Rails MCP Server

Default-deny action registry, append-only spend ledger, and human sign-off audit trail (MCP tools). Exposed over MCP by the rails mcp server, that capability becomes something an assistant can invoke while it works, not something you go and do afterwards.

What it actually does

A self-hosted, caller-configured default-deny action registry + append-only spend ledger + CLI-only sign-off audit trail, exposed as MCP tools. Different category from this author's other six MCP servers (mcp-factory, rag-mcp, bus-mcp, desktop-mcp, github-mcp, discord-mcp) -- those are devtools ("connect an agent to X"); this one is governance and safety: "stop an agent from doing something irreversible without a human noticing."

Adding it to your client

Being a remote server, there is no local install. You register the endpoint with your client, authorise it once, and the tools appear.

Configuration

You will need 3 environment variables: RAILS_MCP_CONFIG_PATH, RAILS_MCP_SIGNOFF_LEDGER_PATH, RAILS_MCP_SPEND_LEDGER_PATH. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

Caveats

• Your data travels to the provider's service, so the usual questions apply about what you send and what they retain.
• MCP clients confirm each tool call by default. Leave that on until you have watched what the rails mcp server does with a few real requests.

When to reach for it

Plenty of developer tooling servers cover similar ground. The differences that matter in practice are scope of access and how much setup stands between you and a working tool call. It is maintained by jaimenbell; worth a glance at recent repository activity before you build anything load-bearing on it.

SyncDev reviews every entry in this directory against the project's own documentation before publishing, and revisits them as servers change.