diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 86aec3f..bfabb72 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,7 +13,7 @@ jobs:
           - { ruby: '3.1', mongo: 'mongo:5.0', mongoid: '7' }
           - { ruby: '3.2', mongo: 'mongo:6.0', mongoid: '8' }
           - { ruby: '3.3', mongo: 'mongo:7.0', mongoid: '9' }
-          - { ruby: '3.4', mongo: 'mongo:8.0', mongoid: '9' }
+          - { ruby: '3.4', mongo: 'mongo:8.0', mongoid: '9', coverage: true }
           - { ruby: '4.0', mongo: 'mongo:8.0', mongoid: '9' }
         experimental: [false]
 
@@ -29,7 +29,7 @@ jobs:
 
     env:
       MONGOID_VERSION: ${{ matrix.entry.mongoid }}
-      COVERAGE: ${{ matrix.entry.ruby == '3.4' }}
+      COVERAGE: ${{ matrix.entry.coverage }}
 
     steps:
     - uses: actions/checkout@v6
@@ -44,7 +44,7 @@ jobs:
       run: bundle exec rspec
 
     - name: Coveralls
-      if: matrix.entry.ruby == '3.4'
+      if: matrix.entry.coverage
       uses: coverallsapp/github-action@v2
       with:
         github-token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d428e4a..0dcf5b8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
 ## 0.6.0 (next)
+* [#156](https://github.com/mongoid/mongoid_search/pull/156): Cover relevance search, configuration, output and Rails indexing tasks; fix scalar relevance scores and highest-relevance-first ordering (see [UPGRADING](UPGRADING.md)) - [@dblock](https://github.com/dblock).
 * Your contribution here.
 * [#155](https://github.com/mongoid/mongoid_search/pull/155): Replace Code Climate with SimpleCov and Coveralls reporting in CI and update status badges - [@dblock](https://github.com/dblock).
 * [#154](https://github.com/mongoid/mongoid_search/pull/154): Test through Ruby 4.0, Mongoid 9, and MongoDB 8.0 with representative legacy coverage and explicitly bundle OpenStruct - [@dblock](https://github.com/dblock).
diff --git a/Gemfile b/Gemfile
index c7b5905..86000e3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -23,6 +23,7 @@ group :development do
   gem 'database_cleaner-mongoid', '>= 2.0.0'
   gem 'mongoid-compatibility'
   gem 'ostruct'
+  gem 'railties', version =~ /^6/ ? '~> 5.2.0' : '~> 7.0.0'
   gem 'rake', '>= 12.3.3'
   gem 'rspec', '~> 3.1'
   gem 'rubocop', '1.56.0'
diff --git a/README.md b/README.md
index d48881e..6382955 100644
--- a/README.md
+++ b/README.md
@@ -161,6 +161,10 @@ Product.full_text_search('amazing apple', relevant_search: true)
 
 Please note that relevant_search will return an Array and not a Criteria object. The search method should always be called in the end of the method chain.
 
+Results are ordered by decreasing numeric relevance (the number of matching indexed keywords). This option uses MongoDB map-reduce, which is deprecated upstream and requires server-side JavaScript.
+
+Upgrading from an earlier release? See [UPGRADING](UPGRADING.md) for the relevance ordering change in 0.6.0.
+
 ### index
 
 Default is `_keywords`.
diff --git a/UPGRADING.md b/UPGRADING.md
new file mode 100644
index 0000000..5711a14
--- /dev/null
+++ b/UPGRADING.md
@@ -0,0 +1,22 @@
+# Upgrading
+
+## Upgrading to 0.6.0
+
+### Relevance search returns highest-relevance results first
+
+Searches with `relevant_search: true`, or with `Mongoid::Search.relevant_search = true`, now return results sorted by **decreasing numeric relevance**. Previously, results were sorted in ascending order, putting lower scores first; the map-reduce reducer could also return arrays instead of numeric scores. Relevance scores are now numeric counts of matching indexed keywords.
+
+For example, a search matching documents with relevance scores of `1` and `2` now returns the document with score `2` first:
+
+```ruby
+Product.full_text_search('amazing apple', relevant_search: true).map(&:relevance)
+# => [2.0, 1.0]
+```
+
+Remove any application-side `.reverse` or other sorting workaround used to put the most relevant results first. If your application intentionally needs the least relevant results first, sort the returned array explicitly:
+
+```ruby
+Product.full_text_search('amazing apple', relevant_search: true).sort_by(&:relevance)
+```
+
+Relevance search still returns an `Array`, not a Mongoid criteria. Searches with relevance disabled (the default) are unaffected. No keyword reindexing is needed.
diff --git a/lib/mongoid_search/mongoid_search.rb b/lib/mongoid_search/mongoid_search.rb
index 18389b4..24e2d2e 100644
--- a/lib/mongoid_search/mongoid_search.rb
+++ b/lib/mongoid_search/mongoid_search.rb
@@ -94,7 +94,7 @@ def search_without_relevance(query, options)
     end
 
