diff --git a/docs/_core_features/thinking.md b/docs/_core_features/thinking.md
new file mode 100644
index 000000000..89b5e122a
--- /dev/null
+++ b/docs/_core_features/thinking.md
@@ -0,0 +1,234 @@
+---
+layout: default
+title: Extended Thinking
+nav_order: 8
+description: Access the model's internal reasoning process with Extended Thinking
+redirect_from:
+  - /guides/thinking
+  - /guides/reasoning
+---
+
+# {{ page.title }}
+{: .no_toc }
+
+{{ page.description }}
+{: .fs-6 .fw-300 }
+
+## Table of contents
+{: .no_toc .text-delta }
+
+1. TOC
+{:toc}
+
+---
+
+After reading this guide, you will know:
+
+*   How to enable Extended Thinking for supported models.
+*   How to access thinking content in responses.
+*   How to stream thinking content in real-time.
+*   How thinking works across different providers.
+*   How to persist thinking content with ActiveRecord.
+
+## What is Extended Thinking?
+
+Extended Thinking (also known as "reasoning") is a feature that exposes the model's internal reasoning process. When enabled, models will "think through" problems step-by-step before providing their final response. This is particularly useful for:
+
+*   Complex mathematical or logical problems
+*   Multi-step reasoning tasks
+*   Debugging and understanding model behavior
+*   Applications where transparency in reasoning is valuable
+
+## Enabling Extended Thinking
+
+Use the `with_thinking` method to enable Extended Thinking on a chat:
+
+```ruby
+chat = RubyLLM.chat(model: 'claude-opus-4-5-20251101')
+  .with_thinking(budget: :medium)
+
+response = chat.ask("What is 15 * 23? Show your reasoning.")
+
+puts "Thinking: #{response.thinking}"
+# => "Let me break this down step by step. 15 * 23 = 15 * 20 + 15 * 3..."
+
+puts "Answer: #{response.content}"
+# => "The answer is 345."
+```
+
+### Budget Options
+
+The `budget` parameter controls how much "thinking" the model should do:
+
+| Budget | Description |
+|--------|-------------|
+| `:low` | Minimal thinking, faster responses |
+| `:medium` | Balanced thinking (default) |
+| `:high` | Maximum thinking, most thorough |
+| Integer | Specific token budget (provider-dependent) |
+
+```ruby
+# Symbol budgets
+chat.with_thinking(budget: :low)
+chat.with_thinking(budget: :medium)
+chat.with_thinking(budget: :high)
+
+# Integer budget (tokens)
+chat.with_thinking(budget: 10_000)
+```
+
+### Checking if Thinking is Enabled
+
+```ruby
+chat = RubyLLM.chat(model: 'claude-opus-4-5-20251101')
+
+chat.thinking_enabled?  # => false
+
+chat.with_thinking(budget: :medium)
+
+chat.thinking_enabled?  # => true
+```
+
+## Streaming with Thinking
+
+When streaming, thinking content is available on each chunk:
+
+```ruby
+chat = RubyLLM.chat(model: 'claude-opus-4-5-20251101')
+  .with_thinking(budget: :medium)
+
+chat.ask("Solve this step by step: What is 127 * 43?") do |chunk|
+  # Print thinking content as it streams
+  if chunk.thinking
+    print "[Thinking] #{chunk.thinking}"
+  end
+
+  # Print response content
+  if chunk.content
+    print chunk.content
+  end
+end
+```
+
+### Separating Thinking from Response
+
+For UI applications, you may want to display thinking separately:
+
+```ruby
+thinking_content = ""
+response_content = ""
+
+chat.ask("Complex question here...") do |chunk|
+  thinking_content << chunk.thinking if chunk.thinking
+  response_content << chunk.content if chunk.content
+
+  # Update UI with separated content
+  update_thinking_panel(thinking_content)
+  update_response_panel(response_content)
+end
+```
+
+## Supported Models
+
+Extended Thinking requires models with the `reasoning` capability. Use `with_thinking` only on supported models:
+
+```ruby
+# Check if a model supports thinking
+model = RubyLLM::Models.find('claude-opus-4-5-20251101')
+model.supports?('reasoning')  # => true
+
+# Using with_thinking on unsupported models raises an error
+chat = RubyLLM.chat(model: 'gpt-4o')
+chat.with_thinking(budget: :medium)
+# => raises RubyLLM::UnsupportedFeatureError
+```
+
+### Provider-Specific Behavior
+
+| Provider | Models | Implementation |
+|----------|--------|----------------|
+| Anthropic | claude-opus-4-*, claude-sonnet-4-* | `thinking` block with `budget_tokens` |
+| Gemini | gemini-2.5-*, gemini-3-* | `thinkingConfig` with budget or effort level |
+| OpenAI/Grok | grok-* models | `reasoning_effort` parameter |
+
+Budget symbols are automatically translated to provider-specific values:
+
+| Symbol | Anthropic | Gemini 2.5 | Gemini 3 | Grok |
+|--------|-----------|------------|----------|------|
+| `:low` | 1,024 tokens | 1,024 tokens | "low" | "low" |
+| `:medium` | 10,000 tokens | 8,192 tokens | "medium" | "high" |
+| `:high` | 32,000 tokens | 24,576 tokens | "high" | "high" |
+
+## Multi-Turn Conversations
+
+Extended Thinking works seamlessly in multi-turn conversations. The model maintains context of its previous reasoning:
+
+```ruby
+chat = RubyLLM.chat(model: 'claude-opus-4-5-20251101')
+  .with_thinking(budget: :medium)
+
+response1 = chat.ask("What is 15 * 23?")
+puts response1.thinking  # Shows step-by-step calculation
+
+response2 = chat.ask("Now multiply that result by 2")
+puts response2.thinking  # References previous calculation
+puts response2.content   # => "690"
+```
+
+## ActiveRecord Integration
+
+When using `acts_as_chat` and `acts_as_message`, thinking content is automatically persisted:
+
+```ruby
+# Migration (generated automatically with new installs)
+# t.text :thinking
+# t.text :thinking_signature
+
+# Using thinking with persisted chats
+chat_record = Chat.create!
+chat_record.with_thinking(budget: :medium)
+
+response = chat_record.ask("Explain quantum entanglement")
+
+# Thinking is saved to the message record
+last_message = chat_record.messages.last
+last_message.thinking  # => "Let me break down quantum entanglement..."
+```
+
+### Upgrading Existing Installations
+
+If you have an existing RubyLLM installation, add the thinking columns:
+
+```ruby
+class AddThinkingToMessages < ActiveRecord::Migration[7.0]
+  def change
+    add_column :messages, :thinking, :text
+    add_column :messages, :thinking_signature, :text
+  end
+end
+```
+
+## Error Handling
+
+```ruby
+begin
+  chat = RubyLLM.chat(model: 'gpt-4o')  # Doesn't support thinking
+  chat.with_thinking(budget: :medium)
+rescue RubyLLM::UnsupportedFeatureError => e
+  puts "This model doesn't support Extended Thinking"
+  puts e.message  # => "Model 'gpt-4o' does not support extended thinking"
+end
+```
+
+## Best Practices
+
+1. **Choose appropriate budgets**: Use `:low` for simple tasks, `:high` for complex reasoning
+2. **Stream for long responses**: Thinking can be lengthy; streaming provides better UX
+3. **Don't always display thinking**: Consider whether users need to see the reasoning
+4. **Handle gracefully**: Check `thinking_enabled?` before relying on thinking content
+
+## Next Steps
+
+*   [Streaming Responses]({% link _core_features/streaming.md %})
+*   [Rails Integration]({% link _advanced/rails.md %})
+*   [Error Handling]({% link _advanced/error-handling.md %})
diff --git a/lib/generators/ruby_llm/install/templates/create_messages_migration.rb.tt b/lib/generators/ruby_llm/install/templates/create_messages_migration.rb.tt
index b8882febf..ddd90def2 100644
--- a/lib/generators/ruby_llm/install/templates/create_messages_migration.rb.tt
+++ b/lib/generators/ruby_llm/install/templates/create_messages_migration.rb.tt
@@ -4,6 +4,8 @@ class Create<%= message_model_name.gsub('::', '').pluralize %> < ActiveRecord::M
       t.string :role, null: false
       t.text :content
       t.json :content_raw
+      t.text :thinking
+      t.text :thinking_signature
       t.integer :input_tokens
       t.integer :output_tokens
       t.integer :cached_tokens
diff --git a/lib/ruby_llm/active_record/chat_methods.rb b/lib/ruby_llm/active_record/chat_methods.rb
index 41930548c..85a6c4beb 100644
--- a/lib/ruby_llm/active_record/chat_methods.rb
+++ b/lib/ruby_llm/active_record/chat_methods.rb
@@ -124,6 +124,11 @@ def with_temperature(...)
         self
       end
 
+      def with_thinking(...)
+        to_llm.with_thinking(...)
+        self
+      end
+
       def with_params(...)
         to_llm.with_params(...)
         self
@@ -262,6 +267,8 @@ def persist_message_completion(message)
           if @message.has_attribute?(:cache_creation_tokens)
             attrs[:cache_creation_tokens] = message.cache_creation_tokens
           end
+          attrs[:thinking] = message.thinking if @message.has_attribute?(:thinking)
+          attrs[:thinking_signature] = Messages.signature_for(message) if @message.has_attribute?(:thinking_signature)
 
