> ## Documentation Index
> Fetch the complete documentation index at: https://sequence-0fb8d9e6-api_docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Merkleized Wallet Configuration

> Single-root wallet configuration for Ecosystem Wallets, enabling signers, sessions, recovery, and extensions with efficient on-chain proofs.

Ecosystem Wallets store a single **Merkle root** on-chain that commits to the entire wallet configuration: signers, weights, thresholds, passkey authenticators, Smart Session rules, recovery mechanisms, and future extensions. Actions provide **Merkle proofs** to validate the parts of the configuration that are relevant at execution time.

## Model

* **Root**: the wallet contract stores one hash root.
* **Leaves**: typed records for signers, sessions, recovery, passkeys, and modules.
* **Extensions**: modules interpret specific leaf types (e.g., session enforcement, passkeys).
* **Proofs**: execution supplies Merkle proofs for the leaves it needs (e.g., signer weight, session rule).

```mermaid theme={null}
flowchart TD
  Root[Merkle Root on-chain]
  subgraph OffchainConfig["Off-chain configuration tree"]
    A[Signer leaves]
    B[Session rules]
    C[Passkey authenticators]
    D[Recovery config]
    E[Future modules]
  end
  OffchainConfig -->|hash| Root
  Tx[Transaction] -->|proofs for needed leaves| Root
```

## Updating configuration

Configuration updates (add device, change session limits, rotate keys) happen off-chain by computing a new tree and root. **Key Machine** service attests to the latest root; transactions can include or reference this attestation so the wallet accepts only the latest configuration.

```mermaid theme={null}
sequenceDiagram
  participant User
  participant Wallet
  participant Key Machine
  User->>Wallet: Propose new config (off-chain tree)
  Wallet->>Key Machine: Submit new root
  Key Machine-->>Wallet: Attest current root (signed)
  User->>Wallet: Execute tx with proofs + checkpointer attestation
  Wallet->>Wallet: Verify proofs match attested root
  Wallet-->>User: Execute
```

## Smart Sessions and Passkeys

* **Smart Sessions**: leaves define scopes for a session key (allowed contracts/functions, spend limits, expiries). Execution validates the session key and rule proofs before allowing actions.
* **Passkeys**: passkey authenticators are leaves; devices produce WebAuthn signatures that are validated by the passkey extension using the relevant leaf proof.

## Recovery

* **Timed recovery keys**: a recovery leaf encodes a time-lock window; initiating recovery starts a countdown where existing signers can cancel. After expiry, the recovery key can rotate primary signers.

## Efficiency

* Only the root is stored on-chain; proofs are provided as calldata when needed.
* Packing and bitmap techniques minimize calldata for multi-sig or multi-proof cases.

## Cross-chain coherency

* The same root governs all chains for a wallet; checkpointer attestations allow each network to accept only the canonical root, preventing replay with stale configurations.

## References

* [Wallet Contracts](https://github.com/0xsequence/wallet-contracts-v3)