---
title: "Loop & Enhance"
description: "Automatic detect-fix-rerun cycles around a workflow; let Cerevisor improve your workflow between rounds."
slug: guides/advanced/loop-and-enhance
section: guides
subsection: advanced
canonical_url: https://cerevisor.com/docs/guides/advanced/loop-and-enhance
last_verified: 2026-05-18
last_verified_version: "1.2.0"
updated_at: 2026-05-18T15:08:18.053416+00:00
---

**Loop & Enhance** wraps a workflow run in a detect-fix-rerun cycle. After each round, the harness analyzes what failed, an LLM planner proposes edits to your workflow, those edits apply, and the next round runs.

The result: workflows that *improve themselves* between rounds, converging on a working version.

> **License gate:** Trial+/Paid only.

## When to use it

- Your workflow mostly works but has reliability issues you can't pin down.
- You want the harness to evolve the workflow toward something more robust.
- You're iterating on the *shape* of a workflow, not just its output.

When not to use it:

- For a workflow that already produces good output reliably: Loop & Enhance is overhead without payoff.
- For one-shot tasks where the cost of multiple rounds isn't justified.

## Enabling it

First time: **Settings → Automation → Loop & Enhance → Setup** opens the **Loop & Enhance Setup Modal** with the key knobs:

| Field | Default | Effect |
|---|---|---|
| **Max rounds** | 3 | Hard cap on cycles. |
| **Budget cap (USD)** | $5.00 | Total cost across all rounds, including planner LLM calls. |
| **Convergence mode** | strict | `strict` = stop only when no failures detected. `lenient` = also accept convergence when the only remaining failures are intentional skips or fallback outputs. |
| **Pause between rounds** | Off | If on, the run pauses after each round and asks you to approve continuation. |
| **Planner provider** | Chat builder's | Provider for the per-round planner LLM. |
| **Planner model** | Inherits | Specific model. |

After setup, toggle Loop & Enhance on per workflow in **Settings → Workflow → Loop & Enhance**.

## How it works

1. You click Run. The workflow runs **round 1**, same as a normal run.
2. At end-of-round, the harness builds a structured **FailureReport**: which agents failed, what their output looked like, what the verifier said, what the user feedback was.
3. The harness checks the report: did anything fail? If no: convergence; stop.
4. If yes: the **planner** LLM reads the FailureReport and proposes a list of **workflow operations** (`add agent`, `set instructions`, `add skill`, etc.) using the same op schema as the chat builder.
5. The orchestrator emits the proposed ops to the renderer. The renderer applies them via the standard `applyWorkflowOp` code path (same as chat-builder edits) and sends an ACK back with the edited workflow.
6. **Round 2** runs against the edited workflow.
7. Loop until convergence, max rounds, or budget cap.

## Safety rails

Multiple guards prevent runaway:

- **Hard `maxRounds` cap**: set per workflow. Run never exceeds.
- **Cumulative budget cap**: covers workflow execution + planner LLM cost. Run halts when reached.
- **Stuck detection**: if two consecutive rounds produce the same FailureReport fingerprint, the FSM emits a `loop_fixation_warning` orchestrator event (consumed by the [Situational Awareness pillar](../situational-awareness/configure-and-run.md#fixation-warnings) to flip the run's state label to `fixation-risk`) and optionally aborts. The planner isn't making progress; we stop.
- **Op allowlist**: the planner can only emit a limited set of ops. It can't delete the workflow, change the provider, or do anything truly destructive. The allowlist is `ENHANCER_ALLOWED_OPS` in code.

## The Loop & Enhance tab

When Loop & Enhance is running, the Execution Modal grows an extra **Loop & Enhance** tab showing:

- Round counter ("Round 2 of 3").
- Budget burn so far.
- Per-round timeline:
  - What failed.
  - What the planner proposed.
  - What was applied.
  - The planner's rationale.

Useful to understand *why* the workflow changed between rounds.

## Pause between rounds

If you turn this on, the FSM stops at the end of each round and waits for you to click **Continue to next round**. Useful when you want to review the proposed edits before committing.

The pause is between rounds, not between agents within a round.

## Planner provider rules

The planner needs a chat surface. **Codex CLI** and **Cursor Agent** as the planner provider are problematic: their output is harder to coax into the op schema. The default planner provider is your chat builder's provider, which is typically Anthropic or OpenAI-compatible for exactly this reason.

If your global default is Codex/Cursor, configure a different planner provider in **Settings → Automation → Loop & Enhance → Planner provider**.

## When convergence isn't possible

Some failures aren't fixable by editing the workflow:

- Provider rate limits.
- Network errors.
- Skill compatibility issues that the planner doesn't know how to resolve.

In these cases, Loop & Enhance will hit max rounds or budget cap and give up gracefully: the workflow's last successful round's output is preserved, and the failure report explains what couldn't be fixed.

## Cost expectations

Each round costs the workflow's normal run cost + a planner LLM call (~few cents on Anthropic Haiku). A 3-round run with $0.50/round workflow and 3¢/round planner = about $1.60.

Set the budget cap to a value you're comfortable spending on an automated optimization cycle.

## Why this exists

It's a different mode of working, instead of "run, edit, run, edit" manually, you set a goal and let the harness drive iteration. Worth it for stable workflows you keep coming back to; not worth it for one-shot tasks.