@helmmasters/agentvault-mcp

MCP server for Helm (AgentVault) — exposes Solana agent-vault operations as Model Context Protocol tools. Read vault, policy, and pending state with no wallet; with a local keypair, propose / approve / veto / execute / suspend / and update guardian-gated transactions. Works in any MCP client: Claude Desktop, Hermes Agent, or your own. Built on @helmmasters/agentvault-sdk.

Install

npm install -g @helmmasters/agentvault-mcp

This installs the agentvault-mcp executable (stdio MCP server).

Configuration

Configured entirely through environment variables:

| Env var | Required | Default | Purpose | |---|---|---|---| | HELM_RPC_URL | no | https://api.mainnet-beta.solana.com | Solana mainnet RPC (use Helius/QuickNode — the public endpoint rate-limits) | | HELM_KEYPAIR_PATH | for write tools | — | Path to a JSON keypair file. Enables signing tools; the key never leaves the local process |

Mode A — read-only (no keypair). All read/utility tools work. Write tools return a clear error telling you to configure a keypair.

Mode B — signing (keypair path). All tools work. The keypair signs and the server simulates every transaction before sending.

Claude Desktop

Add to claude_desktop_config.json (Settings → Developer → Edit Config):

{
  "mcpServers": {
    "helm": {
      "command": "agentvault-mcp",
      "env": {
        "HELM_RPC_URL": "https://api.mainnet-beta.solana.com",
        "HELM_KEYPAIR_PATH": "/absolute/path/to/keypair.json"
      }
    }
  }
}

Omit HELM_KEYPAIR_PATH for read-only mode.

Hermes Agent

Hermes consumes MCP servers the same way. Add an entry to your Hermes MCP config (see the Hermes docs for the exact file location) pointing command at agentvault-mcp with the same env block. For remote setups, run agentvault-mcp behind your own MCP-over-HTTP bridge — but only on a host you control (see the security note below).

Tools

Read & utility tools need no signer. Write tools require HELM_KEYPAIR_PATH and simulate before sending.

| Tool | What it does | Signer | |---|---|:--:| | helm_list_vaults_for_guardian | List all vaults for a guardian wallet | — | | helm_get_vault | Vault state + its policy | — | | helm_get_policy | Policy: caps, whitelist, allowlist, feed, pending update | — | | helm_list_pending_transactions | Pending txs (value, tier, status, approval) | — | | helm_get_protocol_stats | Total vaults, SOL locked, pending count | — | | helm_derive_vault_pda | Derive vault PDA from guardian + id | — | | helm_derive_policy_pda | Derive policy PDA from vault | — | | helm_derive_pending_pda | Derive pending PDA from vault + nonce | — | | helm_create_vault | Initialize a vault (signer = guardian) | ✅ | | helm_propose_transaction | Propose a tx as the agent | ✅ | | helm_approve_pending | Approve a pending tx (guardian) | ✅ | | helm_veto_pending | Veto a pending tx (guardian) | ✅ | | helm_execute_pending | Execute an approved/timelock-elapsed pending tx | ✅ | | helm_suspend_vault / helm_resume_vault | Suspend / resume a vault (guardian) | ✅ | | helm_update_policy | Schedule a policy change (24h timelock) | ✅ | | helm_commit_policy_update | Apply a scheduled policy change after the timelock | ✅ |

USD caps are valued via a Pyth oracle. Policy updates are subject to the program's 24-hour timelock. Write tools are simulated first; on failure the server returns the structured Solana program error (not a generic "failed").

Security

• Your keypair stays local. HELM_KEYPAIR_PATH is read by the local process only and is never transmitted. Treat it like any hot wallet — fund it modestly.
• Do not run this as a hosted/multi-tenant service exposing your keypair. The signing mode is designed for a local MCP client (Claude Desktop / a Hermes instance you run). If you expose it over the network, you are exposing signing authority — put it behind your own auth and run it only on a host you control.
• Helm itself is the guardrail: even with a configured keypair, the vault enforces USD caps and the guardian timelock on-chain. An agent key can only do what the vault's policy allows.

Links

• Helm: helmagent.xyz · app: app.helmagent.xyz
• SDK: @helmmasters/agentvault-sdk
• Code: github.com/HelmMasters/agentvault (mcp/)

License

Apache-2.0