*   [](/v0.2/)
*   [How-to guides](/v0.2/docs/how_to/)
*   How to debug your LLM apps

On this page

How to debug your LLM apps
==========================

Like building any type of software, at some point you'll need to debug when building with LLMs. A model call will fail, or model output will be misformatted, or there will be some nested model calls and it won't be clear where along the way an incorrect output was created.

There are three main methods for debugging:

*   Verbose Mode: This adds print statements for "important" events in your chain.
*   Debug Mode: This add logging statements for ALL events in your chain.
*   LangSmith Tracing: This logs events to [LangSmith](https://docs.smith.langchain.com/) to allow for visualization there.

Verbose Mode

Debug Mode

LangSmith Tracing

Free

✅

✅

✅

UI

❌

❌

✅

Persisted

❌

❌

✅

See all events

❌

✅

✅

See "important" events

✅

❌

✅

Runs Locally

✅

✅

❌

Tracing[​](#tracing "Direct link to Tracing")
---------------------------------------------

Many of the applications you build with LangChain will contain multiple steps with multiple invocations of LLM calls. As these applications get more and more complex, it becomes crucial to be able to inspect what exactly is going on inside your chain or agent. The best way to do this is with [LangSmith](https://smith.langchain.com).

After you sign up at the link above, make sure to set your environment variables to start logging traces:

    export LANGCHAIN_TRACING_V2="true"export LANGCHAIN_API_KEY="..."

Or, if in a notebook, you can set them with:

    import getpassimport osos.environ["LANGCHAIN_TRACING_V2"] = "true"os.environ["LANGCHAIN_API_KEY"] = getpass.getpass()

Let's suppose we have an agent, and want to visualize the actions it takes and tool outputs it receives. Without any debugging, here's what we see:

*   OpenAI
*   Anthropic
*   Azure
*   Google
*   Cohere
*   FireworksAI
*   Groq
*   MistralAI
*   TogetherAI

    pip install -qU langchain-openai

    import getpassimport osos.environ["OPENAI_API_KEY"] = getpass.getpass()from langchain_openai import ChatOpenAIllm = ChatOpenAI(model="gpt-3.5-turbo-0125")

    pip install -qU langchain-anthropic

    import getpassimport osos.environ["ANTHROPIC_API_KEY"] = getpass.getpass()from langchain_anthropic import ChatAnthropicllm = ChatAnthropic(model="claude-3-sonnet-20240229")

    pip install -qU langchain-openai

    import getpassimport osos.environ["AZURE_OPENAI_API_KEY"] = getpass.getpass()from langchain_openai import AzureChatOpenAIllm = AzureChatOpenAI(    azure_endpoint=os.environ["AZURE_OPENAI_ENDPOINT"],    azure_deployment=os.environ["AZURE_OPENAI_DEPLOYMENT_NAME"],    openai_api_version=os.environ["AZURE_OPENAI_API_VERSION"],)

    pip install -qU langchain-google-vertexai

    import getpassimport osos.environ["GOOGLE_API_KEY"] = getpass.getpass()from langchain_google_vertexai import ChatVertexAIllm = ChatVertexAI(model="gemini-pro")

    pip install -qU langchain-cohere

    import getpassimport osos.environ["COHERE_API_KEY"] = getpass.getpass()from langchain_cohere import ChatCoherellm = ChatCohere(model="command-r")

    pip install -qU langchain-fireworks

    import getpassimport osos.environ["FIREWORKS_API_KEY"] = getpass.getpass()from langchain_fireworks import ChatFireworksllm = ChatFireworks(model="accounts/fireworks/models/mixtral-8x7b-instruct")

    pip install -qU langchain-groq

    import getpassimport osos.environ["GROQ_API_KEY"] = getpass.getpass()from langchain_groq import ChatGroqllm = ChatGroq(model="llama3-8b-8192")

    pip install -qU langchain-mistralai

    import getpassimport osos.environ["MISTRAL_API_KEY"] = getpass.getpass()from langchain_mistralai import ChatMistralAIllm = ChatMistralAI(model="mistral-large-latest")

