@title Arcanist User Guide: Configuring a New Project
@group userguide

Explains how to configure Arcanist projects with ##.arcconfig## files.

= .arcconfig Basics =

Arcanist uses ##.arcconfig## files to determine a number of things about project
configuration. For instance, these are things it figures out from
##.arcconfig##:

  - where the logical root directory of a project is;
  - which server Arcanist should send diffs to for code review; and
  - which lint rules should be applied.

An ##.arcconfig## file is a JSON file which you check into your project's root.
A simple, valid file looks something like this:

  {
    "project_id" : "some_project_name",
    "conduit_uri" : "https://phabricator.example.com/api/"
  }

Here's what these options mean:

  - **project_id**: a human-readable string identifying the project
  - **conduit_uri**: the Conduit API URI for the Phabricator installation that
    Arcanist should send diffs to for review. Generally, if you access
    Phabricator at ##https://phabricator.example.com/##, the **conduit_uri** is
    ##https://phabricator.example.com/api/##. Be mindful about "http" vs
    "https".

For an exhaustive list of available options, see below.

= Advanced .arcconfig =

Other options include:

  - **lint_engine**: the name of a subclass of @{class:ArcanistLintEngine},
    which should be used to apply lint rules to this project. See (TODO).
  - **unit_engine**: the name of a subclass of
    @{class:ArcanistBaseUnitTestEngine}, which should be used to apply unit
    test rules to this project. See (TODO).
  - **arcanist_configuration**: the name of a subclass of
    @{class:ArcanistConfiguration} which can add new command flags for this
    project or provide entirely new commands.
  - **remote_hooks_installed**: tells Arcanist that you've set up remote hooks
    in the master repository (see @{article:Installing Arcanist SVN Hooks} for
    SVN, or (TODO) for git).
  - **copyright_holder**: used by @{class:ArcanistLicenseLinter} to apply
    license notices to source files.
  - **phutil_libraries**: map of additional Phutil libraries to load at startup.