feat: Add UI for custom tools (#12585)

### Tools list

<img width="2316" height="666" alt="CleanShot 2025-10-03 at 20 42 41@2x"
src="https://github.com/user-attachments/assets/ccbffd16-804d-4eb8-9c64-2d1cfd407e4e"
/>

### Tools form 

<img width="2294" height="2202" alt="CleanShot 2025-10-03 at 20 43
05@2x"
src="https://github.com/user-attachments/assets/9f49aa09-75a1-4585-a09d-837ca64139b8"
/>

## Response

<img width="800" height="2144" alt="CleanShot 2025-10-03 at 20 45 56@2x"
src="https://github.com/user-attachments/assets/b0c3c899-6050-4c51-baed-c8fbec5aae61"
/>

---------

Co-authored-by: Pranav <pranavrajs@gmail.com>
Co-authored-by: Pranav <pranav@chatwoot.com>

enterprise/app/models/captain/custom_tool.rb

@@ -29,6 +29,8 @@ class Captain::CustomTool < ApplicationRecord
 
   self.table_name = 'captain_custom_tools'
 
+  NAME_PREFIX = 'custom'.freeze
+  NAME_SEPARATOR = '_'.freeze
   PARAM_SCHEMA_VALIDATION = {
     'type': 'array',
     'items': {
@@ -73,16 +75,23 @@ class Captain::CustomTool < ApplicationRecord
 
   def generate_slug
     return if slug.present?
+    return if title.blank?
 
-    base_slug = title.present? ? "custom_#{title.parameterize}" : "custom_#{SecureRandom.uuid}"
+    paramterized_title = title.parameterize(separator: NAME_SEPARATOR)
+
+    base_slug = "#{NAME_PREFIX}#{NAME_SEPARATOR}#{paramterized_title}"
     self.slug = find_unique_slug(base_slug)
   end
 
-  def find_unique_slug(base_slug, counter = 0)
-    slug_candidate = counter.zero? ? base_slug : "#{base_slug}-#{counter}"
-    return find_unique_slug(base_slug, counter + 1) if slug_exists?(slug_candidate)
+  def find_unique_slug(base_slug)
+    return base_slug unless slug_exists?(base_slug)
 
-    slug_candidate
+    5.times do
+      slug_candidate = "#{base_slug}#{NAME_SEPARATOR}#{SecureRandom.alphanumeric(6).downcase}"
+      return slug_candidate unless slug_exists?(slug_candidate)
+    end
+
+    raise ActiveRecord::RecordNotUnique, I18n.t('captain.custom_tool.slug_generation_failed')
   end
 
   def slug_exists?(candidate)

enterprise/app/models/concerns/toolable.rb

@@ -3,7 +3,10 @@ module Concerns::Toolable
 
   def tool(assistant)
     custom_tool_record = self
+    # Convert slug to valid Ruby constant name (replace hyphens with underscores, then camelize)
+    class_name = custom_tool_record.slug.underscore.camelize
 
+    # Always create a fresh class to reflect current metadata
     tool_class = Class.new(Captain::Tools::HttpTool) do
       description custom_tool_record.description
 
@@ -15,6 +18,16 @@ module Concerns::Toolable
       end
     end
 
+    # Register the dynamically created class as a constant in the Captain::Tools namespace.
+    # This is required because RubyLLM's Tool base class derives the tool name from the class name
+    # (via Class#name). Anonymous classes created with Class.new have no name and return empty strings,
+    # which causes "Invalid 'tools[].function.name': empty string" errors from the LLM API.
+    # By setting it as a constant, the class gets a proper name (e.g., "Captain::Tools::CatFactLookup")
+    # which RubyLLM extracts and normalizes to "cat-fact-lookup" for the LLM API.
+    # We refresh the constant on each call to ensure tool metadata changes are reflected.
+    Captain::Tools.send(:remove_const, class_name) if Captain::Tools.const_defined?(class_name, false)
+    Captain::Tools.const_set(class_name, tool_class)
+
     tool_class.new(assistant, self)
   end