    pip install -qU langchain-openai

    import getpassimport osos.environ["TOGETHER_API_KEY"] = getpass.getpass()from langchain_openai import ChatOpenAIllm = ChatOpenAI(    base_url="https://api.together.xyz/v1",    api_key=os.environ["TOGETHER_API_KEY"],    model="mistralai/Mixtral-8x7B-Instruct-v0.1",)

    from langchain.agents import AgentExecutor, create_tool_calling_agentfrom langchain_community.tools.tavily_search import TavilySearchResultsfrom langchain_core.prompts import ChatPromptTemplatetools = [TavilySearchResults(max_results=1)]prompt = ChatPromptTemplate.from_messages(    [        (            "system",            "You are a helpful assistant.",        ),        ("placeholder", "{chat_history}"),        ("human", "{input}"),        ("placeholder", "{agent_scratchpad}"),    ])# Construct the Tools agentagent = create_tool_calling_agent(llm, tools, prompt)# Create an agent executor by passing in the agent and toolsagent_executor = AgentExecutor(agent=agent, tools=tools)agent_executor.invoke(    {"input": "Who directed the 2023 film Oppenheimer and what is their age in days?"})

**API Reference:**[AgentExecutor](https://api.python.langchain.com/en/latest/agents/langchain.agents.agent.AgentExecutor.html) | [create\_tool\_calling\_agent](https://api.python.langchain.com/en/latest/agents/langchain.agents.tool_calling_agent.base.create_tool_calling_agent.html) | [TavilySearchResults](https://api.python.langchain.com/en/latest/tools/langchain_community.tools.tavily_search.tool.TavilySearchResults.html) | [ChatPromptTemplate](https://api.python.langchain.com/en/latest/prompts/langchain_core.prompts.chat.ChatPromptTemplate.html)

    {'input': 'Who directed the 2023 film Oppenheimer and what is their age in days?', 'output': 'The 2023 film "Oppenheimer" was directed by Christopher Nolan.\n\nTo calculate Christopher Nolan\'s age in days, we first need his birthdate, which is July 30, 1970. Let\'s calculate his age in days from his birthdate to today\'s date, December 7, 2023.\n\n1. Calculate the total number of days from July 30, 1970, to December 7, 2023.\n2. Nolan was born on July 30, 1970. From July 30, 1970, to July 30, 2023, is 53 years.\n3. From July 30, 2023, to December 7, 2023, is 130 days.\n\nNow, calculate the total days:\n- 53 years = 53 x 365 = 19,345 days\n- Adding leap years from 1970 to 2023: There are 13 leap years (1972, 1976, 1980, 1984, 1988, 1992, 1996, 2000, 2004, 2008, 2012, 2016, 2020). So, add 13 days.\n- Total days from years and leap years = 19,345 + 13 = 19,358 days\n- Add the days from July 30, 2023, to December 7, 2023 = 130 days\n\nTotal age in days = 19,358 + 130 = 19,488 days\n\nChristopher Nolan is 19,488 days old as of December 7, 2023.'}

We don't get much output, but since we set up LangSmith we can easily see what happened under the hood:

[https://smith.langchain.com/public/a89ff88f-9ddc-4757-a395-3a1b365655bf/r](https://smith.langchain.com/public/a89ff88f-9ddc-4757-a395-3a1b365655bf/r)

`set_debug` and `set_verbose`[​](#set_debug-and-set_verbose "Direct link to set_debug-and-set_verbose")
-------------------------------------------------------------------------------------------------------

If you're prototyping in Jupyter Notebooks or running Python scripts, it can be helpful to print out the intermediate steps of a chain run.

There are a number of ways to enable printing at varying degrees of verbosity.

