> ## Documentation Index
> Fetch the complete documentation index at: https://kenpachi.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Multi-Step Rollbacks

> Undo earlier steps in a multi-tool execution batch if a subsequent step fails.

When a model calls several tools in one turn — reserve a seat, then charge a card — a failure on step two can leave step one's side effects in place. kenpachi implements **saga-style rollback**: register an undo in each tool, and if a later tool in the same batch fails, undos run in reverse order.

<Tip>
  Think of `registerCompensation` as "if anything after me fails, run this cleanup."
</Tip>

***

## Example

```typescript theme={null}
import { z } from "zod";
import { Agent, defineTool } from "kenpachi";

const reserveSeat = defineTool({
  name: "reserve_seat",
  description: "Reserves a seat for a user",
  schema: z.object({ seatId: z.string() }),
  async execute({ seatId }, ctx) {
    console.log(`Reserved seat ${seatId}`);

    // Register compensating action
    ctx.registerCompensation(async () => {
      console.log(`Rollback: Released seat ${seatId}`);
    });

    return { status: "held", seatId };
  },
});

const processPayment = defineTool({
  name: "process_payment",
  description: "Charges user payment card",
  schema: z.object({ amount: z.number() }),
  async execute({ amount }) {
    // Payment fails
    throw new Error("Card declined: Insufficient funds");
  },
});

// If the model calls reserveSeat and processPayment together,
// the reserveSeat hold is automatically released when processPayment throws.
```