InMemoryCache

Example:

from langchain_core.caches import InMemoryCache
from langchain_core.outputs import Generation

# Initialize cache
cache = InMemoryCache()

# Update cache
cache.update(
    prompt="What is the capital of France?",
    llm_string="model='gpt-5.4-mini',
    return_val=[Generation(text="Paris")],
)

# Lookup cache
result = cache.lookup(
    prompt="What is the capital of France?",
    llm_string="model='gpt-5.4-mini',
)
# result is [Generation(text="Paris")]