Note: These still work even with LangSmith enabled, so you can have both turned on and running at the same time

### `set_verbose(True)`[​](#set_verbosetrue "Direct link to set_verbosetrue")

Setting the `verbose` flag will print out inputs and outputs in a slightly more readable format and will skip logging certain raw outputs (like the token usage stats for an LLM call) so that you can focus on application logic.

    from langchain.globals import set_verboseset_verbose(True)agent_executor = AgentExecutor(agent=agent, tools=tools)agent_executor.invoke(    {"input": "Who directed the 2023 film Oppenheimer and what is their age in days?"})

**API Reference:**[set\_verbose](https://api.python.langchain.com/en/latest/globals/langchain.globals.set_verbose.html)

    [1m> Entering new AgentExecutor chain...[0m[32;1m[1;3mInvoking: `tavily_search_results_json` with `{'query': 'director of the 2023 film Oppenheimer'}`[0m[36;1m[1;3m[{'url': 'https://m.imdb.com/title/tt15398776/', 'content': 'Oppenheimer: Directed by Christopher Nolan. With Cillian Murphy, Emily Blunt, Robert Downey Jr., Alden Ehrenreich. The story of American scientist J. Robert Oppenheimer and his role in the development of the atomic bomb.'}][0m[32;1m[1;3mInvoking: `tavily_search_results_json` with `{'query': 'birth date of Christopher Nolan'}`[0m[36;1m[1;3m[{'url': 'https://m.imdb.com/name/nm0634240/bio/', 'content': 'Christopher Nolan. Writer: Tenet. Best known for his cerebral, often nonlinear, storytelling, acclaimed Academy Award winner writer/director/producer Sir Christopher Nolan CBE was born in London, England. Over the course of more than 25 years of filmmaking, Nolan has gone from low-budget independent films to working on some of the biggest blockbusters ever made and became one of the most ...'}][0m[32;1m[1;3mInvoking: `tavily_search_results_json` with `{'query': 'Christopher Nolan birth date'}`responded: The 2023 film **Oppenheimer** was directed by **Christopher Nolan**.To calculate Christopher Nolan's age in days, I need his exact birth date. Let me find that information for you.[0m[36;1m[1;3m[{'url': 'https://m.imdb.com/name/nm0634240/bio/', 'content': 'Christopher Nolan. Writer: Tenet. Best known for his cerebral, often nonlinear, storytelling, acclaimed Academy Award winner writer/director/producer Sir Christopher Nolan CBE was born in London, England. Over the course of more than 25 years of filmmaking, Nolan has gone from low-budget independent films to working on some of the biggest blockbusters ever made and became one of the most ...'}][0m[32;1m[1;3mInvoking: `tavily_search_results_json` with `{'query': 'Christopher Nolan date of birth'}`responded: It appears that I need to refine my search to get the exact birth date of Christopher Nolan. Let me try again to find that specific information.[0m[36;1m[1;3m[{'url': 'https://m.imdb.com/name/nm0634240/bio/', 'content': 'Christopher Nolan. Writer: Tenet. Best known for his cerebral, often nonlinear, storytelling, acclaimed Academy Award winner writer/director/producer Sir Christopher Nolan CBE was born in London, England. Over the course of more than 25 years of filmmaking, Nolan has gone from low-budget independent films to working on some of the biggest blockbusters ever made and became one of the most ...'}][0m[32;1m[1;3mI am currently unable to retrieve the exact birth date of Christopher Nolan from the sources available. However, it is widely known that he was born on July 30, 1970. Using this date, I can calculate his age in days as of today.Let's calculate:- Christopher Nolan's birth date: July 30, 1970.- Today's date: December 7, 2023.The number of days between these two dates can be calculated as follows:1. From July 30, 1970, to July 30, 2023, is 53 years.2. From July 30, 2023, to December 7, 2023, is 130 days.Calculating the total days for 53 years (considering leap years):- 53 years × 365 days/year = 19,345 days- Adding leap years (1972, 1976, ..., 2020, 2024 - 13 leap years): 13 daysTotal days from birth until July 30, 2023: 19,345 + 13 = 19,358 daysAdding the days from July 30, 2023, to December 7, 2023: 130 daysTotal age in days as of December 7, 2023: 19,358 + 130 = 19,488 days.Therefore, Christopher Nolan is 19,488 days old as of December 7, 2023.[0m[1m> Finished chain.[0m

