diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 317f5a80..f4496bef 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -7,6 +7,9 @@ jobs:
     strategy:
       matrix:
         entry:
+          - { ruby: '2.7', allowed-failure: false }
+          - { ruby: '3.0', allowed-failure: false }
+          - { ruby: '3.1', allowed-failure: false }
           - { ruby: '3.2', allowed-failure: false }
           - { ruby: '3.3', allowed-failure: false }
           - { ruby: '3.4', allowed-failure: false }
@@ -29,7 +32,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 3.2 # Specify the oldest supported Ruby version.
+          ruby-version: 4.0 # Specify the latest supported Ruby version.
           bundler-cache: true
       - run: bundle exec rake rubocop
 
@@ -40,6 +43,6 @@ jobs:
       - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 3.2 # Specify the oldest supported Ruby version.
+          ruby-version: 4.0 # Specify the latest supported Ruby version.
           bundler-cache: true
       - run: bundle exec yard --no-output
diff --git a/.rubocop.yml b/.rubocop.yml
index fb1a5cb2..2120de45 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -5,6 +5,9 @@ plugins:
   - rubocop-minitest
   - rubocop-rake
 
+AllCops:
+  TargetRubyVersion: 2.7
+
 Gemspec/DevelopmentDependencies:
   Enabled: true
 
diff --git a/AGENTS.md b/AGENTS.md
index 48dc6ea9..6b269d72 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -6,7 +6,7 @@ This is the official Ruby SDK for the Model Context Protocol (MCP), implementing
 
 ## Dev environment setup
 
-- Ruby 3.2.0+ required
+- Ruby 3.2.0+ required to run the full test suite, including all Sorbet-related features
 - Run `bundle install` to install dependencies
 - Dependencies: `json-schema` >= 4.1 - Schema validation
 
diff --git a/Gemfile b/Gemfile
index 547ccd0d..fa2d2b89 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,17 +8,18 @@ gemspec
 # Specify development dependencies below
 gem "rubocop-minitest", require: false
 gem "rubocop-rake", require: false
-gem "rubocop-shopify", require: false
+gem "rubocop-shopify", ">= 2.18", require: false if RUBY_VERSION >= "3.1"
 
 gem "puma", ">= 5.0.0"
 gem "rackup", ">= 2.1.0"
 
 gem "activesupport"
-gem "debug"
+# Fix io-console install error when Ruby 3.0.
+gem "debug" if RUBY_VERSION >= "3.1"
 gem "rake", "~> 13.0"
-gem "sorbet-static-and-runtime"
+gem "sorbet-static-and-runtime" if RUBY_VERSION >= "3.0"
 gem "yard", "~> 0.9"
-gem "yard-sorbet", "~> 0.9"
+gem "yard-sorbet", "~> 0.9" if RUBY_VERSION >= "3.1"
 
 group :test do
   gem "faraday", ">= 2.0"
diff --git a/lib/json_rpc_handler.rb b/lib/json_rpc_handler.rb
index 309044e9..536406de 100644
--- a/lib/json_rpc_handler.rb
+++ b/lib/json_rpc_handler.rb
@@ -22,14 +22,14 @@ class ErrorCode
 
   def handle(request, id_validation_pattern: DEFAULT_ALLOWED_ID_CHARACTERS, &method_finder)
     if request.is_a?(Array)
-      return error_response(id: :unknown_id, id_validation_pattern:, error: {
+      return error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: {
         code: ErrorCode::INVALID_REQUEST,
         message: "Invalid Request",
         data: "Request is an empty array",
       }) if request.empty?
 
