Give the CLI a stable machine-readable failure surface:
- EXIT_CODES map (0 ok / 1 usage / 2 no-app / 3 auth-required /
4 unreachable / 5 tool-error)
- ErrorEnvelope interface + CliExitCodeError for pre-classified exits
- pure classifyError() (status/cause/pattern heuristics) and
formatErrorOutput()/handleError() that emit one JSON line on stderr
- in-process cli-runner mirrors the binary via formatErrorOutput so tests
observe the real exit code and envelope
- document the exit-code map + envelope shape in clients/cli/README.md
Wave 1 foundation of the PR #1510 decomposition; shapes kept clean for
reuse by --app-info (exit 2), stored-auth (exit 3), and --format json.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S3fTN8H3R8YV4yUGvZjYnX
a5d8d80ffc