# Claude stream-json Compatibility Notes (v1)
This document describes the compatibility posture for parsing Claude Code stream-json outputs.
Normative contract:
- `docs/specs/claude-stream-json-parser-contract.md`
## Compatibility posture
- The parser is tolerant and line-oriented: errors are per-line and do not stop ingestion.
- Unknown outer `type` strings are treated as `Unknown` events (not errors) to allow upstream drift.
- `Normalize` is narrowly scoped in v1: it is emitted only for `type=="result"` subtype/is_error
cross-check inconsistencies when `is_error` is present.
## Field aliases
- `session_id` may also be provided as `sessionId`.