Claude 4 Weekend Migration Playbook: Stop Panicking, Start Migrating

Assess the Damage (5 minutes)

Before fixing anything, understand what's broken. Run this in your project root:

# Find all files referencing Claude 4 models
grep -r "claude-4-opus\|claude-4-sonnet\|claude-4-opus-20250514\|claude-4-sonnet-20250514" \
  --include="*.js" --include="*.ts" --include="*.py" --include="*.json" \
  --include="*.yaml" --include="*.yml" --include="*.toml" --include="*.env" \
  --include="*.go" --include="*.rb" --include="*.java" --include="*.rs" \
  . 2>/dev/null | head -50

Also check your environment variables and config files:

# Check .env files for model references
grep -r "claude-4" .env* config* settings* 2>/dev/null

# Check package.json or requirements for SDK versions
cat package.json | grep -i anthropic
cat requirements.txt | grep -i anthropic

Count the files. If you see 1-5 files, you're looking at a 5-minute fix. If you see 20+, budget 15-20 minutes for a methodical sweep.

Pick Your Migration Path (3 minutes)

You have three options. Pick one based on your situation:

Update Your Code (5-15 minutes)

Path A (stay with Anthropic): The simplest migration. Change one string:

// JavaScript/TypeScript (Anthropic SDK)
// Before:
const model = "claude-4-opus";
// After:
const model = "claude-opus-4-8";

// Python (anthropic library)
# Before:
model = "claude-4-opus"
# After:
model = "claude-opus-4-8"

For Sonnet: claude-4-sonnet → claude-sonnet-4-6

Path B (DeepSeek): Install the SDK and update:

# Python
pip install openai  # DeepSeek uses OpenAI-compatible API

import openai
client = openai.OpenAI(
    api_key="your-deepseek-key",
    base_url="https://api.deepseek.com"
)
response = client.chat.completions.create(
    model="deepseek-chat",  # V4 Pro
    messages=[{"role": "user", "content": "Hello"}]
)

Path C (GPT-5 or Gemini): See the full migration guides linked above. Each includes code examples for Python, JavaScript, Go, and more.

Get a New API Key (if switching providers) (3 minutes)

If staying with Anthropic (Path A), skip this step — your existing key works.

If switching providers:

• DeepSeek: platform.deepseek.com — $5 free credit for new accounts
• OpenAI (GPT-5): platform.openai.com — $5 free credit for new accounts
• Google (Gemini): aistudio.google.com — 1,500 req/day free tier

Set the key in your environment:

# .env file
DEEPSEEK_API_KEY=sk-your-key-here
# or
OPENAI_API_KEY=sk-your-key-here

Test Thoroughly (5-10 minutes)

Don't skip this. Test before deploying:

# Quick smoke test
curl https://api.deepseek.com/v1/chat/completions \
  -H "Authorization: Bearer $DEEPSEEK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "deepseek-chat",
    "messages": [{"role": "user", "content": "Say hello in 3 words"}]
  }'

Check for:

• ✅ Response quality matches your expectations
• ✅ Response time is acceptable
• ✅ Token counts are reasonable
• ✅ No errors in your application logs
• ✅ Edge cases (empty prompts, long prompts, streaming)

Deploy and Monitor (5 minutes)

Deploy your changes. Then monitor for 30 minutes:

• Watch error rates — should drop to zero
• Check response quality — any regressions?
• Monitor API costs — are they in the expected range?
• Set up alerts for the new provider's status page

Pro tip: Run the new provider in parallel with your old code for a few hours. Route 10% of traffic to the new provider, 90% to the old (if it was still working). Gradually increase as confidence builds.