diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 06a0a8b..9cc33dd 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -16,6 +16,8 @@ jobs:
         ruby:
           - 3.0.3
           - 3.1.0
+          - 3.2.2
+          - 3.3.2
 
     steps:
     - uses: actions/checkout@v2
diff --git a/.rubocop.yml b/.rubocop.yml
index 60a7e12..9ece655 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -13,11 +13,13 @@ AllCops:
 Bundler/GemVersion: { EnforcedStyle: forbidden }
 
 Metrics/BlockLength: { Exclude: ["spec/**/*_spec.rb"] }
+RSpec/MessageExpectation: { EnforcedStyle: expect }
 Style/ClassAndModuleChildren: { EnforcedStyle: compact }
 
 Style/MethodCallWithArgsParentheses:
   AllowedMethods:
     - abort
+    - and
     - describe
     - not_to
     - raise
@@ -38,6 +40,8 @@ Layout/LineLength:
 
 Bundler/GemComment: { Enabled: false }
 Lint/ConstantResolution: { Enabled: false }
+RSpec/StubbedMock: { Enabled: false }
 Style/ConstantVisibility: { Enabled: false }
 Style/Copyright: { Enabled: false }
 Style/InlineComment: { Enabled: false }
+Style/MissingElse: { Enabled: false }
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 850c023..73fb175 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 2023-09-18 23:50:42 UTC using RuboCop version 1.56.2.
+# on 2024-06-12 23:47:02 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
@@ -14,6 +14,27 @@ Bundler/GemVersion:
   Exclude:
     - 'Gemfile'
 
+# Offense count: 2
+# This cop supports safe autocorrection (--autocorrect).
+# Configuration parameters: Max, AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, AllowedPatterns.
+# URISchemes: http, https
+Layout/LineLength:
+  Exclude:
+    - 'lib/baes/actions/bisect.rb'
+
+# Offense count: 2
+# Configuration parameters: AllowedMethods, AllowedPatterns, CountRepeatedAttributes, Max.
+Metrics/AbcSize:
+  Exclude:
+    - 'lib/baes/actions/bisect.rb'
+
+# Offense count: 4
+# Configuration parameters: CountComments, Max, CountAsOne, AllowedMethods, AllowedPatterns.
+Metrics/MethodLength:
+  Exclude:
+    - 'lib/baes/actions/bisect.rb'
+    - 'lib/baes/actions/run.rb'
+
 # Offense count: 1
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: EnforcedStyle.
@@ -22,43 +43,38 @@ RSpec/BeNil:
   Exclude:
     - 'spec/baes_spec.rb'
 
-# Offense count: 11
+# Offense count: 16
 # 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'
 
 # Offense count: 1
-# Configuration parameters: Include, CustomTransform, IgnoreMethods, SpecSuffixOnly.
-# Include: **/*_spec*rb*, **/spec/**/*
-RSpec/FilePath:
-  Exclude:
-    - 'spec/baes/actions/load_configuration_spec.rb'
-
-# Offense count: 9
 # Configuration parameters: EnforcedStyle.
 # SupportedStyles: allow, expect
 RSpec/MessageExpectation:
   Exclude:
-    - 'spec/baes/git_spec.rb'
+    - 'spec/support/stub_system.rb'
 
-# Offense count: 9
+# Offense count: 11
 # Configuration parameters: .
 # SupportedStyles: have_received, receive
 RSpec/MessageSpies:
   EnforcedStyle: receive
 
-# Offense count: 6
+# Offense count: 5
 # Configuration parameters: Max.
 RSpec/MultipleExpectations:
   Exclude:
     - 'spec/baes/actions/build_tree_spec.rb'
-    - 'spec/baes/actions/load_configuration_spec.rb'
     - 'spec/baes/git_spec.rb'
 
