Improved documentation

packages/metamask-snap/README.md

@@ -1,8 +1,52 @@
-## Sei Metamask Snap
+# Sei Metamask Snap
 
-This snap is under active development and is not yet ready for use until this packages has been properly audited by a third party.
+This documentation describes the functions and RPC request handler used in a MetaMask Snap to handle cryptocurrency transactions and account management using BIP44 standards.
 
-## Testing
+### `onRpcRequest`
+
+An RPC request handler that processes different request methods including `signDirect`, `signAmino`, and `getPrivateKey`. It handles the signing of transactions both in Amino and Direct mode, and also retrieves the private key.
+
+- **Syntax**: `onRpcRequest({ request }): Promise<TransactionSignature | PrivateKey>`
+- **Parameters**:
+  - `request`: An object representing the RPC request.
+- **Returns**: A Promise that resolves to a `TransactionSignature` or `PrivateKey`.
+
+## RPC Methods
+
+### `signDirect`
+
+Signs a transaction in Direct mode.
+
+- **Parameters**:
+  - `account_index`: The bip44 coin type 118 account index to use for signing.
+  - `signerAddress`: The address of the signer.
+  - `signDoc`: The document to be signed.
+- **Error Handling**: Throws an error if the private key is not available or if the user denies the transaction.
+
+### `signAmino`
+
+Signs a transaction in Amino mode.
+
+- **Parameters**:
+  - `account_index`: The bip44 coin type 118 account index to use for signing.
+  - `signerAddress`: The address of the signer.
+  - `signDoc`: The document to be signed.
+  - `enableExtraEntropy`: Boolean flag for extra entropy.
+  - `isADR36`: Boolean flag for ADR-36 compliance.
+- **Error Handling**: Throws an error if the private key is not available or if the user denies the transaction.
+
+
+### `getPrivateKey`
+
+Retrieves the private key for a specified account index using MetaMask's `snap_getBip44Entropy` method and BIP44 standards and coin type 118.
+
+- **Syntax**: `getPrivateKey(account_index: number = 0): Promise<PrivateKey>`
+- **Parameters**:
+  - `account_index` (number, optional): The index of the account, defaulting to 0.
+- **Returns**: A Promise resolving to a `PrivateKey`.
+
+
+## Local development and testing
 
 ### Setup
 Run `yarn` to install dependencies.
@@ -13,11 +57,9 @@ In order to run the snap locally simply run `yarn start` and the snap will be se
 ### Testing the snap
 
 #### Test UI
+This package has a helpful UI for testing all the exposed functions.
+
 `cd` into the `./test-ui` directory and run `yarn` to install dependencies. Then run `yarn dev` to start the test UI. The test UI will be served at `localhost:3000`. Please checkout the README.md in that directory to learn how to set the snap ID.
 
 #### Unit tests
 Run `yarn test` to run the unit tests.
-
-## Usage
-
-The snap exports three functions: `signAmino`, `signDirect`, and `getPrivateKey`. These functions can be used to create a SeiWallet interface for use with the `@sei-js` packages. `@sei-js/core` has a function to do this called `getMetaMaskSnapSeiWallet`