       # Handle batch requests
-      responses = request.map { |req| process_request(req, id_validation_pattern:, &method_finder) }.compact
+      responses = request.map { |req| process_request(req, id_validation_pattern: id_validation_pattern, &method_finder) }.compact
 
       # A single item is hoisted out of the array
       return responses.first if responses.one?
@@ -38,9 +38,9 @@ def handle(request, id_validation_pattern: DEFAULT_ALLOWED_ID_CHARACTERS, &metho
       responses if responses.any?
     elsif request.is_a?(Hash)
       # Handle single request
-      process_request(request, id_validation_pattern:, &method_finder)
+      process_request(request, id_validation_pattern: id_validation_pattern, &method_finder)
     else
-      error_response(id: :unknown_id, id_validation_pattern:, error: {
+      error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: {
         code: ErrorCode::INVALID_REQUEST,
         message: "Invalid Request",
         data: "Request must be an array or a hash",
@@ -51,9 +51,9 @@ def handle(request, id_validation_pattern: DEFAULT_ALLOWED_ID_CHARACTERS, &metho
   def handle_json(request_json, id_validation_pattern: DEFAULT_ALLOWED_ID_CHARACTERS, &method_finder)
     begin
       request = JSON.parse(request_json, symbolize_names: true)
-      response = handle(request, id_validation_pattern:, &method_finder)
+      response = handle(request, id_validation_pattern: id_validation_pattern, &method_finder)
     rescue JSON::ParserError
-      response = error_response(id: :unknown_id, id_validation_pattern:, error: {
+      response = error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: {
         code: ErrorCode::PARSE_ERROR,
         message: "Parse error",
         data: "Invalid JSON",
@@ -74,7 +74,7 @@ def process_request(request, id_validation_pattern:, &method_finder)
       'Method name must be a string and not start with "rpc."'
     end
 
-    return error_response(id: :unknown_id, id_validation_pattern:, error: {
+    return error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: {
       code: ErrorCode::INVALID_REQUEST,
       message: "Invalid Request",
       data: error,
@@ -84,7 +84,7 @@ def process_request(request, id_validation_pattern:, &method_finder)
     params = request[:params]
 
     unless valid_params?(params)
-      return error_response(id:, id_validation_pattern:, error: {
+      return error_response(id: id, id_validation_pattern: id_validation_pattern, error: {
         code: ErrorCode::INVALID_PARAMS,
         message: "Invalid params",
         data: "Method parameters must be an array or an object or null",
@@ -95,7 +95,7 @@ def process_request(request, id_validation_pattern:, &method_finder)
       method = method_finder.call(method_name)
 
       if method.nil?
-        return error_response(id:, id_validation_pattern:, error: {
+        return error_response(id: id, id_validation_pattern: id_validation_pattern, error: {
           code: ErrorCode::METHOD_NOT_FOUND,
           message: "Method not found",
           data: method_name,
@@ -104,9 +104,9 @@ def process_request(request, id_validation_pattern:, &method_finder)
 
       result = method.call(params)
 
-      success_response(id:, result:)
+      success_response(id: id, result: result)
     rescue StandardError => e
-      error_response(id:, id_validation_pattern:, error: {
+      error_response(id: id, id_validation_pattern: id_validation_pattern, error: {
         code: ErrorCode::INTERNAL_ERROR,
         message: "Internal error",
         data: e.message,
@@ -136,8 +136,8 @@ def valid_params?(params)
   def success_response(id:, result:)
     {
       jsonrpc: Version::V2_0,
-      id:,
-      result:,
+      id: id,
+      result: result,
     } unless id.nil?
   end
 