-# Offense count: 9
-RSpec/StubbedMock:
+# Offense count: 1
+# Configuration parameters: AllowedPatterns.
+# AllowedPatterns: ^expect_, ^assert_
+RSpec/NoExpectationExample:
   Exclude:
-    - 'spec/baes/git_spec.rb'
+    - 'spec/baes/actions/bisect_spec.rb'
diff --git a/lib/baes/actions.rb b/lib/baes/actions.rb
index 82a1d05..9b81d65 100644
--- a/lib/baes/actions.rb
+++ b/lib/baes/actions.rb
@@ -3,7 +3,9 @@
 # namespace for callable modules
 module Baes::Actions; end
 
+require_relative "actions/bisect"
 require_relative "actions/build_tree"
 require_relative "actions/load_configuration"
+require_relative "actions/load_rebase_configuration"
 require_relative "actions/rebase"
 require_relative "actions/run"
diff --git a/lib/baes/actions/bisect.rb b/lib/baes/actions/bisect.rb
new file mode 100644
index 0000000..9fcf11c
--- /dev/null
+++ b/lib/baes/actions/bisect.rb
@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+# class that will attempt to locate the first branch in the current chain that
+# fails with a given command
+module Baes::Actions::Bisect
+  class << self
+    include Baes::Configuration::Helpers
+
+    # 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
+      root_branch = find_root_branch(branches)
+      Baes::Actions::BuildTree.call(branches, root_branch: root_branch)
+
+      current_branch_name = git.current_branch_name
+      current_branch =
+        branches.find { |branch| branch.name == current_branch_name }
+
+      _, _, status = Open3.capture3(command_args)
+
+      if status.success?
+        raise ArgumentError, "command must fail to find failure"
+      end
+
+      fail_branch =
+        find_failing_branch(root_branch, current_branch, command_args)
+
+      git.checkout(fail_branch.name)
+      output.puts("first failing branch: #{fail_branch.name}")
+    end
+
+    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 }
+      else
+        branches.find { |branch| ["main", "master"].include?(branch.name) }
+      end
+    end
+
+    def find_failing_branch(success_branch, fail_branch, command_args)
+      next_branch = find_middle_branch(success_branch, fail_branch)
+
+      return fail_branch if next_branch == fail_branch || next_branch.nil?
+
+      git.checkout(next_branch.name)
+      _, _, status = Open3.capture3(command_args)
+
+      if status.success?
+        output.puts("branch #{next_branch.name} succeeded with command `#{command_args}`")
+        find_failing_branch(next_branch, fail_branch, command_args)
+      else
+        output.puts("branch #{next_branch.name} failed with command `#{command_args}`")
+        find_failing_branch(success_branch, next_branch, command_args)
+      end
+    end
+
+    def find_middle_branch(success_branch, fail_branch)
+      end_number = fail_branch.number
+      start_number = success_branch.number
+
+      child_branch =
+        success_branch.children.find do |next_child_branch|
+          next_child_branch.base_name == fail_branch.base_name
+        end
+
+      start_number ||= child_branch.number
+
+      middle_number = (start_number + end_number) / 2
+
+      next_branch = child_branch
+
+      while next_branch.number < middle_number
+        next_branch =
+          next_branch.children.find do |next_child_branch|
+            next_child_branch.base_name == fail_branch.base_name
+          end
+      end
+
+      next_branch
+    end
+  end
+end
diff --git a/lib/baes/actions/load_configuration.rb b/lib/baes/actions/load_configuration.rb
index df10e61..10881fa 100644
--- a/lib/baes/actions/load_configuration.rb
+++ b/lib/baes/actions/load_configuration.rb
@@ -9,49 +9,18 @@ class << self
     def call(options)
       parser = OptionParser.new
 
