Optional ReadonlycwdThe session's working directory, which Claude Code puts in EVERY hook payload. The fallback project root repo-relative path prefixes resolve against when the runtime does not pass one — see projectRootOf.
Optional ReadonlypromptUserPromptSubmit (prompt-gate).
Optional ReadonlysourceSessionStart / UserPromptSubmit (inject).
Optional Readonlystop_Stop / SubagentStop (stop-gate) — the prior-block loop guard.
Optional Readonlytool_Optional Readonlytool_Optional Readonlytool_PostToolUse response (react).
The raw event fields the decode functions read (the union across roles).