Changing an interface

A service's interface is what its tools and events say of themselves: the records #[tool] and #[event] write into the image. A redeploy that breaks a caller of a public tool, the Stripe tool or an event is refused while a caller used it in the last 30 days, unless forced. See Deploying.

What breaks a caller

• a tool or event is removed;
• a tool is no longer public, no longer a query, no longer takes anonymous calls, or takes fewer kinds of caller;
• the Stripe tool is removed;
• an argument is newly required, or takes fewer values: only some strings where it took any, fewer strings of an enum, or no longer a negative integer;
• a result is no longer declared, or a result or event field is no longer always present;
• a result or event field may hold more values: any string where it held an enum's, more strings of an enum, or a negative integer;
• a type changes.

Added fields break nothing.

Changing one anyway

Keep the old tool beside the new one, marked #[deprecated], until no caller uses it. A deprecated tool's answers carry Deprecation, and Sunset once an owner sets one; see Calling a tool.