When commands like grep, diff, test, or find return non-zero exit codes
that aren't actual errors (grep 1 = no matches, diff 1 = files differ),
the model wastes turns investigating non-problems. This adds an
exit_code_meaning field to the terminal JSON result that explains
informational exit codes, so the agent can move on instead of debugging.
Covers grep/rg/ag/ack (no matches), diff (files differ), find (partial
access), test/[ (condition false), curl (timeouts, DNS, HTTP errors),
and git (context-dependent). Correctly extracts the last command from
pipelines and chains, strips full paths and env var assignments.
The exit_code field itself is unchanged — this is purely additive context.