pub const USAGE_EXIT_CODE: i32 = 2;Expand description
Process exit code returned when the argv is a valid parse but an invalid
combination (EX_USAGE in spirit, 2 by this project’s contract).
GAP-SG-201 / GAP-SG-202 / GAP-SG-203 / GAP-SG-204: the agent-native surface
can only discover some usage errors once it sees the envelope — a --filter
key that exists nowhere in the result elements, or a predicate evaluated over
a page the query already truncated. Refusing those needs an error that maps
to the code clap already returns for a bad command line, so an agent branches
on one number for “you asked for something impossible” regardless of whether
the parser or the surface caught it.
2 rather than EX_USAGE (64): DUPLICATE_EXIT_CODE above was moved off
2 in v1.0.52 precisely to free it, src/main.rs already returns it for a
rejected flag, and introducing 64 now would give this binary two codes for
one meaning — which the exit-code rules forbid.