Uses standard email library

Handles encoded subjects

Email address validation

Handles missing fields

Handles malformed input

Structured JSON output

Error handling present

Step-by-step documentation

Processes all provided emails

Script is self-contained

Standard library email parsing

Step-by-step workflow document

All four categories present

Confidence field populated

Handles missing subject

Error handling in parsing

Extensible classification design

All emails processed

Output is valid JSON

Production-ready error output

Correct billing classification

Correct operations classification

Standard email parsing

Display name extraction

Encoded subject decoding

Email address validation

valid_address column present

Body preview truncated correctly

CSV has header row

Process log documents each email

Validation warning in log

All four emails in output

Error handling present