Struct SessionSpec 

pub struct SessionSpec {

    pub cwd: PathBuf,
    pub prompt: PromptMode,
    pub append_system_prompt: Option<String>,
    pub model: String,
    pub effort: String,
    pub session_id: String,
    pub resume: Option<String>,
    pub permission_mode: Option<String>,
    pub allowed_tools: Vec<String>,
    pub disallowed_tools: Vec<String>,
    pub tools: Vec<String>,
    pub writable: bool,
    pub settings_json: Option<Value>,
    pub json_schema: Option<Value>,
    pub max_budget_usd: Option<f64>,
    pub max_turns: Option<u32>,
    pub env: HashMap<String, String>,
    pub sandbox: Option<ResolvedSandbox>,
    pub hook_status: Option<HookStatusSeed>,
}

Everything needed to spawn one agent session.

Fields

cwd: PathBuf

Working directory (target repo root) — project config loads from here.

prompt: PromptMode

append_system_prompt: Option<String>

Appended to the default Claude Code system prompt (role prompt).

Claude-CLI-ism: --append-system-prompt has no equivalent on other backends, which may ignore this field.

model: String

Model alias or full id (passed to –model).

effort: String

low | medium | high | xhigh | max (passed to –effort).

Claude-CLI-ism: --effort is a Claude Code flag; a non-claude backend may ignore this field.

session_id: String

Engine-chosen session UUID (passed to –session-id) so resume bookkeeping never depends on parsing CLI output.

resume: Option<String>

When set, resume this previous session id instead of starting fresh.

Claude-CLI-ism: session resume is a Claude Code capability; a non-claude backend may ignore (or reject) this field.

permission_mode: Option<String>

Passed to –permission-mode (e.g. “acceptEdits”, “plan”, “dontAsk”).

Claude-CLI-ism: --permission-mode has no equivalent on other backends, which may ignore this field.

allowed_tools: Vec<String>

Passed to –allowedTools (patterns like “Bash(npm test*)”).

Claude-CLI-ism: --allowedTools is a Claude Code permission concept; a non-claude backend may ignore this field.

disallowed_tools: Vec<String>

Passed to –disallowedTools (patterns like “Bash(git push*)”).

Claude-CLI-ism: --disallowedTools is a Claude Code permission concept; a non-claude backend may ignore this field.

tools: Vec<String>

Passed to --tools (the built-in exclusive tool allow-list): empty = CLI default set, no flag emitted. Distinct from allowed_tools/disallowed_tools, which are permission patterns.

Claude-CLI-ism: --tools is a Claude Code flag; a non-claude backend may ignore this field.

writable: bool

Whether this session’s role is expected to edit the working tree.

Non-Claude backends use this to select a write-capable local workspace mode for workers while keeping validators and orchestrators read-only. Claude continues to use permission_mode/tool rules and ignores this.

settings_json: Option<Value>

Extra settings JSON (hooks etc.) passed via –settings.

Claude-CLI-ism: --settings (hooks, etc.) is a Claude Code concept; a non-claude backend may ignore this field.

json_schema: Option<Value>

JSON Schema enforced on the session’s structured output (–json-schema).

Claude-CLI-ism: --json-schema is a Claude Code flag; a non-claude backend may ignore this field.

max_budget_usd: Option<f64>

Hard dollar cap for the run (–max-budget-usd).

Claude-CLI-ism: --max-budget-usd is a Claude Code flag; a non-claude backend may ignore this field (and should enforce cost caps engine-side via its own pricing table instead).

max_turns: Option<u32>

Soft turn budget: the engine counts assistant turns and aborts the session when exceeded (the CLI no longer has –max-turns).

env: HashMap<String, String>

Extra environment variables for the child process.

sandbox: Option<ResolvedSandbox>

Resolved OS sandbox, when the role opted into enforcement and the platform supports it (None otherwise).

Additive field (docs/scoping/worker-sandboxing.md): populated by runner.rs for worker/validator sessions. Non-claude backends ignore it.

hook_status: Option<HookStatusSeed>

Hook-status lane seed (ticket agent-hooks-status-signals): when the mission config opts in AND the role’s backend is hook-capable (crate::types::BackendKind::supports_hook_status_signals), the runner registers a per-run capability token and carries it here so the backend can install its lifecycle-hook projection at spawn. Backends without a hook surface ignore this field exactly like settings_json — a Some on them is a byte-identical no-op.

Trait Implementations

impl Clone for SessionSpec

fn clone(&self) -> SessionSpec

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SessionSpec

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

Formats the value using the given formatter.