Elixir Phoenix Guide: Now on GitHub Copilot

The Elixir Phoenix Guide is now available for GitHub Copilot. Everything from the Claude Code version, ported into Copilot’s native instruction and hook system. Nothing was cut.

What the Plugin Does

The plugin gives your AI assistant opinionated, production-grade Elixir and Phoenix knowledge. It covers 19 domains across the framework and enforces 27 rules automatically as you write code.

19 Context-Aware Instructions

Each instruction targets a specific area of Phoenix development and loads automatically based on the file you’re editing. Open a LiveView module and the LiveView rules are there. Open a test file and the testing guidance activates. No manual invocation needed.

The full set:

Each instruction contains concrete rules with code examples showing both the wrong pattern and the correct one. They’re not vague best-practice lists. They tell the model exactly what to write and what to avoid.

27 Automated Hooks

Hooks run on every tool call and catch problems before they make it into your codebase. 21 run before code is written. 6 run after, validating what was produced.

Blocking hooks stop known-dangerous patterns outright:

• String.to_atom/1 on user input (atom table exhaustion)
• String interpolation inside Ecto fragment (SQL injection)
• Redirects built from user input without validation (open redirect)
• mix ecto.reset and force push (data loss)
• Deprecated APIs like form_for, live_redirect, and .flash_group

Warning hooks flag patterns that are usually wrong but sometimes intentional:

• raw/1 in templates (XSS risk)
• Passwords, tokens, or secrets in Logger calls
• == comparison on tokens instead of Plug.Crypto.secure_compare/2
• Association access without a visible preload (N+1 queries)
• with blocks missing an else clause
• Repo calls directly in LiveView modules
• Nested conditionals, string concatenation in loops, hardcoded upload sizes

Every warning includes a copy-pasteable fix so you don’t have to stop and look up the correct pattern.

4 Analysis Scripts

These run outside the instruction system and analyze your project directly:

• code_quality.exs detects code duplication, high complexity functions, and unused functions using AST analysis
• detect_template_duplication.sh identifies repeated HEEx blocks that should be extracted into components
• detect_project.sh maps your project’s stack (Phoenix version, LiveView presence, Ecto adapter, Oban) so hooks can adapt their behavior
• run_analysis.sh orchestrates all of the above in one pass

Project Detection

The plugin detects your project’s stack at session start and adjusts accordingly. Building a JSON API without LiveView? The LiveView hooks stay silent. On Phoenix 1.7 instead of 1.8? You won’t see warnings about @current_scope. The rules fit the project.

Installation

Clone the repo and copy four things into your project root:

git clone https://github.com/j-morgan6/elixir-phoenix-guide-copilot.git

cp -r elixir-phoenix-guide-copilot/.github your-project/.github
cp -r elixir-phoenix-guide-copilot/hooks your-project/hooks
cp -r elixir-phoenix-guide-copilot/scripts your-project/scripts
cp elixir-phoenix-guide-copilot/AGENTS.md your-project/AGENTS.md

Copilot picks up the instructions automatically. No configuration, no restart.

Try It

GitHub: elixir-phoenix-guide-copilot

Works with any Elixir/Phoenix project. Elixir only required locally if you want to run code_quality.exs.