diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f65159d..6d63153 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -17,7 +17,16 @@ jobs:
           - "3.3"
           - "3.4"
           - "4.0"
-
+        ruby_llm:
+          - "1.5"
+          - "1.6"
+          - "1.10"
+          - "1.13"
+          - "1.14"
+          - "current"
+    env:
+      BUNDLE_GEMFILE: ${{ github.workspace }}/gemfiles/ruby_llm_${{ matrix.ruby_llm }}.gemfile
+      BUNDLE_PATH_RELATIVE_TO_CWD: true
     steps:
       - uses: actions/checkout@v6
       - name: Set up Ruby
diff --git a/.gitignore b/.gitignore
index 9106b2a..998e5f2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 /_yardoc/
 /coverage/
 /doc/
+/gemfiles/*.lock
 /pkg/
 /spec/reports/
 /tmp/
diff --git a/.rubocop.yml b/.rubocop.yml
index 39be2af..898d9dc 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -6,6 +6,7 @@ plugins:
 AllCops:
   TargetRubyVersion: 3.3
   Exclude:
+    - "gemfiles/**/*"
     - "ruby_llm-test.gemspec"
     - "Rakefile"
     - "vendor/**/*"
@@ -15,6 +16,13 @@ AllCops:
 Layout/SpaceInsideArrayLiteralBrackets:
   EnforcedStyle: space
 
+Metrics/ClassLength:
+  Exclude:
+    - "test/**/*"
+Metrics/MethodLength:
+  Exclude:
+    - "test/**/*"
+
 Style/StringLiterals:
   EnforcedStyle: double_quotes
 Style/StringLiteralsInInterpolation:
diff --git a/Appraisals b/Appraisals
new file mode 100644
index 0000000..6fc69a7
--- /dev/null
+++ b/Appraisals
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+appraise "ruby_llm-1.5" do
+  gem "ruby_llm", "~> 1.5.0"
+end
+
+appraise "ruby_llm-1.6" do
+  gem "ruby_llm", "~> 1.6.0"
+end
+
+appraise "ruby_llm-1.10" do
+  gem "ruby_llm", "~> 1.10.0"
+end
+
+appraise "ruby_llm-1.13" do
+  gem "ruby_llm", "~> 1.13.0"
+end
+
+appraise "ruby_llm-1.14" do
+  gem "ruby_llm", "~> 1.14.0"
+end
+
+appraise "ruby_llm-current" do
+  gem "ruby_llm"
+end
diff --git a/Gemfile b/Gemfile
index 2cb825a..e3b089f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,6 +8,7 @@ git_source(:github) { |repo_name| "https://github.com/#{repo_name}" }
 gemspec
 
 group :development, :test do
+  gem "appraisal", "~> 2.5"
   gem "minitest", "~> 6.0"
   gem "rake", "~> 13.0"
   gem "rubocop", "~> 1.86"
diff --git a/Gemfile.lock b/Gemfile.lock
index 748a59d..c7530fe 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,11 +2,15 @@ PATH
   remote: .
   specs:
     ruby_llm-test (0.1.0)
-      ruby_llm (>= 1.14.0)
+      ruby_llm (>= 1.5.0)
 
 GEM
   remote: https://gem.coop/
   specs:
+    appraisal (2.5.0)
+      bundler
+      rake
+      thor (>= 0.14.0)
     ast (2.4.3)
     base64 (0.3.0)
     docile (1.4.1)
@@ -78,6 +82,7 @@ GEM
       simplecov_json_formatter (~> 0.1)
     simplecov-html (0.13.2)
     simplecov_json_formatter (0.1.4)
+    thor (1.5.0)
     unicode-display_width (3.2.0)
       unicode-emoji (~> 4.1)
     unicode-emoji (4.2.0)
@@ -89,6 +94,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  appraisal (~> 2.5)
   minitest (~> 6.0)
   rake (~> 13.0)
   rubocop (~> 1.86)
@@ -97,4 +103,4 @@ DEPENDENCIES
   simplecov (~> 0.22)
 