           # Add model association dynamically
           attrs[self.class.model_association_name] = model_association
diff --git a/lib/ruby_llm/active_record/message_methods.rb b/lib/ruby_llm/active_record/message_methods.rb
index 334352409..eede61830 100644
--- a/lib/ruby_llm/active_record/message_methods.rb
+++ b/lib/ruby_llm/active_record/message_methods.rb
@@ -11,24 +11,39 @@ module MessageMethods
       end
 
       def to_llm
-        cached = has_attribute?(:cached_tokens) ? self[:cached_tokens] : nil
-        cache_creation = has_attribute?(:cache_creation_tokens) ? self[:cache_creation_tokens] : nil
-
         RubyLLM::Message.new(
           role: role.to_sym,
           content: extract_content,
+          thinking: thinking_value,
+          thinking_signature: thinking_signature_value,
           tool_calls: extract_tool_calls,
           tool_call_id: extract_tool_call_id,
           input_tokens: input_tokens,
           output_tokens: output_tokens,
-          cached_tokens: cached,
-          cache_creation_tokens: cache_creation,
+          cached_tokens: cached_value,
+          cache_creation_tokens: cache_creation_value,
           model_id: model_association&.model_id
         )
       end
 
       private
 
+      def thinking_value
+        has_attribute?(:thinking) ? self[:thinking] : nil
+      end
+
+      def thinking_signature_value
+        has_attribute?(:thinking_signature) ? self[:thinking_signature] : nil
+      end
+
+      def cached_value
+        has_attribute?(:cached_tokens) ? self[:cached_tokens] : nil
+      end
+
+      def cache_creation_value
+        has_attribute?(:cache_creation_tokens) ? self[:cache_creation_tokens] : nil
+      end
+
       def extract_tool_calls
         tool_calls_association.to_h do |tool_call|
           [
diff --git a/lib/ruby_llm/chat.rb b/lib/ruby_llm/chat.rb
index d03d872ca..e0bce5dde 100644
--- a/lib/ruby_llm/chat.rb
+++ b/lib/ruby_llm/chat.rb
@@ -22,6 +22,7 @@ def initialize(model: nil, provider: nil, assume_model_exists: false, context: n
       @params = {}
       @headers = {}
       @schema = nil
+      @thinking_budget = nil
       @on = {
         new_message: nil,
         end_message: nil,
@@ -67,6 +68,16 @@ def with_temperature(temperature)
       self
     end
 
+    def with_thinking(budget: :medium)
+      validate_thinking_support!
+      @thinking_budget = budget
+      self
+    end
+
+    def thinking_enabled?
+      !@thinking_budget.nil?
+    end
+
     def with_context(context)
       @context = context
       @config = context.config
@@ -130,6 +141,7 @@ def complete(&) # rubocop:disable Metrics/PerceivedComplexity
         params: @params,
         headers: @headers,
         schema: @schema,
+        thinking: @thinking_budget,
         &wrap_streaming_block(&)
       )
 
@@ -169,6 +181,18 @@ def instance_variables
 
     private
 
+    def validate_thinking_support!
+      return if @model.supports?('reasoning')
+      return if gemini_thinking_model?
+
+      raise UnsupportedFeatureError,
+            "Model '#{@model.id}' does not support extended thinking"
+    end
+
+    def gemini_thinking_model?
+      @model.id.to_s.match?(/gemini-[23]|gemini-2\.\d-.*thinking/)
+    end
+
     def wrap_streaming_block(&block)
       return nil unless block_given?
 
diff --git a/lib/ruby_llm/error.rb b/lib/ruby_llm/error.rb
index 3908bee27..631f5f21d 100644
--- a/lib/ruby_llm/error.rb
+++ b/lib/ruby_llm/error.rb
@@ -18,6 +18,13 @@ class InvalidRoleError < StandardError; end
   class ModelNotFoundError < StandardError; end
   class UnsupportedAttachmentError < StandardError; end
 
+  # Error raised when a feature is not supported by a model
+  class UnsupportedFeatureError < Error
+    def initialize(message)
+      super(nil, message)
+    end
+  end
+
   # Error classes for different HTTP status codes
   class BadRequestError < Error; end
   class ForbiddenError < Error; end
diff --git a/lib/ruby_llm/message.rb b/lib/ruby_llm/message.rb
index 0a710b15f..64510bf03 100644
--- a/lib/ruby_llm/message.rb
+++ b/lib/ruby_llm/message.rb
@@ -6,7 +6,7 @@ class Message
     ROLES = %i[system user assistant tool].freeze
 
     attr_reader :role, :model_id, :tool_calls, :tool_call_id, :input_tokens, :output_tokens,
-                :cached_tokens, :cache_creation_tokens, :raw
+                :cached_tokens, :cache_creation_tokens, :raw, :thinking
     attr_writer :content
 
     def initialize(options = {})
@@ -20,6 +20,8 @@ def initialize(options = {})
       @cached_tokens = options[:cached_tokens]
       @cache_creation_tokens = options[:cache_creation_tokens]
       @raw = options[:raw]
+      @thinking = options[:thinking]
+      @thinking_signature = options[:thinking_signature]
 
       ensure_valid_role
     end
@@ -54,7 +56,8 @@ def to_h
         input_tokens: input_tokens,
         output_tokens: output_tokens,
         cached_tokens: cached_tokens,
-        cache_creation_tokens: cache_creation_tokens
+        cache_creation_tokens: cache_creation_tokens,
+        thinking: thinking
       }.compact
     end
 
@@ -62,6 +65,10 @@ def instance_variables
       super - [:@raw]
     end
 
+    protected
+
+    attr_reader :thinking_signature
+
     private
 
     def normalize_content(content)
diff --git a/lib/ruby_llm/messages.rb b/lib/ruby_llm/messages.rb
new file mode 100644
index 000000000..435064a63
--- /dev/null
+++ b/lib/ruby_llm/messages.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module RubyLLM
+  # Internal helper module for accessing protected message attributes
+  module Messages
+    module_function
+
+    def signature_for(message)
+      message.send(:thinking_signature) if message.respond_to?(:thinking_signature, true)
+    end
+  end
+end
diff --git a/lib/ruby_llm/models.json b/lib/ruby_llm/models.json
index 2e6033e17..52b077e80 100644
--- a/lib/ruby_llm/models.json
+++ b/lib/ruby_llm/models.json
@@ -316,6 +316,43 @@
     },
     "metadata": {}
   },
+  {
+    "id": "claude-opus-4-5-20251101",
+    "name": "Claude Opus 4.5",
+    "provider": "anthropic",
+    "family": "claude-2",
+    "created_at": "2025-11-24 00:00:00 UTC",
+    "context_window": 200000,
+    "max_output_tokens": 4096,
+    "knowledge_cutoff": null,
+    "modalities": {
+      "input": [
+        "text",
+        "image",
+        "pdf"
+      ],
+      "output": [
+        "text"
+      ]
+    },
+    "capabilities": [
+      "streaming",
+      "reasoning"
+    ],
+    "pricing": {
+      "text_tokens": {
+        "standard": {
+          "input_per_million": 3.0,
+          "output_per_million": 15.0
+        },
+        "batch": {
+          "input_per_million": 1.5,
+          "output_per_million": 7.5
+        }
+      }
+    },
+    "metadata": {}
+  },
   {
     "id": "claude-sonnet-4-20250514",
     "name": "Claude Sonnet 4",
@@ -2775,7 +2812,8 @@
     "capabilities": [
       "batch",
       "function_calling",
-      "structured_output"
+      "structured_output",
+      "reasoning"
     ],
     "pricing": {
       "text_tokens": {
@@ -31394,7 +31432,8 @@
     "capabilities": [
       "streaming",
       "function_calling",
-      "structured_output"
+      "structured_output",
+      "reasoning"
     ],
     "pricing": {
       "text_tokens": {
diff --git a/lib/ruby_llm/models.rb b/lib/ruby_llm/models.rb
index 54d7cc6d8..8d624269a 100644
--- a/lib/ruby_llm/models.rb
+++ b/lib/ruby_llm/models.rb
@@ -19,7 +19,7 @@ def load_models(file = RubyLLM.config.model_registry_file)
       end
 
       def read_from_json(file = RubyLLM.config.model_registry_file)
-        data = File.exist?(file) ? File.read(file) : '[]'
+        data = File.exist?(file) ? File.read(file, encoding: 'UTF-8') : '[]'
         JSON.parse(data, symbolize_names: true).map { |model| Model::Info.new(model) }
       rescue JSON::ParserError
         []
diff --git a/lib/ruby_llm/provider.rb b/lib/ruby_llm/provider.rb
index 2fdb3ca11..feaedbac2 100644
--- a/lib/ruby_llm/provider.rb
+++ b/lib/ruby_llm/provider.rb
@@ -37,7 +37,7 @@ def configuration_requirements
       self.class.configuration_requirements
     end
 
-    def complete(messages, tools:, temperature:, model:, params: {}, headers: {}, schema: nil, &) # rubocop:disable Metrics/ParameterLists
+    def complete(messages, tools:, temperature:, model:, params: {}, headers: {}, schema: nil, thinking: nil, &) # rubocop:disable Metrics/ParameterLists
       normalized_temperature = maybe_normalize_temperature(temperature, model)
 
       payload = Utils.deep_merge(
@@ -47,7 +47,8 @@ def complete(messages, tools:, temperature:, model:, params: {}, headers: {}, sc
           temperature: normalized_temperature,
           model: model,
           stream: block_given?,
-          schema: schema
+          schema: schema,
+          thinking: thinking
         ),
         params
       )
diff --git a/lib/ruby_llm/providers/anthropic/chat.rb b/lib/ruby_llm/providers/anthropic/chat.rb
index cbc9f1161..741d9574d 100644
--- a/lib/ruby_llm/providers/anthropic/chat.rb
+++ b/lib/ruby_llm/providers/anthropic/chat.rb
@@ -3,7 +3,7 @@
 module RubyLLM
   module Providers
     class Anthropic
-      # Chat methods of the OpenAI API integration
+      # Chat methods for the Anthropic API implementation
       module Chat
         module_function
 
@@ -11,11 +11,11 @@ def completion_url
           '/v1/messages'
         end
 
-        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil) # rubocop:disable Metrics/ParameterLists,Lint/UnusedMethodArgument
+        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil, thinking: nil) # rubocop:disable Metrics/ParameterLists,Lint/UnusedMethodArgument
           system_messages, chat_messages = separate_messages(messages)
           system_content = build_system_content(system_messages)
 
