4.6 — Production MCP Patterns

Pattern 1: Server-Per-Domain (Avoid Tool Flooding)

Pattern 2: Tool Versioning

# Version your tools to prevent schema drift
@mcp.tool()
def create_ticket_v2(
    account_id: str,
    summary: str,
    priority: str,
    labels: list[str] = None  # New field in v2
) -> dict:
    """Create a support ticket (v2 — supports labels).
    Supersedes create_ticket. Use this version for all new ticket creation."""
    ...

# Deprecation: keep old version with redirect notice
@mcp.tool()
def create_ticket(account_id: str, summary: str, priority: str) -> dict:
    """[DEPRECATED] Use create_ticket_v2 instead. Creates a support ticket."""
    return create_ticket_v2(account_id, summary, priority)

Pattern 3: Human-in-the-Loop for Destructive Operations