 BUNDLED WITH
-   4.0.10
+  4.0.10
diff --git a/gemfiles/ruby_llm_1.10.gemfile b/gemfiles/ruby_llm_1.10.gemfile
new file mode 100644
index 0000000..4fec377
--- /dev/null
+++ b/gemfiles/ruby_llm_1.10.gemfile
@@ -0,0 +1,16 @@
+# This file was generated by Appraisal
+
+source "https://gem.coop"
+
+gem "ruby_llm", "~> 1.10.0"
+
+group :development, :test do
+  gem "appraisal", "~> 2.5"
+  gem "minitest", "~> 6.0"
+  gem "rake", "~> 13.0"
+  gem "rubocop", "~> 1.86"
+  gem "rubocop-minitest", "~> 0.39"
+  gem "simplecov", "~> 0.22"
+end
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_llm_1.13.gemfile b/gemfiles/ruby_llm_1.13.gemfile
new file mode 100644
index 0000000..0623e37
--- /dev/null
+++ b/gemfiles/ruby_llm_1.13.gemfile
@@ -0,0 +1,16 @@
+# This file was generated by Appraisal
+
+source "https://gem.coop"
+
+gem "ruby_llm", "~> 1.13.0"
+
+group :development, :test do
+  gem "appraisal", "~> 2.5"
+  gem "minitest", "~> 6.0"
+  gem "rake", "~> 13.0"
+  gem "rubocop", "~> 1.86"
+  gem "rubocop-minitest", "~> 0.39"
+  gem "simplecov", "~> 0.22"
+end
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_llm_1.14.gemfile b/gemfiles/ruby_llm_1.14.gemfile
new file mode 100644
index 0000000..b66c6a9
--- /dev/null
+++ b/gemfiles/ruby_llm_1.14.gemfile
@@ -0,0 +1,16 @@
+# This file was generated by Appraisal
+
+source "https://gem.coop"
+
+gem "ruby_llm", "~> 1.14.0"
+
+group :development, :test do
+  gem "appraisal", "~> 2.5"
+  gem "minitest", "~> 6.0"
+  gem "rake", "~> 13.0"
+  gem "rubocop", "~> 1.86"
+  gem "rubocop-minitest", "~> 0.39"
+  gem "simplecov", "~> 0.22"
+end
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_llm_1.5.gemfile b/gemfiles/ruby_llm_1.5.gemfile
new file mode 100644
index 0000000..56aaa79
--- /dev/null
+++ b/gemfiles/ruby_llm_1.5.gemfile
@@ -0,0 +1,16 @@
+# This file was generated by Appraisal
+
+source "https://gem.coop"
+
+gem "ruby_llm", "~> 1.5.0"
+
+group :development, :test do
+  gem "appraisal", "~> 2.5"
+  gem "minitest", "~> 6.0"
+  gem "rake", "~> 13.0"
+  gem "rubocop", "~> 1.86"
+  gem "rubocop-minitest", "~> 0.39"
+  gem "simplecov", "~> 0.22"
+end
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_llm_1.6.gemfile b/gemfiles/ruby_llm_1.6.gemfile
new file mode 100644
index 0000000..4056125
--- /dev/null
+++ b/gemfiles/ruby_llm_1.6.gemfile
@@ -0,0 +1,16 @@
+# This file was generated by Appraisal
+
+source "https://gem.coop"
+
+gem "ruby_llm", "~> 1.6.0"
+
+group :development, :test do
+  gem "appraisal", "~> 2.5"
+  gem "minitest", "~> 6.0"
+  gem "rake", "~> 13.0"
+  gem "rubocop", "~> 1.86"
+  gem "rubocop-minitest", "~> 0.39"
+  gem "simplecov", "~> 0.22"
+end
+
+gemspec path: "../"
diff --git a/gemfiles/ruby_llm_current.gemfile b/gemfiles/ruby_llm_current.gemfile
new file mode 100644
index 0000000..8c11c66
--- /dev/null
+++ b/gemfiles/ruby_llm_current.gemfile
@@ -0,0 +1,16 @@
+# This file was generated by Appraisal
+
+source "https://gem.coop"
+
+gem "ruby_llm"
+
+group :development, :test do
+  gem "appraisal", "~> 2.5"
+  gem "minitest", "~> 6.0"
+  gem "rake", "~> 13.0"
+  gem "rubocop", "~> 1.86"
+  gem "rubocop-minitest", "~> 0.39"
+  gem "simplecov", "~> 0.22"
+end
+
+gemspec path: "../"
diff --git a/lib/ruby_llm/test/complete_parameters.rb b/lib/ruby_llm/test/complete_parameters.rb
index 9753cb4..9565920 100644
--- a/lib/ruby_llm/test/complete_parameters.rb
+++ b/lib/ruby_llm/test/complete_parameters.rb
@@ -2,27 +2,65 @@
 
