tests/use_cases/ holds scenario-driven tests run by the Claude Code agent, which acts as both the test runner and mock user. Each test prints a structured transcript; Claude evaluates correctness. First test: test_cli_startup.py — spawns cli.py with a subprocess, reads the welcome banner, sends EOF, and verifies exit code 0. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>