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View your agent’s internal reasoning process for debugging, transparency, and understanding decision-making.This guide demonstrates two provider-specific approaches:
Anthropic Extended Thinking - Claude’s thinking blocks for complex reasoning
OpenAI Reasoning via Responses API - GPT’s reasoning effort parameter
Anthropic’s Claude models support extended thinking, which allows you to access the model’s internal reasoning process
through thinking blocks. This is useful for understanding how Claude approaches complex problems step-by-step.
Claude uses thinking blocks to reason through complex problems step-by-step. There are two types:
ThinkingBlock (related anthropic docs): Contains the full reasoning text from Claude’s internal thought process
RedactedThinkingBlock (related anthropic docs): Contains redacted or summarized thinking data
By registering a callback with your conversation, you can intercept and display these thinking blocks in real-time,
giving you insight into how Claude is approaching the problem.
"""Example demonstrating Anthropic's extended thinking feature with thinking blocks."""import osfrom pydantic import SecretStrfrom openhands.sdk import ( LLM, Agent, Conversation, Event, LLMConvertibleEvent, RedactedThinkingBlock, ThinkingBlock,)from openhands.sdk.tool import Toolfrom openhands.tools.terminal import TerminalTool# Configure LLM for Anthropic Claude with extended thinkingapi_key = os.getenv("LLM_API_KEY")assert api_key is not None, "LLM_API_KEY environment variable is not set."model = os.getenv("LLM_MODEL", "anthropic/claude-sonnet-4-5-20250929")base_url = os.getenv("LLM_BASE_URL")llm = LLM( usage_id="agent", model=model, base_url=base_url, api_key=SecretStr(api_key),)# Setup agent with bash toolagent = Agent(llm=llm, tools=[Tool(name=TerminalTool.name)])# Callback to display thinking blocksdef show_thinking(event: Event): if isinstance(event, LLMConvertibleEvent): message = event.to_llm_message() if hasattr(message, "thinking_blocks") and message.thinking_blocks: print(f"\n🧠 Found {len(message.thinking_blocks)} thinking blocks") for i, block in enumerate(message.thinking_blocks): if isinstance(block, RedactedThinkingBlock): print(f" Block {i + 1}: {block.data}") elif isinstance(block, ThinkingBlock): print(f" Block {i + 1}: {block.thinking}")conversation = Conversation( agent=agent, callbacks=[show_thinking], workspace=os.getcwd())conversation.send_message( "Calculate compound interest for $10,000 at 5% annually, " "compounded quarterly for 3 years. Show your work.",)conversation.run()conversation.send_message( "Now, write that number to RESULTs.txt.",)conversation.run()print("✅ Done!")# Report costcost = llm.metrics.accumulated_costprint(f"EXAMPLE_COST: {cost}")
You can run the example code as-is.
The model name should follow the LiteLLM convention: provider/model_name (e.g., anthropic/claude-sonnet-4-5-20250929, openai/gpt-4o).
The LLM_API_KEY should be the API key for your chosen provider.
ChatGPT Plus/Pro subscribers: You can use LLM.subscription_login() to authenticate with your ChatGPT account and access Codex models without consuming API credits. See the LLM Subscriptions guide for details.
OpenAI’s latest models (e.g., GPT-5, GPT-5-Codex) support a Responses API
that provides access to the model’s reasoning process.
By setting the reasoning_effort parameter, you can control how much reasoning the model performs and access those reasoning traces.
The reasoning_effort parameter can be set to "none", "low", "medium", or "high" to control the amount of
reasoning performed by the model.Then capture reasoning traces in your callback:
def conversation_callback(event: Event): if isinstance(event, LLMConvertibleEvent): msg = event.to_llm_message() llm_messages.append(msg)
The OpenAI Responses API provides reasoning traces that show how the model approached the problem.
These traces are available in the LLM messages and can be inspected to understand the model’s decision-making process.
Unlike Anthropic’s thinking blocks, OpenAI’s reasoning is more tightly integrated with the response generation process.
"""Example: Responses API path via LiteLLM in a Real Agent Conversation- Runs a real Agent/Conversation to verify /responses path works- Demonstrates rendering of Responses reasoning within normal conversation events"""from __future__ import annotationsimport osfrom pydantic import SecretStrfrom openhands.sdk import ( Conversation, Event, LLMConvertibleEvent, get_logger,)from openhands.sdk.llm import LLMfrom openhands.tools.preset.default import get_default_agentlogger = get_logger(__name__)api_key = os.getenv("LLM_API_KEY") or os.getenv("OPENAI_API_KEY")assert api_key, "Set LLM_API_KEY or OPENAI_API_KEY in your environment."model = "openhands/gpt-5-mini-2025-08-07" # Use a model that supports Responses APIbase_url = os.getenv("LLM_BASE_URL")llm = LLM( model=model, api_key=SecretStr(api_key), base_url=base_url, # Responses-path options reasoning_effort="high", # Logging / behavior tweaks log_completions=False, usage_id="agent",)print("\n=== Agent Conversation using /responses path ===")agent = get_default_agent( llm=llm, cli_mode=True, # disable browser tools for env simplicity)llm_messages = [] # collect raw LLM-convertible messages for inspectiondef conversation_callback(event: Event): if isinstance(event, LLMConvertibleEvent): llm_messages.append(event.to_llm_message())conversation = Conversation( agent=agent, callbacks=[conversation_callback], workspace=os.getcwd(),)# Keep the tasks short for demo purposesconversation.send_message("Read the repo and write one fact into FACTS.txt.")conversation.run()conversation.send_message("Now delete FACTS.txt.")conversation.run()print("=" * 100)print("Conversation finished. Got the following LLM messages:")for i, message in enumerate(llm_messages): ms = str(message) print(f"Message {i}: {ms[:200]}{'...' if len(ms) > 200 else ''}")# Report costcost = llm.metrics.accumulated_costprint(f"EXAMPLE_COST: {cost}")
You can run the example code as-is.
The model name should follow the LiteLLM convention: provider/model_name (e.g., anthropic/claude-sonnet-4-5-20250929, openai/gpt-4o).
The LLM_API_KEY should be the API key for your chosen provider.
ChatGPT Plus/Pro subscribers: You can use LLM.subscription_login() to authenticate with your ChatGPT account and access Codex models without consuming API credits. See the LLM Subscriptions guide for details.
Debugging: Understand why the agent made specific decisions or took certain actions.Transparency: Show users how the AI arrived at its conclusions.Quality Assurance: Identify flawed reasoning patterns or logic errors.Learning: Study how models approach complex problems.