diff --git a/Gemfile b/Gemfile
index 6ca5ca7c..29e0a104 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,9 +3,9 @@ source "https://rubygems.org"
 ruby File.read(".ruby-version").chomp
 
 gem "faraday-retry"
-gem "octokit", "~> 8.1"
-gem "rubocop-govuk", require: false
-gem "slack-poster", "~> 2.2.2"
+gem "octokit"
+gem "rubocop-govuk"
+gem "slack-poster"
 
 group :test do
   gem "fakefs"
diff --git a/Gemfile.lock b/Gemfile.lock
index dfe30926..bb3041cc 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -141,12 +141,12 @@ DEPENDENCIES
   fakefs
   faraday-retry
   jsonlint
-  octokit (~> 8.1)
+  octokit
   pry-byebug
   rake
   rspec
   rubocop-govuk
-  slack-poster (~> 2.2.2)
+  slack-poster
   timecop
   webmock
 
diff --git a/Rakefile b/Rakefile
index c8889725..ebad37e0 100644
--- a/Rakefile
+++ b/Rakefile
@@ -17,7 +17,16 @@ rescue LoadError
   # no jsonlint available
 end
 
+begin
+  require "rubocop/rake_task"
+
+  RuboCop::RakeTask.new
+rescue LoadError
+  # no rubocop available
+end
+
 task default: %i[
   jsonlint
+  rubocop
   spec
 ]
diff --git a/lib/bank_holidays.rb b/lib/bank_holidays.rb
index 1cc8c3b6..fbb12651 100644
--- a/lib/bank_holidays.rb
+++ b/lib/bank_holidays.rb
@@ -8,12 +8,12 @@ def self.bank_holidays
       .then { JSON.parse _1 }
       .dig("england-and-wales", "events")
       .map { |e| Date.iso8601(e["date"]) }
-    rescue StandardError => e
-      puts "Error fetching bank holidays JSON: #{e.message}"
-      []
+  rescue StandardError => e
+    puts "Error fetching bank holidays JSON: #{e.message}"
+    []
   end
 
   def bank_holiday?
     Date.bank_holidays.include? self
   end
-end
\ No newline at end of file
+end
diff --git a/lib/github_fetcher.rb b/lib/github_fetcher.rb
index 8c746459..547f5157 100644
--- a/lib/github_fetcher.rb
+++ b/lib/github_fetcher.rb
@@ -160,7 +160,7 @@ def has_sca_sast_scans?(repo)
     snyk_string = "uses: alphagov/govuk-infrastructure/.github/workflows/snyk-security.yml@main"
 
     ci_file.include?(sca_string) && ci_file.include?(sast_string) && ci_file.include?(snyk_string)
-  rescue Octokit::NotFound => e
+  rescue Octokit::NotFound
     true # if a CI file is not present assume no scans are needed
   end
 end
diff --git a/lib/message_builder.rb b/lib/message_builder.rb
index 59b00bbd..90ff8da0 100644
--- a/lib/message_builder.rb
+++ b/lib/message_builder.rb
@@ -3,9 +3,9 @@
 require_relative "message"
 
 class MessageBuilder
-  TEMPLATE_DIR = Pathname.new(File.join(File.dirname(__FILE__), *%w[.. templates]))
+  TEMPLATE_DIR = File.join(File.dirname(__FILE__), *%w[.. templates])
 
-  attr_accessor :pull_requests, :report, :mood, :poster_mood
+  attr_accessor :report, :mood, :poster_mood
 
   def initialize(team, mode)
     @team = team
@@ -58,15 +58,15 @@ def build_ci_message
   end
 
   def ci_message
-    @repos = check_team_repos_ci.reject { |_,v| v }.keys
+    @repos = check_team_repos_ci.reject { |_, v| v }.keys
     return nil if @repos.empty?
 
-    template_file = TEMPLATE_DIR + "list_ci_issues.text.erb"
-    ERB.new(template_file.read, trim_mode: '-').result(binding).strip
+    template_file = Pathname.new("#{TEMPLATE_DIR}/list_ci_issues.text.erb")
+    ERB.new(template_file.read, trim_mode: "-").result(binding).strip
   end
 
-  def pr_date(pr)
-    pr[:marked_ready_for_review_at] || pr[:created]
+  def pr_date(pull_request)
+    pull_request[:marked_ready_for_review_at] || pull_request[:created]
   end
 
   def github_fetcher
@@ -128,8 +128,8 @@ def dependapanda_message
         .map { |pr| pr.merge(pr_link: pr[:link], pr_title: pr[:title]) }.reverse
     end
 