diff --git a/lib/mcp/client/http.rb b/lib/mcp/client/http.rb
index 7b065a89..084178f3 100644
--- a/lib/mcp/client/http.rb
+++ b/lib/mcp/client/http.rb
@@ -18,42 +18,42 @@ def send_request(request:)
       rescue Faraday::BadRequestError => e
         raise RequestHandlerError.new(
           "The #{method} request is invalid",
-          { method:, params: },
+          { method: method, params: params },
           error_type: :bad_request,
           original_error: e,
         )
       rescue Faraday::UnauthorizedError => e
         raise RequestHandlerError.new(
           "You are unauthorized to make #{method} requests",
-          { method:, params: },
+          { method: method, params: params },
           error_type: :unauthorized,
           original_error: e,
         )
       rescue Faraday::ForbiddenError => e
         raise RequestHandlerError.new(
           "You are forbidden to make #{method} requests",
-          { method:, params: },
+          { method: method, params: params },
           error_type: :forbidden,
           original_error: e,
         )
       rescue Faraday::ResourceNotFound => e
         raise RequestHandlerError.new(
           "The #{method} request is not found",
-          { method:, params: },
+          { method: method, params: params },
           error_type: :not_found,
           original_error: e,
         )
       rescue Faraday::UnprocessableEntityError => e
         raise RequestHandlerError.new(
           "The #{method} request is unprocessable",
-          { method:, params: },
+          { method: method, params: params },
           error_type: :unprocessable_entity,
           original_error: e,
         )
       rescue Faraday::Error => e # Catch-all
         raise RequestHandlerError.new(
           "Internal error handling #{method} request",
-          { method:, params: },
+          { method: method, params: params },
           error_type: :internal_error,
           original_error: e,
         )
diff --git a/lib/mcp/configuration.rb b/lib/mcp/configuration.rb
index a0f038e7..03105bdb 100644
--- a/lib/mcp/configuration.rb
+++ b/lib/mcp/configuration.rb
@@ -85,10 +85,10 @@ def merge(other)
       validate_tool_call_arguments = other.validate_tool_call_arguments
 
       Configuration.new(
-        exception_reporter:,
-        instrumentation_callback:,
-        protocol_version:,
-        validate_tool_call_arguments:,
+        exception_reporter: exception_reporter,
+        instrumentation_callback: instrumentation_callback,
+        protocol_version: protocol_version,
+        validate_tool_call_arguments: validate_tool_call_arguments,
       )
     end
 
diff --git a/lib/mcp/content.rb b/lib/mcp/content.rb
index 7f4f9214..7ab984d6 100644
--- a/lib/mcp/content.rb
+++ b/lib/mcp/content.rb
@@ -11,7 +11,7 @@ def initialize(text, annotations: nil)
       end
 
       def to_h
-        { text:, annotations:, type: "text" }.compact
+        { text: text, annotations: annotations, type: "text" }.compact
       end
     end
 
@@ -25,7 +25,7 @@ def initialize(data, mime_type, annotations: nil)
       end
 
       def to_h
-        { data:, mime_type:, annotations:, type: "image" }.compact
+        { data: data, mime_type: mime_type, annotations: annotations, type: "image" }.compact
       end
     end
   end
diff --git a/lib/mcp/instrumentation.rb b/lib/mcp/instrumentation.rb
index 5632fdda..40975a91 100644
--- a/lib/mcp/instrumentation.rb
+++ b/lib/mcp/instrumentation.rb
@@ -6,7 +6,7 @@ def instrument_call(method, &block)
       start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
       begin
         @instrumentation_data = {}
-        add_instrumentation_data(method:)
+        add_instrumentation_data(method: method)
 
         result = yield block
 
diff --git a/lib/mcp/prompt.rb b/lib/mcp/prompt.rb
index 317df7e0..9445cf74 100644
--- a/lib/mcp/prompt.rb
+++ b/lib/mcp/prompt.rb
@@ -96,7 +96,7 @@ def define(name: nil, title: nil, description: nil, icons: [], arguments: [], me
           icons icons
           arguments arguments
           define_singleton_method(:template) do |args, server_context: nil|
-            instance_exec(args, server_context:, &block)
+            instance_exec(args, server_context: server_context, &block)
           end
           meta meta
         end
diff --git a/lib/mcp/prompt/message.rb b/lib/mcp/prompt/message.rb
index aa203019..906ebd19 100644
--- a/lib/mcp/prompt/message.rb
+++ b/lib/mcp/prompt/message.rb
@@ -11,7 +11,7 @@ def initialize(role:, content:)
       end
 
