How to Use DeepSeek-V3.1 in Claude Code

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How to Use DeepSeek-V3.1 in Claude Code

Claude Code is a lightweight coding assistant that normally connects to Anthropic’s Claude models. Thanks to DeepSeek’s Anthropic-compatible API, you can also run Claude Code on top of DeepSeek V3.1 with just a few environment variables.

This guide walks you through installation, configuration, and usage.

1. Install Claude Code

Claude Code can be installed in two ways:

Option A (curl installer):

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

Option B (npm):

npm install -g @anthropic-ai/claude-code

2. Configure for DeepSeek V3.1

Claude Code relies on Anthropic API variables. To redirect it to DeepSeek’s Anthropic-compatible endpoint, set these environment variables:

# Point to DeepSeek's Anthropic-compatible endpoint
export ANTHROPIC_BASE_URL="https://api.deepseek.com/anthropic"

# Your DeepSeek API Key
export ANTHROPIC_AUTH_TOKEN="YOUR_DEEPSEEK_API_KEY"

# Use DeepSeek V3.1 as the main model
export ANTHROPIC_MODEL="deepseek-chat"

# Use DeepSeek V3.1 also as the small/fast model
export ANTHROPIC_SMALL_FAST_MODEL="deepseek-chat"

Notes:

deepseek-chat = DeepSeek V3.1 (non-reasoning mode)
deepseek-reasoner = DeepSeek V3.1 reasoning mode (supports detailed “thinking” traces, but limited tool use)

If you want the reasoning model, replace deepseek-chat with deepseek-reasoner.

3. One-Click Startup Script

To simplify usage, you can create a shell script called start-claude-deepseek.sh:

#!/bin/bash
# DeepSeek V3.1 with Claude Code

export ANTHROPIC_BASE_URL="https://api.deepseek.com/anthropic"
export ANTHROPIC_AUTH_TOKEN="YOUR_DEEPSEEK_API_KEY"
export ANTHROPIC_MODEL="deepseek-chat"
export ANTHROPIC_SMALL_FAST_MODEL="deepseek-chat"

# Launch Claude Code
claude "$@"

Make it executable:

chmod +x start-claude-deepseek.sh

Now run Claude Code with:

./start-claude-deepseek.sh

4. Usage

Navigate into your project folder and run the script:

cd your-project
../start-claude-deepseek.sh

From here, Claude Code behaves exactly the same—except now it’s powered by DeepSeek V3.1.

5. Troubleshooting

Invalid token error → check that ANTHROPIC_AUTH_TOKEN is set to your real DeepSeek API key.
No response → confirm the ANTHROPIC_BASE_URL is correct (https://api.deepseek.com/anthropic).
Tool/function calling → supported in deepseek-chat; deepseek-reasoner may fall back to deepseek-chat.

✅ You’re now ready to use Claude Code with DeepSeek V3.1 as your AI coding assistant.