actions/bisect.rb
@@ -9,9 +9,8 @@ class << self
     # run the command and return the first branch that fails
     def call(command_args)
       output.puts("searching for branch that fails command: `#{command_args}`")
-      branches = generate_branches
+      branches = Baes::Actions::BuildTree.call
       root_branch = find_root_branch(branches)
-      Baes::Actions::BuildTree.call(branches, root_branch: root_branch)
 
       current_branch_name = git.current_branch_name
       current_branch =
@@ -32,12 +31,6 @@ def call(command_args)
 
     private
 
-    def generate_branches
-      git.branch_names.map do |branch_name|
-        Baes::Branch.new(branch_name)
-      end
-    end
-
     def find_root_branch(branches)
       if root_name
         branches.find { |branch| branch.name == root_name }
diff --git a/lib/baes/actions/build_tree.rb b/lib/baes/actions/build_tree.rb
index 82fabd9..c80f88a 100644
--- a/lib/baes/actions/build_tree.rb
+++ b/lib/baes/actions/build_tree.rb
@@ -8,7 +8,9 @@ class << self
     include Baes::Configuration::Helpers
 
     # generate a tree of Branch records linked to their children
-    def call(branches, root_branch:)
+    def call
+      branches = generate_branches
+      root_branch = find_root_branch(branches)
       indexed_branches = index_branches(branches)
 
       branches.each do |branch|
@@ -20,10 +22,25 @@ def call(branches, root_branch:)
       end
 
       prune(root_branch)
+      branches
     end
 
     private
 
+    def find_root_branch(branches)
+      if root_name
+        branches.find { |branch| branch.name == root_name }
+      else
+        branches.find { |branch| ["main", "master"].include?(branch.name) }
+      end
+    end
+
+    def generate_branches
+      git.branch_names.map do |branch_name|
+        Baes::Branch.new(branch_name)
+      end
+    end
+
     def prune(branch)
       branch.children.delete_if do |child|
         ignored_branch_names.include?(child.name)
diff --git a/lib/baes/actions/rebase.rb b/lib/baes/actions/rebase.rb
index 283c2e9..bbb4232 100644
--- a/lib/baes/actions/rebase.rb
+++ b/lib/baes/actions/rebase.rb
@@ -7,9 +7,8 @@ class << self
 
     # rebase branches
     def call
-      branches = generate_branches
+      branches = Baes::Actions::BuildTree.call
       root_branch = find_root_branch(branches)
-      Baes::Actions::BuildTree.call(branches, root_branch: root_branch)
 
       if dry_run?
         output.puts(root_branch.inspect)
@@ -22,12 +21,6 @@ def call
 
     private
 
-    def generate_branches
-      git.branch_names.map do |branch_name|
-        Baes::Branch.new(branch_name)
-      end
-    end
-
     def find_root_branch(branches)
       if root_name
         branches.find { |branch| branch.name == root_name }
diff --git a/spec/baes/actions/build_tree_spec.rb b/spec/baes/actions/build_tree_spec.rb
index 5ae6fc4..c5c398e 100644
--- a/spec/baes/actions/build_tree_spec.rb
+++ b/spec/baes/actions/build_tree_spec.rb
@@ -3,90 +3,69 @@
 RSpec.describe Baes::Actions::BuildTree do
   describe "#call" do
     it "links branches to the root branch" do
-      branch1 = Baes::Branch.new("main")
-      branch2 = Baes::Branch.new("some_branch")
+      FakeGit.branch_names = ["main", "some_branch"]
 
-      described_class.call([branch1, branch2], root_branch: branch1)
+      branches = described_class.call
 
-      expect(branch1.children).to eq([branch2])
+      expect(branches.first.children.map(&:name)).to eq(["some_branch"])
     end
 
     it "links numbered branches to the previous number" do
-      branch1 = Baes::Branch.new("main")
-      branch2 = Baes::Branch.new("some_branch_1")
-      branch3 = Baes::Branch.new("some_branch_2")
-      branches = [branch1, branch2, branch3]
+      FakeGit.branch_names = ["main", "some_branch_1", "some_branch_2"]
 
-      described_class.call(branches, root_branch: branch1)
+      branches = described_class.call
 
-      expect(branch2.children).to eq([branch3])
+      expect(branches[1].children.map(&:name)).to eq(["some_branch_2"])
     end
 
     it "links numbered branches to the root when no previous number" do
-      branch1 = Baes::Branch.new("main")
-      branch2 = Baes::Branch.new("some_branch_5")
+      FakeGit.branch_names = ["main", "some_branch_5"]
 
-      described_class.call([branch1, branch2], root_branch: branch1)
+      branches = described_class.call
 
-      expect(branch1.children).to eq([branch2])
+      expect(branches.first.children.map(&:name)).to eq(["some_branch_5"])
     end
 
     it "links numbered branches with leading zeros" do
-      branch1 = Baes::Branch.new("main")
-      branch2 = Baes::Branch.new("some_branch_09")
-      branch3 = Baes::Branch.new("some_branch_10")
-      branches = [branch1, branch2, branch3]
+      FakeGit.branch_names = ["main", "some_branch_09", "some_branch_10"]
 
