MCPheonix MCP Server

MCPheonix MCP server exists for a simple reason — assistants are far more useful when they can act on MCPheonix directly instead of describing what you should do. A simplified implementation of the Model Context Protocol (MCP) server using Elixir's Phoenix Framework.

What you get

MCP server built on Phoenix Framework (Elixir). Exposes Server-Sent Events and JSON-RPC endpoints for MCP clients, with support for managing multiple child MCP servers through JSON configuration.

Setting it up

Setup follows the usual MCP pattern — install or clone the server, register it in your client's configuration file, restart the client.

What the assistant can call

Once MCPheonix is connected, these are the calls the assistant has available:

• Area — State
• Transport — HTTP (SSE + JSON-RPC)
• Framework — Phoenix 1.7, Elixir >= 1.14, Erlang >= 25
• Tests — ExUnit, 2 test files (Cloudflare DO client, mock websocket)
• Dependency — Version
• Elixir — >= 1.14
• Phoenix — ~> 1.7.0
• Node.js — >= 18 (for child MCP servers)
• Integration — What's Needed
• Endpoint — Method
• Package — Version
• phoenix — ~> 1.7.0

Configuration and credentials

You will need 6 environment variables: API_KEY, BFL_API_KEY, DART_TOKEN, CLOUDFLARE_WORKER_URL, CLOUDFLARE_ACCOUNT_ID, CLOUDFLARE_API_TOKEN. 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.

| Dependency | Version | |-----------|---------| | Elixir | >= 1.14 | | Erlang/OTP | >= 25 | | Phoenix | ~> 1.7.0 | | Node.js | >= 18 (for child MCP servers) | | Python | >= 3.9 (for Flux/Dart integration) |

Before you rely on it

• 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.
• With 14 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch MCPheonix.
• 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 mcpheonix mcp server does with a few real requests.

Choosing this one

This sits in the cloud and infrastructure group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. MCPheonix's toolset — Area, Transport, Framework and 11 more — is a fair guide to whether it matches your workflow. It is maintained by jmanhype; worth a glance at recent repository activity before you build anything load-bearing on it.

This entry was verified against MCPheonix's own documentation before publication; SyncDev keeps the directory reviewed rather than auto-generated.