-    template_file = TEMPLATE_DIR + "dependapanda.text.erb"
-    ERB.new(template_file.read, trim_mode: '-').result(binding).strip
+    template_file = Pathname.new("#{TEMPLATE_DIR}/dependapanda.text.erb")
+    ERB.new(template_file.read, trim_mode: "-").result(binding).strip
   end
 
   def comments(pull_request)
@@ -154,10 +154,10 @@ def pr_plural(pr_count)
     end
   end
 
-  def present(pr, index)
+  def present(pull_request, index)
     @index = index
-    @pr = pr
-    @title = pr[:title]
+    @pr = pull_request
+    @title = pull_request[:title]
     @days = age_in_days(pr_date(@pr))
 
     @thumbs_up = if (@pr[:thumbs_up]).positive?
@@ -209,7 +209,7 @@ def apply_style(template_name)
   end
 
   def render(template_name)
-    template_file = TEMPLATE_DIR + "#{apply_style(template_name)}.text.erb"
+    template_file = Pathname.new("#{TEMPLATE_DIR}/#{apply_style(template_name)}.text.erb")
     ERB.new(template_file.read).result(binding).strip
   end
 
diff --git a/lib/seal.rb b/lib/seal.rb
index 3d238ea0..9b6742a0 100755
--- a/lib/seal.rb
+++ b/lib/seal.rb
@@ -47,11 +47,11 @@ def bark_at(team, mode: nil)
   rescue StandardError => e
     puts "Error barking at team '#{team.name}': #{e.message}"
   end
-  
+
   def send_quotes_message(team, mode)
     today_is_quote_day = team.quotes_days.map(&:downcase).include?(Date.today.strftime("%A").downcase)
-    team_has_enabled_this_mode = team.public_send("#{mode}")
-    
+    team_has_enabled_this_mode = team.public_send(mode.to_s)
+
     Message.new(team.quotes.sample) if today_is_quote_day && team_has_enabled_this_mode
   end
 end
diff --git a/lib/slack_poster.rb b/lib/slack_poster.rb
index 9368498a..d10c2dc9 100644
--- a/lib/slack_poster.rb
+++ b/lib/slack_poster.rb
@@ -1,5 +1,5 @@
 class SlackPoster
-  attr_accessor :webhook_url, :poster, :mood, :mood_hash, :channel, :season_name
+  attr_accessor :webhook_url, :poster, :mood, :season_name
 
   def initialize(team_channel, mood)
     @webhook_url = ENV["SLACK_WEBHOOK"]
@@ -48,28 +48,29 @@ def mood_hash
   end
 
   def assign_poster_settings
-    @mood_hash[:icon_emoji], @mood_hash[:username] = case @mood
-    when "panda"
-      [":panda_face:", "Dependapanda"]
-    when "informative"
-      [":#{@season_symbol}informative_seal:", "#{@season_name}Informative Seal"]
-    when "approval"
-      [":#{@season_symbol}seal_of_approval:", "#{@season_name}Seal of Approval"]
-    when "angry"
-      [":#{@season_symbol}angrier_seal:", "#{@season_name}Angry Seal"]
-    when "robot_face"
-      [":robot_face:", "Angry CI Robot"]
-    when "tea"
-      [":manatea:", "Tea Seal"]
-    when "charter"
-      [":happyseal:", "Team Charter Seal"]
-    when "fun-workstream"
-      [":wholesome-seal:", "It's ok Seal"]
-    when "govuk-green-team"
-      [":happybabyseal:", "Elephant Seal"]
-    else
-      raise "Bad mood: #{mood}."
-    end
+    @mood_hash[:icon_emoji], @mood_hash[:username] =
+      case @mood
+      when "panda"
+        [":panda_face:", "Dependapanda"]
+      when "informative"
+        [":#{@season_symbol}informative_seal:", "#{@season_name}Informative Seal"]
+      when "approval"
+        [":#{@season_symbol}seal_of_approval:", "#{@season_name}Seal of Approval"]
+      when "angry"
+        [":#{@season_symbol}angrier_seal:", "#{@season_name}Angry Seal"]
+      when "robot_face"
+        [":robot_face:", "Angry CI Robot"]
+      when "tea"
+        [":manatea:", "Tea Seal"]
+      when "charter"
+        [":happyseal:", "Team Charter Seal"]
+      when "fun-workstream"
+        [":wholesome-seal:", "It's ok Seal"]
+      when "govuk-green-team"
+        [":happybabyseal:", "Elephant Seal"]
+      else
+        raise "Bad mood: #{mood}."
+      end
   end
 