-      configure_dry_run(parser)
       configure_help(parser)
-      configure_root_name(parser)
-      configure_auto_skip(parser)
-      configure_ignored_branches(parser)
 
       parser.parse(options)
     end
 
     private
 
-    def configure_dry_run(parser)
-      parser.on("--dry-run", "prints branch chain without rebasing") do
-        Baes::Configuration.dry_run = true
-      end
-    end
-
     def configure_help(parser)
       parser.on("-h", "--help", "prints this help") do
         Baes::Configuration.output.puts(parser)
         exit
       end
     end
-
-    def configure_root_name(parser)
-      message = "specify a root branch to rebase on"
-      parser.on("-r", "--root ROOT", message) do |root_name|
-        Baes::Configuration.root_name = root_name
-      end
-    end
-
-    def configure_auto_skip(parser)
-      message = "automatically skip all but the most recent commit"
-      parser.on("--auto-skip", message) do
-        Baes::Configuration.auto_skip = true
-      end
-    end
-
-    def configure_ignored_branches(parser)
-      message = "don't rebase specified branches or their child branches"
-      parser.on("--ignore BRANCH1,BRANCH2", Array, message) do |branches|
-        Baes::Configuration.ignored_branch_names += branches
-      end
-    end
   end
 end
diff --git a/lib/baes/actions/load_rebase_configuration.rb b/lib/baes/actions/load_rebase_configuration.rb
new file mode 100644
index 0000000..c7473a9
--- /dev/null
+++ b/lib/baes/actions/load_rebase_configuration.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+require "optparse"
+
+# callable module to load configuration
+module Baes::Actions::LoadRebaseConfiguration
+  class << self
+    # loads options, typically passed via the command line
+    def call(options)
+      parser = OptionParser.new
+
+      configure_dry_run(parser)
+      configure_help(parser)
+      configure_root_name(parser)
+      configure_auto_skip(parser)
+      configure_ignored_branches(parser)
+
+      parser.parse(options)
+    end
+
+    private
+
+    def configure_dry_run(parser)
+      parser.on("--dry-run", "prints branch chain without rebasing") do
+        Baes::Configuration.dry_run = true
+      end
+    end
+
+    def configure_help(parser)
+      parser.on("-h", "--help", "prints this help") do
+        Baes::Configuration.output.puts(parser)
+        exit
+      end
+    end
+
+    def configure_root_name(parser)
+      message = "specify a root branch to rebase on"
+      parser.on("-r", "--root ROOT", message) do |root_name|
+        Baes::Configuration.root_name = root_name
+      end
+    end
+
+    def configure_auto_skip(parser)
+      message = "automatically skip all but the most recent commit"
+      parser.on("--auto-skip", message) do
+        Baes::Configuration.auto_skip = true
+      end
+    end
+
+    def configure_ignored_branches(parser)
+      message = "don't rebase specified branches or their child branches"
+      parser.on("--ignore BRANCH1,BRANCH2", Array, message) do |branches|
+        Baes::Configuration.ignored_branch_names += branches
+      end
+    end
+  end
+end
diff --git a/lib/baes/actions/run.rb b/lib/baes/actions/run.rb
index 27d2296..c1cd5cb 100644
--- a/lib/baes/actions/run.rb
+++ b/lib/baes/actions/run.rb
@@ -4,8 +4,19 @@
 module Baes::Actions::Run
   # parse options and execute command
   def self.call(options)
-    Baes::Actions::LoadConfiguration.call(options)
+    case options.first
+    when "bisect"
+      Baes::Actions::Bisect.call(options[1..].join(" "))
+    when "rebase"
+      Baes::Actions::LoadRebaseConfiguration.call(options)
 
-    Baes::Actions::Rebase.call
+      Baes::Actions::Rebase.call
+    when nil
+      Baes::Actions::LoadConfiguration.call(["-h"])
+    when /^-/
+      Baes::Actions::LoadConfiguration.call(options)
+    else
+      abort("Invalid command #{options.inspect}")
+    end
   end
 end
diff --git a/lib/baes/git.rb b/lib/baes/git.rb
index 6b17a80..603872e 100644
--- a/lib/baes/git.rb
+++ b/lib/baes/git.rb
@@ -31,6 +31,17 @@ def self.rebase(branch_name)
     status
   end
 
