From 542e96a096351fd3caaff2d5f671ab0691c16e08 Mon Sep 17 00:00:00 2001
From: Lasmar Khalifa <lasmar.khalifa@shopify.com>
Date: Tue, 30 Jun 2026 17:01:59 -0400
Subject: [PATCH] add bash tool formatters

---
 .../pi/messages/tool_call_message.rb          | 18 ++++++++++
 .../pi/messages/tool_result_message.rb        | 21 ++++++++++++
 .../pi/messages/tool_call_message_test.rb     | 15 +++++++++
 .../pi/messages/tool_result_message_test.rb   | 33 +++++++++++++++++++
 4 files changed, 87 insertions(+)

diff --git a/lib/roast/cogs/agent/providers/pi/messages/tool_call_message.rb b/lib/roast/cogs/agent/providers/pi/messages/tool_call_message.rb
index 1b188d86..3a60a721 100644
--- a/lib/roast/cogs/agent/providers/pi/messages/tool_call_message.rb
+++ b/lib/roast/cogs/agent/providers/pi/messages/tool_call_message.rb
@@ -45,6 +45,24 @@ def format
 
               private
 
+              # Formats a bash tool call.
+              #
+              # Input fields:
+              #   :command (String) – shell command to execute   [required]
+              #
+              # Output: "BASH <command>", with :command truncated to TRUNCATE_LIMIT
+              # chars. A missing command renders the bare "BASH".
+              #
+              # Examples:
+              #   BASH ls -la
+              #   BASH
+              #
+              #: () -> String
+              def format_bash
+                command = truncate(arguments[:command])
+                command.empty? ? "BASH" : "BASH #{command}"
+              end
+
               # Formats a tool call for which Roast has no dedicated formatter.
               #
               # Output: "<NAME> <key>: <value>, ..." – the upcased tool name, then each
diff --git a/lib/roast/cogs/agent/providers/pi/messages/tool_result_message.rb b/lib/roast/cogs/agent/providers/pi/messages/tool_result_message.rb
index bf84b828..55d6b5bc 100644
--- a/lib/roast/cogs/agent/providers/pi/messages/tool_result_message.rb
+++ b/lib/roast/cogs/agent/providers/pi/messages/tool_result_message.rb
@@ -55,6 +55,27 @@ def format(context)
 
               private
 
+              # Formats a bash tool result.
+              #
+              # Content: the command's output text.
+              #
+              # Output: "BASH OK <n> <line|lines> · <preview>" – <n> is the line count
+              # (pluralized) and <preview> is the first line, stripped and truncated to
+              # TRUNCATE_LIMIT chars. The preview is omitted when there is no output.
+              #
+              # Examples:
+              #   BASH OK 12 lines · Cloning into 'roast'...
+              #   BASH OK 1 line · hello world
+              #   BASH OK 0 lines
+              #
+              #: () -> String
+              def format_bash
+                lines = content.to_s.lines
+                count = lines.length
+                preview = truncate(lines.first.to_s.strip)
+                ok_line("#{count} #{"line".pluralize(count)}", preview)
+              end
+
               # Formats a result for which Roast has no dedicated formatter.
               #
               # Content: the tool's output text.
diff --git a/test/roast/cogs/agent/providers/pi/messages/tool_call_message_test.rb b/test/roast/cogs/agent/providers/pi/messages/tool_call_message_test.rb
index f53d33a8..f429c3aa 100644
--- a/test/roast/cogs/agent/providers/pi/messages/tool_call_message_test.rb
+++ b/test/roast/cogs/agent/providers/pi/messages/tool_call_message_test.rb
@@ -11,6 +11,21 @@ class ToolCallMessageTest < ActiveSupport::TestCase
           assert_nil msg.format
         end
 
+        test "format renders BASH with the command" do
+          msg = ToolCallMessage.new(id: "1", name: "bash", arguments: { command: "ls -la" })
+          assert_equal "BASH ls -la", msg.format
+        end
+
+        test "format renders a bare BASH when the command is missing" do
+          msg = ToolCallMessage.new(id: "1", name: "bash", arguments: {})
+          assert_equal "BASH", msg.format
+        end
+
+        test "format truncates a long bash command" do
+          msg = ToolCallMessage.new(id: "1", name: "bash", arguments: { command: "x" * 100 })
+          assert_equal "BASH #{"x" * (ToolCallMessage::TRUNCATE_LIMIT - 3)}...", msg.format
+        end
+
         test "format renders an unhandled tool as NAME key: value, ..." do
           msg = ToolCallMessage.new(
             id: "1",
diff --git a/test/roast/cogs/agent/providers/pi/messages/tool_result_message_test.rb b/test/roast/cogs/agent/providers/pi/messages/tool_result_message_test.rb
index 719e285c..85ad549d 100644
--- a/test/roast/cogs/agent/providers/pi/messages/tool_result_message_test.rb
+++ b/test/roast/cogs/agent/providers/pi/messages/tool_result_message_test.rb
@@ -10,6 +10,39 @@ def setup
           @context = Roast::Cogs::Agent::Providers::Pi::PiInvocation::Context.new
         end
 
+        test "format summarizes bash output with a line count and preview" do
+          msg = ToolResultMessage.new(
+            tool_call_id: "1",
+            tool_name: "bash",
+            content: "file1.rb\nfile2.rb",
+            is_error: false,
+          )
+
+          assert_equal "BASH OK 2 lines · file1.rb", msg.format(@context)
+        end
+
+        test "format pluralizes a single line of bash output" do
+          msg = ToolResultMessage.new(
+            tool_call_id: "1",
+            tool_name: "bash",
+            content: "hello world",
+            is_error: false,
+          )
+
+          assert_equal "BASH OK 1 line · hello world", msg.format(@context)
+        end
+
+        test "format reports zero lines when bash produced no output" do
+          msg = ToolResultMessage.new(
+            tool_call_id: "1",
+            tool_name: "bash",
+            content: nil,
+            is_error: false,
+          )
+
+          assert_equal "BASH OK 0 lines", msg.format(@context)
+        end
+
         test "format renders NAME ERROR with the message for an error result" do
           msg = ToolResultMessage.new(
             tool_call_id: "1",