Counting chat tokens
This example demonstrates how to count tokens in a chat history with the Gemini API, incorporating a cat theme.
Import the Gemini API
from google import genai
from google.genai import types
import osConfigure the Gemini API with your API key
client = genai.Client(api_key=os.getenv("GEMINI_API_KEY"))Start a chat session with a cat-related history
chat = client.chats.create(
model="gemini-2.0-flash",
history=[
types.Content(role="user", parts=[types.Part(text="Hey there! I love cats!")]),
types.Content(
role="model",
parts=[
types.Part(
text="Me too! Cats are the best. What's your favorite breed?"
)
],
),
],
)Count the tokens in the initial chat history
token_count = client.models.count_tokens(
model="gemini-2.0-flash", contents=chat.get_history()
)
print(f"Tokens in initial chat history: {token_count.total_tokens} tokens")Send a new message to the chat, asking about cat breeds
response = chat.send_message(message="Tell me more about Ragdoll cats.")Print the token usage metadata from the response
print(
f"Token usage for the last turn: input_tokens={response.usage_metadata.prompt_token_count}, output_tokens={response.usage_metadata.candidates_token_count}, total_tokens={response.usage_metadata.total_token_count}"
)Count tokens including next turn question
extra = types.UserContent(
parts=[
types.Part(
text="Do you know Neko the cat?",
)
]
)
history = chat.get_history()
history.append(extra)
final_count = client.models.count_tokens(model="gemini-2.0-flash", contents=history)
print(f"Total tokens with additional question: {final_count.total_tokens} tokens")Running the Example
Install the Google Generative AI library
$ pip install google-genai
Run the Python script
$ python count_chat_tokens.py
Tokens in initial chat history: 24 tokens
Token usage for the last turn: input_tokens=30, output_tokens=843, total_tokens=873
Total tokens with additional question: 892 tokens