@b402ai/solana-mcp

Model Context Protocol server exposing the b402 Solana SDK as agent-callable tools. Compatible with Claude Code, Cursor, and any other MCP runtime that speaks the protocol over stdio.

One-line install

claude mcp add b402-solana -- npx -y @b402ai/solana-mcp

That's it. Defaults to mainnet using your existing Solana CLI keypair (~/.config/solana/id.json) — circuit artifacts are bundled in the package, no separate clone needed. Set B402_CLUSTER=devnet for risk-free testing.

Then in any Claude Code session: "What's my private balance on b402?" → tools fire.

Tools

| Tool | What it does | |---|---| | shield | Move SPL tokens from the wallet into a private balance | | unshield | Withdraw a private deposit to a public address | | private_swap | Atomic private swap through a registered adapter (Jupiter on mainnet, mock on devnet) | | status | Wallet pubkey + private balances by mint | | holdings | Per-deposit private holdings (id, mint, amount) | | balance | Aggregate private balance per mint | | quote_swap | Jupiter quote (mainnet routes only): expected OUT, slippage, price impact | | watch_incoming | Cursor-based poll for newly-arrived private deposits |

Optional env overrides

All four are optional — set only when you need to override a default.

| Variable | Default | |---|---| | B402_CLUSTER | devnet (one of mainnet / devnet / localnet) | | B402_RPC_URL | public RPC for the cluster (use Helius / Triton in production) | | B402_KEYPAIR_PATH | ~/.config/solana/id.json | | B402_CIRCUITS_ROOT | bundled artifacts shipped inside this package |

Example with overrides:

claude mcp add b402-solana \
  --env B402_CLUSTER=mainnet \
  --env B402_RPC_URL=https://your-helius-rpc \
  -- npx -y @b402ai/solana-mcp

Security

• Keypair loaded once from disk; never logged, never returned in tool responses.
• Tool responses include only public values: signatures, pubkeys, opaque deposit IDs, mints, amounts.
• Input pubkeys validated as base58; amounts validated as u64 strings (no floats).
• Stdout is the MCP transport; status messages go to stderr only.

Caveats

• Circuit artifacts shipped here are throwaway-devnet ceremony output. Mainnet-grade ceremony zkey ships separately when the b402 mainnet ceremony completes.
• Jupiter quote works only on mainnet — devnet calls return RouteNotFound because Jupiter doesn't index devnet liquidity.
• private_swap on devnet uses the mock adapter (constant 2x echo) since devnet has no AMM liquidity. Mainnet routes through Jupiter.

License

Apache-2.0. Source: https://github.com/mmchougule/b402-solana