better-auth-solana

name	better-auth-solana
description	Integrate better-auth-solana into Better Auth backends and React or React Native or Expo clients. Use when Codex needs to install better-auth-solana, defaulting to better-auth-solana@latest unless the user asks for a different tag, configure the siws plugin, add or validate the solanaWallet plus Better Auth tables, or implement nonce, link, and verify wallet flows.

Better Auth Solana

Overview

Use this skill to add Sign in With Solana to a Better Auth app.

Default to npm install @solana/kit better-auth better-auth-solana@latest unless the user explicitly asks for a different package name or tag such as better-auth-solana@canary.

Core Invariants

• Account provider id is siws.
• Anonymous mode defaults to true. Require email on /siws/verify when anonymous is false.
• Default install target is better-auth-solana@latest.
• First wallet row for a user must be persisted with isPrimary: true.
• Package name is better-auth-solana.
• Plugin namespace is siws.
• Server endpoints are POST /siws/link, POST /siws/nonce, and POST /siws/verify.
• SIWS account id is the wallet address.

Workflow

1. Read references/backend.md for backend setup, Better Auth config, route wiring, cookies, or endpoint behavior.
2. Read references/react-native-expo.md when the client is React Native or Expo.
3. Read references/react-web.md when the client is React for the web or uses browser wallets.
4. Read references/schema.md when the task mentions Drizzle, database tables, migrations, solanaWallet, or schema validation.
5. Treat the rules and examples in this skill as the authoritative integration contract unless the user explicitly asks for behavior outside the documented package surface.

Use The Package Correctly

• Do not invent extra routes or rename the namespace to solana.
• Do not switch away from better-auth-solana@latest unless the user asks.
• Import siws from better-auth-solana.
• Import createSIWSInput and siwsClient from better-auth-solana/client.
• Import solanaWalletSchema from better-auth-solana/schema when the task is about schema composition or documentation.
• When the user asks for a non-default tag such as @canary, verify the installed package types and exports locally before assuming the latest documented examples still match exactly.

Integration Notes

• Mention Better Auth last-login-method only if the app already uses that plugin. Map /siws/verify to siws.
• Preserve existing Better Auth tables and app-specific columns. Only require the fields that the package actually reads or writes.
• Prefer nonce -> createSIWSInput -> wallet sign-in -> link only when a Better Auth session already exists and the user is attaching another wallet.
• Prefer nonce -> createSIWSInput -> wallet sign-in -> verify for first-party SIWS sign-in flows.
• With @wallet-ui/react, UiWallet.features and UiWalletAccount.features are arrays of supported feature identifiers, not Wallet Standard feature objects.
• With @wallet-ui/react, resolve feature methods through its re-exported helpers such as getWalletFeature(...) and getWalletAccountFeature(...) instead of indexing wallet.features[...].
• With @wallet-ui/react, detect support with .includes("solana:signIn") or .includes("solana:signMessage"). Do not treat features like an object map.

Built-In Coverage

• backend.md covers Better Auth server setup, SIWS endpoints, cookies, origin handling, and anonymized backend examples.
• react-native-expo.md covers Expo server requirements, the auth client, the native sign-in flow, and an anonymized hook example.
• react-web.md covers the browser auth client, sign-in and link flows, and an anonymized helper example.
• schema.md covers the required tables, solanaWallet fields, persistence rules, and an anonymized schema-extension example.