    {'input': 'Who directed the 2023 film Oppenheimer and what is their age in days?', 'output': "I am currently unable to retrieve the exact birth date of Christopher Nolan from the sources available. However, it is widely known that he was born on July 30, 1970. Using this date, I can calculate his age in days as of today.\n\nLet's calculate:\n\n- Christopher Nolan's birth date: July 30, 1970.\n- Today's date: December 7, 2023.\n\nThe number of days between these two dates can be calculated as follows:\n\n1. From July 30, 1970, to July 30, 2023, is 53 years.\n2. From July 30, 2023, to December 7, 2023, is 130 days.\n\nCalculating the total days for 53 years (considering leap years):\n- 53 years × 365 days/year = 19,345 days\n- Adding leap years (1972, 1976, ..., 2020, 2024 - 13 leap years): 13 days\n\nTotal days from birth until July 30, 2023: 19,345 + 13 = 19,358 days\nAdding the days from July 30, 2023, to December 7, 2023: 130 days\n\nTotal age in days as of December 7, 2023: 19,358 + 130 = 19,488 days.\n\nTherefore, Christopher Nolan is 19,488 days old as of December 7, 2023."}

### `set_debug(True)`[​](#set_debugtrue "Direct link to set_debugtrue")

Setting the global `debug` flag will cause all LangChain components with callback support (chains, models, agents, tools, retrievers) to print the inputs they receive and outputs they generate. This is the most verbose setting and will fully log raw inputs and outputs.

    from langchain.globals import set_debugset_debug(True)set_verbose(False)agent_executor = AgentExecutor(agent=agent, tools=tools)agent_executor.invoke(    {"input": "Who directed the 2023 film Oppenheimer and what is their age in days?"})