   def check_season
diff --git a/lib/team_builder.rb b/lib/team_builder.rb
index 16be7d90..2779ee16 100644
--- a/lib/team_builder.rb
+++ b/lib/team_builder.rb
@@ -101,6 +101,6 @@ def govuk_team_repos(team_channel)
   end
 
   def is_govuk_team?(team)
-    @govuk_data.any? { | repo | repo["team"] == "##{team}"}
+    @govuk_data.any? { |repo| repo["team"] == "##{team}" }
   end
 end
diff --git a/spec/bank_holidays_spec.rb b/spec/bank_holidays_spec.rb
index c775493e..8348e7fc 100644
--- a/spec/bank_holidays_spec.rb
+++ b/spec/bank_holidays_spec.rb
@@ -41,4 +41,4 @@
       expect(Date.new(2018, 3, 28).bank_holiday?).to eq(false)
     end
   end
-end
\ No newline at end of file
+end
diff --git a/spec/message_builder_spec.rb b/spec/message_builder_spec.rb
index 47fb731e..5fd836f9 100644
--- a/spec/message_builder_spec.rb
+++ b/spec/message_builder_spec.rb
@@ -320,4 +320,4 @@
       end
     end
   end
-end
\ No newline at end of file
+end
diff --git a/spec/seal_spec.rb b/spec/seal_spec.rb
index 86a03202..bbe73937 100644
--- a/spec/seal_spec.rb
+++ b/spec/seal_spec.rb
@@ -9,7 +9,7 @@
     Team.new(
       slack_channel: "#lions",
       quotes: ["go lions!"],
-      quotes_days: ["Monday", "tuesday", "Wednesday"],
+      quotes_days: %w[Monday tuesday Wednesday],
       morning_seal_quotes: true,
       seal_prs: true,
     )
@@ -24,7 +24,7 @@
     Team.new(
       slack_channel: "#cats",
       quotes: ["go cats!"],
-      quotes_days: ["yarn", "catnip", "nap", "scratches", "mischief"],
+      quotes_days: %w[yarn catnip nap scratches mischief],
       morning_seal_quotes: true,
       seal_prs: true,
     )
@@ -68,7 +68,7 @@
       let(:teams) { [lions, cats] }
 
       it "posts quotes if a quotes day" do
-        Timecop.freeze(Time.local(2023, 04, 24)) # Monday
+        Timecop.freeze(Time.local(2023, 0o4, 24)) # Monday
         expect(Message).to receive(:new).with("go lions!").and_return(message)
         expect(SlackPoster).to receive(:new).with(lions.channel, anything)
 
@@ -76,7 +76,7 @@
       end
 
       it "doesn't posts quotes if not a quotes day" do
-        Timecop.freeze(Time.local(2023, 04, 27)) # Thursday
+        Timecop.freeze(Time.local(2023, 0o4, 27)) # Thursday
         expect(Message).not_to receive(:new).with("go lions!")
         expect(SlackPoster).not_to receive(:new).with(lions.channel, anything)
 
@@ -91,7 +91,7 @@
       end
 
       it "posts quotes if day downcased" do
-        Timecop.freeze(Time.local(2023, 04, 25)) # Tuesday
+        Timecop.freeze(Time.local(2023, 0o4, 25)) # Tuesday
         expect(Message).to receive(:new).with("go lions!").and_return(message)
         expect(SlackPoster).to receive(:new).with(lions.channel, anything)
 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 09875199..598e8f6f 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -45,8 +45,8 @@
     Timecop.return
   end
 
-  config.before do 
-    allow($stdout).to receive(:puts) 
+  config.before do
+    allow($stdout).to receive(:puts)
   end
 
   # The settings below are suggested to provide a good initial experience
diff --git a/spec/team_builder_spec.rb b/spec/team_builder_spec.rb
index b8945926..65e1900e 100644
--- a/spec/team_builder_spec.rb
+++ b/spec/team_builder_spec.rb
@@ -40,15 +40,15 @@
                      "This is a quote",
                      "This is also a quote",
                    ],
-                   "quotes_days" => [
-                      "Monday",
-                      "Tuesday",
-                      "Wednesday",
-                      "Thursday",
-                      "Friday",
-                    ],
-                   "repos" => [
-                     "Africa"
+                   "quotes_days" => %w[
+                     Monday
+                     Tuesday
+                     Wednesday
+                     Thursday
+                     Friday
+                   ],
+                   "repos" => %w[
+                     Africa
                    ],
                  },
                  "tigers" => {
@@ -65,8 +65,8 @@
                  },
                  "govuk-generic-team" => {
                    "channel" => "#govuk-generic-team",
-                   "repos" => [
-                     "generic-repo"
+                   "repos" => %w[
+                     generic-repo
                    ],
                  },
                ))