+  # get current branch name and raise on error
+  def self.current_branch_name
+    stdout, stderr, status = Open3.capture3("git rev-parse --abbrev-ref HEAD")
+
+    output.puts(stderr) unless stderr.empty?
+
+    raise GitError, "failed to get current branch" unless status.success?
+
+    stdout.strip
+  end
+
   # list branch names and raise on failure
   def self.branch_names
     stdout, stderr, status = Open3.capture3("git branch")
diff --git a/spec/baes/actions/bisect_spec.rb b/spec/baes/actions/bisect_spec.rb
new file mode 100644
index 0000000..3c8e298
--- /dev/null
+++ b/spec/baes/actions/bisect_spec.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+RSpec.describe Baes::Actions::Bisect do
+  include Baes::Configuration::Helpers
+
+  def stub3(command, stdout: "", stderr: "", success: true)
+    status = instance_double(Process::Status, success?: success)
+    result = [stdout, stderr, status]
+    expect(Open3).to receive(:capture3).with(command).and_return(result)
+  end
+
+  it "raises an error when command does not fail" do
+    FakeGit.branch_names = ["main", "my_branch_1", "my_branch_2"]
+    stub3(["echo 'foo'"])
+
+    expect { described_class.call(["echo 'foo'"]) }
+      .to raise_error(ArgumentError, "command must fail to find failure")
+  end
+
+  it "checks out the first failing branch" do
+    FakeGit.branch_names = ["main", "my_branch_1", "my_branch_2"]
+    FakeGit.current_branch_name = "my_branch_2"
+    stub3(["echo 'foo'"], success: false)
+    stub3(["echo 'foo'"], success: false)
+
+    described_class.call(["echo 'foo'"])
+
+    expect(FakeGit.current_branch_name).to eq("my_branch_1")
+  end
+
+  it "prints the first failing branch" do
+    FakeGit.branch_names = ["main", "my_branch_1", "my_branch_2"]
+    FakeGit.current_branch_name = "my_branch_2"
+    stub3(["echo 'foo'"], success: false)
+    stub3(["echo 'foo'"], success: false)
+
+    described_class.call(["echo 'foo'"])
+
+    expect(output.string).to include("first failing branch: my_branch_1\n")
+  end
+
+  it "uses the configured root branch" do
+    FakeGit.branch_names = ["main", "my_branch_1", "my_branch_2"]
+    FakeGit.current_branch_name = "my_branch_2"
+    Baes::Configuration.root_name = "main"
+    stub3(["echo 'foo'"], success: false)
+    stub3(["echo 'foo'"], success: false)
+
+    described_class.call(["echo 'foo'"])
+  end
+
+  it "checks out the failed branch" do
+    FakeGit.branch_names = ["main", "my_branch_1", "my_branch_2"]
+    FakeGit.current_branch_name = "my_branch_2"
+    stub3(["echo 'foo'"], success: false)
+    stub3(["echo 'foo'"], success: true)
+
+    described_class.call(["echo 'foo'"])
+
+    expect(FakeGit.current_branch_name).to eq("my_branch_2")
+  end
+
+  it "jumps forward when current branch is success" do
+    FakeGit.branch_names = ["main", "my_branch_1", "my_branch_2", "my_branch_3"]
+    FakeGit.current_branch_name = "my_branch_3"
+    stub3(["echo 'foo'"], success: false)
+    stub3(["echo 'foo'"], success: true)
+
+    described_class.call(["echo 'foo'"])
+
+    expect(FakeGit.current_branch_name).to eq("my_branch_3")
+  end
+end
diff --git a/spec/baes/actions/load_configuration_spec.rb b/spec/baes/actions/load_rebase_configuration_spec.rb
similarity index 86%
rename from spec/baes/actions/load_configuration_spec.rb
rename to spec/baes/actions/load_rebase_configuration_spec.rb
index d180d3c..07ac366 100644
--- a/spec/baes/actions/load_configuration_spec.rb
+++ b/spec/baes/actions/load_rebase_configuration_spec.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-RSpec.describe Baes::Actions::LoadConfiguration, "#call" do
+RSpec.describe Baes::Actions::LoadRebaseConfiguration do
   it "sets the dry_run configuration given --dry-run" do
     described_class.call(["--dry-run"])
 
