diff --git a/app/controllers/application_chatops_controller.rb b/app/controllers/application_chatops_controller.rb
index 9b86fb3..6932739 100644
--- a/app/controllers/application_chatops_controller.rb
+++ b/app/controllers/application_chatops_controller.rb
@@ -8,4 +8,13 @@ def verify_slack_hmac
   rescue Slack::Events::Request::MissingSigningSecret, Slack::Events::Request::InvalidSignature, Slack::Events::Request::TimestampExpired
     render plain: "Nope.", status: :unauthorized
   end
+
+  def subcommand
+    Utils::ParsesCliStyleCommandArgs.new.call(text: params[:text]).subcommand
+  end
+
+  def command_params
+    parsed = Utils::ParsesCliStyleCommandArgs.new.call(text: params[:text])
+    ActionController::Parameters.new(parsed.args)
+  end
 end
diff --git a/app/controllers/chatops/slack_slash_command_list_controller.rb b/app/controllers/chatops/slack_slash_command_list_controller.rb
new file mode 100644
index 0000000..4d1453d
--- /dev/null
+++ b/app/controllers/chatops/slack_slash_command_list_controller.rb
@@ -0,0 +1,24 @@
+module Chatops
+  class SlackSlashCommandListController < ::ApplicationChatopsController
+    def handle
+      config = Matchmaking.config
+      message = config.to_h.keys.sort.each_with_object([]) do |key, result|
+        grouping = config[key]
+        next unless include_grouping_in_list?(grouping)
+        result << "*#{key.to_s.titleize}*: Meets #{grouping.schedule} in groups of #{grouping.size} (Join: ##{grouping.channel})"
+      end.join("\n")
+
+      if config.to_h.keys.any?
+        render plain: message
+      else
+        render plain: "Sorry! There are no configured channels for groupings."
+      end
+    end
+
+    private
+
+    def include_grouping_in_list?(grouping)
+      grouping.active || command_params.key?(:all)
+    end
+  end
+end
diff --git a/app/lib/matchmaking.rb b/app/lib/matchmaking.rb
new file mode 100644
index 0000000..10e8559
--- /dev/null
+++ b/app/lib/matchmaking.rb
@@ -0,0 +1,6 @@
+module Matchmaking
+  def config
+    Rails.application.config.x.matchmaking
+  end
+  module_function :config
+end
diff --git a/config/routes.rb b/config/routes.rb
index 0f1521f..72ede75 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,8 +1,20 @@
+class SlackSlashSubcommandConstraint
+  def initialize(matches_subcommand:)
+    @subcommand = matches_subcommand
+  end
+
+  def matches?(request)
+    parsed = Utils::ParsesCliStyleCommandArgs.new.call(text: request.params["text"])
+    parsed.subcommand == @subcommand
+  end
+end
+
 Rails.application.routes.draw do
   if Rails.env.test?
     TestOnlyRoutes = ActionDispatch::Routing::RouteSet.new unless defined?(::TestOnlyRoutes)
     mount TestOnlyRoutes, at: "/"
   end
 
+  post "/command/doubleup", to: "chatops/slack_slash_command_list#handle", constraints: SlackSlashSubcommandConstraint.new(matches_subcommand: "channels:list")
   post "/command/doubleup", to: "chatops/slack_slash_command#handle"
 end
diff --git a/spec/requests/chatops/slack_slash_command_list_controller_spec.rb b/spec/requests/chatops/slack_slash_command_list_controller_spec.rb
new file mode 100644
index 0000000..235b5d1
--- /dev/null
+++ b/spec/requests/chatops/slack_slash_command_list_controller_spec.rb
@@ -0,0 +1,161 @@
+require "rails_helper"
+
+RSpec.describe "SlackSlashCommandListController", type: :request do
+  scenario "responds with default message when no channels configured" do
+    allow(Matchmaking).to receive(:config).and_return({})
+
+    signed = signed_request_body(params: {
+      "team_id" => "T02PF6RHYSY",
+      "team_domain" => "testdouble-hq",
+      "channel_id" => "C02NYBB3VPH",
+      "channel_name" => "some-channel",
+      "user_id" => "U02PRHH0XEV",
+      "user_name" => "cliff.pruitt",
+      "command" => "/doubleup",
+      "text" => "channels:list",
+      "api_app_id" => "A02PD0DUE03",
+      "is_enterprise_install" => "false",
+      "response_url" =>
+       "https://hooks.slack.com/commands/T02PF6RHYSY/2823421496992/0WC0HfWeGJpHetxmF8yUmawo",
+      "trigger_id" => "2801968477828.2797229610916.883001cf5008d6d02fd58a3cf70f449e"
+    })
+
+    request_headers = {
+      "X-Slack-Signature" => signed.signature,
+      "X-Slack-Request-Timestamp" => signed.timestamp
+    }
+
+    post "/command/doubleup",
+      params: signed.body,
+      headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expect(response.body).to eq("Sorry! There are no configured channels for groupings.")
