Claude Code with Anthropic API compatibility · Ollama Blog

Ollama v0.14.0 and later are now compatible with the Anthropic Messages API, making it possible to use tools like Claude Code with open-source models.

Run Claude Code with local models on your machine, or connect to cloud models through ollama.com.

Using Claude Code with Ollama

Claude Code is Anthropic’s agentic coding tool that lives in your terminal. With Anthropic API support, you can now use Claude Code with any Ollama model.

Get started

Install Claude Code

macOS, Linux, WSL:

curl -fsSL https://claude.ai/install.sh | bash

Windows PowerShell:

irm https://claude.ai/install.ps1 | iex

Windows CMD:

curl -fsSL https://claude.ai/install.cmd -o install.cmd && install.cmd && del install.cmd

Connect Ollama

Configure environment variables to use Ollama:

export ANTHROPIC_AUTH_TOKEN=ollama
export ANTHROPIC_BASE_URL=http://localhost:11434

Run Claude Code with an Ollama model:

claude --model gpt-oss:20b

Models in Ollama’s Cloud also work with Claude Code:

claude --model glm-4.7:cloud

It is recommended to run a model with at least 32K tokens context length.

For more information, please see context length documentation on how to make changes.

Ollama’s cloud models always run at their full context length.

Recommended models

For coding use cases with Claude Code:

Local models:

• gpt-oss:20b

• qwen3-coder

Cloud models:

• glm-4.7:cloud

• minimax-m2.1:cloud

Using the Anthropic SDK

Existing applications using the Anthropic SDK can connect to Ollama by changing the base URL. See the Anthropic compatibility documentation for details.

Python

import anthropic

client = anthropic.Anthropic(
    base_url='http://localhost:11434',
    api_key='ollama',  # required but ignored
)

message = client.messages.create(
    model='qwen3-coder',
    messages=[
        {'role': 'user', 'content': 'Write a function to check if a number is prime'}
    ]
)
print(message.content[0].text)

JavaScript

import Anthropic from '@anthropic-ai/sdk'

const anthropic = new Anthropic({
  baseURL: 'http://localhost:11434',
  apiKey: 'ollama',
})

const message = await anthropic.messages.create({
  model: 'qwen3-coder',
  messages: [{ role: 'user', content: 'Write a function to check if a number is prime' }],
})

console.log(message.content[0].text)

Tool calling

Models can use tools to interact with external systems:

import anthropic

client = anthropic.Anthropic(
    base_url='http://localhost:11434',
    api_key='ollama',
)

message = client.messages.create(
    model='qwen3-coder',
    tools=[
        {
            'name': 'get_weather',
            'description': 'Get the current weather in a 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 in San Francisco?"}]
)

for block in message.content:
    if block.type == 'tool_use':
        print(f'Tool: {block.name}')
        print(f'Input: {block.input}')

Supported features

• Messages and multi-turn conversations
• Streaming
• System prompts
• Tool calling / function calling
• Extended thinking
• Vision (image input)

For a complete list of supported features, see the Anthropic compatibility documentation.

Learn more

For more detailed setup instructions and configuration options, see the Claude Code guide.