Module scheduler 

Scheduler

Scheduler: loop guard and 6-state turn FSM.

Overview

The scheduler is the core orchestration component that manages agent turn execution. It implements a finite state machine (FSM) with the following states:

1. Start: Initialize turn, load session
2. LLM Call: Send request to LLM
3. Parse Action: Parse LLM response into structured action
4. Execute Tool: Run tool if action is a tool call
5. Update State: Update session state with results
6. Loop/Finish: Either continue or complete the turn

Loop Guard

The LoopGuard ensures turn termination by tracking:

• Number of steps (LLM calls)
• Number of tool calls
• Consecutive errors
• Elapsed time

If any limit is exceeded, the turn is terminated with an appropriate GuardReason.

Example

use bob_runtime::scheduler::LoopGuard;
use bob_core::types::TurnPolicy;

let policy = TurnPolicy::default();
let mut guard = LoopGuard::new(policy);

while guard.can_continue() {
    guard.record_step();
    // Execute step...
}

Structs

LoopGuard

Safety net that guarantees turn termination by tracking steps, tool calls, consecutive errors, and elapsed time against TurnPolicy limits.

Functions

run_turn

Execute a single agent turn as a 6-state FSM.

run_turn_stream

Execute a single turn in streaming mode and return an event stream.