diff --git a/Library/Homebrew/dev-cmd/generate-cask-ci-matrix.rb b/Library/Homebrew/dev-cmd/generate-cask-ci-matrix.rb
index b16ff6339b652..b248a88ed75bb 100644
--- a/Library/Homebrew/dev-cmd/generate-cask-ci-matrix.rb
+++ b/Library/Homebrew/dev-cmd/generate-cask-ci-matrix.rb
@@ -48,15 +48,6 @@ class GenerateCaskCiMatrix < AbstractCommand
         hide_from_man_page!
       end
 
-      sig { params(args: T::Array[String]).void }
-      def initialize(*args)
-        super
-        repository = ENV.fetch("GITHUB_REPOSITORY", "homebrew/homebrew-cask")
-        raise UsageError, "The GITHUB_REPOSITORY environment variable must be set." if repository.blank?
-
-        @tap = T.let(Tap.fetch(repository), Tap)
-      end
-
       sig { override.void }
       def run
         skip_install = args.skip_install?
@@ -64,14 +55,17 @@ def run
         casks = args.named if args.casks?
         pr_url = args.named if args.url?
         syntax_only = args.syntax_only?
-        tap = @tap
+
+        repository = ENV.fetch("GITHUB_REPOSITORY", nil)
+        raise UsageError, "The GITHUB_REPOSITORY environment variable must be set." if repository.blank?
+
+        tap = T.let(Tap.fetch(repository), Tap)
 
         raise UsageError, "Either `--cask` or `--url` must be specified." if casks.blank? && pr_url.blank?
         raise UsageError, "Only one url can be specified" if pr_url&.count&.> 1
-        raise UsageError, "This command must be run from inside a tap directory." if Dir.pwd.to_s != tap.path.to_s
 
         labels = if pr_url
-          pr = GitHub::API.open_rest(pr_url)
+          pr = GitHub::API.open_rest(pr_url.first)
           pr.fetch("labels").map { |l| l.fetch("name") }
         else
           []
@@ -225,7 +219,7 @@ def runners(cask_content:)
       def generate_matrix(tap, labels: [], cask_names: [], skip_install: false, new_cask: false)
         odie "This command must be run from inside a tap directory." unless tap
 
-        changed_files = find_changed_files
+        changed_files = find_changed_files(tap)
 
         ruby_files_in_wrong_directory =
           T.must(changed_files[:modified_ruby_files]) - (
@@ -310,10 +304,8 @@ def generate_matrix(tap, labels: [], cask_names: [], skip_install: false, new_ca
         end
       end
 
-      sig { returns(T::Hash[Symbol, T::Array[String]]) }
-      def find_changed_files
-        tap = @tap
-
+      sig { params(tap: Tap).returns(T::Hash[Symbol, T::Array[String]]) }
+      def find_changed_files(tap)
         commit_range_start = Utils.safe_popen_read("git", "rev-parse", "origin").chomp
         commit_range_end = Utils.safe_popen_read("git", "rev-parse", "HEAD").chomp
         commit_range = "#{commit_range_start}...#{commit_range_end}"
diff --git a/Library/Homebrew/test/dev-cmd/generate-cask-ci-matrix_spec.rb b/Library/Homebrew/test/dev-cmd/generate-cask-ci-matrix_spec.rb
index 802d47bf68e73..0299fbfecef36 100644
--- a/Library/Homebrew/test/dev-cmd/generate-cask-ci-matrix_spec.rb
+++ b/Library/Homebrew/test/dev-cmd/generate-cask-ci-matrix_spec.rb
@@ -4,15 +4,5 @@
 require "dev-cmd/generate-cask-ci-matrix"
 
 RSpec.describe Homebrew::DevCmd::GenerateCaskCiMatrix do
-  ENV["GITHUB_REPOSITORY"] = "homebrew/homebrew-cask"
-
   it_behaves_like "parseable arguments"
-
-  it "fails when not from inside a tap directory", :integration_test do
-    expect do
-      brew "generate-cask-ci-matrix", "--cask", "google-chrome",
-           "GITHUB_REPOSITORY" => ENV.fetch("GITHUB_REPOSITORY")
-    end
-      .to output(/Error: Invalid usage: This command must be run from inside a tap directory./).to_stderr
-  end
 end