**API Reference:**[set\_debug](https://api.python.langchain.com/en/latest/globals/langchain.globals.set_debug.html)

    [32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor] Entering Chain run with input:[0m{  "input": "Who directed the 2023 film Oppenheimer and what is their age in days?"}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence] Entering Chain run with input:[0m{  "input": ""}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 3:chain:RunnableAssign<agent_scratchpad>] Entering Chain run with input:[0m{  "input": ""}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 3:chain:RunnableAssign<agent_scratchpad> > 4:chain:RunnableParallel<agent_scratchpad>] Entering Chain run with input:[0m{  "input": ""}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 3:chain:RunnableAssign<agent_scratchpad> > 4:chain:RunnableParallel<agent_scratchpad> > 5:chain:RunnableLambda] Entering Chain run with input:[0m{  "input": ""}[36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 3:chain:RunnableAssign<agent_scratchpad> > 4:chain:RunnableParallel<agent_scratchpad> > 5:chain:RunnableLambda] [1ms] Exiting Chain run with output:[0m{  "output": []}[36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 3:chain:RunnableAssign<agent_scratchpad> > 4:chain:RunnableParallel<agent_scratchpad>] [2ms] Exiting Chain run with output:[0m{  "agent_scratchpad": []}[36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 3:chain:RunnableAssign<agent_scratchpad>] [5ms] Exiting Chain run with output:[0m{  "input": "Who directed the 2023 film Oppenheimer and what is their age in days?",  "intermediate_steps": [],  "agent_scratchpad": []}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 6:prompt:ChatPromptTemplate] Entering Prompt run with input:[0m{  "input": "Who directed the 2023 film Oppenheimer and what is their age in days?",  "intermediate_steps": [],  "agent_scratchpad": []}[36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 6:prompt:ChatPromptTemplate] [1ms] Exiting Prompt run with output:[0m[outputs][32;1m[1;3m[llm/start][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 7:llm:ChatOpenAI] Entering LLM run with input:[0m{  "prompts": [    "System: You are a helpful assistant.\nHuman: Who directed the 2023 film Oppenheimer and what is their age in days?"  ]}[36;1m[1;3m[llm/end][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 7:llm:ChatOpenAI] [3.17s] Exiting LLM run with output:[0m{  "generations": [    [      {        "text": "",        "generation_info": {          "finish_reason": "tool_calls"        },        "type": "ChatGenerationChunk",        "message": {          "lc": 1,          "type": "constructor",          "id": [            "langchain",            "schema",            "messages",            "AIMessageChunk"          ],          "kwargs": {            "content": "",            "example": false,            "additional_kwargs": {              "tool_calls": [                {                  "index": 0,                  "id": "call_fnfq6GjSQED4iF6lo4rxkUup",                  "function": {                    "arguments": "{\"query\": \"director of the 2023 film Oppenheimer\"}",                    "name": "tavily_search_results_json"                  },                  "type": "function"                },                {                  "index": 1,                  "id": "call_mwhVi6pk49f4OIo5rOWrr4TD",                  "function": {                    "arguments": "{\"query\": \"birth date of Christopher Nolan\"}",                    "name": "tavily_search_results_json"                  },                  "type": "function"                }              ]            },            "tool_call_chunks": [              {                "name": "tavily_search_results_json",                "args": "{\"query\": \"director of the 2023 film Oppenheimer\"}",                "id": "call_fnfq6GjSQED4iF6lo4rxkUup",                "index": 0              },              {                "name": "tavily_search_results_json",                "args": "{\"query\": \"birth date of Christopher Nolan\"}",                "id": "call_mwhVi6pk49f4OIo5rOWrr4TD",                "index": 1              }            ],            "response_metadata": {              "finish_reason": "tool_calls"            },            "id": "run-6e160323-15f9-491d-aadf-b5d337e9e2a1",            "tool_calls": [              {                "name": "tavily_search_results_json",                "args": {                  "query": "director of the 2023 film Oppenheimer"                },                "id": "call_fnfq6GjSQED4iF6lo4rxkUup"              },              {                "name": "tavily_search_results_json",                "args": {                  "query": "birth date of Christopher Nolan"                },                "id": "call_mwhVi6pk49f4OIo5rOWrr4TD"              }            ],            "invalid_tool_calls": []          }        }      }    ]  ],  "llm_output": null,  "run": null}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 8:parser:ToolsAgentOutputParser] Entering Parser run with input:[0m[inputs][36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence > 8:parser:ToolsAgentOutputParser] [1ms] Exiting Parser run with output:[0m[outputs][36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 2:chain:RunnableSequence] [3.18s] Exiting Chain run with output:[0m[outputs][32;1m[1;3m[tool/start][0m [1m[1:chain:AgentExecutor > 9:tool:tavily_search_results_json] Entering Tool run with input:[0m"{'query': 'director of the 2023 film Oppenheimer'}"``````outputError in ConsoleCallbackHandler.on_tool_end callback: AttributeError("'list' object has no attribute 'strip'")``````output[32;1m[1;3m[tool/start][0m [1m[1:chain:AgentExecutor > 10:tool:tavily_search_results_json] Entering Tool run with