add ls tool formatters

lib/roast/cogs/agent/providers/pi/messages/tool_call_message.rb

@@ -195,6 +195,23 @@ def format_find
                 details.any? ? "FIND #{pattern} (#{details.join(", ")})" : "FIND #{pattern}"
               end
 
+              # Formats an ls tool call.
+              #
+              # Input fields:
+              #   :path (String) – directory to list   [optional]
+              #
+              # Output: "LS <path>" – a missing path renders the bare "LS".
+              #
+              # Examples:
+              #   LS lib/roast
+              #   LS
+              #
+              #: () -> String
+              def format_ls
+                path = arguments[:path]
+                path.to_s.empty? ? "LS" : "LS #{path}"
+              end
+
               # Formats a tool call for which Roast has no dedicated formatter.
               #
               # Output: "<NAME> <key>: <value>, ..." – the upcased tool name, then each

lib/roast/cogs/agent/providers/pi/messages/tool_result_message.rb

@@ -165,6 +165,24 @@ def format_find
                 ok_line("#{count} #{"path".pluralize(count)}")
               end
 
+              # Formats an ls tool result.
+              #
+              # Content: directory entries, one per line.
+              #
+              # Output: "LS OK <n> <entry|entries>" – <n> is the number of non-blank
+              # lines (pluralized).
+              #
+              # Examples:
+              #   LS OK 8 entries
+              #   LS OK 1 entry
+              #   LS OK 0 entries
+              #
+              #: () -> String
+              def format_ls
+                count = content.to_s.lines.map(&:strip).reject(&:empty?).length
+                ok_line("#{count} #{"entry".pluralize(count)}")
+              end
+
               # Formats a result for which Roast has no dedicated formatter.
               #
               # Content: the tool's output text.

test/roast/cogs/agent/providers/pi/messages/tool_call_message_test.rb

@@ -178,6 +178,16 @@ class ToolCallMessageTest < ActiveSupport::TestCase
           assert_equal "FIND *.rb", msg.format
         end
 
+        test "format renders LS with the path" do
+          msg = ToolCallMessage.new(id: "1", name: "ls", arguments: { path: "lib/roast" })
+          assert_equal "LS lib/roast", msg.format
+        end
+
+        test "format renders a bare LS when the path is missing" do
+          msg = ToolCallMessage.new(id: "1", name: "ls", arguments: {})
+          assert_equal "LS", msg.format
+        end
+
         test "format renders an unhandled tool as NAME key: value, ..." do
           msg = ToolCallMessage.new(
             id: "1",

test/roast/cogs/agent/providers/pi/messages/tool_result_message_test.rb

@@ -203,6 +203,39 @@ def setup
           assert_equal "FIND OK 0 paths", msg.format(@context)
         end
 
+        test "format summarizes ls output with an entry count" do
+          msg = ToolResultMessage.new(
+            tool_call_id: "1",
+            tool_name: "ls",
+            content: "lib\ntest\nREADME.md",
+            is_error: false,
+          )
+
+          assert_equal "LS OK 3 entries", msg.format(@context)
+        end
+
+        test "format pluralizes a single ls entry" do
+          msg = ToolResultMessage.new(
+            tool_call_id: "1",
+            tool_name: "ls",
+            content: "README.md",
+            is_error: false,
+          )
+
+          assert_equal "LS OK 1 entry", msg.format(@context)
+        end
+
+        test "format reports zero ls entries when there is no output" do
+          msg = ToolResultMessage.new(
+            tool_call_id: "1",
+            tool_name: "ls",
+            content: nil,
+            is_error: false,
+          )
+
+          assert_equal "LS OK 0 entries", msg.format(@context)
+        end
+
         test "format renders NAME ERROR with the message for an error result" do
           msg = ToolResultMessage.new(
             tool_call_id: "1",