-          build_base_payload(chat_messages, model, stream).tap do |payload|
+          build_base_payload(chat_messages, model, stream, thinking).tap do |payload|
             add_optional_fields(payload, system_content:, tools:, temperature:)
           end
         end
@@ -45,13 +45,41 @@ def build_system_content(system_messages)
           end
         end
 
-        def build_base_payload(chat_messages, model, stream)
-          {
+        def build_base_payload(chat_messages, model, stream, thinking)
+          payload = {
             model: model.id,
-            messages: chat_messages.map { |msg| format_message(msg) },
+            messages: chat_messages.map { |msg| format_message(msg, thinking_enabled: thinking) },
             stream: stream,
-            max_tokens: model.max_tokens || 4096
+            max_tokens: calculate_max_tokens(model, thinking)
           }
+
+          if thinking
+            payload[:thinking] = {
+              type: 'enabled',
+              budget_tokens: resolve_budget(thinking, model)
+            }
+          end
+
+          payload
+        end
+
+        def calculate_max_tokens(model, thinking)
+          base = model.max_tokens || 4096
+          return base unless thinking
+
+          budget = resolve_budget(thinking, model)
+          [base, budget + 8000].max
+        end
+
+        def resolve_budget(thinking, _model)
+          return thinking if thinking.is_a?(Integer)
+
+          case thinking
+          when :low then 1024
+          when :medium then 10_000
+          when :high then 32_000
+          else 10_000 # rubocop:disable Lint/DuplicateBranch
+          end
         end
 
         def add_optional_fields(payload, system_content:, tools:, temperature:)
@@ -65,9 +93,11 @@ def parse_completion_response(response)
           content_blocks = data['content'] || []
 
           text_content = extract_text_content(content_blocks)
+          thinking_content = extract_thinking_content(content_blocks)
+          thinking_sig = extract_thinking_signature(content_blocks)
           tool_use_blocks = Tools.find_tool_uses(content_blocks)
 
-          build_message(data, text_content, tool_use_blocks, response)
+          build_message(data, text_content, thinking_content, thinking_sig, tool_use_blocks, response)
         end
 
         def extract_text_content(blocks)
@@ -75,7 +105,18 @@ def extract_text_content(blocks)
           text_blocks.map { |c| c['text'] }.join
         end
 
-        def build_message(data, content, tool_use_blocks, response)
+        def extract_thinking_content(blocks)
+          thinking_blocks = blocks.select { |c| c['type'] == 'thinking' }
+          thoughts = thinking_blocks.map { |c| c['thinking'] }.join
+          thoughts.empty? ? nil : thoughts
+        end
+
+        def extract_thinking_signature(blocks)
+          thinking_block = blocks.find { |c| c['type'] == 'thinking' }
+          thinking_block&.dig('signature')
+        end
+
+        def build_message(data, content, thinking, thinking_sig, tool_use_blocks, response) # rubocop:disable Metrics/ParameterLists
           usage = data['usage'] || {}
           cached_tokens = usage['cache_read_input_tokens']
           cache_creation_tokens = usage['cache_creation_input_tokens']
@@ -86,6 +127,8 @@ def build_message(data, content, tool_use_blocks, response)
           Message.new(
             role: :assistant,
             content: content,
+            thinking: thinking,
+            thinking_signature: thinking_sig,
             tool_calls: Tools.parse_tool_calls(tool_use_blocks),
             input_tokens: usage['input_tokens'],
             output_tokens: usage['output_tokens'],
@@ -96,20 +139,68 @@ def build_message(data, content, tool_use_blocks, response)
           )
         end
 
-        def format_message(msg)
+        def format_message(msg, thinking_enabled: false)
           if msg.tool_call?
-            Tools.format_tool_call(msg)
+            format_tool_call_with_thinking(msg, thinking_enabled)
           elsif msg.tool_result?
             Tools.format_tool_result(msg)
           else
-            format_basic_message(msg)
+            format_basic_message_with_thinking(msg, thinking_enabled)
           end
         end
 
-        def format_basic_message(msg)
+        def format_basic_message_with_thinking(msg, thinking_enabled)
+          content_blocks = []
+
+          if msg.role == :assistant && thinking_enabled
+            sig = Messages.signature_for(msg)
+
+            if msg.thinking && !msg.thinking.empty?
+              content_blocks << {
+                type: 'thinking',
+                thinking: msg.thinking,
+                signature: sig
+              }.compact
+            elsif sig
+              content_blocks << {
+                type: 'redacted_thinking',
+                data: sig
+              }
+            end
+          end
+
+          content_blocks.concat(Media.format_content(msg.content))
+
           {
             role: convert_role(msg.role),
-            content: Media.format_content(msg.content)
+            content: content_blocks
+          }
+        end
+
+        def format_tool_call_with_thinking(msg, thinking_enabled)
+          content_blocks = []
+
+          if thinking_enabled && msg.thinking && !msg.thinking.empty?
+            sig = Messages.signature_for(msg)
+            content_blocks << {
+              type: 'thinking',
+              thinking: msg.thinking,
+              signature: sig
+            }.compact
+          end
+
+          msg.tool_calls.each_value do |tool_call|
+            content_blocks << {
+              type: 'tool_use',
+              id: tool_call.id,
+              name: tool_call.name,
+              input: tool_call.arguments
+            }
+          end
+
+          {
+            role: 'assistant',
+            content: content_blocks
           }
         end
 
diff --git a/lib/ruby_llm/providers/anthropic/streaming.rb b/lib/ruby_llm/providers/anthropic/streaming.rb
index 5fed14710..f634471c8 100644
--- a/lib/ruby_llm/providers/anthropic/streaming.rb
+++ b/lib/ruby_llm/providers/anthropic/streaming.rb
@@ -12,10 +12,14 @@ def stream_url
         end
 
         def build_chunk(data)
+          delta_type = data.dig('delta', 'type')
+
           Chunk.new(
             role: :assistant,
             model_id: extract_model_id(data),
-            content: data.dig('delta', 'text'),
+            content: extract_content_delta(data, delta_type),
+            thinking: extract_thinking_delta(data, delta_type),
+            thinking_signature: extract_signature_delta(data, delta_type),
             input_tokens: extract_input_tokens(data),
             output_tokens: extract_output_tokens(data),
             cached_tokens: extract_cached_tokens(data),
@@ -24,6 +28,24 @@ def build_chunk(data)
           )
         end
 
+        def extract_content_delta(data, delta_type)
+          return data.dig('delta', 'text') if delta_type == 'text_delta'
+
+          nil
+        end
+
+        def extract_thinking_delta(data, delta_type)
+          return data.dig('delta', 'thinking') if delta_type == 'thinking_delta'
+
+          nil
+        end
+
+        def extract_signature_delta(data, delta_type)
+          return data.dig('delta', 'signature') if delta_type == 'signature_delta'
+
+          nil
+        end
+
         def json_delta?(data)
           data['type'] == 'content_block_delta' && data.dig('delta', 'type') == 'input_json_delta'
         end
diff --git a/lib/ruby_llm/providers/bedrock/chat.rb b/lib/ruby_llm/providers/bedrock/chat.rb
index 4abdae3f3..68570ce47 100644
--- a/lib/ruby_llm/providers/bedrock/chat.rb
+++ b/lib/ruby_llm/providers/bedrock/chat.rb
@@ -39,7 +39,7 @@ def completion_url
           "model/#{@model_id}/invoke"
         end
 
-        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil) # rubocop:disable Lint/UnusedMethodArgument,Metrics/ParameterLists
+        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil, thinking: nil) # rubocop:disable Lint/UnusedMethodArgument,Metrics/ParameterLists
           @model_id = model.id
 
           system_messages, chat_messages = Anthropic::Chat.separate_messages(messages)
diff --git a/lib/ruby_llm/providers/gemini/chat.rb b/lib/ruby_llm/providers/gemini/chat.rb
index bab33f79a..3a9cdea48 100644
--- a/lib/ruby_llm/providers/gemini/chat.rb
+++ b/lib/ruby_llm/providers/gemini/chat.rb
@@ -14,7 +14,7 @@ def completion_url
           "models/#{@model}:generateContent"
         end
 
-        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil) # rubocop:disable Metrics/ParameterLists,Lint/UnusedMethodArgument
+        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil, thinking: nil) # rubocop:disable Metrics/ParameterLists,Lint/UnusedMethodArgument
           @model = model.id
           payload = {
             contents: format_messages(messages),
@@ -25,10 +25,52 @@ def render_payload(messages, tools:, temperature:, model:, stream: false, schema
 
           payload[:generationConfig].merge!(structured_output_config(schema, model)) if schema
 
+          payload[:generationConfig][:thinkingConfig] = build_thinking_config(model, thinking) if thinking
+
           payload[:tools] = format_tools(tools) if tools.any?
           payload
         end
 
+        def build_thinking_config(model, thinking)
+          config = { includeThoughts: true }
+
+          if gemini_3_model?(model)
+            config[:thinkingLevel] = resolve_effort_level(thinking)
+          else
+            config[:thinkingBudget] = resolve_budget(thinking)
+          end
+
+          config
+        end
+
+        # Gemini 3 uses thinkingLevel (string) while Gemini 2.5 uses thinkingBudget (integer).
+        # String matching is unavoidable until Google provides a capability flag or stabilizes
+        # their API versioning. This detection is confined to the Gemini provider where the
+        # coupling is appropriate.
+        def gemini_3_model?(model)
+          model.id.to_s.include?('gemini-3')
+        end
+
+        def resolve_effort_level(thinking)
+          case thinking
+          when :low then 'low'
+          when :medium then 'medium'
+          when :high then 'high'
+          when Integer then thinking > 16_000 ? 'high' : 'low'
+          else 'high' # rubocop:disable Lint/DuplicateBranch
+          end
+        end
+
+        def resolve_budget(thinking)
+          case thinking
+          when Integer then thinking
+          when :low then 1024
+          when :medium then 8192
+          when :high then 24_576
+          else 8192 # rubocop:disable Lint/DuplicateBranch
+          end
+        end
+
         private
 
         def format_messages(messages)
@@ -62,11 +104,16 @@ def format_parts(msg)
 
         def parse_completion_response(response)
           data = response.body
+          parts = data.dig('candidates', 0, 'content', 'parts') || []
+
+          text_content = extract_text_parts(parts)
+          thinking_content = extract_thought_parts(parts)
           tool_calls = extract_tool_calls(data)
 
