Struct Agent 

pub struct Agent { /* private fields */ }

Builder for a single agent invocation.

Create with Agent::new, chain configuration methods, then call run with an AgentProvider to execute.

Examples

use ironflow_core::prelude::*;

let provider = ClaudeCodeProvider::new();

let result = Agent::new()
    .system_prompt("You are a Rust expert.")
    .prompt("Review this code for safety issues.")
    .model(Model::OPUS)
    .allowed_tools(&["Read", "Grep"])
    .max_turns(5)
    .max_budget_usd(0.50)
    .working_dir("/tmp/project")
    .permission_mode(PermissionMode::Auto)
    .run(&provider)
    .await?;

println!("Cost: ${:.4}", result.cost_usd().unwrap_or(0.0));

Implementations

impl Agent

pub fn new() -> Self

Create a new agent builder with default settings.

Defaults: Model::SONNET, no system prompt, no tool restrictions, no budget/turn limits, PermissionMode::Default.

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

Set the system prompt that defines the agent’s persona or constraints.

pub fn prompt(self, prompt: &str) -> Self

Set the user prompt - the main instruction sent to the agent.

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

Set the model to use for this invocation.

Accepts any string-like value. Use Model constants for well-known Claude models, or pass an arbitrary string for custom providers.

Defaults to Model::SONNET if not called.

pub fn allowed_tools(self, tools: &[&str]) -> Self

Restrict which tools the agent may invoke.

Pass an empty slice (or do not call this method) to allow the provider default set of tools.

pub fn max_turns(self, turns: u32) -> Self

Set the maximum number of agentic turns.

Panics

Panics if turns is 0.

pub fn max_budget_usd(self, budget: f64) -> Self

Set the maximum spend in USD for this invocation.

Panics

Panics if budget is negative, NaN, or infinity.

pub fn working_dir(self, dir: &str) -> Self

Set the working directory for the agent process.

pub fn mcp_config(self, config: &str) -> Self

Set the path to an MCP (Model Context Protocol) server configuration file.

pub fn permission_mode(self, mode: PermissionMode) -> Self

Set the permission mode controlling tool-use approval behavior.

See PermissionMode for details on each variant.

pub fn output<T: JsonSchema>(self) -> Self

Request structured (typed) output from the agent.

The type T must implement JsonSchema. The generated schema is sent to the provider so the model returns JSON conforming to T, which can then be deserialized with AgentResult::json.

Examples

use ironflow_core::prelude::*;

#[derive(Deserialize, JsonSchema)]
struct Review {
    score: u8,
    summary: String,
}

let provider = ClaudeCodeProvider::new();
let result = Agent::new()
    .prompt("Review the codebase")
    .output::<Review>()
    .run(&provider)
    .await?;

let review: Review = result.json().expect("schema-validated output");
println!("Score: {}/10 - {}", review.score, review.summary);

pub fn output_schema_raw(self, schema: &str) -> Self

Set structured output from a pre-serialized JSON Schema string.

Use this when the schema comes from configuration or another source rather than a Rust type. For type-safe schema generation, prefer output.

Important: structured output requires max_turns >= 2. The Claude CLI uses the first turn for reasoning and a second turn to produce the schema-conforming JSON.

Examples

use ironflow_core::prelude::*;

let schema = r#"{"type":"object","properties":{"labels":{"type":"array","items":{"type":"string"}}}}"#;
let agent = Agent::new()
    .prompt("Classify this email")
    .output_schema_raw(schema);

pub fn retry(self, max_retries: u32) -> Self

Retry the agent invocation up to max_retries times on transient failures.

Uses default exponential backoff settings (200ms initial, 2x multiplier, 30s cap). For custom backoff parameters, use retry_policy.

Only transient errors are retried: process failures and timeouts. Deterministic errors (prompt too large, schema validation) are never retried.

Panics

Panics if max_retries is 0.

Examples

use ironflow_core::prelude::*;

let provider = ClaudeCodeProvider::new();
let result = Agent::new()
    .prompt("Summarize the codebase")
    .retry(2)
    .run(&provider)
    .await?;

pub fn retry_policy(self, policy: RetryPolicy) -> Self

Set a custom RetryPolicy for this agent invocation.

Allows full control over backoff duration, multiplier, and max delay. See RetryPolicy for details.

Examples

use std::time::Duration;
use ironflow_core::prelude::*;
use ironflow_core::retry::RetryPolicy;

let provider = ClaudeCodeProvider::new();
let result = Agent::new()
    .prompt("Analyze the code")
    .retry_policy(
        RetryPolicy::new(3)
            .backoff(Duration::from_secs(1))
            .max_backoff(Duration::from_secs(60))
    )
    .run(&provider)
    .await?;

pub fn dry_run(self, enabled: bool) -> Self

Enable or disable dry-run mode for this specific operation.

When dry-run is active, the agent call is logged but not executed. A synthetic AgentResult is returned with a placeholder text, zero cost, and zero tokens.

If not set, falls back to the global dry-run setting (see set_dry_run).

pub fn resume(self, session_id: &str) -> Self

Resume a previous agent conversation by session ID.

Pass the session ID from a previous AgentResult::session_id() to continue the multi-turn conversation.

Examples

use ironflow_core::prelude::*;

let provider = ClaudeCodeProvider::new();

let first = Agent::new()
    .prompt("Analyze the src/ directory")
    .max_budget_usd(0.10)
    .run(&provider)
    .await?;

let session = first.session_id().expect("provider returned session ID");

let followup = Agent::new()
    .prompt("Now suggest improvements")
    .resume(session)
    .max_budget_usd(0.10)
    .run(&provider)
    .await?;

Panics

Panics if session_id is empty or contains characters other than alphanumerics, hyphens, and underscores.

pub async fn run( self, provider: &dyn AgentProvider, ) -> Result<AgentResult, OperationError>

Execute the agent invocation using the given AgentProvider.

If a retry_policy is configured, transient failures (process crashes, timeouts) are retried with exponential backoff. Deterministic errors (prompt too large, schema validation) are returned immediately without retry.

Errors

Returns OperationError::Agent if the provider reports a failure (process crash, timeout, or schema validation error).

Panics

Panics if prompt was never called or the prompt is empty (whitespace-only counts as empty).

Trait Implementations

impl Default for Agent

fn default() -> Self

Returns the “default value” for a type.