> ## 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.

# Vault Members & Multisig

> Add team members to vaults and configure multi-signature policies.

## Adding Vault Members

Only vault managers can add members. Invitees must already be part of the organization ([invite members first](/guides/3-how-to-invite-members-to-your-organization/index)).

### Via Web Console

1. Select the vault and go to **Team & Tx policies**.

2. Click **Edit member** > **+ Add vault members**.

   <img src="https://mintcdn.com/mpcvault-47/kq3LAw0DIlTzrGcF/guides/5-how-to-add-vault-members-and-set-up-multisig/vaultmember1.png?fit=max&auto=format&n=kq3LAw0DIlTzrGcF&q=85&s=519e635a72f48469d9c6573dedf0774c" alt="Add Members" width="3470" height="1556" data-path="guides/5-how-to-add-vault-members-and-set-up-multisig/vaultmember1.png" />

3. Select members, assign roles, and click **Continue** > **Confirm**.

   <img src="https://mintcdn.com/mpcvault-47/kq3LAw0DIlTzrGcF/guides/5-how-to-add-vault-members-and-set-up-multisig/vaultmember2.png?fit=max&auto=format&n=kq3LAw0DIlTzrGcF&q=85&s=6fb4a6fe34b26092faf9450de1805cc3" alt="Assign Roles" width="3470" height="1720" data-path="guides/5-how-to-add-vault-members-and-set-up-multisig/vaultmember2.png" />

All vault managers receive a **Vault setting update** signing request.

### Via Mobile App

1. Select the vault from the home page.
2. Tap **...** > **Vault members** > **Manage members**.
3. Select members, assign roles, and tap **Confirm**.

   <img src="https://mintcdn.com/mpcvault-47/kq3LAw0DIlTzrGcF/guides/5-how-to-add-vault-members-and-set-up-multisig/appinvite.png?fit=max&auto=format&n=kq3LAw0DIlTzrGcF&q=85&s=d684236bbc89b76be2cd956a3c4b9ebc" alt="Mobile Add Members" width="3320" height="1978" data-path="guides/5-how-to-add-vault-members-and-set-up-multisig/appinvite.png" />

## Configuring Multisig Policies

Set approval requirements based on transaction volume, destination, or type. Each vault can have different policies.

### Setup Steps

1. Go to **Team & Tx policies** and click **+ New policy**.
2. Select the [policy type](/guides/15-vault-transaction-policies/index).
3. Configure the rules and click **Confirm**.
4. Approve the signing request in the app.

<Note>
  The number of required managers cannot exceed the [manager quorum](/guides/16-what-is-a-quorum/index).
</Note>

### Example

For a reserve vault holding significant funds:

| Daily Volume | Approval Required |
| ------------ | ----------------- |
| \< \$10,000  | Any member        |
| ≥ \$10,000   | 3 managers        |

***

## How Multisig Works

MPCVault's multisig is implemented through **system-enforced approval policies**, not traditional on-chain multisig.

### Policy Enforcement

When a signing request is created:

1. The MPCVault server checks the transaction against configured policies
2. If the required approvals are not met, the server **refuses to participate** in the MPC signing protocol
3. Only when all policy conditions are satisfied does the server allow the signing to proceed

```mermaid theme={null}
flowchart LR
    A[Signing Request] --> B{Policy Check}
    B -->|Not Met| C[Server Refuses]
    B -->|Met| D[MPC Signing Proceeds]
    D --> E[Transaction Signed]
```

### Key Security Model

<Warning>
  **MPCVault cannot sign transactions alone.** The server holds only one of three key shares required for signing.
</Warning>

Even though the server enforces policies, it cannot unilaterally sign transactions because:

| Component               | Key Share | Role                                   |
| ----------------------- | --------- | -------------------------------------- |
| Your device             | Share 1   | You control this share                 |
| MPCVault (Google Cloud) | Share 2   | Enforces policies, participates in MPC |
| MPCVault (Azure)        | Share 3   | Participates in MPC                    |

All three shares must participate in the MPC computation to produce a valid signature. The server's policy enforcement is an **additional security layer** on top of the cryptographic requirement that you must provide your key share.

### What This Means

* **You remain in control**: No signature is possible without your key share
* **Policies are enforced**: The server won't participate unless your configured rules are met
* **No single point of failure**: Even if the server were compromised, attackers cannot sign without your share