           Message.new(
             role: :assistant,
-            content: parse_content(data),
+            content: text_content,
+            thinking: thinking_content,
             tool_calls: tool_calls,
             input_tokens: data.dig('usageMetadata', 'promptTokenCount'),
             output_tokens: calculate_output_tokens(data),
@@ -75,6 +122,18 @@ def parse_completion_response(response)
           )
         end
 
+        def extract_text_parts(parts)
+          text_parts = parts.reject { |p| p['thought'] }
+          content = text_parts.filter_map { |p| p['text'] }.join
+          content.empty? ? nil : content
+        end
+
+        def extract_thought_parts(parts)
+          thought_parts = parts.select { |p| p['thought'] }
+          thoughts = thought_parts.filter_map { |p| p['text'] }.join
+          thoughts.empty? ? nil : thoughts
+        end
+
         def convert_schema_to_gemini(schema)
           return nil unless schema
 
diff --git a/lib/ruby_llm/providers/gemini/streaming.rb b/lib/ruby_llm/providers/gemini/streaming.rb
index 8aa630b27..ec2288243 100644
--- a/lib/ruby_llm/providers/gemini/streaming.rb
+++ b/lib/ruby_llm/providers/gemini/streaming.rb
@@ -10,10 +10,13 @@ def stream_url
         end
 
         def build_chunk(data)
+          parts = data.dig('candidates', 0, 'content', 'parts') || []
+
           Chunk.new(
             role: :assistant,
             model_id: extract_model_id(data),
-            content: extract_content(data),
+            content: extract_text_content(parts),
+            thinking: extract_thought_content(parts),
             input_tokens: extract_input_tokens(data),
             output_tokens: extract_output_tokens(data),
             tool_calls: extract_tool_calls(data)
@@ -26,6 +29,18 @@ def extract_model_id(data)
           data['modelVersion']
         end
 
+        def extract_text_content(parts)
+          text_parts = parts.reject { |p| p['thought'] }
+          text = text_parts.filter_map { |p| p['text'] }.join
+          text.empty? ? nil : text
+        end
+
+        def extract_thought_content(parts)
+          thought_parts = parts.select { |p| p['thought'] }
+          thoughts = thought_parts.filter_map { |p| p['text'] }.join
+          thoughts.empty? ? nil : thoughts
+        end
+
         def extract_content(data)
           return nil unless data['candidates']&.any?
 
diff --git a/lib/ruby_llm/providers/mistral/chat.rb b/lib/ruby_llm/providers/mistral/chat.rb
index 10ec965e4..816733504 100644
--- a/lib/ruby_llm/providers/mistral/chat.rb
+++ b/lib/ruby_llm/providers/mistral/chat.rb
@@ -12,7 +12,7 @@ def format_role(role)
         end
 
         # rubocop:disable Metrics/ParameterLists
-        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil)
+        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil, thinking: nil)
           payload = super
           payload.delete(:stream_options)
           payload
diff --git a/lib/ruby_llm/providers/openai/capabilities.rb b/lib/ruby_llm/providers/openai/capabilities.rb
index 37c320da8..317c24ea2 100644
--- a/lib/ruby_llm/providers/openai/capabilities.rb
+++ b/lib/ruby_llm/providers/openai/capabilities.rb
@@ -224,12 +224,12 @@ def special_prefix_format(prefix)
         end
 
         def self.normalize_temperature(temperature, model_id)
-          if model_id.match?(/^(o\d|gpt-5)/)
-            RubyLLM.logger.debug "Model #{model_id} requires temperature=1.0, ignoring provided value"
-            1.0
-          elsif model_id.match?(/-search/)
+          if model_id.match?(/-search/)
             RubyLLM.logger.debug "Model #{model_id} does not accept temperature parameter, removing"
             nil
+          elsif model_id.match?(/^(o\d|gpt-5)/)
+            RubyLLM.logger.debug "Model #{model_id} requires temperature=1.0, ignoring provided value"
+            1.0
           else
             temperature
           end
diff --git a/lib/ruby_llm/providers/openai/chat.rb b/lib/ruby_llm/providers/openai/chat.rb
index 68522811e..f774b52c7 100644
--- a/lib/ruby_llm/providers/openai/chat.rb
+++ b/lib/ruby_llm/providers/openai/chat.rb
@@ -11,7 +11,7 @@ def completion_url
 
         module_function
 
-        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil) # rubocop:disable Metrics/ParameterLists
+        def render_payload(messages, tools:, temperature:, model:, stream: false, schema: nil, thinking: nil) # rubocop:disable Metrics/ParameterLists
           payload = {
             model: model.id,
             messages: format_messages(messages),
@@ -34,10 +34,26 @@ def render_payload(messages, tools:, temperature:, model:, stream: false, schema
             }
           end
 
+          payload[:reasoning_effort] = resolve_effort(thinking) if thinking && grok_model?(model)
+
           payload[:stream_options] = { include_usage: true } if stream
           payload
         end
 
+        # Grok models are accessed via OpenRouter, which inherits from OpenAI.
+        # They support the reasoning_effort parameter for extended thinking.
+        def grok_model?(model)
+          model.id.to_s.include?('grok')
+        end
+
+        def resolve_effort(thinking)
+          case thinking
+          when :low then 'low'
+          when Integer then thinking > 10_000 ? 'high' : 'low'
+          else 'high'
+          end
+        end
+
         def parse_completion_response(response)
           data = response.body
           return if data.empty?
@@ -53,6 +69,7 @@ def parse_completion_response(response)
           Message.new(
             role: :assistant,
             content: message_data['content'],
+            thinking: message_data['reasoning_content'],
             tool_calls: parse_tool_calls(message_data['tool_calls']),
             input_tokens: usage['prompt_tokens'],
             output_tokens: usage['completion_tokens'],
diff --git a/lib/ruby_llm/providers/openai/streaming.rb b/lib/ruby_llm/providers/openai/streaming.rb
index 99d7866df..f76fae74b 100644
--- a/lib/ruby_llm/providers/openai/streaming.rb
+++ b/lib/ruby_llm/providers/openai/streaming.rb
@@ -14,12 +14,14 @@ def stream_url
         def build_chunk(data)
           usage = data['usage'] || {}
           cached_tokens = usage.dig('prompt_tokens_details', 'cached_tokens')
+          delta = data.dig('choices', 0, 'delta') || {}
 
           Chunk.new(
             role: :assistant,
             model_id: data['model'],
-            content: data.dig('choices', 0, 'delta', 'content'),
-            tool_calls: parse_tool_calls(data.dig('choices', 0, 'delta', 'tool_calls'), parse_arguments: false),
+            content: delta['content'],
+            thinking: delta['reasoning_content'],
+            tool_calls: parse_tool_calls(delta['tool_calls'], parse_arguments: false),
             input_tokens: usage['prompt_tokens'],
             output_tokens: usage['completion_tokens'],
             cached_tokens: cached_tokens,
diff --git a/lib/ruby_llm/stream_accumulator.rb b/lib/ruby_llm/stream_accumulator.rb
index 33bb9730d..e19b3047e 100644
--- a/lib/ruby_llm/stream_accumulator.rb
+++ b/lib/ruby_llm/stream_accumulator.rb
@@ -3,10 +3,12 @@
 module RubyLLM
   # Assembles streaming responses from LLMs into complete messages.
   class StreamAccumulator
-    attr_reader :content, :model_id, :tool_calls
+    attr_reader :content, :model_id, :tool_calls, :thinking
 
     def initialize
       @content = +''
+      @thinking = +''
+      @thinking_signature = nil
       @tool_calls = {}
       @input_tokens = nil
       @output_tokens = nil
@@ -15,7 +17,7 @@ def initialize
       @latest_tool_call_id = nil
     end
 
-    def add(chunk)
+    def add(chunk) # rubocop:disable Metrics/PerceivedComplexity
       RubyLLM.logger.debug chunk.inspect if RubyLLM.config.log_stream_debug
       @model_id ||= chunk.model_id
 
@@ -23,8 +25,11 @@ def add(chunk)
         accumulate_tool_calls chunk.tool_calls
       else
         @content << (chunk.content || '')
+        @thinking << (chunk.thinking || '')
       end
 