+  end
+
+  scenario "responds with list of only active channels" do
+    allow(Matchmaking).to receive(:config).and_return(OpenStruct.new({
+      active_one: OpenStruct.new({
+        active: true,
+        schedule: "weekly",
+        size: 2,
+        channel: "active-1"
+      }),
+      not_active_one: OpenStruct.new({
+        active: false,
+        schedule: "weekly",
+        size: 2,
+        channel: "not-active-1"
+      }),
+      active_two: OpenStruct.new({
+        active: true,
+        schedule: "weekly",
+        size: 2,
+        channel: "active-2"
+      })
+    }))
+
+    signed = signed_request_body(params: {
+      "team_id" => "T02PF6RHYSY",
+      "team_domain" => "testdouble-hq",
+      "channel_id" => "C02NYBB3VPH",
+      "channel_name" => "some-channel",
+      "user_id" => "U02PRHH0XEV",
+      "user_name" => "cliff.pruitt",
+      "command" => "/doubleup",
+      "text" => "channels:list",
+      "api_app_id" => "A02PD0DUE03",
+      "is_enterprise_install" => "false",
+      "response_url" =>
+        "https://hooks.slack.com/commands/T02PF6RHYSY/2823421496992/0WC0HfWeGJpHetxmF8yUmawo",
+      "trigger_id" => "2801968477828.2797229610916.883001cf5008d6d02fd58a3cf70f449e"
+    })
+
+    request_headers = {
+      "X-Slack-Signature" => signed.signature,
+      "X-Slack-Request-Timestamp" => signed.timestamp
+    }
+
+    post "/command/doubleup",
+      params: signed.body,
+      headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expected_response = <<~MSG.chomp
+      *Active One*: Meets weekly in groups of 2 (Join: #active-1)
+      *Active Two*: Meets weekly in groups of 2 (Join: #active-2)
+    MSG
+    expect(response.body).to eq(expected_response)
+  end
+
+  scenario "responds with list of active and inactive channels with --all" do
+    allow(Matchmaking).to receive(:config).and_return(OpenStruct.new({
+      active_one: OpenStruct.new({
+        active: true,
+        schedule: "weekly",
+        size: 2,
+        channel: "active-1"
+      }),
+      not_active_one: OpenStruct.new({
+        active: false,
+        schedule: "weekly",
+        size: 2,
+        channel: "not-active-1"
+      }),
+      active_two: OpenStruct.new({
+        active: true,
+        schedule: "weekly",
+        size: 2,
+        channel: "active-2"
+      })
+    }))
+
+    signed = signed_request_body(params: {
+      "team_id" => "T02PF6RHYSY",
+      "team_domain" => "testdouble-hq",
+      "channel_id" => "C02NYBB3VPH",
+      "channel_name" => "some-channel",
+      "user_id" => "U02PRHH0XEV",
+      "user_name" => "cliff.pruitt",
+      "command" => "/doubleup",
+      "text" => "channels:list --all",
+      "api_app_id" => "A02PD0DUE03",
+      "is_enterprise_install" => "false",
+      "response_url" =>
+        "https://hooks.slack.com/commands/T02PF6RHYSY/2823421496992/0WC0HfWeGJpHetxmF8yUmawo",
+      "trigger_id" => "2801968477828.2797229610916.883001cf5008d6d02fd58a3cf70f449e"
+    })
+
+    request_headers = {
+      "X-Slack-Signature" => signed.signature,
+      "X-Slack-Request-Timestamp" => signed.timestamp
+    }
+
+    post "/command/doubleup",
+      params: signed.body,
+      headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expected_response = <<~MSG.chomp
+      *Active One*: Meets weekly in groups of 2 (Join: #active-1)
+      *Active Two*: Meets weekly in groups of 2 (Join: #active-2)
+      *Not Active One*: Meets weekly in groups of 2 (Join: #not-active-1)
+    MSG
+    expect(response.body).to eq(expected_response)
+  end
+
+  private
+
+  def signed_request_body(params: {})
+    slack_signing_secret = Slack::Events.config.signing_secret
+    timestamp = Time.zone.now.to_i
+    request_body = params.to_param
+    data = ["v0", timestamp, request_body].join(":")
+    mac = OpenSSL::HMAC.hexdigest("SHA256", slack_signing_secret, data)
+    OpenStruct.new({
+      signature: "v0=#{mac}",
+      timestamp: timestamp,
+      body: request_body
+    })
+  end
+end
diff --git a/spec/requests/chatops_controller_command_params_spec.rb b/spec/requests/chatops_controller_command_params_spec.rb
new file mode 100644
index 0000000..f07d3c6
--- /dev/null
+++ b/spec/requests/chatops_controller_command_params_spec.rb
@@ -0,0 +1,95 @@
+require "rails_helper"
+
+class CommandParamsChatopsController < ApplicationChatopsController
+  def index
+    render plain: "Got command <#{subcommand}> with name <#{command_params[:name]}> and group size <#{command_params[:group_size]}>"
+  end
+end
+
+RSpec.describe "ApplicationChatopsController command params", type: :request do
+  before :all do
+    TestOnlyRoutes.draw do
+      post "/chatops/test-params", to: "command_params_chatops#index"
+    end
+  end
+
+  after :all do
+    TestOnlyRoutes.clear!
