Struct HookInput 

pub struct HookInput {
    pub command: String,
    pub cwd: Option<String>,
    pub root: Option<String>,
    pub session_id: Option<String>,
}

Fields

command: String

cwd: Option<String>

root: Option<String>

The project root, when the harness supplies one (HP-19) — a *_PROJECT_DIR env var for most, workspace_roots in the payload for cursor. Absent for codex/copilot.

session_id: Option<String>

The harness’s session/conversation id, when it supplies one (session_id for Claude/Gemini/Qwen/Droid, sessionId for grok, conversation_id for cursor). It comes from the harness’s own envelope, so the agent cannot forge it — which is what makes it usable as the anchor for recognizing the session’s scratchpad (see pathctx::session_scratchpad).