@@ -10,8 +10,7 @@
   it "displays the help and exits when given -h" do
     expect { described_class.call(["-h"]) }
       .to raise_error(SystemExit)
-
-    expect(Baes::Configuration.output.string).to include("prints this help")
+      .and output(/prints this help/).to_configured_output
   end
 
   it "sets the root_name configuration given --root" do
diff --git a/spec/baes/actions/run_spec.rb b/spec/baes/actions/run_spec.rb
index 4887c6d..06b247b 100644
--- a/spec/baes/actions/run_spec.rb
+++ b/spec/baes/actions/run_spec.rb
@@ -1,22 +1,47 @@
 # frozen_string_literal: true
 
 RSpec.describe Baes::Actions::Run do
+  def stub3(command, stdout: "", stderr: "", success: true)
+    status = instance_double(Process::Status, success?: success)
+    result = [stdout, stderr, status]
+    expect(Open3).to receive(:capture3).with(command).and_return(result)
+  end
+
   describe ".call" do
     it "loads configuration" do
-      FakeGit.branch_names = ["main", "my_branch"]
-      options = ["--dry-run"]
+      expect { described_class.call(["-h"]) }
+        .to raise_error(SystemExit)
+        .and output(/prints this help/).to_configured_output
+    end
 
-      described_class.call(options)
+    it "displays help when no arguments are given" do
+      expect { described_class.call([]) }
+        .to raise_error(SystemExit)
+        .and output(/prints this help/).to_configured_output
+    end
 
-      expect(Baes::Configuration.dry_run?).to be(true)
+    it "bisects when given the bisect command" do
+      FakeGit.branch_names = ["main", "my_branch_1"]
+      FakeGit.current_branch_name = "my_branch_1"
+      stub3("foo", success: false)
+
+      described_class.call(["bisect", "foo"])
+
+      expect(FakeGit.current_branch_name).to eq("my_branch_1")
     end
 
-    it "rebases branches" do
+    it "rebases branches when given the rebase command" do
       FakeGit.branch_names = ["main", "my_branch"]
 
-      described_class.call([])
+      described_class.call(["rebase"])
 
       expect(FakeGit.rebases).to eq([["my_branch", "main"]])
     end
+
+    it "raises an error when given an invalid command" do
+      expect { described_class.call(["foo"]) }
+        .to raise_error(SystemExit)
+        .and output("Invalid command [\"foo\"]\n").to_stderr
+    end
   end
 end
diff --git a/spec/baes/git_spec.rb b/spec/baes/git_spec.rb
index d96ef47..1ac7bff 100644
--- a/spec/baes/git_spec.rb
+++ b/spec/baes/git_spec.rb
@@ -60,6 +60,31 @@ def stub3(command, stdout: "", stderr: "", success: true)
     end
   end
 