+  end
+
+  scenario "provides subcommand and command_params to actions" do
+    slack_signing_secret = Slack::Events.config.signing_secret
+    timestamp = Time.zone.now.to_i
+    request_body = "token=#{slack_signing_secret}&team_id=T02PF6RHYSY&team_domain=testdouble-hq&channel_id=C02NYBB3VPH&channel_name=some-channel&user_id=U02PRHH0XEV&user_name=cliff.pruitt&command=%2Fdoubleup&text=snazzy%3Acommand+--name%3Dblargh+--group-size%3D4&api_app_id=A02PD0DUE03&is_enterprise_install=false&response_url=https%3A%2F%2Fhooks.slack.com%2Fcommands%2FT02PF6RHYSY%2F2823421496992%2F0WC0HfWeGJpHetxmF8yUmawo&trigger_id=2801968477828.2797229610916.883001cf5008d6d02fd58a3cf70f449e"
+    data = ["v0", timestamp, request_body].join(":")
+    mac = OpenSSL::HMAC.hexdigest("SHA256", slack_signing_secret, data)
+    signature = "v0=#{mac}"
+
+    request_headers = {
+      "X-Slack-Signature" => signature,
+      "X-Slack-Request-Timestamp" => timestamp
+    }
+
+    request_params = {
+      "token" => slack_signing_secret,
+      "team_id" => "T02PF6RHYSY",
+      "team_domain" => "testdouble-hq",
+      "channel_id" => "C02NYBB3VPH",
+      "channel_name" => "some-channel",
+      "user_id" => "U02PRHH0XEV",
+      "user_name" => "cliff.pruitt",
+      "command" => "/doubleup",
+      "text" => "snazzy:command --name=blargh --group-size=4",
+      "api_app_id" => "A02PD0DUE03",
+      "is_enterprise_install" => "false",
+      "response_url" =>
+       "https://hooks.slack.com/commands/T02PF6RHYSY/2823421496992/0WC0HfWeGJpHetxmF8yUmawo",
+      "trigger_id" => "2801968477828.2797229610916.883001cf5008d6d02fd58a3cf70f449e"
+    }
+
+    post "/chatops/test-params",
+      params: request_params,
+      headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expect(response.body).to eq("Got command <snazzy:command> with name <blargh> and group size <4>")
+  end
+
+  scenario "provides subcommand and command_params to actions for empty params" do
+    slack_signing_secret = Slack::Events.config.signing_secret
+    timestamp = Time.zone.now.to_i
+    request_body = "token=#{slack_signing_secret}&team_id=T02PF6RHYSY&team_domain=testdouble-hq&channel_id=C02NYBB3VPH&channel_name=some-channel&user_id=U02PRHH0XEV&user_name=cliff.pruitt&command=%2Fdoubleup&text=&api_app_id=A02PD0DUE03&is_enterprise_install=false&response_url=https%3A%2F%2Fhooks.slack.com%2Fcommands%2FT02PF6RHYSY%2F2823421496992%2F0WC0HfWeGJpHetxmF8yUmawo&trigger_id=2801968477828.2797229610916.883001cf5008d6d02fd58a3cf70f449e"
+    data = ["v0", timestamp, request_body].join(":")
+    mac = OpenSSL::HMAC.hexdigest("SHA256", slack_signing_secret, data)
+    signature = "v0=#{mac}"
+
+    request_headers = {
+      "X-Slack-Signature" => signature,
+      "X-Slack-Request-Timestamp" => timestamp
+    }
+
+    request_params = {
+      "token" => slack_signing_secret,
+      "team_id" => "T02PF6RHYSY",
+      "team_domain" => "testdouble-hq",
+      "channel_id" => "C02NYBB3VPH",
+      "channel_name" => "some-channel",
+      "user_id" => "U02PRHH0XEV",
+      "user_name" => "cliff.pruitt",
+      "command" => "/doubleup",
+      "text" => "",
+      "api_app_id" => "A02PD0DUE03",
+      "is_enterprise_install" => "false",
+      "response_url" =>
+       "https://hooks.slack.com/commands/T02PF6RHYSY/2823421496992/0WC0HfWeGJpHetxmF8yUmawo",
+      "trigger_id" => "2801968477828.2797229610916.883001cf5008d6d02fd58a3cf70f449e"
+    }
+
+    post "/chatops/test-params",
+      params: request_params,
+      headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expect(response.body).to eq("Got command <> with name <> and group size <>")
+  end
+end