 module RubyLLM
   module Test
-    # This class encapsulates all the parameters that are passed to the `complete` method of the `Test` class. It
-    # serves as a structured way to manage and access these parameters throughout the testing process.
+    # This class encapsulates all the parameters that are passed to the `complete` method of the wrapped provider. It
+    # stores the raw arguments and uses the wrapped provider's actual method signature to expose named accessors for
+    # inspection in tests.
     class CompleteParameters
-      attr_reader :messages, :tools, :temperature, :model, :params, :headers, :schema, :thinking, :tool_prefs, :block
-
-      def initialize(messages:, tools:, temperature:, model:, params:, # rubocop:disable Metrics/ParameterLists
-                     headers:, schema:, thinking:, tool_prefs:, block:)
-        @messages = messages
-        @tools = tools
-        @temperature = temperature
-        @model = model
-        @params = params
-        @headers = headers
-        @schema = schema
-        @thinking = thinking
-        @tool_prefs = tool_prefs
+      attr_reader :args, :kwargs, :block, :parameter_definitions
+
+      def self.capture_from(provider, *args, **kwargs, &block)
+        parameters = provider.method(:complete).parameters
+        new(args:, kwargs:, block:, parameter_definitions: parameters)
+      end
+
+      def initialize(args:, kwargs:, block:, parameter_definitions:)
+        @args = args
+        @kwargs = kwargs
         @block = block
+        @parameter_definitions = parameter_definitions
       end
 
       def block_received?
-        !@block.nil?
+        !block.nil?
+      end
+
+      def [](name)
+        name = name.to_sym
+        return block if name == :block
+
+        positional_name_to_value[name] || kwargs[name]
+      end
+
+      def key?(name)
+        name = name.to_sym
+        name == :block || positional_name_to_value.key?(name) || kwargs.key?(name)
+      end
+
+      def to_h
+        positional_name_to_value.merge(kwargs).merge(block: block)
+      end
+
+      def method_missing(name, *call_args)
+        return super unless call_args.empty?
+        return self[name] if key?(name)
+
+        super
+      end
+
+      def respond_to_missing?(name, include_private = false)
+        key?(name) || super
+      end
+
+      private
+
+      def positional_name_to_value
+        @positional_name_to_value ||= begin
+          positional_names = parameter_definitions
+                             .select { |parameter| %i[req opt].include?(parameter.first) }
+                             .map(&:last)
+
+          positional_names.each_with_index.to_h { |param_name, index| [ param_name, args[index] ] }
+        end
       end
     end
   end
diff --git a/lib/ruby_llm/test/test_provider.rb b/lib/ruby_llm/test/test_provider.rb
index f5a090e..5e268a0 100644
--- a/lib/ruby_llm/test/test_provider.rb
+++ b/lib/ruby_llm/test/test_provider.rb
@@ -10,8 +10,7 @@ class TestProvider < SimpleDelegator
 
       attr_reader :complete_calls
 
-      def_delegators :last_call, :messages, :tools, :temperature, :model, :params, :headers, :schema, :thinking,
-                     :tool_prefs, :block_received?
+      def_delegators :last_call, :messages, :block_received?
 