-      described_class.call(branches, root_branch: branch1)
+      branches = described_class.call
 
-      expect(branch2.children).to eq([branch3])
+      expect(branches[1].children.map(&:name)).to eq(["some_branch_10"])
     end
 
     it "links numbered branches when number of digits differs" do
-      branch1 = Baes::Branch.new("main")
-      branch2 = Baes::Branch.new("some_branch_9")
-      branch3 = Baes::Branch.new("some_branch_10")
-      branches = [branch1, branch2, branch3]
+      FakeGit.branch_names = ["main", "some_branch_9", "some_branch_10"]
 
-      described_class.call(branches, root_branch: branch1)
+      branches = described_class.call
 
-      expect(branch2.children).to eq([branch3])
+      expect(branches[1].children.map(&:name)).to eq(["some_branch_10"])
     end
 
     it "raises an error when multiple branches have same index" do
-      branch1 = Baes::Branch.new("main")
-      branch2 = Baes::Branch.new("some_branch_9")
-      branch3 = Baes::Branch.new("some_branch_09")
-      branches = [branch1, branch2, branch3]
+      FakeGit.branch_names = ["main", "some_branch_9", "some_branch_09"]
       message = "duplicate branch index [\"some_branch_\", 9]"
 
-      expect { described_class.call(branches, root_branch: branch1) }
-        .to raise_error(Baes::Error, message)
+      expect { described_class.call }.to raise_error(Baes::Error, message)
     end
 
     it "prunes ignored branches" do
       Baes::Configuration.ignored_branch_names = ["some_branch_10"]
-      branch1 = Baes::Branch.new("main")
-      branch2 = Baes::Branch.new("some_branch_9")
-      branch3 = Baes::Branch.new("some_branch_10")
-      branches = [branch1, branch2, branch3]
+      FakeGit.branch_names = ["main", "some_branch_9", "some_branch_10"]
 
-      described_class.call(branches, root_branch: branch1)
+      branches = described_class.call
 
-      expect(branch1.children).to eq([branch2])
-      expect(branch2.children).to be_empty
+      expect(branches.first.children.map(&:name)).to eq(["some_branch_9"])
+      expect(branches[1].children).to be_empty
     end
 
     it "prunes descendant branches" do
       Baes::Configuration.ignored_branch_names = ["some_branch_9"]
-      branch1 = Baes::Branch.new("main")
-      branch2 = Baes::Branch.new("some_branch_9")
-      branch3 = Baes::Branch.new("some_branch_10")
-      branches = [branch1, branch2, branch3]
+      FakeGit.branch_names = ["main", "some_branch_9", "some_branch_10"]
 
-      described_class.call(branches, root_branch: branch1)
+      branches = described_class.call
 
-      expect(branch1.children).to be_empty
+      expect(branches.first.children).to be_empty
     end
   end
 end
diff --git a/spec/baes/actions/rebase_spec.rb b/spec/baes/actions/rebase_spec.rb
index 7a0943f..88d8341 100644
--- a/spec/baes/actions/rebase_spec.rb
+++ b/spec/baes/actions/rebase_spec.rb
@@ -5,15 +5,13 @@
     it "rebases branches on main" do
       FakeGit.branch_names = ["main", "my_branch"]
 
-      expect { described_class.call }
-        .to rebase("my_branch").on("main")
+      expect { described_class.call }.to rebase("my_branch").on("main")
     end
 
     it "rebases branches on master" do
       FakeGit.branch_names = ["master", "my_branch"]
 
-      expect { described_class.call }
-        .to rebase("my_branch").on("master")
+      expect { described_class.call }.to rebase("my_branch").on("master")
     end
 
     it "rebases chained branches" do
@@ -46,8 +44,7 @@
         FakeGit.branch_names = ["main", "my_branch_1", "my_branch_2"]
         Baes::Configuration.dry_run = true
 
-        expect { described_class.call }
-          .not_to(rebase("my_branch_1").on("main"))
+        expect { described_class.call }.not_to(rebase("my_branch_1").on("main"))
       end
     end
 
diff --git a/spec/baes_spec.rb b/spec/baes_spec.rb
index 1ae8237..70090c6 100644
--- a/spec/baes_spec.rb
+++ b/spec/baes_spec.rb
@@ -10,8 +10,7 @@
       "Don't use system calls. Use `Open3.capture3` instead. " \
       "Called with `echo 'blah'`"
 
-    expect { `echo 'blah'` }
-      .to raise_error(TestingError, message)
+    expect { `echo 'blah'` }.to raise_error(TestingError, message)
   end
 
   it "does not allow system calls" do
@@ -19,7 +18,6 @@
       "Don't use system calls. Use `Open3.capture3` instead. " \
       "Called with `echo 'blah'`"
 
-    expect { system("echo 'blah'") }
-      .to raise_error(TestingError, message)
+    expect { system("echo 'blah'") }.to raise_error(TestingError, message)
   end
 end