Claude Code Authentication: Subscription, API Key, Amazon Bedrock, and Claude Platform on AWS

I'm a big fan of using Claude and Claude Code for development. Many organizations are currently using these tools to improve developer productivity and ultimately build better products. Our role and our tools have changed — we went from powerful autocomplete to autonomous agents that can refactor, review, and implement features, most of the time better than we can on our own. Authentication methods There are several authentication methods, each with different billing, cost tracking, and governance options. Depending on your organization, you will choose the one that fits best. Personal development — Anthropic API key I use this for experimenting with the Anthropic library for learning and prototyping. You set ANTHROPIC_API_KEY in your environment (or a .env file), and the SDK picks it up automatically. Pay-as-you-go per token, no infrastructure needed. from dotenv import load_dotenv load_dotenv () import json import anthropic client = anthropic . Anthropic () tools = [ { " name " : " get_weather " , " description " : ( " Returns current weather for a city. Use ONLY for weather queries. " " Input: city name (string). Output: temperature in Celsius and conditions. " ), " input_schema " : { " type " : " object " , " properties " : { " city " : { " type " : " string " }}, " required " : [ " city " ], }, }, { " name " : " get_time " , " description " : ( " Returns the current local time for a city. Use ONLY for time/timezone queries. " " Input: city name (string). Output: local time string. " ), " input_schema " : { " type " : " object " , " properties " : { " city " : { " type " : " string " }}, " required " : [ " city " ], }, }, ] def get_weather ( city : str ) -> dict : return { " city " : city , " temp_c " : 22 , " conditions " : " sunny " } def get_time ( city : str ) -> dict : return { " city " : city , " local_time " : " 14:35 " } TOOL_FUNCTIONS = { " get_weather " : get_weather , " get_time " : get_time , } def run_agent ( user_message : str ) -> str : messages =