       def initialize(provider, test_harness = RubyLLM::Test)
         super(provider)
@@ -19,11 +18,10 @@ def initialize(provider, test_harness = RubyLLM::Test)
         @complete_calls = []
       end
 
-      def complete(messages, tools:, temperature:, model:, params: {}, # rubocop:disable Metrics/ParameterLists
-                   headers: {}, schema: nil, thinking: nil, tool_prefs: nil, &block)
-        @complete_calls << CompleteParameters.new(messages:, tools:, temperature:, model:, params:, headers:, schema:,
-                                                  thinking:, tool_prefs:, block:)
-        raise Errors::NoResponseProvidedError, messages if @test_harness.responses_empty?
+      def complete(...)
+        call = CompleteParameters.capture_from(__getobj__, ...)
+        @complete_calls << call
+        raise Errors::NoResponseProvidedError, call.messages if @test_harness.responses_empty?
 
         response = @test_harness.next_response
         return response if response.is_a?(Message)
diff --git a/ruby_llm-test.gemspec b/ruby_llm-test.gemspec
index 342df24..b025c20 100644
--- a/ruby_llm-test.gemspec
+++ b/ruby_llm-test.gemspec
@@ -19,5 +19,5 @@ Gem::Specification.new do |spec|
 
   spec.files = Dir["lib/**/*", "LICENSE.txt", "README.md"]
 
-  spec.add_dependency "ruby_llm", ">= 1.14.0"
+  spec.add_dependency "ruby_llm", ">= 1.5.0"
 end
diff --git a/test/ruby_llm/test/complete_parameters_test.rb b/test/ruby_llm/test/complete_parameters_test.rb
index 3695368..fe85908 100644
--- a/test/ruby_llm/test/complete_parameters_test.rb
+++ b/test/ruby_llm/test/complete_parameters_test.rb
@@ -5,25 +5,131 @@
 module RubyLLM
   module Test
     class CompleteParametersTest < Minitest::Test
+      class ProviderDouble
+        def complete(messages, tools:, temperature:, model:, params: {}, # rubocop:disable Metrics/ParameterLists
+                     headers: {}, schema: nil, thinking: nil, tool_prefs: nil, &)
+        end
+      end
+
       def test_with_block
-        params_with_block = CompleteParameters.new(
-          messages: [], tools: [], temperature: 0.5, model: "test-model", params: {}, headers: {}, schema: nil,
-          thinking: nil, tool_prefs: nil,
-          block: -> { "test block" }
+        params_with_block = CompleteParameters.capture_from(
+          ProviderDouble.new,
+          [],
+          tools: [],
+          temperature: 0.5,
+          model: "test-model",
+          params: {},
+          headers: {},
+          schema: nil,
+          thinking: nil,
+          tool_prefs: nil,
+          &-> { "test block" }
         )
 
         assert_predicate params_with_block, :block_received?
       end
 
       def test_without_block
-        params_without_block = CompleteParameters.new(
-          messages: [], tools: [], temperature: 0.5, model: "test-model", params: {}, headers: {}, schema: nil,
-          thinking: nil, tool_prefs: nil,
-          block: nil
+        params_without_block = CompleteParameters.capture_from(
+          ProviderDouble.new,
+          [],
+          tools: [],
+          temperature: 0.5,
+          model: "test-model",
+          params: {},
+          headers: {},
+          schema: nil,
+          thinking: nil,
+          tool_prefs: nil
         )
 