     def search_relevant(query, options)
-      results_with_relevance(query, options).sort_by { |o| o['value'] }.map do |r|
+      results_with_relevance(query, options).sort_by { |o| -o['value'] }.map do |r|
         new(r['_id'].merge(relevance: r['value'])) do |o|
           # Need to match the actual object
           o.instance_variable_set('@new_record', false)
@@ -124,7 +124,7 @@ def results_with_relevance(query, options)
 
       reduce = %{
           function(key, values) {
-            return(values);
+            return Array.sum(values);
           }
       }
 
diff --git a/spec/configuration_spec.rb b/spec/configuration_spec.rb
new file mode 100644
index 0000000..d876aaf
--- /dev/null
+++ b/spec/configuration_spec.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Mongoid::Search do
+  it 'yields the public configuration module' do
+    expect { |block| described_class.setup(&block) }.to yield_with_args(described_class)
+  end
+end
diff --git a/spec/log_spec.rb b/spec/log_spec.rb
new file mode 100644
index 0000000..805e768
--- /dev/null
+++ b/spec/log_spec.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Mongoid::Search::Log do
+  around do |example|
+    original = described_class.silent
+    described_class.silent = false
+    example.run
+  ensure
+    described_class.silent = original
+  end
+
+  it 'prints failures in red' do
+    expect { described_class.red('F') }.to output("\033[31mF\033[0m").to_stdout
+  end
+
+  it 'prints successes in green' do
+    expect { described_class.green('.') }.to output("\033[32m.\033[0m").to_stdout
+  end
+
+  it 'does not print when silent' do
+    described_class.silent = true
+    expect { described_class.red('F') }.not_to output.to_stdout
+  end
+end
diff --git a/spec/mongoid_search_spec.rb b/spec/mongoid_search_spec.rb
index 2b91346..a6cb8c8 100644
--- a/spec/mongoid_search_spec.rb
+++ b/spec/mongoid_search_spec.rb
@@ -306,13 +306,16 @@
     end
   end
 
-  # relevant search specs are currently broken due to calling sort on an array of arrays
-  xcontext 'relevant search' do
+  context 'relevant search' do
     before do
       Mongoid::Search.relevant_search = true
       @imac = Product.create name: 'apple imac'
     end
 
+    after do
+      Mongoid::Search.relevant_search = false
+    end
+
     it 'should return results ordered by relevance and with correct ids' do
       expect(Product.full_text_search('apple imac').map(&:_id)).to eq [@imac._id, @product._id]
     end
diff --git a/spec/railtie_spec.rb b/spec/railtie_spec.rb
new file mode 100644
index 0000000..798556e
--- /dev/null
+++ b/spec/railtie_spec.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'rake'
+require 'rails/railtie'
+require 'rails/application'
+require 'mongoid_search/railtie'
+
+describe Mongoid::Search::Railtie do
+  before(:all) do
+    @rake_application = Rake.application
+    Rake.application = Rake::Application.new
+    described_class.instance.send(:run_tasks_blocks, described_class.instance)
+    Rake::Task.define_task(:environment)
+  end
+
+  after(:all) do
+    Rake.application = @rake_application
+  end
+
+  around do |example|
+    silent = Mongoid::Search::Log.silent
+    example.run
+  ensure
+    Rake::Task['mongoid_search:index'].reenable
+    Mongoid::Search::Log.silent = silent
+  end
+
+  before do
+    application = instance_double(Rails::Application, eager_load!: nil)
+    allow(Rails).to receive(:application).and_return(application)
+  end
+
+  it 'registers the public indexing rake task with Rails' do
+    expect(Rake::Task.task_defined?('mongoid_search:index')).to be true
+    expect(Rake::Task['mongoid_search:index'].prerequisites).to include('environment')
+  end
+
+  it 'eager loads the application and reports when no models are registered' do
+    allow(Mongoid::Search).to receive(:classes).and_return([])
+    expect(Rails.application).to receive(:eager_load!)
+
+    expect { Rake::Task['mongoid_search:index'].invoke }
+      .to output("No model to index keywords.\n").to_stdout
+  end
+
+  it 'indexes the registered models' do
+    product = Product.create!(name: 'Coverage')
+    Product.collection.find(_id: product.id).update_one('$unset' => { _keywords: '' })
+    allow(Mongoid::Search).to receive(:classes).and_return([Product])
+    expect(Rails.application).to receive(:eager_load!)
+
+    expect { Rake::Task['mongoid_search:index'].invoke }
+      .to output(/Indexing documents for Product:.*Done/m).to_stdout
+    expect(product.reload._keywords).to eq(['coverage'])
+  end
+end