claude-code-parserStream-JSON Protocol Parser

Parse Claude Code's undocumented NDJSON protocol into fully typed TypeScript events. Zero dependencies. 9 kB.

Protocol Parser

Parse --output-format stream-json NDJSON lines into typed ClaudeEvent objects. Handles invalid JSON gracefully.

Solves the --verbose cumulative snapshot problem. Content fingerprinting handles multi-agent interleaving.

Construct --input-format stream-json messages — the undocumented stdin protocol for user messages, tool approval/denial, and tool results.

The first standalone reference for Claude Code's undocumented stream-json protocol. Output events, input messages, edge cases, gotchas.