         refute_predicate params_without_block, :block_received?
       end
+
+      def test_exposes_captured_arguments_by_name # rubocop:disable Metrics/AbcSize, Minitest/MultipleAssertions
+        params = CompleteParameters.capture_from(
+          ProviderDouble.new,
+          [ Message.new(role: :user, content: "Hello") ],
+          tools: %w[tool1 tool2],
+          temperature: 0.7,
+          model: "test-model",
+          params: { param1: "value1" },
+          headers: { "Authorization" => "Bearer token" },
+          schema: { type: "object" },
+          thinking: "thinking process",
+          tool_prefs: { prefer_tool1: true }
+        )
+
+        assert_equal "Hello", params.messages.first.content.to_s
+        assert_equal :user, params.messages.first.role
+        assert_equal %w[tool1 tool2], params.tools
+        assert_in_delta(0.7, params.temperature)
+        assert_equal "test-model", params.model
+        assert_equal({ param1: "value1" }, params.params)
+        assert_equal({ "Authorization" => "Bearer token" }, params.headers)
+        assert_equal({ type: "object" }, params.schema)
+        assert_equal "thinking process", params.thinking
+        assert_equal({ prefer_tool1: true }, params.tool_prefs)
+      end
+
+      def test_supports_hash_style_access # rubocop:disable Minitest/MultipleAssertions
+        params = CompleteParameters.capture_from(
+          ProviderDouble.new,
+          [],
+          tools: [],
+          temperature: 0.5,
+          model: "test-model"
+        )
+
+        assert_equal [], params[:messages]
+        assert_equal [], params[:tools]
+        assert_in_delta(0.5, params[:temperature])
+        assert_equal "test-model", params[:model]
+      end
+
+      def test_to_h
+        hash = {
+          messages: [ Message.new(role: :user, content: "Hello") ],
+          tools: %w[tool1 tool2],
+          temperature: 0.7,
+          model: "test-model",
+          params: { param1: "value1" },
+          headers: { "Authorization" => "Bearer token" },
+          schema: { type: "object" },
+          thinking: "thinking process",
+          tool_prefs: { prefer_tool1: true },
+          block: nil
+        }
+        params = CompleteParameters.capture_from(ProviderDouble.new, **hash)
+
+        assert_equal hash, params.to_h
+      end
+
+      def test_invalid_parameter_access
+        params = CompleteParameters.capture_from(ProviderDouble.new, [], tools: [], temperature: 0.5,
+                                                                         model: "test-model")
+
+        assert_raises(NoMethodError) { params.invalid_param }
+      end
+
+      def test_block_access_via_hash_style
+        block = -> { "test block" }
+        params = CompleteParameters.capture_from(ProviderDouble.new, [], tools: [], temperature: 0.5,
+                                                                         model: "test-model", &block)
+
+        assert_equal block, params[:block]
+      end
+
+      def test_respond_to_missing # rubocop:disable Minitest/MultipleAssertions
+        params = CompleteParameters.capture_from(ProviderDouble.new, [], tools: [], temperature: 0.5,
+                                                                         model: "test-model")
+
+        assert_respond_to params, :messages
+        assert_respond_to params, :tools
+        assert_respond_to params, :temperature
+        assert_respond_to params, :model
+        refute_respond_to params, :invalid_param
+      end
     end
   end
 end
diff --git a/test/ruby_llm/test/test_provider_test.rb b/test/ruby_llm/test/test_provider_test.rb
index 208ef7b..c969f69 100644
--- a/test/ruby_llm/test/test_provider_test.rb
+++ b/test/ruby_llm/test/test_provider_test.rb
@@ -5,6 +5,12 @@
 module RubyLLM
   module Test
     class TestProviderTest < Minitest::Test
+      class ProviderDouble
+        def complete(messages, tools:, temperature:, model:, params: {}, # rubocop:disable Metrics/ParameterLists
+                     headers: {}, schema: nil, thinking: nil, tool_prefs: nil, &)
+        end
+      end
+
       def setup
         RubyLLM::Test.reset
       end
@@ -12,7 +18,7 @@ def setup
       def test_provider_returns_stubbed_response
         RubyLLM::Test.stub_response("stubbed response")
 
