Struct Options 

pub struct Options { /* private fields */ }

The options a session starts (or resumes) with. Every field left unset takes R2.2’s default, which switches off everything personal.

Implementations

impl Options

pub fn new() -> Self

Every field at its default.

pub fn plain(system_prompt: impl Into<String>) -> Self

An agent that is not a coding agent (R4): no built-in tools, and system_prompt in place of harness’s own.

pub fn model(self, model: impl Into<String>) -> Self

The model, as --model takes it.

pub fn thinking(self, thinking: impl Into<String>) -> Self

The thinking level, as --thinking takes it.

pub fn mode(self, mode: Mode) -> Self

The starting mode; it governs the built-in tools.

pub fn sandbox(self, sandbox: Sandbox) -> Self

The sandbox for built-in commands.

pub fn builtin_tools<I, S>(self, names: I) -> Self

where I: IntoIterator<Item = S>, S: Into<String>,

The most built-in tools the session ever offers (R2.2.3); empty offers none.

pub fn system_prompt(self, prompt: SystemPrompt) -> Self

The system prompt policy (R2.3).

pub fn project_instructions(self, on: bool) -> Self

Read the project’s AGENTS.md / CLAUDE.md.

pub fn user_config(self, on: bool) -> Self

Read the user’s own setup (config, account, saved model).

pub fn skills(self, on: bool) -> Self

Discover skills.

pub fn agents(self, on: bool) -> Self

Discover agent definitions.

pub fn hooks(self, on: bool) -> Self

Run hooks from config; needs user_config(true).

pub fn mcp_server(self, name: impl Into<String>, server: Value) -> Self

One MCP server for the session, in the [mcp.servers] table’s shape as JSON.

pub fn approval_timeout(self, timeout: Option<Duration>) -> Self

How long an approval request waits for an answer; None waits for ever. Sent in whole seconds, rounded up, at least one.

pub fn allow_escapes(self, on: bool) -> Self

As --allow-escapes.

pub fn max_iterations(self, n: u32) -> Self

As --max-iterations.

pub fn cwd(self, dir: impl Into<PathBuf>) -> Self

The session’s working folder.

pub fn env(self, key: impl Into<OsString>, value: impl Into<OsString>) -> Self

A variable added to the session’s environment.

pub fn binary(self, path: impl Into<PathBuf>) -> Self

Use this harness binary (R12.1).

pub fn mock(self, path: impl Into<PathBuf>) -> Self

Answer the model from this mock file, with no key and no network (R5).

pub fn tool(self, tool: Tool) -> Self

A tool the program runs (R8.4), offered to the model after the built-in tools, in the order added.

pub fn on_approval<F, Fut>(self, callback: F) -> Self

where F: Fn(ApprovalRequest) -> Fut + Send + Sync + 'static, Fut: Future<Output = Decision> + Send + 'static,

Answers every approval request with callback’s decision (R8.3.2); the requests are then not yielded as events. A callback that panics, or returns a decision not among the request’s choices, answers Deny with the failure as the reason.

Trait Implementations

impl Clone for Options

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Options

The environment’s values are left out: they may hold keys.

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

Formats the value using the given formatter.

impl Default for Options

fn default() -> Self

Returns the “default value” for a type.