# Tidewave Phoenix

This MCP server connects an agent to a running Phoenix app so it can evaluate Elixir code, inspect logs, and query the development database. It helps when debugging against the app’s live state.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed · ★ 858
- Author: tidewave-ai
- License: Apache-2.0 · policy=link-only · description only; the file stays with the author
- Source: https://github.com/tidewave-ai/tidewave_phoenix
- Updated: 2026-10-23
- HTML: https://affpapa.org/en/nevibecode/mcp/tidewave-phoenix

## What it does

Tidewave gives an agent access to a Phoenix app running in development. Its tools evaluate Elixir code with access to the app’s runtime and in-memory data, read server logs, and locate module or function definitions in your app and its dependencies. Documentation is matched to package versions recorded in `mix.lock`.

The server can also run SQL against the development database. Queries target that database, so keep the development environment in mind. To connect, add the `tidewave` package to `mix.exs`, plug `Tidewave` into the app’s endpoint, and configure your MCP client to use `/tidewave/mcp` at the host and port where the web app runs. An automated installation path uses `igniter`.

The project recommends Phoenix LiveView v1.1 or later; some debugging options belong in `config/dev.exs` if they are not already enabled. Worktrees can run web servers on different ports. For that setup, the instructions describe `mix tidewave.proxy` as an STDIO MCP server that dispatches requests using a port parameter.

## Install

### Claude Code (native platform)

**Install**
- The MCP registry has no launch command for it: see the repository README

## When to use it
- check a function’s behavior in the running app
- inspect request logs to investigate a failure
- run SQL against the development database
- locate a function definition in the app or a dependency
- check documentation against versions in `mix.lock`

## Example prompts
- Check what this function returns in the running Phoenix app.
- Read the logs after this request and find the cause of the error.
- Run a SQL query against the development database and verify the result.

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md