input:[0m"{'query': 'birth date of Christopher Nolan'}"``````outputError in ConsoleCallbackHandler.on_tool_end callback: AttributeError("'list' object has no attribute 'strip'")``````output[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence] Entering Chain run with input:[0m{  "input": ""}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 12:chain:RunnableAssign<agent_scratchpad>] Entering Chain run with input:[0m{  "input": ""}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 12:chain:RunnableAssign<agent_scratchpad> > 13:chain:RunnableParallel<agent_scratchpad>] Entering Chain run with input:[0m{  "input": ""}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 12:chain:RunnableAssign<agent_scratchpad> > 13:chain:RunnableParallel<agent_scratchpad> > 14:chain:RunnableLambda] Entering Chain run with input:[0m{  "input": ""}[36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 12:chain:RunnableAssign<agent_scratchpad> > 13:chain:RunnableParallel<agent_scratchpad> > 14:chain:RunnableLambda] [1ms] Exiting Chain run with output:[0m[outputs][36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 12:chain:RunnableAssign<agent_scratchpad> > 13:chain:RunnableParallel<agent_scratchpad>] [4ms] Exiting Chain run with output:[0m[outputs][36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 12:chain:RunnableAssign<agent_scratchpad>] [8ms] Exiting Chain run with output:[0m[outputs][32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 15:prompt:ChatPromptTemplate] Entering Prompt run with input:[0m[inputs][36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 15:prompt:ChatPromptTemplate] [1ms] Exiting Prompt run with output:[0m[outputs][32;1m[1;3m[llm/start][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 16:llm:ChatOpenAI] Entering LLM run with input:[0m{  "prompts": [    "System: You are a helpful assistant.\nHuman: Who directed the 2023 film Oppenheimer and what is their age in days?\nAI: \nTool: [{\"url\": \"https://m.imdb.com/title/tt15398776/fullcredits/\", \"content\": \"Oppenheimer (2023) cast and crew credits, including actors, actresses, directors, writers and more. Menu. ... director of photography: behind-the-scenes Jason Gary ... best boy grip ... film loader Luc Poullain ... aerial coordinator\"}]\nTool: [{\"url\": \"https://en.wikipedia.org/wiki/Christopher_Nolan\", \"content\": \"In early 2003, Nolan approached Warner Bros. with the idea of making a new Batman film, based on the character's origin story.[58] Nolan was fascinated by the notion of grounding it in a more realistic world than a comic-book fantasy.[59] He relied heavily on traditional stunts and miniature effects during filming, with minimal use of computer-generated imagery (CGI).[60] Batman Begins (2005), the biggest project Nolan had undertaken to that point,[61] was released to critical acclaim and commercial success.[62][63] Starring Christian Bale as Bruce Wayne / Batman—along with Michael Caine, Gary Oldman, Morgan Freeman and Liam Neeson—Batman Begins revived the franchise.[64][65] Batman Begins was 2005's ninth-highest-grossing film and was praised for its psychological depth and contemporary relevance;[63][66] it is cited as one of the most influential films of the 2000s.[67] Film author Ian Nathan wrote that within five years of his career, Nolan \\\"[went] from unknown to indie darling to gaining creative control over one of the biggest properties in Hollywood, and (perhaps unwittingly) fomenting the genre that would redefine the entire industry\\\".[68]\\nNolan directed, co-wrote and produced The Prestige (2006), an adaptation of the Christopher Priest novel about two rival 19th-century magicians.[69] He directed, wrote and edited the short film Larceny (1996),[19] which was filmed over a weekend in black and white with limited equipment and a small cast and crew.[12][20] Funded by Nolan and shot with the UCL Union Film society's equipment, it appeared at the Cambridge Film Festival in 1996 and is considered one of UCL's best shorts.[21] For unknown reasons, the film has since been removed from public view.[19] Nolan filmed a third short, Doodlebug (1997), about a man seemingly chasing an insect with his shoe, only to discover that it is a miniature of himself.[14][22] Nolan and Thomas first attempted to make a feature in the mid-1990s with Larry Mahoney, which they scrapped.[23] During this period in his career, Nolan had little to no success getting his projects off the ground, facing several rejections; he added, \\\"[T]here's a very limited pool of finance in the UK. Philosophy professor David Kyle Johnson wrote that \\\"Inception became a classic almost as soon as it was projected on silver screens\\\", praising its exploration of philosophical ideas, including leap of faith and allegory of the cave.[97] The film grossed over $836 million worldwide.[98] Nominated for eight Academy Awards—including Best Picture and Best Original Screenplay—it won Best Cinematography, Best Sound Mixing, Best Sound Editing and Best Visual Effects.[99] Nolan was nominated for a BAFTA Award and a Golden Globe Award for Best Director, among other accolades.[40]\\nAround the release of The Dark Knight Rises (2012), Nolan's third and final Batman film, Joseph Bevan of the British Film Institute wrote a profile on him: \\\"In the space of just over a decade, Christopher Nolan has shot from promising British indie director to undisputed master of a new brand of intelligent escapism. He further wrote that Nolan's body of work reflect \\\"a heterogeneity of conditions of products\\\" extending from low-budget films to lucrative blockbusters, \\\"a wide range of genres and settings\\\" and \\\"a diversity of styles that trumpet his versatility\\\".