client = anthropic.Anthropic()

response = client.messages.count_tokens(
 model="claude-opus-4-8",
 system="You are a scientist",
 messages=[{"role": "user", "content": "Hello, Claude"}],
)

print(response.json())

{ "input_tokens": 14 }

client = anthropic.Anthropic()

response = client.messages.count_tokens(
 model="claude-opus-4-8",
 tools=[
 {
 "name": "get_weather",
 "description": "Get the current weather in a given location",
 "input_schema": {
 "type": "object",
 "properties": {
 "location": {
 "type": "string",
 "description": "The city and state, e.g. San Francisco, CA",
 }
 },
 "required": ["location"],
 },
 }
 ],
 messages=[{"role": "user", "content": "What's the weather like in San Francisco?"}],
)

print(response.json())

{ "input_tokens": 403 }

import base64
import httpx

image_url = "https://upload.wikimedia.org/wikipedia/commons/a/a7/Camponotus_flavomarginatus_ant.jpg"
image_media_type = "image/jpeg"
image_data = base64.standard_b64encode(httpx.get(image_url).content).decode("utf-8")

client = anthropic.Anthropic()

response = client.messages.count_tokens(
 model="claude-opus-4-8",
 messages=[
 {
 "role": "user",
 "content": [
 {
 "type": "image",
 "source": {
 "type": "base64",
 "media_type": image_media_type,
 "data": image_data,
 },
 },
 {"type": "text", "text": "Describe this image"},
 ],
 }
 ],
)
print(response.json())

{ "input_tokens": 1551 }

client = anthropic.Anthropic()

response = client.messages.count_tokens(
 model="claude-sonnet-4-6",
 thinking={"type": "enabled", "budget_tokens": 16000},
 messages=[
 {
 "role": "user",
 "content": "Are there an infinite number of prime numbers such that n mod 4 == 3?",
 },
 {
 "role": "assistant",
 "content": [
 {
 "type": "thinking",
 "thinking": "This is a nice number theory question. Let's think about it step by step...",
 "signature": "EuYBCkQYAiJAgCs1le6/Pol5Z4/JMomVOouGrWdhYNsH3ukzUECbB6iWrSQtsQuRHJID6lWV...",
 },
 {
 "type": "text",
 "text": "Yes, there are infinitely many prime numbers p such that p mod 4 = 3...",
 },
 ],
 },
 {"role": "user", "content": "Can you write a formal proof?"},
 ],
)

print(response.json())

{ "input_tokens": 88 }

import base64
import anthropic

client = anthropic.Anthropic()

with open("document.pdf", "rb") as pdf_file:
 pdf_base64 = base64.standard_b64encode(pdf_file.read()).decode("utf-8")

response = client.messages.count_tokens(
 model="claude-opus-4-8",
 messages=[
 {
 "role": "user",
 "content": [
 {
 "type": "document",
 "source": {
 "type": "base64",
 "media_type": "application/pdf",
 "data": pdf_base64,
 },
 },
 {"type": "text", "text": "Please summarize this document."},
 ],
 }
 ],
)

print(response.json())

{ "input_tokens": 2188 }