+  describe "#current_branch_name" do
+    it "prints stderr when present" do
+      stub3("git rev-parse --abbrev-ref HEAD", stderr: "error")
+
+      described_class.current_branch_name
+
+      expect(output.string).to eq("error\n")
+    end
+
+    it "raises an error when status is not success" do
+      stub3("git rev-parse --abbrev-ref HEAD", success: false)
+
+      expect { described_class.current_branch_name }
+        .to raise_error("failed to get current branch")
+    end
+
+    it "returns the current branch name from stdout" do
+      stub3("git rev-parse --abbrev-ref HEAD", stdout: "main")
+
+      result = described_class.current_branch_name
+
+      expect(result).to eq("main")
+    end
+  end
+
   describe "#branch_names" do
     it "prints stderr when present" do
       stub3("git branch", stdout: "out", stderr: "error")
diff --git a/spec/matchers/capture_configured_output_spec.rb b/spec/matchers/capture_configured_output_spec.rb
new file mode 100644
index 0000000..d445e01
--- /dev/null
+++ b/spec/matchers/capture_configured_output_spec.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+RSpec.describe CaptureConfiguredOutput do
+  describe ".name" do
+    it "returns the name of the matcher" do
+      expect(described_class.name).to eq("configured output")
+    end
+  end
+
+  describe ".capture" do
+    it "captures the output of a block" do
+      output =
+        described_class.capture(-> { Baes::Configuration.output.puts("foo") })
+
+      expect(output).to eq("foo\n")
+    end
+
+    it "does not modify the original output stream" do
+      described_class.capture(-> { Baes::Configuration.output.puts("foo") })
+
+      expect(Baes::Configuration.output.string).to be_empty
+    end
+
+    it "restores the original output stream when an error occurs" do
+      begin
+        described_class.capture(-> { raise StandardError, "error" })
+      rescue StandardError
+        # noop
+      end
+
+      expect(Baes::Configuration.output.string).to be_empty
+    end
+  end
+end
diff --git a/spec/support/coverage.rb b/spec/support/coverage.rb
index 667a4a4..bbbab3e 100644
--- a/spec/support/coverage.rb
+++ b/spec/support/coverage.rb
@@ -5,6 +5,7 @@
 SimpleCov.start do
   enable_coverage :branch
   add_filter "_spec.rb"
+  add_filter "spec/support/stub_system.rb"
   add_group "Lib", "lib"
   add_group "Support", "spec/support"
 end
diff --git a/spec/support/fake_git.rb b/spec/support/fake_git.rb
index b90cb9c..347c255 100644
--- a/spec/support/fake_git.rb
+++ b/spec/support/fake_git.rb
@@ -26,7 +26,7 @@ def self.rebase(base_branch_name)
   end
 
   def self.branch_names
-    @branch_names ||= ""
+    @branch_names ||= []
   end
 
   def self.rebase_skip
diff --git a/spec/support/matchers.rb b/spec/support/matchers.rb
index e8e51c0..2916336 100644
--- a/spec/support/matchers.rb
+++ b/spec/support/matchers.rb
@@ -6,4 +6,5 @@ def rebase(branch_name)
   end
 end
 
+require_relative "matchers/capture_configured_output"
 require_relative "matchers/rebase"
diff --git a/spec/support/matchers/capture_configured_output.rb b/spec/support/matchers/capture_configured_output.rb
new file mode 100644
index 0000000..8078fc0
--- /dev/null
+++ b/spec/support/matchers/capture_configured_output.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module CaptureConfiguredOutput
+  def self.name
+    "configured output"
+  end
+
+  def self.capture(block)
+    old_output = Baes::Configuration.output
+    new_output = StringIO.new
+    Baes::Configuration.output = new_output
+
+    block.call
+
+    new_output.string
+  ensure
+    Baes::Configuration.output = old_output
+  end
+end
+
+module Matchers::OutputExtensions
+  def to_configured_output
+    @stream_capturer = CaptureConfiguredOutput
+    self
+  end
+end
+
+RSpec::Matchers::BuiltIn::Output.include(Matchers::OutputExtensions)
diff --git a/spec/support/stub_system.rb b/spec/support/stub_system.rb
index 7302687..8d76a03 100644
--- a/spec/support/stub_system.rb
+++ b/spec/support/stub_system.rb
@@ -23,4 +23,11 @@ def system(command)
     Baes::Configuration.dry_run = false
     Baes::Configuration.auto_skip = false
   end
+
+  config.around do |example|
+    example.run
+  rescue SystemExit => e
+    puts(e.backtrace)
+    raise StandardError, "uncaught SystemExit"
+  end
 end