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

# Resimulation

> Re-run the simulation of a pending signing request.

Re-runs the simulation of a pending signing request and returns the stored simulation. The encoding of `simulation` is described under [Simulation](/api-reference/signing-request#simulation): raw bytes holding UTF-8 JSON text in a network-specific form, for reference only.

A successful re-run replaces the stored simulation with the result of the run. If the simulation provider returns an error, or the organization's simulation allowance is used up, the call still succeeds and `simulation` is empty. A simulation that does not finish within 5 seconds fails a custom transaction with an error, and returns the earlier stored simulation for a dApp transaction. A returned simulation therefore does not show that it was just re-run.

The request must be pending, belong to a vault the API token can access, and have been created by the same API user. Only custom transactions and EVM dApp transactions are simulated; for any other request `simulation` is empty.

## Endpoint

```
rpc Resimulation
```

Request message: `mpcvault.platform.v1.ResimulationRequest`. Response message: `mpcvault.platform.v1.ResimulationResponse`.

## Request

| Field | Type | Required | Description |
| - | - | - | - |
| signing\_request\_uuid | string | Yes | UUID of the signing request. |

## Response

| Field | Type | Description |
| - | - | - |
| simulation | bytes | UTF-8 JSON text of the stored simulation, as described under [Simulation](/api-reference/signing-request#simulation). Empty when the request is not simulated. |
| error | mpcvault.platform.v1.Error | Not used by this call; always unset. Failures are returned as gRPC status errors. |

## Errors

| Code | Message | When |
| - | - | - |
| `FailedPrecondition` | `Signing request uuid required` | `signing_request_uuid` is empty. |
| `InvalidArgument` | `Invalid uuid` | The request does not exist, is in another organization or an inaccessible vault, or was created by another API user. |
| `FailedPrecondition` | `Signing request already done` | The request is not pending. |


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