       def to_h
-        { role:, content: content.to_h }.compact
+        { role: role, content: content.to_h }.compact
       end
     end
   end
diff --git a/lib/mcp/prompt/result.rb b/lib/mcp/prompt/result.rb
index 53a5e21c..b55b2424 100644
--- a/lib/mcp/prompt/result.rb
+++ b/lib/mcp/prompt/result.rb
@@ -11,7 +11,7 @@ def initialize(description: nil, messages: [])
       end
 
       def to_h
-        { description:, messages: messages.map(&:to_h) }.compact
+        { description: description, messages: messages.map(&:to_h) }.compact
       end
     end
   end
diff --git a/lib/mcp/resource/contents.rb b/lib/mcp/resource/contents.rb
index d87ded84..4c3bf116 100644
--- a/lib/mcp/resource/contents.rb
+++ b/lib/mcp/resource/contents.rb
@@ -11,7 +11,7 @@ def initialize(uri:, mime_type: nil)
       end
 
       def to_h
-        { uri:, mime_type: }.compact
+        { uri: uri, mime_type: mime_type }.compact
       end
     end
 
diff --git a/lib/mcp/resource/embedded.rb b/lib/mcp/resource/embedded.rb
index 343f86ea..9df04c65 100644
--- a/lib/mcp/resource/embedded.rb
+++ b/lib/mcp/resource/embedded.rb
@@ -10,7 +10,7 @@ def initialize(resource:, annotations: nil)
       end
 
       def to_h
-        { resource: resource.to_h, annotations: }.compact
+        { resource: resource.to_h, annotations: annotations }.compact
       end
     end
   end
diff --git a/lib/mcp/server.rb b/lib/mcp/server.rb
index 688a52d3..74c014dd 100644
--- a/lib/mcp/server.rb
+++ b/lib/mcp/server.rb
@@ -114,7 +114,7 @@ def handle_json(request)
     end
 
     def define_tool(name: nil, title: nil, description: nil, input_schema: nil, annotations: nil, meta: nil, &block)
-      tool = Tool.define(name:, title:, description:, input_schema:, annotations:, meta:, &block)
+      tool = Tool.define(name: name, title: title, description: description, input_schema: input_schema, annotations: annotations, meta: meta, &block)
       tool_name = tool.name_value
 
       @tool_names << tool_name
@@ -124,7 +124,7 @@ def define_tool(name: nil, title: nil, description: nil, input_schema: nil, anno
     end
 
     def define_prompt(name: nil, title: nil, description: nil, arguments: [], &block)
-      prompt = Prompt.define(name:, title:, description:, arguments:, &block)
+      prompt = Prompt.define(name: name, title: title, description: description, arguments: arguments, &block)
       @prompts[prompt.name_value] = prompt
 
       validate!
@@ -289,11 +289,11 @@ def default_capabilities
 
     def server_info
       @server_info ||= {
-        description:,
-        icons:,
-        name:,
-        title:,
-        version:,
+        description: description,
+        icons: icons,
+        name: name,
+        title: title,
+        version: version,
         websiteUrl: website_url,
       }.compact
     end
@@ -316,13 +316,13 @@ def call_tool(request)
 
       tool = tools[tool_name]
       unless tool
-        add_instrumentation_data(tool_name:, error: :tool_not_found)
+        add_instrumentation_data(tool_name: tool_name, error: :tool_not_found)
 
         return error_tool_response("Tool not found: #{tool_name}")
       end
 
       arguments = request[:arguments] || {}
-      add_instrumentation_data(tool_name:)
+      add_instrumentation_data(tool_name: tool_name)
 
       if tool.input_schema&.missing_required_arguments?(arguments)
         add_instrumentation_data(error: :missing_required_arguments)
@@ -360,7 +360,7 @@ def get_prompt(request)
         raise RequestHandlerError.new("Prompt not found #{prompt_name}", request, error_type: :prompt_not_found)
       end
 
