How do I read Line CLI's JSON output from a script?

Example in Python:

import json, subprocess

p = subprocess.run(
    ["line", "-p", "Summarize the open TODOs", "--output-format", "json", "--permission-mode", "dont-ask"],
    capture_output=True, text=True,
)
result = json.loads(p.stdout.strip().splitlines()[-1])
if result["is_error"]:
    print("failed:", result["subtype"], result["error"])
else:
    print(result["result"])
    print("tokens in/out:", result["usage"]["input_tokens"], result["usage"]["output_tokens"])

Also check p.returncode: 0 success, 1 error, 2 max turns, 130 interrupted. With stream-json, parse each line as its own event.