+      @thinking_signature = Messages.signature_for(chunk) || @thinking_signature
+
       count_tokens chunk
       RubyLLM.logger.debug inspect if RubyLLM.config.log_stream_debug
     end
@@ -33,6 +38,8 @@ def to_message(response)
       Message.new(
         role: :assistant,
         content: content.empty? ? nil : content,
+        thinking: thinking.empty? ? nil : thinking,
+        thinking_signature: @thinking_signature,
         model_id: model_id,
         tool_calls: tool_calls_from_stream,
         input_tokens: @input_tokens,
diff --git a/lib/ruby_llm/tool.rb b/lib/ruby_llm/tool.rb
index 2846a995d..24d2468c7 100644
--- a/lib/ruby_llm/tool.rb
+++ b/lib/ruby_llm/tool.rb
@@ -186,7 +186,7 @@ def resolve_schema
       def resolve_direct_schema(schema)
         return extract_schema(schema.to_json_schema) if schema.respond_to?(:to_json_schema)
         return RubyLLM::Utils.deep_dup(schema) if schema.is_a?(Hash)
-        if schema.is_a?(Class) && schema.instance_methods.include?(:to_json_schema)
+        if schema.is_a?(Class) && schema.method_defined?(:to_json_schema)
           return extract_schema(schema.new.to_json_schema)
         end
 
