Crate agent_line 

A batteries-included Rust library for building agent workflows.

Define agents, wire them into workflows, and let the runner execute them. Agents communicate through shared context (Ctx) and control flow with outcomes like Outcome::Continue, Outcome::Next, Outcome::Retry, and Outcome::Done.

Quick start

use agent_line::{Agent, Ctx, Outcome, Runner, StepResult, Workflow};

#[derive(Clone)]
struct State { n: i32 }

struct AddOne;
impl Agent<State> for AddOne {
    fn name(&self) -> &'static str { "add_one" }
    fn run(&mut self, state: State, _ctx: &mut Ctx) -> StepResult<State> {
        Ok((State { n: state.n + 1 }, Outcome::Done))
    }
}

let mut ctx = Ctx::new();
let wf = Workflow::builder("demo")
    .register(AddOne)
    .build()
    .unwrap();

let result = Runner::new(wf).run(State { n: 0 }, &mut ctx).unwrap();
assert_eq!(result.n, 1);

Modules

tools

Standalone utility functions for common agent tasks.

Structs

Ctx

Execution context for agents (services, config, etc.)

ErrorEvent

Passed to the on_error hook when an agent errors or a limit is exceeded.

RetryHint

Metadata attached to an Outcome::Retry to explain why the agent wants to retry.

Runner

Executes a Workflow step by step, handling retries, waits, and routing.

StepEvent

Passed to the on_step hook after each successful agent step.

Workflow

A validated workflow of agents. Built via Workflow::builder.

WorkflowBuilder

Step-by-step builder for a Workflow. Obtained via Workflow::builder.

Enums

Outcome

Control flow for the runner.

StepError

Error type for agent steps, with variants designed around what the caller can do about them.

WorkflowError

Errors returned by WorkflowBuilder::build.

Traits

Agent

A sync agent that transforms state one step at a time.

Type Aliases

StepResult

The result of running a step: a new state plus what to do next.