diff --git a/src/spectator/formatting/document_formatter.cr b/src/spectator/formatting/document_formatter.cr
index c5cb5db..61c298e 100644
--- a/src/spectator/formatting/document_formatter.cr
+++ b/src/spectator/formatting/document_formatter.cr
@@ -2,13 +2,5 @@ require "./formatter"
 
 module Spectator::Formatting
   class DocumentFormatter < Formatter
-    def pass(notification)
-    end
-
-    def fail(notification)
-    end
-
-    def pending(notification)
-    end
   end
 end
diff --git a/src/spectator/formatting/formatter.cr b/src/spectator/formatting/formatter.cr
index 125c149..bfbbec2 100644
--- a/src/spectator/formatting/formatter.cr
+++ b/src/spectator/formatting/formatter.cr
@@ -2,6 +2,109 @@ module Spectator::Formatting
   # Base class and interface used to notify systems of events.
   # This is typically used for producing output from test results,
   # but can also be used to send data to external systems.
+  #
+  # All event methods are implemented as no-ops.
+  # To respond to an event, override its method.
+  # Every method receives a notification object containing information about the event.
+  #
+  # Methods are called in this order:
+  # 1.  `#start`
+  # 2.  `#example_started`
+  # 3.  `#example_finished`
+  # 4.  `#example_passed`
+  # 5.  `#example_pending`
+  # 6.  `#example_failed`
+  # 7.  `#stop`
+  # 8.  `#start_dump`
+  # 9.  `#dump_pending`
+  # 10. `#dump_failures`
+  # 11. `#dump_summary`
+  # 12. `#dump_profile`
+  # 13. `#close`
+  #
+  # Only one of the `#example_passed`, `#example_pending`, or `#example_failed` methods
+  # will be called after `#example_finished`, depending on the outcome of the test.
+  #
+  # The "dump" methods are called after all tests that will run have run.
+  # They are provided summarized information.
   abstract class Formatter
+    # This method is the first method to be invoked
+    # and will be called only once.
+    # It is called before any examples run.
+    def start(_notification)
+    end
+
+    # Invoked just before an example runs.
+    # This method is called once for every example.
+    def example_started(_notification)
+    end
+
+    # Invoked just after an example completes.
+    # This method is called once for every example.
+    # One of `#example_passed`, `#example_pending` or `#example_failed`
+    # will be called immediately after this method, depending on the example's result.
+    def example_finished(_notification)
+    end
+
+    # Invoked after an example completes successfully.
+    # This is called right after `#example_finished`.
+    def example_passed(_notification)
+    end
+
+    # Invoked after an example is skipped or marked as pending.
+    # This is called right after `#example_finished`.
+    def example_pending(_notification)
+    end
+
+    # Invoked after an example fails.
+    # This is called right after `#example_finished`.
+    # Errors are considered failures and will cause this method to be called.
+    def example_failed(_notification)
+    end
+
+    # Called whenever the example or framework produces a message.
+    # This is typically used for logging.
+    def message(_notification)
+    end
+
+    # Invoked after all tests that will run have completed.
+    # When this method is called, it should be considered that the testing is done.
+    # Summary (dump) methods will be called after this.
+    def stop(_notification)
+    end
+
+    # Invoked after all examples finished.
+    # Indicates that summarized report data is about to be produced.
+    # This method is called after `#stop` and before `#dump_pending`.
+    def start_dump(_notification)
+    end
+
+    # Invoked after testing completes with a list of pending examples.
+    # This method will be called with an empty list if there were no pending (skipped) examples.
+    # Called after `#start_dump` and before `#dump_failures`.
+    def dump_pending(_notification)
+    end
+
+    # Invoked after testing completes with a list of failed examples.
+    # This method will be called with an empty list if there were no failures.
+    # Called after `#dump_pending` and before `#dump_summary`.
+    def dump_failures(_notification)
+    end
+
+    # Invoked after testing completes with summarized information from the test suite.
+    # Called after `#dump_failures` and before `#dump_profile`.
+    def dump_summary(_notification)
+    end
+
+    # Invoked after testing completes with profiling information.
+    # This method is only called if profiling is enabled.
+    # Called after `#dump_summary` and before `#close`.
+    def dump_profile(_notification)
+    end
+
+    # Invoked at the end of the program.
+    # Allows the formatter to perform any cleanup and teardown.
+    def close(_notification)
+    end
   end
 end
diff --git a/src/spectator/formatting/json_formatter.cr b/src/spectator/formatting/json_formatter.cr
index 8ef2e24..996e94a 100644
--- a/src/spectator/formatting/json_formatter.cr
+++ b/src/spectator/formatting/json_formatter.cr
@@ -2,13 +2,5 @@ require "./formatter"
 
 module Spectator::Formatting
   class JSONFormatter < Formatter
-    def pass(notification)
-    end
-
-    def fail(notification)
-    end
-
-    def pending(notification)
-    end
   end
 end
diff --git a/src/spectator/formatting/junit_formatter.cr b/src/spectator/formatting/junit_formatter.cr
index f05adc8..32cec45 100644
--- a/src/spectator/formatting/junit_formatter.cr
+++ b/src/spectator/formatting/junit_formatter.cr
@@ -4,14 +4,5 @@ module Spectator::Formatting
   class JUnitFormatter < Formatter
     def initialize(output_dir)
     end
-
-    def pass(notification)
-    end
-
-    def fail(notification)
-    end
-
-    def pending(notification)
-    end
   end
 end
diff --git a/src/spectator/formatting/progress_formatter.cr b/src/spectator/formatting/progress_formatter.cr
index dbb0f6e..05321aa 100644
--- a/src/spectator/formatting/progress_formatter.cr
+++ b/src/spectator/formatting/progress_formatter.cr
@@ -4,13 +4,5 @@ module Spectator::Formatting
   # Output formatter that produces a single character for each test as it completes.
   # A '.' indicates a pass, 'F' a failure, and '*' a skipped or pending test.
   class ProgressFormatter < Formatter
-    def pass(notification)
-    end
-
-    def fail(notification)
-    end
-
-    def pending(notification)
-    end
   end
 end
diff --git a/src/spectator/formatting/tap_formatter.cr b/src/spectator/formatting/tap_formatter.cr
index 69f8d86..3da03db 100644
--- a/src/spectator/formatting/tap_formatter.cr
+++ b/src/spectator/formatting/tap_formatter.cr
@@ -2,13 +2,5 @@ require "./formatter"
 
 module Spectator::Formatting
   class TAPFormatter < Formatter
-    def pass(notification)
-    end
-
-    def fail(notification)
-    end
-
-    def pending(notification)
-    end
   end
 end
diff --git a/src/spectator/spec/runner.cr b/src/spectator/spec/runner.cr
index a0c1e63..4bc9d7b 100644
--- a/src/spectator/spec/runner.cr
+++ b/src/spectator/spec/runner.cr
@@ -8,7 +8,9 @@ module Spectator
       # Creates the runner.
       # The collection of *examples* should be pre-filtered and shuffled.
       # This runner will run each example in the order provided.
-      def initialize(@examples : Enumerable(Example), @run_flags = RunFlags::None)
+      # The *formatter* will be called for various events.
+      def initialize(@examples : Enumerable(Example),
+        @formatter : Formatting::Formatter, @run_flags = RunFlags::None)
       end
 
       # Runs the spec.