diff --git a/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_anthropic_claude-opus-4-20250514_maintains_thinking_across_multi-turn_conversation.yml b/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_anthropic_claude-opus-4-20250514_maintains_thinking_across_multi-turn_conversation.yml
new file mode 100644
index 000000000..c8931e622
--- /dev/null
+++ b/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_anthropic_claude-opus-4-20250514_maintains_thinking_across_multi-turn_conversation.yml
@@ -0,0 +1,163 @@
+---
+http_interactions:
+- request:
+    method: post
+    uri: https://api.anthropic.com/v1/messages
+    body:
+      encoding: UTF-8
+      string: '{"model":"claude-opus-4-20250514","messages":[{"role":"user","content":[{"type":"text","text":"What
+        is 5 + 3?"}]}],"stream":false,"max_tokens":9024,"thinking":{"type":"enabled","budget_tokens":1024}}'
+    headers:
+      User-Agent:
+      - Faraday v2.14.0
+      X-Api-Key:
+      - "<ANTHROPIC_API_KEY>"
+      Anthropic-Version:
+      - '2023-06-01'
+      Content-Type:
+      - application/json
+      Accept-Encoding:
+      - gzip;q=1.0,deflate;q=0.6,identity;q=0.3
+      Accept:
+      - "*/*"
+  response:
+    status:
+      code: 200
+      message: OK
+    headers:
+      Date:
+      - Fri, 02 Jan 2026 17:23:48 GMT
+      Content-Type:
+      - application/json
+      Transfer-Encoding:
+      - chunked
+      Connection:
+      - keep-alive
+      Anthropic-Ratelimit-Input-Tokens-Limit:
+      - '2000000'
+      Anthropic-Ratelimit-Input-Tokens-Remaining:
+      - '2000000'
+      Anthropic-Ratelimit-Input-Tokens-Reset:
+      - '2026-01-02T17:23:47Z'
+      Anthropic-Ratelimit-Output-Tokens-Limit:
+      - '400000'
+      Anthropic-Ratelimit-Output-Tokens-Remaining:
+      - '400000'
+      Anthropic-Ratelimit-Output-Tokens-Reset:
+      - '2026-01-02T17:23:48Z'
+      Anthropic-Ratelimit-Requests-Limit:
+      - '4000'
+      Anthropic-Ratelimit-Requests-Remaining:
+      - '3999'
+      Anthropic-Ratelimit-Requests-Reset:
+      - '2026-01-02T17:23:46Z'
+      Anthropic-Ratelimit-Tokens-Limit:
+      - '2400000'
+      Anthropic-Ratelimit-Tokens-Remaining:
+      - '2400000'
+      Anthropic-Ratelimit-Tokens-Reset:
+      - '2026-01-02T17:23:47Z'
+      Request-Id:
+      - "<REQUEST_ID>"
+      Strict-Transport-Security:
+      - max-age=31536000; includeSubDomains; preload
+      Anthropic-Organization-Id:
+      - "<ANTHROPIC_ORGANIZATION_ID>"
+      Server:
+      - cloudflare
+      X-Envoy-Upstream-Service-Time:
+      - '1709'
+      Cf-Cache-Status:
+      - DYNAMIC
+      X-Robots-Tag:
+      - none
+      Cf-Ray:
+      - "<CF_RAY>"
+    body:
+      encoding: ASCII-8BIT
+      string: '{"model":"claude-opus-4-20250514","id":"msg_018yPka2cXUnko1tS8fTffEA","type":"message","role":"assistant","content":[{"type":"thinking","thinking":"This
+        is a simple addition problem. 5 + 3 = 8.","signature":"EtUBCkYICxgCKkBTKgGEUioRSsJoxhuzo1AT0IuxJmwIxAkRRNe15z10h5e8CMTYppvz7xt2wwXONyqpRoWYmGBQfSlspsv8kJpBEgzfxXZ1wQu4sH36WBkaDEtyQwE6aidRDab8tiIw0SeAOeWHV3Kz9igF+uxfN/ww/WHadiRgHbyPPcJL/sTUXxp28q+SEsYCLUan2R//Kj2OqqUYy2+MMbcNwgkU+UM9NcfIrkO3R9JOLsCrWtvuiajR2DIoqIdYICkvgW2sgcTI50hMOT8rl+uHy7qDGAE="},{"type":"text","text":"5
+        + 3 = 8"}],"stop_reason":"end_turn","stop_sequence":null,"usage":{"input_tokens":45,"cache_creation_input_tokens":0,"cache_read_input_tokens":0,"cache_creation":{"ephemeral_5m_input_tokens":0,"ephemeral_1h_input_tokens":0},"output_tokens":38,"service_tier":"standard"}}'
+  recorded_at: Fri, 02 Jan 2026 17:23:48 GMT
+- request:
+    method: post
+    uri: https://api.anthropic.com/v1/messages
+    body:
+      encoding: UTF-8
+      string: '{"model":"claude-opus-4-20250514","messages":[{"role":"user","content":[{"type":"text","text":"What
+        is 5 + 3?"}]},{"role":"assistant","content":[{"type":"thinking","thinking":"This
+        is a simple addition problem. 5 + 3 = 8.","signature":"EtUBCkYICxgCKkBTKgGEUioRSsJoxhuzo1AT0IuxJmwIxAkRRNe15z10h5e8CMTYppvz7xt2wwXONyqpRoWYmGBQfSlspsv8kJpBEgzfxXZ1wQu4sH36WBkaDEtyQwE6aidRDab8tiIw0SeAOeWHV3Kz9igF+uxfN/ww/WHadiRgHbyPPcJL/sTUXxp28q+SEsYCLUan2R//Kj2OqqUYy2+MMbcNwgkU+UM9NcfIrkO3R9JOLsCrWtvuiajR2DIoqIdYICkvgW2sgcTI50hMOT8rl+uHy7qDGAE="},{"type":"text","text":"5
+        + 3 = 8"}]},{"role":"user","content":[{"type":"text","text":"Now multiply
+        that by 2"}]}],"stream":false,"max_tokens":9024,"thinking":{"type":"enabled","budget_tokens":1024}}'
+    headers:
+      User-Agent:
+      - Faraday v2.14.0
+      X-Api-Key:
+      - "<ANTHROPIC_API_KEY>"
+      Anthropic-Version:
+      - '2023-06-01'
+      Content-Type:
+      - application/json
+      Accept-Encoding:
+      - gzip;q=1.0,deflate;q=0.6,identity;q=0.3
+      Accept:
+      - "*/*"
+  response:
+    status:
+      code: 200
+      message: OK
+    headers:
+      Date:
+      - Fri, 02 Jan 2026 17:23:50 GMT
+      Content-Type:
+      - application/json
+      Transfer-Encoding:
+      - chunked
+      Connection:
+      - keep-alive
+      Anthropic-Ratelimit-Input-Tokens-Limit:
+      - '2000000'
+      Anthropic-Ratelimit-Input-Tokens-Remaining:
+      - '2000000'
+      Anthropic-Ratelimit-Input-Tokens-Reset:
+      - '2026-01-02T17:23:49Z'
+      Anthropic-Ratelimit-Output-Tokens-Limit:
+      - '400000'
+      Anthropic-Ratelimit-Output-Tokens-Remaining:
+      - '400000'
+      Anthropic-Ratelimit-Output-Tokens-Reset:
+      - '2026-01-02T17:23:50Z'
+      Anthropic-Ratelimit-Requests-Limit:
+      - '4000'
+      Anthropic-Ratelimit-Requests-Remaining:
+      - '3999'
+      Anthropic-Ratelimit-Requests-Reset:
+      - '2026-01-02T17:23:48Z'
+      Anthropic-Ratelimit-Tokens-Limit:
+      - '2400000'
+      Anthropic-Ratelimit-Tokens-Remaining:
+      - '2400000'
+      Anthropic-Ratelimit-Tokens-Reset:
+      - '2026-01-02T17:23:49Z'
+      Request-Id:
+      - "<REQUEST_ID>"
+      Strict-Transport-Security:
+      - max-age=31536000; includeSubDomains; preload
+      Anthropic-Organization-Id:
+      - "<ANTHROPIC_ORGANIZATION_ID>"
+      Server:
+      - cloudflare
+      X-Envoy-Upstream-Service-Time:
+      - '2086'
+      Cf-Cache-Status:
+      - DYNAMIC
+      X-Robots-Tag:
+      - none
+      Cf-Ray:
+      - "<CF_RAY>"
+    body:
+      encoding: ASCII-8BIT
+      string: !binary |-
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+  recorded_at: Fri, 02 Jan 2026 12:40:16 GMT
+recorded_with: VCR 6.4.0
diff --git a/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_gemini_gemini-2_5-flash_maintains_thinking_across_multi-turn_conversation.yml b/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_gemini_gemini-2_5-flash_maintains_thinking_across_multi-turn_conversation.yml
new file mode 100644
index 000000000..efeb1be60
--- /dev/null
+++ b/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_gemini_gemini-2_5-flash_maintains_thinking_across_multi-turn_conversation.yml
@@ -0,0 +1,168 @@
+---
+http_interactions:
+- request:
+    method: post
+    uri: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent
+    body:
+      encoding: UTF-8
+      string: '{"contents":[{"role":"user","parts":[{"text":"What is 5 + 3?"}]}],"generationConfig":{"thinkingConfig":{"includeThoughts":true,"thinkingBudget":1024}}}'
+    headers:
+      User-Agent:
+      - Faraday v2.14.0
+      X-Goog-Api-Key:
+      - "<GEMINI_API_KEY>"
+      Content-Type:
+      - application/json
+      Accept-Encoding:
+      - gzip;q=1.0,deflate;q=0.6,identity;q=0.3
+      Accept:
+      - "*/*"
+  response:
+    status:
+      code: 200
+      message: OK
+    headers:
+      Content-Type:
+      - application/json; charset=UTF-8
+      Vary:
+      - Origin
+      - Referer
+      - X-Origin
+      Date:
+      - Fri, 02 Jan 2026 21:49:33 GMT
+      Server:
+      - scaffolding on HTTPServer2
+      X-Xss-Protection:
+      - '0'
+      X-Frame-Options:
+      - SAMEORIGIN
+      X-Content-Type-Options:
+      - nosniff
+      Server-Timing:
+      - gfet4t7; dur=1786
+      Alt-Svc:
+      - h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
+      Transfer-Encoding:
+      - chunked
+    body:
+      encoding: ASCII-8BIT
+      string: |
+        {
+          "candidates": [
+            {
+              "content": {
+                "parts": [
+                  {
+                    "text": "**A Simple Addition Problem**\n\nOkay, so I'm looking at this simple math problem. First thing I see is that plus sign, that's addition, no doubt about it.  Then I spot the numbers: 5 and 3.  Alright, let's do this.  I'll start with 5, and I need to add 3 to it. I can easily do this in my head, but let's make it explicit for demonstration's sake. So, 5... then count up three: 6, 7, 8. And that's it! The sum, or the answer, is 8. Elementary.\n",
+                    "thought": true
+                  },
+                  {
+                    "text": "5 + 3 = 8"
+                  }
+                ],
+                "role": "model"
+              },
+              "finishReason": "STOP",
+              "index": 0
+            }
+          ],
+          "usageMetadata": {
+            "promptTokenCount": 9,
+            "candidatesTokenCount": 8,
+            "totalTokenCount": 96,
+            "promptTokensDetails": [
+              {
+                "modality": "TEXT",
+                "tokenCount": 9
+              }
+            ],
+            "thoughtsTokenCount": 79
+          },
+          "modelVersion": "gemini-2.5-flash",
+          "responseId": "bT1YaavfAbCkkdUPjdvRiAo"
+        }
+  recorded_at: Fri, 02 Jan 2026 21:49:33 GMT
+- request:
+    method: post
+    uri: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent
+    body:
+      encoding: UTF-8
+      string: '{"contents":[{"role":"user","parts":[{"text":"What is 5 + 3?"}]},{"role":"model","parts":[{"text":"5
+        + 3 = 8"}]},{"role":"user","parts":[{"text":"Now multiply that by 2"}]}],"generationConfig":{"thinkingConfig":{"includeThoughts":true,"thinkingBudget":1024}}}'
+    headers:
+      User-Agent:
+      - Faraday v2.14.0
+      X-Goog-Api-Key:
+      - "<GEMINI_API_KEY>"
+      Content-Type:
+      - application/json
+      Accept-Encoding:
+      - gzip;q=1.0,deflate;q=0.6,identity;q=0.3
+      Accept:
+      - "*/*"
+  response:
+    status:
+      code: 200
+      message: OK
+    headers:
+      Content-Type:
+      - application/json; charset=UTF-8
+      Vary:
+      - Origin
+      - Referer
+      - X-Origin
+      Date:
+      - Fri, 02 Jan 2026 21:49:34 GMT
+      Server:
+      - scaffolding on HTTPServer2
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+      - '0'
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+      - SAMEORIGIN
+      X-Content-Type-Options:
+      - nosniff
+      Server-Timing:
+      - gfet4t7; dur=1043
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+      Transfer-Encoding:
+      - chunked
+    body:
+      encoding: ASCII-8BIT
+      string: |
+        {
+          "candidates": [
+            {
+              "content": {
+                "parts": [
+                  {
+                    "text": "**Calculating the Next Step**\n\nOkay, so we've got our previous result, which is 8. Now, the goal is to multiply that by 2. Let's keep it simple and just do the math: 8 multiplied by 2. That's a straightforward calculation. I know it's 16. Done. Next!\n",
+                    "thought": true
+                  },
+                  {
+                    "text": "Okay, 8 multiplied by 2 is 16."
+                  }
+                ],
+                "role": "model"
+              },
+              "finishReason": "STOP",
+              "index": 0
+            }
+          ],
+          "usageMetadata": {
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+            "promptTokensDetails": [
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+          },
+          "modelVersion": "gemini-2.5-flash",
+          "responseId": "bj1YabylCrCkkdUPjdvRiAo"
+        }
+  recorded_at: Fri, 02 Jan 2026 21:49:34 GMT
+recorded_with: VCR 6.4.0
