Build and Deploy LangChain Agent

CRITICAL: For Vercel, you MUST use vercel build --prod then vercel deploy --prebuilt --prod. Do NOT use vercel --prod or vercel deploy --prod directly - these will fail due to Git author permission issues in VM environments.

Workflow

1. Setup Environment Variables

Read .env.example to see all required variables:

cat .env.example

Create .env by reading values from current environment:

For each variable in .env.example, read the value from the current environment and write to .env. Example approach:

# Read .env.example and create .env with values from current environment
while IFS= read -r line || [[ -n "$line" ]]; do
  # Skip comments and empty lines
  [[ "$line" =~ ^#.*$ || -z "$line" ]] && continue
  # Extract variable name (before = sign)
  var_name=$(echo "$line" | cut -d'=' -f1)
  # Get value from environment
  var_value="${!var_name}"
  # Write to .env
  echo "${var_name}=${var_value}" >> .env
done < .env.example

Or manually inspect .env.example and create .env with the required values from environment variables.

2. Install Dependencies

yarn install

3. Build

yarn build

4. Deploy

Vercel:

All vercel CLI commands require -t <token> or --token <token> for authentication.

# Pull project settings (also links project, creates .vercel/project.json)
vercel pull --yes -t $VERCEL_TOKEN

# Push env vars to Vercel (first time only)
# Must add to each environment separately
while IFS='=' read -r key value; do
  [[ "$key" =~ ^#.*$ || -z "$key" || -z "$value" ]] && continue
  for env in production preview development; do
    printf '%s' "$value" | vercel env add "$key" $env -t $VERCEL_TOKEN
  done
done < .env

# Build locally for production
vercel build --prod -t $VERCEL_TOKEN

# Deploy prebuilt
vercel deploy --prebuilt --prod --yes -t $VERCEL_TOKEN

Netlify:

# Import all env vars from .env (first time only)
netlify env:import .env

# Deploy
netlify deploy --prod

Critical Notes

• VERCEL PREBUILT MODE IS MANDATORY: Always use vercel build --prod followed by vercel deploy --prebuilt --prod. Never use vercel --prod or vercel deploy --prod without --prebuilt flag.
• Environment Variables: All values come from current environment - inspect .env.example for required variables
• LLM Provider: Supports OpenAI, Anthropic, and Google - set LLM_PROVIDER accordingly
• No Dev Server: Never run yarn dev in VM environment