-      add_instrumentation_data(prompt_name:)
+      add_instrumentation_data(prompt_name: prompt_name)
 
       prompt_args = request[:arguments]
       prompt.validate_arguments!(prompt_args)
diff --git a/lib/mcp/server/transports/streamable_http_transport.rb b/lib/mcp/server/transports/streamable_http_transport.rb
index 91f5ae3c..4c88085d 100644
--- a/lib/mcp/server/transports/streamable_http_transport.rb
+++ b/lib/mcp/server/transports/streamable_http_transport.rb
@@ -42,7 +42,7 @@ def send_notification(method, params = nil, session_id: nil)
 
           notification = {
             jsonrpc: "2.0",
-            method:,
+            method: method,
           }
           notification[:params] = params if params
 
diff --git a/lib/mcp/tool/annotations.rb b/lib/mcp/tool/annotations.rb
index 328a24cd..381cda7c 100644
--- a/lib/mcp/tool/annotations.rb
+++ b/lib/mcp/tool/annotations.rb
@@ -19,7 +19,7 @@ def to_h
           idempotentHint: idempotent_hint,
           openWorldHint: open_world_hint,
           readOnlyHint: read_only_hint,
-          title:,
+          title: title,
         }.compact
       end
     end
diff --git a/lib/mcp/tool/response.rb b/lib/mcp/tool/response.rb
index af3ec8ff..0d9dccbb 100644
--- a/lib/mcp/tool/response.rb
+++ b/lib/mcp/tool/response.rb
@@ -23,7 +23,7 @@ def error?
       end
 
       def to_h
-        { content:, isError: error?, structuredContent: @structured_content }.compact
+        { content: content, isError: error?, structuredContent: @structured_content }.compact
       end
     end
   end
diff --git a/mcp.gemspec b/mcp.gemspec
index eb87aeb5..34677655 100644
--- a/mcp.gemspec
+++ b/mcp.gemspec
@@ -13,7 +13,8 @@ Gem::Specification.new do |spec|
   spec.homepage      = "https://github.com/modelcontextprotocol/ruby-sdk"
   spec.license       = "MIT"
 
-  spec.required_ruby_version = ">= 3.2.0"
+  # Since this library is used by a broad range of users, it does not align its support policy with Ruby's EOL.
+  spec.required_ruby_version = ">= 2.7.0"
 
   spec.metadata["allowed_push_host"] = "https://rubygems.org"
   spec.metadata["changelog_uri"] = "https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v#{spec.version}"
diff --git a/test/json_rpc_handler_test.rb b/test/json_rpc_handler_test.rb
index 38004e69..751d1404 100644
--- a/test/json_rpc_handler_test.rb
+++ b/test/json_rpc_handler_test.rb
@@ -94,7 +94,7 @@
       register("add") { |params| params[:a] + params[:b] }
       id = "request-123_abc"
 
-      handle jsonrpc: "2.0", id:, method: "add", params: { a: 1, b: 2 }
+      handle jsonrpc: "2.0", id: id, method: "add", params: { a: 1, b: 2 }
 
       assert_rpc_success expected_result: 3
       assert_equal id, @response[:id]
@@ -104,7 +104,7 @@
       register("add") { |params| params[:a] + params[:b] }
       id = 42
 
-      handle jsonrpc: "2.0", id:, method: "add", params: { a: 1, b: 2 }
+      handle jsonrpc: "2.0", id: id, method: "add", params: { a: 1, b: 2 }
 
       assert_rpc_success expected_result: 3
       assert_equal id, @response[:id]
@@ -124,7 +124,7 @@
       register("add") { |params| params[:a] + params[:b] }
       id = "request-123_ABC"
 