-        provider = TestProvider.new(nil, RubyLLM::Test)
+        provider = TestProvider.new(ProviderDouble.new, RubyLLM::Test)
         response = provider.complete([], tools: [], temperature: 0.5, model: "test-model", params: {}, headers: {})
 
         assert_kind_of Message, response
@@ -20,7 +26,7 @@ def test_provider_returns_stubbed_response
       end
 
       def test_when_response_not_stubbed
-        provider = TestProvider.new(nil, RubyLLM::Test)
+        provider = TestProvider.new(ProviderDouble.new, RubyLLM::Test)
         message = Message.new(role: :user, content: "What is the capital of France?")
 
         exception = assert_raises(Errors::NoResponseProvidedError) do
@@ -34,7 +40,7 @@ def test_when_stub_is_a_message
         stubbed_message = Message.new(role: :assistant, content: "This is a stubbed message.")
         RubyLLM::Test.stub_response(stubbed_message)
 
-        provider = TestProvider.new(nil, RubyLLM::Test)
+        provider = TestProvider.new(ProviderDouble.new, RubyLLM::Test)
         response = provider.complete([], tools: [], temperature: 0.5, model: "test-model", params: {}, headers: {})
 
         assert_equal stubbed_message, response
@@ -44,7 +50,7 @@ def test_hash_stub_is_converted_to_json_message
         stubbed_hash = { answer: "42" }
         RubyLLM::Test.stub_response(stubbed_hash)
 
-        provider = TestProvider.new(nil, RubyLLM::Test)
+        provider = TestProvider.new(ProviderDouble.new, RubyLLM::Test)
         response = provider.complete([], tools: [], temperature: 0.5, model: "test-model", params: {}, headers: {})
 
         assert_kind_of Message, response
@@ -53,12 +59,18 @@ def test_hash_stub_is_converted_to_json_message
     end
 
     class TestProviderLastCallTest < Minitest::Test
+      class ProviderDouble
+        def complete(messages, tools:, temperature:, model:, params: {}, # rubocop:disable Metrics/ParameterLists
+                     headers: {}, schema: nil, thinking: nil, tool_prefs: nil, &)
+        end
+      end
+
       def setup
         RubyLLM::Test.reset
         RubyLLM::Test.stub_response("stubbed response")
 
         initialize_arguments
-        provider = TestProvider.new(nil, RubyLLM::Test)
+        provider = TestProvider.new(ProviderDouble.new, RubyLLM::Test)
         provider.complete(@messages, tools: @tools, temperature: @temperature, model: @model, params: @params,
                                      headers: @headers, schema: @schema, thinking: @thinking, tool_prefs: @tool_prefs)
 
diff --git a/test/system/chat_test.rb b/test/system/chat_test.rb
new file mode 100644
index 0000000..2f51a65
--- /dev/null
+++ b/test/system/chat_test.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class ChatTest < Minitest::Test
+  def test_chat_response
+    RubyLLM::Test.reset
+    RubyLLM::Test.stub_response("42")
+
+    chat = RubyLLM::Chat.new(model: "gpt-4")
+    response = chat.ask("What is the meaning of life?")
+
+    assert_equal "42", response.content
+  end
+
+  def test_block_stub
+    RubyLLM::Test.with_responses("stubbed response") do
+      chat = RubyLLM::Chat.new(model: "gpt-4")
+      response = chat.ask("What is the meaning of life?")
+
+      assert_equal "stubbed response", response.content
+    end
+  end
+end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 0e40b00..1be6da0 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -9,3 +9,12 @@
 
 require "ruby_llm/test"
 require "minitest/autorun"
+
+RubyLLM::Models.singleton_class.prepend(RubyLLM::Test::ResolveWithTestProvider)
+
+# need to provide a dummy value for the API key
+# the two models used need to exist in the JSON file that comes with the gem
+RubyLLM.configure do |config|
+  config.openai_api_key = "dummy-test-api-key"
+  config.default_model = "gpt-5.4"
+end