[193]\\nDavid Bordwell, a film theorist, wrote that Nolan has been able to blend his \\\"experimental impulses\\\" with the demands of mainstream entertainment, describing his oeuvre as \\\"experiments with cinematic time by means of techniques of subjective viewpoint and crosscutting\\\".[194] Nolan's use of practical, in-camera effects, miniatures and models, as well as shooting on celluloid film, has been highly influential in early 21st century cinema.[195][196] IndieWire wrote in 2019 that, Nolan \\\"kept a viable alternate model of big-budget filmmaking alive\\\", in an era where blockbuster filmmaking has become \\\"a largely computer-generated art form\\\".[196] Initially reluctant to make a sequel, he agreed after Warner Bros. repeatedly insisted.[78] Nolan wanted to expand on the noir quality of the first film by broadening the canvas and taking on \\\"the dynamic of a story of the city, a large crime story ... where you're looking at the police, the justice system, the vigilante, the poor people, the rich people, the criminals\\\".[79] Continuing to minimalise the use of CGI, Nolan employed high-resolution IMAX cameras, making it the first major motion picture to use this technology.[80][81]\"}]"  ]}[36;1m[1;3m[llm/end][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 16:llm:ChatOpenAI] [20.22s] Exiting LLM run with output:[0m{  "generations": [    [      {        "text": "The 2023 film \"Oppenheimer\" was directed by Christopher Nolan.\n\nTo calculate Christopher Nolan's age in days, we first need his birth date, which is July 30, 1970. Let's calculate his age in days from his birth date to today's date, December 7, 2023.\n\n1. Calculate the total number of days from July 30, 1970, to December 7, 2023.\n2. Christopher Nolan was born on July 30, 1970. From July 30, 1970, to July 30, 2023, is 53 years.\n3. From July 30, 2023, to December 7, 2023, is 130 days.\n\nNow, calculate the total days for 53 years:\n- Each year has 365 days, so 53 years × 365 days/year = 19,345 days.\n- Adding the leap years from 1970 to 2023: 1972, 1976, 1980, 1984, 1988, 1992, 1996, 2000, 2004, 2008, 2012, 2016, 2020, and 2024 (up to February). This gives us 14 leap years.\n- Total days from leap years: 14 days.\n\nAdding all together:\n- Total days = 19,345 days (from years) + 14 days (from leap years) + 130 days (from July 30, 2023, to December 7, 2023) = 19,489 days.\n\nTherefore, as of December 7, 2023, Christopher Nolan is 19,489 days old.",        "generation_info": {          "finish_reason": "stop"        },        "type": "ChatGenerationChunk",        "message": {          "lc": 1,          "type": "constructor",          "id": [            "langchain",            "schema",            "messages",            "AIMessageChunk"          ],          "kwargs": {            "content": "The 2023 film \"Oppenheimer\" was directed by Christopher Nolan.\n\nTo calculate Christopher Nolan's age in days, we first need his birth date, which is July 30, 1970. Let's calculate his age in days from his birth date to today's date, December 7, 2023.\n\n1. Calculate the total number of days from July 30, 1970, to December 7, 2023.\n2. Christopher Nolan was born on July 30, 1970. From July 30, 1970, to July 30, 2023, is 53 years.\n3. From July 30, 2023, to December 7, 2023, is 130 days.\n\nNow, calculate the total days for 53 years:\n- Each year has 365 days, so 53 years × 365 days/year = 19,345 days.\n- Adding the leap years from 1970 to 2023: 1972, 1976, 1980, 1984, 1988, 1992, 1996, 2000, 2004, 2008, 2012, 2016, 2020, and 2024 (up to February). This gives us 14 leap years.\n- Total days from leap years: 14 days.\n\nAdding all together:\n- Total days = 19,345 days (from years) + 14 days (from leap years) + 130 days (from July 30, 2023, to December 7, 2023) = 19,489 days.\n\nTherefore, as of December 7, 2023, Christopher Nolan is 19,489 days old.",            "example": false,            "additional_kwargs": {},            "tool_call_chunks": [],            "response_metadata": {              "finish_reason": "stop"            },            "id": "run-1c08a44f-db70-4836-935b-417caaf422a5",            "tool_calls": [],            "invalid_tool_calls": []          }        }      }    ]  ],  "llm_output": null,  "run": null}[32;1m[1;3m[chain/start][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 17:parser:ToolsAgentOutputParser] Entering Parser run with input:[0m[inputs][36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence > 17:parser:ToolsAgentOutputParser] [2ms] Exiting Parser run with output:[0m[outputs][36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor > 11:chain:RunnableSequence] [20.27s] Exiting Chain run with output:[0m[outputs][36;1m[1;3m[chain/end][0m [1m[1:chain:AgentExecutor] [26.37s] Exiting Chain run with output:[0m{  "output": "The 2023 film \"Oppenheimer\" was directed by Christopher Nolan.\n\nTo calculate Christopher Nolan's age in days, we first need his birth date, which is July 30, 1970. Let's calculate his age in days from his birth date to today's date, December 7, 2023.\n\n1. Calculate the total number of days from July 30, 1970, to December 7, 2023.\n2. Christopher Nolan was born on July 30, 1970. From July 30, 1970, to July 30, 2023, is 53 years.\n3. From July 30, 2023, to December 7, 2023, is 130 days.\n\nNow, calculate the total days for 53 years:\n- Each year has 365 days, so 53 years × 365 days/year = 19,345 days.\n- Adding the leap years from 1970 to 2023: 1972, 1976, 1980, 1984, 1988, 1992, 1996, 2000, 2004, 2008, 2012, 2016, 2020, and 2024 (up to February). This gives us 14 leap years.\n- Total days from leap years: 14 days.\n\nAdding all together:\n- Total days = 19,345 days (from years) + 14 days (from leap years) + 130 days (from July 30, 2023, to December 7, 2023) = 19,489 days.\n\nTherefore, as of December 7, 2023, Christopher Nolan is 19,489 days old."}

