Struct SubprocessSpawnConfig 

pub struct SubprocessSpawnConfig {
    pub cli_command: String,
    pub cli_args: Vec<String>,
    pub working_dir: String,
    pub env_vars: HashMap<String, String>,
    pub message: String,
    pub resume_flag: String,
    pub session_id_field: String,
    pub message_id: Option<String>,
    pub session_id: Option<String>,
}

Configuration for spawning a subprocess turn.

Fields

cli_command: String

CLI executable (e.g., “claude”).

cli_args: Vec<String>

CLI arguments (e.g., [“-p”, “–output-format”, “stream-json”, …]).

working_dir: String

Working directory for the subprocess.

env_vars: HashMap<String, String>

Environment variables to set.

message: String

The user’s JSON message to write to stdin.

resume_flag: String

Flag used to resume a previous session, e.g. “–resume” (Claude), “-r” (Gemini). Empty string means this provider does not support simple-flag resume.

session_id_field: String

JSON field name in the CLI’s init event that contains the session/thread ID. e.g. “session_id” (Claude/Gemini) or “thread_id” (Codex).

message_id: Option<String>

Optional client-supplied message id. Echoed back via the agent-message-accepted event when this config transitions from queued → running so the frontend can pair the event with a pending PendingMessage. None means no feedback is emitted.

session_id: Option<String>

Session id to hydrate inner.session_id with BEFORE the first turn — used by the picker “My Agents” reattach path. The caller reads this from block.meta["agent:sessionid"] which the frontend pre-populates from the prior block’s session id when launching with continueOfInstanceId. Without this hydration spawn_turn would only see the captured session id AFTER the first turn — meaning the first turn always launches the CLI fresh (no --resume <sid>) and starts a new conversation that re-injects the startup context.

Empty / None means “no prior session” (greenfield launch).

Best-effort, not authoritative: if the hydrated id is stale, the CLI’s stdout-emitted session id always overwrites it at capture time (see spawn_turn’s stdout-reader block). The reattach turn passes the (possibly stale) hydrated id via --resume; the CLI either accepts it or starts a new session and emits its own id, which then becomes the in- memory authority for every subsequent turn.

Trait Implementations

impl Clone for SubprocessSpawnConfig

fn clone(&self) -> SubprocessSpawnConfig

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SubprocessSpawnConfig

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.