-      handle jsonrpc: "2.0", id:, method: "add", params: { a: 1, b: 2 }
+      handle jsonrpc: "2.0", id: id, method: "add", params: { a: 1, b: 2 }
 
       assert_rpc_success expected_result: 3
       assert_equal id, @response[:id]
@@ -134,7 +134,7 @@
       register("add") { |params| params[:a] + params[:b] }
       id = "550e8400-e29b-41d4-a716-446655440000"
 
-      handle jsonrpc: "2.0", id:, method: "add", params: { a: 1, b: 2 }
+      handle jsonrpc: "2.0", id: id, method: "add", params: { a: 1, b: 2 }
 
       assert_rpc_success expected_result: 3
       assert_equal id, @response[:id]
diff --git a/test/mcp/client_test.rb b/test/mcp/client_test.rb
index b56f011d..168ed944 100644
--- a/test/mcp/client_test.rb
+++ b/test/mcp/client_test.rb
@@ -18,7 +18,7 @@ def test_tools_sends_request_to_transport_and_returns_tools_array
 
       # Only checking for the essential parts of the request
       transport.expects(:send_request).with do |args|
-        args in { request: { method: "tools/list", jsonrpc: "2.0" } }
+        args.dig(:request, :method) == "tools/list" && args.dig(:request, :jsonrpc) == "2.0"
       end.returns(mock_response).once
 
       client = Client.new(transport: transport)
@@ -35,7 +35,7 @@ def test_tools_returns_empty_array_when_no_tools
 
       # Only checking for the essential parts of the request
       transport.expects(:send_request).with do |args|
-        args in { request: { method: "tools/list", jsonrpc: "2.0" } }
+        args.dig(:request, :method) == "tools/list" && args.dig(:request, :jsonrpc) == "2.0"
       end.returns(mock_response).once
 
       client = Client.new(transport: transport)
@@ -54,16 +54,10 @@ def test_call_tool_sends_request_to_transport_and_returns_content
 
       # Only checking for the essential parts of the request
       transport.expects(:send_request).with do |args|
-        args in {
-          request: {
-            method: "tools/call",
-            jsonrpc: "2.0",
-            params: {
-              name: "tool1",
-              arguments: arguments,
-            },
-          },
-        }
+        args.dig(:request, :method) == "tools/call" &&
+          args.dig(:request, :jsonrpc) == "2.0" &&
+          args.dig(:request, :params, :name) == "tool1" &&
+          args.dig(:request, :params, :arguments) == arguments
       end.returns(mock_response).once
 
       client = Client.new(transport: transport)
@@ -86,7 +80,7 @@ def test_resources_sends_request_to_transport_and_returns_resources_array
 
       # Only checking for the essential parts of the request
       transport.expects(:send_request).with do |args|
-        args in { request: { method: "resources/list", jsonrpc: "2.0" } }
+        args.dig(:request, :method) == "resources/list" && args.dig(:request, :jsonrpc) == "2.0"
       end.returns(mock_response).once
 
       client = Client.new(transport: transport)
@@ -124,15 +118,9 @@ def test_read_resource_sends_request_to_transport_and_returns_contents
 
       # Only checking for the essential parts of the request
       transport.expects(:send_request).with do |args|
-        args in {
-          request: {
-            method: "resources/read",
-            jsonrpc: "2.0",
-            params: {
-              uri: uri,
-            },
-          },
-        }
+        args.dig(:request, :method) == "resources/read" &&
+          args.dig(:request, :jsonrpc) == "2.0" &&
+          args.dig(:request, :params, :uri) == uri
       end.returns(mock_response).once
 
       client = Client.new(transport: transport)
@@ -190,7 +178,7 @@ def test_prompts_sends_request_to_transport_and_returns_prompts_array
 
