Read-only Ethereum MCP tools that stay local

RPC Relay Pro exposes Ethereum reads, health, and diagnostics over MCP stdio. The agent talks to localhost; the Pro credential remains in an owner-only accelerator configuration file.

Credential isolation

The API token never enters the prompt, tool arguments, or MCP response.

Read-only boundary

Signing, account management, and transaction-submission methods are rejected.

Local warm path

Repeated reads can resolve from device memory without revealing the access pattern upstream.

Install and configure

curl -fsSL https://rpc-relay.pages.dev/install.sh | sh
rpc-relay-pro setup
rpc-relay-pro mcp-config
rpc-relay-pro mcp

Available MCP capabilities

ethereum_rpc_read executes an explicit allowlist of read-only JSON-RPC methods. rpc_relay_health and rpc_relay_diagnostics expose cache, connection, reorg, validation, and fallback counters without returning credentials.

Why device-local MCP matters

Remote MCP tools add another service hop to an already remote RPC call. A localhost tool can answer warm state reads below the network floor, keep repetitive intent patterns off the network, and still use a canonical upstream for misses.

RPC Relay is not a wallet and cannot sign or submit a transaction through MCP. That narrow boundary is intentional.

Ethereum MCP questions

Which clients can use it?

Any MCP client that supports stdio servers and JSON-RPC tool calls can launch rpc-relay-pro mcp.

Can an agent send ETH through it?

No. Transaction and signing methods are outside the MCP allowlist.

Are warm reads always current?

Cache behavior depends on method, block tag, TTL, observed head, finality, and reorg policy. Diagnostics expose the actual cache status.