Function is_interactive 

pub fn is_interactive() -> bool

Returns true when stdin is connected to a terminal (i.e. the process is running interactively), false otherwise (e.g. stdin is a pipe or redirected file, which is the common case in CI environments).

This centralises the TTY check so that add and init both branch on the same predicate rather than each duplicating the IsTerminal import and call site. The function is a thin wrapper over std::io::IsTerminal::is_terminal and carries no additional state; it can be replaced with a test double by injecting a bool at the call site when unit testing the callers.

Why a dedicated module instead of an inline call?

std::io::IsTerminal cannot be meaningfully unit-tested without spawning a real subprocess with a controlled stdin (the trait’s return value is determined by the OS, not by Rust code). The integration-test coverage for the non-interactive path lives in crates/callisto-cli/tests/cli_tests.rs — specifically test_add_non_interactive_via_pipe — which pipes stdin and asserts that callisto add selects the non-interactive code path rather than trying to drive a TTY wizard.