       # Only checking for the essential parts of the request
       transport.expects(:send_request).with do |args|
-        args in { request: { method: "prompts/list", jsonrpc: "2.0" } }
+        args.dig(:request, :method) == "prompts/list" && args.dig(:request, :jsonrpc) == "2.0"
       end.returns(mock_response).once
 
       client = Client.new(transport: transport)
@@ -242,15 +230,9 @@ def test_get_prompt_sends_request_to_transport_and_returns_contents
 
       # Only checking for the essential parts of the request
       transport.expects(:send_request).with do |args|
-        args in {
-          request: {
-            method: "prompts/get",
-            jsonrpc: "2.0",
-            params: {
-              name: name,
-            },
-          },
-        }
+        args.dig(:request, :method) == "prompts/get" &&
+          args.dig(:request, :jsonrpc) == "2.0" &&
+          args.dig(:request, :params, :name) == name
       end.returns(mock_response).once
 
       client = Client.new(transport: transport)
diff --git a/test/mcp/prompt_test.rb b/test/mcp/prompt_test.rb
index 64630b8f..16bb5847 100644
--- a/test/mcp/prompt_test.rb
+++ b/test/mcp/prompt_test.rb
@@ -132,7 +132,7 @@ def template(args, server_context:)
           description: "Hello, world!",
           messages: [
             Prompt::Message.new(role: "user", content: Content::Text.new("Hello, world!")),
-            Prompt::Message.new(role: "assistant", content:),
+            Prompt::Message.new(role: "assistant", content: content),
           ],
         )
       end
diff --git a/test/mcp/server/transports/streamable_http_transport_test.rb b/test/mcp/server/transports/streamable_http_transport_test.rb
index acae7b6f..743268e0 100644
--- a/test/mcp/server/transports/streamable_http_transport_test.rb
+++ b/test/mcp/server/transports/streamable_http_transport_test.rb
@@ -388,7 +388,7 @@ class StreamableHTTPTransportTest < ActiveSupport::TestCase
           @server.define_singleton_method(:handle_json) do |request|
             result = original_handle_json.call(request)
             # Send notification while still in request context - broadcast to all sessions
-            transport.send_notification("test_notification", { session: "current" })
+            transport.send_notification("test_notification", { session: "current" }, **{})
             result
           end
 
@@ -500,7 +500,7 @@ class StreamableHTTPTransportTest < ActiveSupport::TestCase
           sleep(0.1)
 
           # Broadcast notification to all sessions
-          sent_count = @transport.send_notification("broadcast", { message: "Hello everyone" })
+          sent_count = @transport.send_notification("broadcast", { message: "Hello everyone" }, **{})
 
           assert_equal 2, sent_count
 
@@ -517,7 +517,7 @@ class StreamableHTTPTransportTest < ActiveSupport::TestCase
         end
 
         test "send_notification returns false for non-existent session" do
-          result = @transport.send_notification({ message: "test" }, session_id: "non_existent")
+          result = @transport.send_notification("test", { message: "test" }, session_id: "non_existent")
           refute result
         end
 
@@ -549,7 +549,7 @@ class StreamableHTTPTransportTest < ActiveSupport::TestCase
           io.close
 
           # Try to send notification
-          result = @transport.send_notification({ message: "test" }, session_id: session_id)
+          result = @transport.send_notification("test", { message: "test" }, session_id: session_id)
 
           # Should return false and clean up the session
           refute result
diff --git a/test/mcp/server_test.rb b/test/mcp/server_test.rb
index 588faab9..b9ef6e51 100644
--- a/test/mcp/server_test.rb
+++ b/test/mcp/server_test.rb
@@ -80,7 +80,7 @@ class ServerTest < ActiveSupport::TestCase
         prompts: [@prompt],
         resources: [@resource],
         resource_templates: [@resource_template],
-        configuration:,
+        configuration: configuration,
       )
     end
 
@@ -244,7 +244,13 @@ class ServerTest < ActiveSupport::TestCase
       tool_args = { arg: "value" }
       tool_response = Tool::Response.new([{ result: "success" }])
 