    {'input': 'Who directed the 2023 film Oppenheimer and what is their age in days?', 'output': 'The 2023 film "Oppenheimer" was directed by Christopher Nolan.\n\nTo calculate Christopher Nolan\'s age in days, we first need his birth date, which is July 30, 1970. Let\'s calculate his age in days from his birth date to today\'s date, December 7, 2023.\n\n1. Calculate the total number of days from July 30, 1970, to December 7, 2023.\n2. Christopher Nolan was born on July 30, 1970. From July 30, 1970, to July 30, 2023, is 53 years.\n3. From July 30, 2023, to December 7, 2023, is 130 days.\n\nNow, calculate the total days for 53 years:\n- Each year has 365 days, so 53 years × 365 days/year = 19,345 days.\n- Adding the leap years from 1970 to 2023: 1972, 1976, 1980, 1984, 1988, 1992, 1996, 2000, 2004, 2008, 2012, 2016, 2020, and 2024 (up to February). This gives us 14 leap years.\n- Total days from leap years: 14 days.\n\nAdding all together:\n- Total days = 19,345 days (from years) + 14 days (from leap years) + 130 days (from July 30, 2023, to December 7, 2023) = 19,489 days.\n\nTherefore, as of December 7, 2023, Christopher Nolan is 19,489 days old.'}

[Edit this page](https://github.com/langchain-ai/langchain/edit/master/docs/docs/how_to/debugging.ipynb)

* * *

#### Was this page helpful?

  

#### You can also leave detailed feedback [on GitHub](https://github.com/langchain-ai/langchain/issues/new?assignees=&labels=03+-+Documentation&projects=&template=documentation.yml&title=DOC%3A+%3CPlease+write+a+comprehensive+title+after+the+%27DOC%3A+%27+prefix%3E).

[

Previous

How to create custom tools

](/v0.2/docs/how_to/custom_tools/)[

Next

How to load CSVs

](/v0.2/docs/how_to/document_loader_csv/)

*   [Tracing](#tracing)
*   [`set_debug` and `set_verbose`](#set_debug-and-set_verbose)
    *   [`set_verbose(True)`](#set_verbosetrue)
    *   [`set_debug(True)`](#set_debugtrue)