add technical overview

Author: alexandratran

delegation-toolkit/concepts/erc7715.md

@@ -16,6 +16,26 @@ It also enables dapps to execute transactions for users without an active wallet
 This feature requires [MetaMask Flask 12.14.2](/snaps/get-started/install-flask) or later.
 :::
 
+## ERC-7715 technical overview
+
+[ERC-7715](https://eips.ethereum.org/EIPS/eip-7715) defines a JSON-RPC method `wallet_grantPermissions`. Dapps can use this method to request a wallet to grant the dapp permission to execute transactions on a user's behalf.
+`wallet_grantPermissions` includes a `signer` parameter, which identifies the entity requesting or managing the permission.
+Common signer implementations include wallet signers, single key and multisig signers, and account signers.
+
+The Delegation Toolkit's implementation uses an account signer.
+A session account is created and used for the single purpose of requesting and redeeming ERC-7715 permissions, and does not contain tokens.
+The account can be granted with permissions and redeem them as specified in [ERC-7710](https://eips.ethereum.org/EIPS/eip-7710).
+The account can be a smart account or an externally owned account (EOA).
+
+
+The MetaMask user that the session account requests permissions from must be upgraded to a [MetaMask smart account](smart-accounts.md).
+
+:::info ERC-7715 vs. delegations
+ERC-7715 expands on regular [delegations](delegation/index.md) by enabling permission sharing *via the MetaMask browser extension*.
+Regular delegations cannot be signed through the MetaMask extension, because if a dapp requests a delegation without constraints, the whole wallet can be exposed to the dapp.
+In contrast, ERC-7715 requires a [permission type](#permission-types) which displays a readable confirmation for the MetaMask user.
+:::
+
 ## ERC-7715 permissions lifecycle
 
 The ERC-7715 permissions lifecycle is as follows:
@@ -39,7 +59,3 @@ The Delegation Toolkit currently supports the following types of ERC-7715 permis
 - **Native token permissions** - Define how dapps can use users' native tokens.
 
 - **ERC-20 token permissions** - Define how dapps can use users' ERC-20 tokens.
-
-## ERC-7715 permissions vs. delegation
-
-Requesting and redeeming ERC-7715 permissions differ from [creating and redeeming delegations](delegation/index.md).