Firefly III MCP Server

MCP Server for Firefly III. Exposed over MCP by the firefly iii mcp server, that capability becomes something an assistant can invoke while it works, not something you go and do afterwards.

What it actually does

This is a Model Context Protocol (MCP) server for Firefly III, a free and open-source personal finance manager. Through this MCP server, users can leverage AI tools to manage their Firefly III accounts and transactions, creating AI assistants for personal finance and accounting.

• Interact with Firefly III instances via AI
• Programmatically manage accounts and transactions
• Extensible toolset for various financial operations
• Support for both local and cloud deployment
• Compatible with the Model Context Protocol standard
• Tool filtering via presets or custom tags to reduce token usage

Adding it to your client

The server ships on npm as @firefly-iii-mcp/local, so your MCP client can launch it on demand — there is no separate build step. Add the server block to your client's configuration, restart it, and the tools register themselves.

Configuration

You will need 3 environment variables: FIREFLY_III_BASE_URL, YOUR_FIREFLY_III_INSTANCE_URL, YOUR_FIREFLY_III_URL. The server will not start without them, which is usually why the tools fail to appear on a first run. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

• A running Firefly III instance * A Cloudflare account if you plan to deploy using the "Deploy to Cloudflare" button

Caveats

• It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
• Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
• MCP clients confirm each tool call by default. Leave that on until you have watched what the firefly iii mcp server does with a few real requests.

When to reach for it

This sits in the developer tooling group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. It is maintained by etnperlong; worth a glance at recent repository activity before you build anything load-bearing on it.

We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.