tlx AGENTS.md

usage_rules usage

A config-driven dev tool for Elixir projects to manage AGENTS.md files and agent skills from dependencies

Using Usage Rules

Many packages have usage rules, which you should thoroughly consult before taking any action. These usage rules contain guidelines and rules directly from the package authors. They are your best source of knowledge for making decisions.

Modules & functions in the current app and dependencies

When looking for docs for modules & functions that are dependencies of the current project, or for Elixir itself, use mix usage_rules.docs

# Search a whole module
mix usage_rules.docs Enum

# Search a specific function
mix usage_rules.docs Enum.zip

# Search a specific function & arity
mix usage_rules.docs Enum.zip/1

Searching Documentation

You should also consult the documentation of any tools you are using, early and often. The best way to accomplish this is to use the usage_rules.search_docs mix task. Once you have found what you are looking for, use the links in the search results to get more detail. For example:

# Search docs for all packages in the current application, including Elixir
mix usage_rules.search_docs Enum.zip

# Search docs for specific packages
mix usage_rules.search_docs Req.get -p req

# Search docs for multi-word queries
mix usage_rules.search_docs "making requests" -p req

# Search only in titles (useful for finding specific functions/modules)
mix usage_rules.search_docs "Enum.zip" --query-by title

usage_rules:elixir usage

Elixir Core Usage Rules

Pattern Matching

• Use pattern matching over conditional logic when possible
• Prefer to match on function heads instead of using if/else or case in function bodies
• %{} matches ANY map, not just empty maps. Use map_size(map) == 0 guard to check for truly empty maps

Error Handling

• Use {:ok, result} and {:error, reason} tuples for operations that can fail
• Avoid raising exceptions for control flow
• Use with for chaining operations that return {:ok, _} or {:error, _}