diff --git a/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_gemini_gemini-2_5-flash_returns_thinking_content_when_streaming.yml b/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_gemini_gemini-2_5-flash_returns_thinking_content_when_streaming.yml
new file mode 100644
index 000000000..321817ba6
--- /dev/null
+++ b/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_gemini_gemini-2_5-flash_returns_thinking_content_when_streaming.yml
@@ -0,0 +1,134 @@
+---
+http_interactions:
+- request:
+    method: post
+    uri: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:streamGenerateContent?alt=sse
+    body:
+      encoding: UTF-8
+      string: '{"contents":[{"role":"user","parts":[{"text":"What is 8 * 7? Show your
+        work."}]}],"generationConfig":{"thinkingConfig":{"includeThoughts":true,"thinkingBudget":1024}}}'
+    headers:
+      User-Agent:
+      - Faraday v2.14.0
+      X-Goog-Api-Key:
+      - "<GEMINI_API_KEY>"
+      Content-Type:
+      - application/json
+      Accept-Encoding:
+      - gzip;q=1.0,deflate;q=0.6,identity;q=0.3
+      Accept:
+      - "*/*"
+  response:
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+      code: 200
+      message: OK
+    headers:
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+      - text/event-stream
+      Content-Disposition:
+      - attachment
+      Vary:
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+      - Referer
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+      Server:
+      - scaffolding on HTTPServer2
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+      Alt-Svc:
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+    body:
+      encoding: UTF-8
+      string: "data: {\"candidates\": [{\"content\": {\"parts\": [{\"text\": \"**Decomposing
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+        problem (8 * 7). The challenge is providing the \\\"work\\\" to solve it.
+        I've successfully recalled the answer: 56. Now, I'm brainstorming the best
+        way to demonstrate the steps, even for such a basic calculation.\\n\\n\\n\",\"thought\":
+        true}],\"role\": \"model\"},\"index\": 0}],\"usageMetadata\": {\"promptTokenCount\":
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+        \"Zj1Yae2KBcXrkdUPhdPckQg\"}\r\n\r\ndata: {\"candidates\": [{\"content\":
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+        the distributive property to showcase a more complex method of thinking. I'm
+        focusing on the clarity of demonstration. I'm aiming for methods that convey
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+        0}],\"usageMetadata\": {\"promptTokenCount\": 13,\"totalTokenCount\": 419,\"promptTokensDetails\":
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+        \"gemini-2.5-flash\",\"responseId\": \"Zj1Yae2KBcXrkdUPhdPckQg\"}\r\n\r\ndata:
+        {\"candidates\": [{\"content\": {\"parts\": [{\"text\": \"**Crafting the Final
+        Response**\\n\\nI've finalized my presentation. After exploring several options,
+        I've selected repeated addition and the distributive property as the strongest
+        ways to illustrate the process for the user's request. My emphasis is on clarity
+        and showing common mental math strategies. The \\\"work\\\" is now in the
+        final stages of the draft, and I'm ready to present my complete response.\\n\\n\\n\",\"thought\":
+        true}],\"role\": \"model\"},\"index\": 0}],\"usageMetadata\": {\"promptTokenCount\":
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+        {\"parts\": [{\"text\": \"**Formulating a Response**\\n\\nI'm now putting
+        together the complete answer, starting with the direct result (56). Next,
+        I'll present repeated addition and break-down methods, including explanations.
+        I'll make sure to clearly and accurately illustrate the steps I came up with.
+        I'm prioritizing providing a complete and helpful response that addresses
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+        {\"candidates\": [{\"content\": {\"parts\": [{\"text\": \"To find 8 * 7, we
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+        number 7 to itself 8 times\"}],\"role\": \"model\"},\"index\": 0}],\"usageMetadata\":
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+        {\"candidates\": [{\"content\": {\"parts\": [{\"text\": \":\\n7 + 7 + 7 +
+        7 + 7 + 7 + 7 + 7 = 56\\n\\nOr, you can add the number 8 to itself 7 times:\\n8
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+        \"gemini-2.5-flash\",\"responseId\": \"Zj1Yae2KBcXrkdUPhdPckQg\"}\r\n\r\ndata:
+        {\"candidates\": [{\"content\": {\"parts\": [{\"text\": \" 8 + 8 + 8 + 8 +
+        8 = 56\\n\\n**Method 2: Breaking Down One Number (Distributive Property)**\\nYou
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+        \"model\"},\"index\": 0}],\"usageMetadata\": {\"promptTokenCount\": 13,\"candidatesTokenCount\":
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+        \"Zj1Yae2KBcXrkdUPhdPckQg\"}\r\n\r\ndata: {\"candidates\": [{\"content\":
+        {\"parts\": [{\"text\": \". For example, let's break 7 into 5 + 2:\\n\\n8
+        * 7 = 8 * (5 + 2)\\nNow, distribute the 8 to each part:\\n= (8 * \"}],\"role\":
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+        {\"parts\": [{\"text\": \"5) + (8 * 2)\\n= 40 + 16\\n= 56\\n\\nAlternatively,
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+        0}],\"usageMetadata\": {\"promptTokenCount\": 13,\"candidatesTokenCount\":
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+        {\"parts\": [{\"text\": \" 7\\n= (4 * 7) + (4 * 7)\\n= 28 + 28\\n= 56\\n\\n---\\n\\nUsing
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+        {\"parts\": [{\"text\": \" 56**\"}],\"role\": \"model\"},\"finishReason\":
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+  recorded_at: Fri, 02 Jan 2026 21:49:31 GMT
+recorded_with: VCR 6.4.0
diff --git a/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_gemini_gemini-2_5-flash_returns_thinking_content_with_response.yml b/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_gemini_gemini-2_5-flash_returns_thinking_content_with_response.yml
new file mode 100644
index 000000000..ee57bef1d
--- /dev/null
+++ b/spec/fixtures/vcr_cassettes/chat_extended_thinking_integration_with_gemini_gemini-2_5-flash_returns_thinking_content_with_response.yml
@@ -0,0 +1,53 @@
+---
+http_interactions:
+- request:
+    method: post
+    uri: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent
+    body:
+      encoding: UTF-8
+      string: '{"contents":[{"role":"user","parts":[{"text":"What is 15 * 23? Think
+        through this step by step."}]}],"generationConfig":{"thinkingConfig":{"includeThoughts":true,"thinkingBudget":1024}}}'
+    headers:
+      User-Agent:
+      - Faraday v2.14.0
+      X-Goog-Api-Key:
+      - "<GEMINI_API_KEY>"
+      Content-Type:
+      - application/json
+      Accept-Encoding:
+      - gzip;q=1.0,deflate;q=0.6,identity;q=0.3
+      Accept:
+      - "*/*"
+  response:
+    status:
+      code: 200
+      message: OK
+    headers:
+      Content-Type:
+      - application/json; charset=UTF-8
+      Vary:
+      - Origin
+      - Referer
+      - X-Origin
+      Date:
+      - Fri, 02 Jan 2026 21:49:25 GMT
+      Server:
+      - scaffolding on HTTPServer2
+      X-Xss-Protection:
+      - '0'
+      X-Frame-Options:
+      - SAMEORIGIN
+      X-Content-Type-Options:
+      - nosniff
+      Server-Timing:
+      - gfet4t7; dur=7574
+      Alt-Svc:
+      - h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
+      Transfer-Encoding:
+      - chunked
+    body:
+      encoding: ASCII-8BIT
+      string: !binary |-
+        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
+  recorded_at: Fri, 02 Jan 2026 21:49:25 GMT
+recorded_with: VCR 6.4.0
diff --git a/spec/ruby_llm/thinking_spec.rb b/spec/ruby_llm/thinking_spec.rb
new file mode 100644
index 000000000..a07d10afe
--- /dev/null
+++ b/spec/ruby_llm/thinking_spec.rb
@@ -0,0 +1,551 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+# Extended Thinking is a cross-cutting feature that spans multiple classes.
+# This spec file tests the feature holistically rather than per-class.
+# rubocop:disable RSpec/MultipleDescribes
+
+# Models with reasoning capability for integration tests
+# Note: Grok via OpenRouter doesn't expose reasoning_content, so it's not included
+THINKING_MODELS = [
+  { provider: :anthropic, model: 'claude-sonnet-4-20250514' },
+  { provider: :anthropic, model: 'claude-opus-4-20250514' },
+  { provider: :anthropic, model: 'claude-opus-4-5-20251101' },
+  { provider: :gemini, model: 'gemini-2.5-flash' }
+].freeze
+
+RSpec.describe RubyLLM::Message do
+  include_context 'with configured RubyLLM'
+
+  describe 'thinking attribute' do
+    it 'stores thinking content' do
+      message = described_class.new(
+        role: :assistant,
+        content: 'The answer is 42',
+        thinking: 'Let me calculate this carefully...'
+      )
+
+      expect(message.thinking).to eq('Let me calculate this carefully...')
+    end
+
+    it 'can be nil when not present' do
+      message = described_class.new(
+        role: :assistant,
+        content: 'The answer is 42'
+      )
+
+      expect(message.thinking).to be_nil
+    end
+
+    it 'includes thinking in to_h output' do
+      message = described_class.new(
+        role: :assistant,
+        content: 'The answer is 42',
+        thinking: 'Let me calculate this carefully...'
+      )
+
+      hash = message.to_h
+
+      expect(hash[:thinking]).to eq('Let me calculate this carefully...')
+      expect(hash[:content]).to eq('The answer is 42')
+      expect(hash[:role]).to eq(:assistant)
+    end
+
+    it 'excludes thinking from to_h when nil' do
+      message = described_class.new(
+        role: :assistant,
+        content: 'The answer is 42'
+      )
+
+      hash = message.to_h
+
+      expect(hash).not_to have_key(:thinking)
+    end
+
+    it 'stores thinking_signature as protected attribute' do
+      message = described_class.new(
+        role: :assistant,
+        content: 'Response',
+        thinking: 'Thoughts',
+        thinking_signature: 'sig-abc123'
+      )
+
+      expect(message.respond_to?(:thinking_signature, true)).to be true
+      expect { message.thinking_signature }.to raise_error(NoMethodError)
+    end
+  end
+end
+
+RSpec.describe RubyLLM::Messages do
+  include_context 'with configured RubyLLM'
+
+  describe '.signature_for' do
+    it 'returns thinking_signature when present' do
+      message = RubyLLM::Message.new(
+        role: :assistant,
+        content: 'Response',
+        thinking: 'Thoughts',
+        thinking_signature: 'sig-xyz789'
+      )
+
+      signature = described_class.signature_for(message)
+
+      expect(signature).to eq('sig-xyz789')
+    end
+
+    it 'returns nil when thinking_signature is not present' do
+      message = RubyLLM::Message.new(
+        role: :assistant,
+        content: 'Response',
+        thinking: 'Thoughts'
+      )
+
+      signature = described_class.signature_for(message)
+
+      expect(signature).to be_nil
+    end
+
+    it 'returns nil for messages without thinking' do
+      message = RubyLLM::Message.new(
+        role: :assistant,
+        content: 'Response'
+      )
+
+      signature = described_class.signature_for(message)
+
+      expect(signature).to be_nil
+    end
+
+    it 'handles non-message objects gracefully' do
+      object = Object.new
+
+      signature = described_class.signature_for(object)
+
+      expect(signature).to be_nil
+    end
+  end
+end
+
+RSpec.describe RubyLLM::StreamAccumulator do
+  include_context 'with configured RubyLLM'
+
+  describe 'thinking accumulation' do
+    it 'accumulates thinking from multiple chunks' do
+      accumulator = described_class.new
+
+      chunk1 = RubyLLM::Chunk.new(
+        role: :assistant,
+        content: 'First ',
+        thinking: 'Let me think... ',
+        model_id: 'claude-sonnet-4-20250514'
+      )
+      chunk2 = RubyLLM::Chunk.new(
+        role: :assistant,
+        content: 'second',
+        thinking: 'about this problem',
