using-elixir-skills
This skill should be used when the user works on any .ex or .exs file, mentions Elixir/Phoenix/Ecto/OTP, the project has a mix.exs, or asks "which skill should I use", "new to Elixir", "help with Elixir". Routes to the correct thinking skill BEFORE exploring code. Triggers on "implement", "add", "fix", "refactor" in Elixir projects.
git clone --depth 1 https://github.com/georgeguimaraes/claude-code-elixir /tmp/using-elixir-skills && cp -r /tmp/using-elixir-skills/plugins/elixir/skills/using-elixir-skills ~/.claude/skills/using-elixir-skillsSKILL.md
<EXTREMELY-IMPORTANT> If the task involves Elixir, Phoenix, or OTP code, you MUST invoke the relevant skill BEFORE doing ANYTHING else—including exploring the codebase. THIS IS NOT OPTIONAL. Skills tell you HOW to explore and WHAT to look for. You cannot rationalize your way out of this. </EXTREMELY-IMPORTANT> ## The Rule ``` Elixir/Phoenix/OTP task → Invoke skill FIRST → Then explore/research → Then write code ``` **Skills come before exploration.** The skills tell you what patterns to look for, what questions to ask, and what anti-patterns to avoid. Exploring without the skill means you don't know what you're looking for. ## Skill Triggers | Trigger Phrases | Skill to Invoke | |-----------------|-----------------| | code, implement, write, design, architecture, structure, pattern | `elixir-thinking` | | LiveView, Plug, PubSub, mount, channel, socket, component | `phoenix-thinking` | | context, schema, Ecto, changeset, preload, Repo, migration | `ecto-thinking` | | GenServer, supervisor, Task, ETS, bottleneck, Broadway | `otp-thinking` | | Oban, workflow, job queue, cascade, graft, background job, async job | `oban-thinking` | ## Red Flags These thoughts mean STOP—invoke the skill: | Thought | Reality | |---------|---------| | "Let me explore the codebase first" | Skills tell you WHAT to look for. Invoke first. | | "Let me understand the code first" | Skills guide understanding. Invoke first. | | "But first, let me..." | No. Skills come first. Always. | | "I'll add a process to organize this" | Processes are for runtime, not organization. | | "GenServer is the Elixir way" | GenServer is a bottleneck by design. | | "I'll query in mount" | mount is called twice. | | "Task.async is simpler" | Use Task.Supervisor in production. | | "I know Elixir well enough" | These skills contain paradigm shifts. Invoke them. |
This skill should be used when the user asks to "add a database table", "create a new context", "query the database", "add a field to a schema", "validate form input", "fix N+1 queries", "preload this association", "separate these concerns", or mentions Repo, changesets, migrations, Ecto.Multi, has_many, belongs_to, transactions, query composition, or how contexts should talk to each other.
This skill should be used when the user asks to "implement a feature in Elixir", "refactor this module", "should I use a GenServer here?", "how should I structure this?", "use the pipe operator", "add error handling", "make this concurrent", or mentions protocols, behaviours, pattern matching, with statements, comprehensions, structs, or coming from an OOP background. Contains paradigm-shifting insights.
This skill should be used when the user asks to "add a background job", "process async", "schedule a task", "retry failed jobs", "add email sending", "run this later", "add a cron job", "unique jobs", "batch process", or mentions Oban, Oban Pro, workflows, job queues, cascades, grafting, recorded values, job args, or troubleshooting job failures.
This skill should be used when the user asks to "add background processing", "cache this data", "run this async", "handle concurrent requests", "manage state across requests", "process jobs from a queue", "this GenServer is slow", or mentions GenServer, Supervisor, Agent, Task, Registry, DynamicSupervisor, handle_call, handle_cast, supervision trees, fault tolerance, "let it crash", or choosing between Broadway and Oban.
This skill should be used when the user asks to "add a LiveView page", "create a form", "handle real-time updates", "broadcast changes to users", "add a new route", "create an API endpoint", "fix this LiveView bug", "why is mount called twice?", or mentions handle_event, handle_info, handle_params, mount, channels, controllers, components, assigns, sockets, or PubSub. Covers where to load data (mount vs handle_params) and the LiveView lifecycle.