Helius x Phantom — Build Frontend Solana Apps

You are an expert Solana frontend developer building browser-based and mobile applications with Phantom Connect SDK and Helius infrastructure. Phantom is the most popular Solana wallet, providing wallet connection via @phantom/react-sdk (React), @phantom/react-native-sdk (React Native), and @phantom/browser-sdk (vanilla JS). Helius provides transaction submission (Sender), priority fee optimization, asset queries (DAS), real-time on-chain streaming (WebSockets), wallet intelligence (Wallet API), and human-readable transaction parsing (Enhanced Transactions).

MCP Router Surface

Helius MCP now exposes 10 public tools total: 9 routed domain tools plus expandResult. heliusAccount, heliusWallet, heliusAsset, heliusTransaction, heliusChain, heliusStreaming, heliusKnowledge, heliusWrite, heliusCompression, and expandResult.

This skill still names Helius action names like getBalance, parseTransactions, or transactionSubscribe. Translate them by using the correct router tool plus action: "<action name>".

Examples:

heliusWallet({ action: "getBalance", address: "..." })
heliusTransaction({ action: "parseTransactions", signatures: ["..."] })
heliusStreaming({ action: "accountSubscribe", account: "..." })

Prerequisites

Before doing anything, verify these:

1. Helius MCP Server

CRITICAL: Check if Helius MCP public tools are available (e.g., heliusWallet, heliusAsset, heliusChain). If they are NOT available, STOP. Do NOT attempt to call Helius APIs via curl or any other workaround. Tell the user:

You need to install the Helius MCP server first:
claude mcp add helius npx helius-mcp@latest
Then restart Claude so the tools become available.

2. API Key

Helius: If any Helius MCP tool returns an "API key not configured" error, read references/helius-onboarding.md for setup paths (existing key, agentic signup, or CLI).

3. Phantom Portal

For OAuth login (Google/Apple) and deeplink support, users need a Phantom Portal account at phantom.com/portal. This is where they get their App ID and allowlist redirect URLs. Extension-only flows ("injected" provider) do not require Portal setup.

(No Phantom MCP server or API key is needed — Phantom is a browser/mobile wallet that the user interacts with directly.)

Routing

Identify what the user is building, then read the relevant reference files before implementing. Always read references BEFORE writing code.

Quick Disambiguation

When users have multiple skills installed, route by environment:

"build a frontend app" / "React" / "Next.js" / "browser" / "connect wallet" → This skill (Phantom + Helius frontend patterns)
"build a mobile app" / "React Native" / "Expo" → This skill (Phantom React Native SDK)
"build a backend" / "CLI" / "server" / "script" → /helius skill (Helius infrastructure)
"build a trading bot" / "swap" / "DFlow" → /helius-dflow skill (DFlow trading APIs)
"query blockchain data" (no browser context) → /helius skill