+        model_id: 'claude-sonnet-4-20250514'
+      )
+
+      accumulator.add(chunk1)
+      accumulator.add(chunk2)
+
+      expect(accumulator.thinking).to eq('Let me think... about this problem')
+      expect(accumulator.content).to eq('First second')
+    end
+
+    it 'returns empty string for thinking when no chunks have thinking' do
+      accumulator = described_class.new
+
+      chunk = RubyLLM::Chunk.new(
+        role: :assistant,
+        content: 'Regular response',
+        model_id: 'claude-sonnet-4-20250514'
+      )
+
+      accumulator.add(chunk)
+
+      expect(accumulator.thinking).to eq('')
+    end
+
+    it 'preserves thinking_signature from chunks' do
+      accumulator = described_class.new
+
+      chunk1 = RubyLLM::Chunk.new(
+        role: :assistant,
+        content: 'Response',
+        thinking: 'Thinking',
+        thinking_signature: 'sig-first',
+        model_id: 'claude-sonnet-4-20250514'
+      )
+      chunk2 = RubyLLM::Chunk.new(
+        role: :assistant,
+        content: ' more',
+        thinking: ' more',
+        model_id: 'claude-sonnet-4-20250514'
+      )
+
+      accumulator.add(chunk1)
+      accumulator.add(chunk2)
+
+      # Build a mock response object for to_message
+      mock_env = Struct.new(:request_body).new('{}')
+      mock_response = Struct.new(:headers, :body, :status, :env).new({}, {}, 200, mock_env)
+      message = accumulator.to_message(mock_response)
+
+      expect(RubyLLM::Messages.signature_for(message)).to eq('sig-first')
+    end
+
+    it 'converts empty thinking to nil in message' do
+      accumulator = described_class.new
+
+      chunk = RubyLLM::Chunk.new(
+        role: :assistant,
+        content: 'Response',
+        model_id: 'claude-sonnet-4-20250514'
+      )
+
+      accumulator.add(chunk)
+
+      mock_env = Struct.new(:request_body).new('{}')
+      mock_response = Struct.new(:headers, :body, :status, :env).new({}, {}, 200, mock_env)
+      message = accumulator.to_message(mock_response)
+
+      expect(message.thinking).to be_nil
+    end
+
+    it 'preserves non-empty thinking in message' do
+      accumulator = described_class.new
+
+      chunk = RubyLLM::Chunk.new(
+        role: :assistant,
+        content: 'Answer',
+        thinking: 'Internal reasoning',
+        model_id: 'claude-sonnet-4-20250514'
+      )
+
+      accumulator.add(chunk)
+
+      mock_env = Struct.new(:request_body).new('{}')
+      mock_response = Struct.new(:headers, :body, :status, :env).new({}, {}, 200, mock_env)
+      message = accumulator.to_message(mock_response)
+
+      expect(message.thinking).to eq('Internal reasoning')
+    end
+  end
+end
+
+RSpec.describe RubyLLM::Chat do
+  include_context 'with configured RubyLLM'
+
+  describe '#with_thinking configuration' do
+    THINKING_MODELS.each do |model_info|
+      model = model_info[:model]
+      provider = model_info[:provider]
+
+      context "with #{provider}/#{model}" do
+        it 'returns self for method chaining' do
+          chat = RubyLLM.chat(model: model, provider: provider)
+          result = chat.with_thinking(budget: :medium)
+
+          expect(result).to be(chat)
+        end
+
+        it 'accepts symbol budgets' do
+          chat = RubyLLM.chat(model: model, provider: provider)
+
+          expect { chat.with_thinking(budget: :low) }.not_to raise_error
+        end
+
+        it 'accepts integer budgets' do
+          chat = RubyLLM.chat(model: model, provider: provider)
+
+          expect { chat.with_thinking(budget: 5000) }.not_to raise_error
+        end
+
+        it 'defaults to medium budget when not specified' do
+          chat = RubyLLM.chat(model: model, provider: provider)
+
+          expect { chat.with_thinking }.not_to raise_error
+        end
+      end
+    end
+
+    it 'raises UnsupportedFeatureError for models without reasoning capability' do
+      chat = RubyLLM.chat(model: 'gpt-4.1-nano', provider: :openai)
+
+      expect { chat.with_thinking(budget: :medium) }
+        .to raise_error(RubyLLM::UnsupportedFeatureError, /does not support extended thinking/)
+    end
+  end
+
+  describe '#thinking_enabled?' do
+    THINKING_MODELS.each do |model_info|
+      model = model_info[:model]
+      provider = model_info[:provider]
+
+      context "with #{provider}/#{model}" do
+        it 'returns false by default' do
+          chat = RubyLLM.chat(model: model, provider: provider)
+
+          expect(chat.thinking_enabled?).to be false
+        end
+
+        it 'returns true after with_thinking is called' do
+          chat = RubyLLM.chat(model: model, provider: provider)
+          chat.with_thinking(budget: :medium)
+
+          expect(chat.thinking_enabled?).to be true
+        end
+      end
+    end
+  end
+
+  describe 'extended thinking integration' do
+    THINKING_MODELS.each do |model_info|
+      model = model_info[:model]
+      provider = model_info[:provider]
+
+      context "with #{provider}/#{model}" do
+        it 'returns thinking content with response' do
+          chat = RubyLLM.chat(model: model, provider: provider)
+                        .with_thinking(budget: :low)
+
+          response = chat.ask('What is 15 * 23? Think through this step by step.')
+
+          expect(response.content).to be_present
+          expect(response.thinking).to be_present
+          expect(response.thinking.length).to be > 10
+        end
+
+        it 'returns thinking content when streaming' do
+          chat = RubyLLM.chat(model: model, provider: provider)
+                        .with_thinking(budget: :low)
+
+          chunks = []
+          response = chat.ask('What is 8 * 7? Show your work.') do |chunk|
+            chunks << chunk
+          end
+
+          expect(response.content).to be_present
+          expect(response.thinking).to be_present
+          expect(chunks).not_to be_empty
+        end
+
+        it 'maintains thinking across multi-turn conversation' do
+          chat = RubyLLM.chat(model: model, provider: provider)
+                        .with_thinking(budget: :low)
+
+          first_response = chat.ask('What is 5 + 3?')
+          expect(first_response.thinking).to be_present
+
+          second_response = chat.ask('Now multiply that by 2')
+          expect(second_response.thinking).to be_present
+          expect(second_response.content).to be_present
+        end
+      end
+    end
+  end
+end
+
+RSpec.describe RubyLLM::Providers::Anthropic::Chat do
+  include_context 'with configured RubyLLM'
+
+  describe '.resolve_budget' do
+    let(:model) { RubyLLM.models.find('claude-sonnet-4-20250514') }
+
+    it 'resolves :low to 1024 tokens' do
+      expect(described_class.resolve_budget(:low, model)).to eq(1024)
+    end
+
+    it 'resolves :medium to 10,000 tokens' do
+      expect(described_class.resolve_budget(:medium, model)).to eq(10_000)
+    end
+
+    it 'resolves :high to 32,000 tokens' do
+      expect(described_class.resolve_budget(:high, model)).to eq(32_000)
+    end
+
+    it 'passes through integer budgets unchanged' do
+      expect(described_class.resolve_budget(15_000, model)).to eq(15_000)
+    end
+
+    it 'defaults unknown symbols to 10,000' do
+      expect(described_class.resolve_budget(:unknown, model)).to eq(10_000)
+    end
+  end
+end
+
+RSpec.describe RubyLLM::Providers::Gemini::Chat do
+  include_context 'with configured RubyLLM'
+
+  describe '.resolve_budget' do
+    it 'resolves :low to 1024 tokens' do
+      expect(described_class.resolve_budget(:low)).to eq(1024)
+    end
+
+    it 'resolves :medium to 8192 tokens' do
+      expect(described_class.resolve_budget(:medium)).to eq(8192)
+    end
+
+    it 'resolves :high to 24,576 tokens' do
+      expect(described_class.resolve_budget(:high)).to eq(24_576)
+    end
+
+    it 'passes through integer budgets unchanged' do
+      expect(described_class.resolve_budget(12_000)).to eq(12_000)
+    end
+
+    it 'defaults unknown symbols to 8192' do
+      expect(described_class.resolve_budget(:unknown)).to eq(8192)
+    end
+  end
+
+  describe '.resolve_effort_level' do
+    it 'resolves :low to "low"' do
+      expect(described_class.resolve_effort_level(:low)).to eq('low')
+    end
+
+    it 'resolves :medium to "medium"' do
+      expect(described_class.resolve_effort_level(:medium)).to eq('medium')
+    end
+
+    it 'resolves :high to "high"' do
+      expect(described_class.resolve_effort_level(:high)).to eq('high')
+    end
+
+    it 'resolves large integers to "high"' do
+      expect(described_class.resolve_effort_level(20_000)).to eq('high')
+    end
+
+    it 'resolves small integers to "low"' do
+      expect(described_class.resolve_effort_level(5000)).to eq('low')
+    end
+
+    it 'defaults unknown symbols to "high"' do
+      expect(described_class.resolve_effort_level(:unknown)).to eq('high')
+    end
+  end
+
+  describe '.gemini_3_model?' do
+    it 'detects Gemini 3 models by name' do
+      model = RubyLLM::Model::Info.new(
+        id: 'gemini-3-flash',
+        name: 'Gemini 3 Flash',
+        provider: 'gemini'
+      )
+
+      expect(described_class.gemini_3_model?(model)).to be true
+    end
+
+    it 'does not detect Gemini 2.5 as Gemini 3' do
+      model = RubyLLM::Model::Info.new(
+        id: 'gemini-2.5-pro',
+        name: 'Gemini 2.5 Pro',
+        provider: 'gemini'
+      )
+
+      expect(described_class.gemini_3_model?(model)).to be false
+    end
+  end
+end
+
+RSpec.describe RubyLLM::Providers::OpenAI::Chat do
+  include_context 'with configured RubyLLM'
+
+  describe '.resolve_effort' do
+    it 'resolves :low to "low"' do
+      expect(described_class.resolve_effort(:low)).to eq('low')
+    end
+
+    it 'resolves :medium to "high"' do
+      expect(described_class.resolve_effort(:medium)).to eq('high')
+    end
+
+    it 'resolves :high to "high"' do
+      expect(described_class.resolve_effort(:high)).to eq('high')
+    end
+
+    it 'resolves large integers to "high"' do
+      expect(described_class.resolve_effort(15_000)).to eq('high')
+    end
+
+    it 'resolves small integers to "low"' do
+      expect(described_class.resolve_effort(5000)).to eq('low')
+    end
+
+    it 'defaults unknown symbols to "high"' do
+      expect(described_class.resolve_effort(:unknown)).to eq('high')
+    end
+  end
+
+  describe '.grok_model?' do
+    it 'detects Grok models by name' do
+      model = RubyLLM::Model::Info.new(
+        id: 'grok-4',
+        name: 'Grok 4',
+        provider: 'openai'
+      )
+
+      expect(described_class.grok_model?(model)).to be true
+    end
+
+    it 'does not detect regular OpenAI models as Grok' do
+      model = RubyLLM::Model::Info.new(
+        id: 'gpt-4o',
+        name: 'GPT-4o',
+        provider: 'openai'
+      )
+
+      expect(described_class.grok_model?(model)).to be false
+    end
+  end
+end
+
+RSpec.describe RubyLLM::Chunk do
+  include_context 'with configured RubyLLM'
+
+  it 'can include thinking content' do
+    chunk = described_class.new(
+      role: :assistant,
+      content: 'Answer',
+      thinking: 'Reasoning',
+      model_id: 'claude-sonnet-4-20250514'
+    )
+
+    expect(chunk.thinking).to eq('Reasoning')
+  end
+
+  it 'can include thinking_signature' do
+    chunk = described_class.new(
+      role: :assistant,
+      content: 'Answer',
+      thinking: 'Reasoning',
+      thinking_signature: 'sig-123',
+      model_id: 'claude-sonnet-4-20250514'
+    )
+
+    expect(RubyLLM::Messages.signature_for(chunk)).to eq('sig-123')
+  end
+end
+
+RSpec.describe RubyLLM::UnsupportedFeatureError do
+  include_context 'with configured RubyLLM'
+
+  it 'is a subclass of RubyLLM::Error' do
+    expect(described_class).to be < RubyLLM::Error
+  end
+
+  it 'can be raised with a custom message' do
+    expect { raise described_class, 'Feature not supported' }
+      .to raise_error(described_class, 'Feature not supported')
+  end
+
+  it 'does not require a response object' do
+    error = described_class.new('Test error')
+
+    expect(error.response).to be_nil
+    expect(error.message).to eq('Test error')
+  end
+end
+# rubocop:enable RSpec/MultipleDescribes