Epic: JSON Formatter & Event Schema

[thm-design]

Epic: JSON Formatter & Event Schema

Card: t_8fc3132c

Contains

• US-1: Single-Command JSON Output (NDJSON)
• US-4: Pretty JSON Mode

Technical Notes

• JsonFormatter helper class in cortex/agent.py or new file
• Nargs=? on --json argparse with const="ndjson", choices=["ndjson","pretty"]
• Envelope schema: type + timestamp + data
• 5 event types: session_start, tool_call, tool_result, say, error
• Rich output completely suppressed when --json is active
• --json is opt-in (default=None, current behavior unchanged)

Files Changed

• cortex/cli/init.py (~15 lines)
• cortex/agent.py (~50 lines)

Definition of Done

• --json flag accepted by argparse
• JsonFormatter emits NDJSON and pretty JSON
• session_start event emitted on startup
• say event emitted as final response
• All Rich output suppressed in JSON mode
• Existing tests pass unchanged