-      @tool.expects(:call).with(arg: "value", server_context: nil).returns(tool_response)
+      if RUBY_VERSION >= "3.1"
+        # Ruby 3.1+: Mocha stub preserves `method.parameters` info.
+        @tool.expects(:call).with(arg: "value", server_context: nil).returns(tool_response)
+      else
+        # Ruby 3.0: Mocha stub changes `method.parameters`, so `accepts_server_context?` returns false.
+        @tool.expects(:call).with(arg: "value").returns(tool_response)
+      end
 
       request = {
         jsonrpc: "2.0",
@@ -258,7 +264,7 @@ class ServerTest < ActiveSupport::TestCase
 
       response = @server.handle(request)
       assert_equal tool_response.to_h, response[:result]
-      assert_instrumentation_data({ method: "tools/call", tool_name: })
+      assert_instrumentation_data({ method: "tools/call", tool_name: tool_name })
     end
 
     test "#handle tools/call returns error response with isError true if required tool arguments are missing" do
@@ -296,7 +302,13 @@ class ServerTest < ActiveSupport::TestCase
       tool_args = { arg: "value" }
       tool_response = Tool::Response.new([{ result: "success" }])
 
-      @tool.expects(:call).with(arg: "value", server_context: nil).returns(tool_response)
+      if RUBY_VERSION >= "3.1"
+        # Ruby 3.1+: Mocha stub preserves `method.parameters` info.
+        @tool.expects(:call).with(arg: "value", server_context: nil).returns(tool_response)
+      else
+        # Ruby 3.0: Mocha stub changes `method.parameters`, so `accepts_server_context?` returns false.
+        @tool.expects(:call).with(arg: "value").returns(tool_response)
+      end
 
       request = JSON.generate({
         jsonrpc: "2.0",
@@ -308,10 +320,12 @@ class ServerTest < ActiveSupport::TestCase
       raw_response = @server.handle_json(request)
       response = JSON.parse(raw_response, symbolize_names: true) if raw_response
       assert_equal tool_response.to_h, response[:result] if response
-      assert_instrumentation_data({ method: "tools/call", tool_name: })
+      assert_instrumentation_data({ method: "tools/call", tool_name: tool_name })
     end
 
     test "#handle_json tools/call executes tool and returns result, when the tool is typed with Sorbet" do
+      skip "Sorbet is not available" unless defined?(T::Sig)
+
       class TypedTestTool < Tool
         tool_name "test_tool"
         description "a test tool for testing"
@@ -836,7 +850,7 @@ class Example < Tool
       configuration.instrumentation_callback = local_callback
       configuration.exception_reporter = local_exception_reporter
 
-      server = Server.new(name: "test_server", configuration:)
+      server = Server.new(name: "test_server", configuration: configuration)
 
       assert_equal local_callback, server.configuration.instrumentation_callback
       assert_equal local_exception_reporter, server.configuration.exception_reporter
diff --git a/test/mcp/tool_test.rb b/test/mcp/tool_test.rb
index ee71827e..3d8369c8 100644
--- a/test/mcp/tool_test.rb
+++ b/test/mcp/tool_test.rb
@@ -243,6 +243,8 @@ class UpdatableMetaTool < Tool
     end
 
     test "#call with Sorbet typed tools invokes the tool block and returns the response" do
+      skip "sorbet-static-and-runtime requires Ruby 3.0+." if RUBY_VERSION < "3.0"
+
       class TypedTestTool < Tool
         tool_name "test_tool"
         description "a test tool for testing"
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 9a712f5b..19e9974b 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -9,6 +9,6 @@
 require "active_support"
 require "active_support/test_case"
 
-require "sorbet-runtime"
+require "sorbet-runtime" if RUBY_VERSION >= "3.0"
 
 require_relative "instrumentation_test_helper"