DEV: artifact system update (#1096)

### Why

This pull request fundamentally restructures how AI bots create and update web artifacts to address critical limitations in the previous approach:

1.  **Improved Artifact Context for LLMs**: Previously, artifact creation and update tools included the *entire* artifact source code directly in the tool arguments. This overloaded the Language Model (LLM) with raw code, making it difficult for the LLM to maintain a clear understanding of the artifact's current state when applying changes. The LLM would struggle to differentiate between the base artifact and the requested modifications, leading to confusion and less effective updates.
2.  **Reduced Token Usage and History Bloat**: Including the full artifact source code in every tool interaction was extremely token-inefficient.  As conversations progressed, this redundant code in the history consumed a significant number of tokens unnecessarily. This not only increased costs but also diluted the context for the LLM with less relevant historical information.
3.  **Enabling Updates for Large Artifacts**: The lack of a practical diff or targeted update mechanism made it nearly impossible to efficiently update larger web artifacts.  Sending the entire source code for every minor change was both computationally expensive and prone to errors, effectively blocking the use of AI bots for meaningful modifications of complex artifacts.

**This pull request addresses these core issues by**:

*   Introducing methods for the AI bot to explicitly *read* and understand the current state of an artifact.
*   Implementing efficient update strategies that send *targeted* changes rather than the entire artifact source code.
*   Providing options to control the level of artifact context included in LLM prompts, optimizing token usage.

### What

The main changes implemented in this PR to resolve the above issues are:

1.  **`Read Artifact` Tool for Contextual Awareness**:
    - A new `read_artifact` tool is introduced, enabling AI bots to fetch and process the current content of a web artifact from a given URL (local or external).
    - This provides the LLM with a clear and up-to-date representation of the artifact's HTML, CSS, and JavaScript, improving its understanding of the base to be modified.
    - By cloning local artifacts, it allows the bot to work with a fresh copy, further enhancing context and control.

2.  **Refactored `Update Artifact` Tool with Efficient Strategies**:
    - The `update_artifact` tool is redesigned to employ more efficient update strategies, minimizing token usage and improving update precision:
        - **`diff` strategy**:  Utilizes a search-and-replace diff algorithm to apply only the necessary, targeted changes to the artifact's code. This significantly reduces the amount of code sent to the LLM and focuses its attention on the specific modifications.
        - **`full` strategy**:  Provides the option to replace the entire content sections (HTML, CSS, JavaScript) when a complete rewrite is required.
    - Tool options enhance the control over the update process:
        - `editor_llm`:  Allows selection of a specific LLM for artifact updates, potentially optimizing for code editing tasks.
        - `update_algorithm`: Enables choosing between `diff` and `full` update strategies based on the nature of the required changes.
        - `do_not_echo_artifact`:  Defaults to true, and by *not* echoing the artifact in prompts, it further reduces token consumption in scenarios where the LLM might not need the full artifact context for every update step (though effectiveness might be slightly reduced in certain update scenarios).

3.  **System and General Persona Tool Option Visibility and Customization**:
    - Tool options, including those for system personas, are made visible and editable in the admin UI. This allows administrators to fine-tune the behavior of all personas and their tools, including setting specific LLMs or update algorithms. This was previously limited or hidden for system personas.

4.  **Centralized and Improved Content Security Policy (CSP) Management**:
    - The CSP for AI artifacts is consolidated and made more maintainable through the `ALLOWED_CDN_SOURCES` constant. This improves code organization and future updates to the allowed CDN list, while maintaining the existing security posture.

5.  **Codebase Improvements**:
    - Refactoring of diff utilities, introduction of strategy classes, enhanced error handling, new locales, and comprehensive testing all contribute to a more robust, efficient, and maintainable artifact management system.

By addressing the issues of LLM context confusion, token inefficiency, and the limitations of updating large artifacts, this pull request significantly improves the practicality and effectiveness of AI bots in managing web artifacts within Discourse.

app/controllers/discourse_ai/ai_bot/artifacts_controller.rb

@@ -12,7 +12,7 @@ module DiscourseAi
         artifact = AiArtifact.find(params[:id])
 
         post = Post.find_by(id: artifact.post_id)
-        if artifact.metadata&.dig("public")
+        if artifact.public?
           # no guardian needed
         else
           raise Discourse::NotFound if !post&.topic&.private_message?
@@ -81,7 +81,7 @@ module DiscourseAi
         response.headers.delete("X-Frame-Options")
         response.headers[
           "Content-Security-Policy"
-        ] = "script-src 'self' 'unsafe-inline' 'wasm-unsafe-eval' https://unpkg.com https://cdnjs.cloudflare.com https://ajax.googleapis.com https://cdn.jsdelivr.net;"
+        ] = "script-src 'self' 'unsafe-inline' 'wasm-unsafe-eval' #{AiArtifact::ALLOWED_CDN_SOURCES.join(" ")};"
         response.headers["X-Robots-Tag"] = "noindex"
 
         # Render the content

app/models/ai_artifact.rb

@@ -8,6 +8,15 @@ class AiArtifact < ActiveRecord::Base
   validates :css, length: { maximum: 65_535 }
   validates :js, length: { maximum: 65_535 }
 
+  ALLOWED_CDN_SOURCES = %w[
+    https://cdn.jsdelivr.net
+    https://cdnjs.cloudflare.com
+    https://unpkg.com
+    https://ajax.googleapis.com
+    https://d3js.org
+    https://code.jquery.com
+  ]
+
   def self.iframe_for(id, version = nil)
     <<~HTML
       <div class='ai-artifact'>
@@ -70,6 +79,10 @@ class AiArtifact < ActiveRecord::Base
 
     version
   end
+
+  def public?
+    !!metadata&.dig("public")
+  end
 end
 
 # == Schema Information

app/models/ai_persona.rb

@@ -130,8 +130,6 @@ class AiPersona < ActiveRecord::Base
       tool_details
     ]
 
-    persona_class = DiscourseAi::AiBot::Personas::Persona.system_personas_by_id[self.id]
-
     instance_attributes = {}
     attributes.each do |attr|
       value = self.read_attribute(attr)
@@ -140,14 +138,6 @@ class AiPersona < ActiveRecord::Base
 
     instance_attributes[:username] = user&.username_lower
 
-    if persona_class
-      instance_attributes.each do |key, value|
-        # description/name are localized
-        persona_class.define_singleton_method(key) { value } if key != :description && key != :name
-      end
-      return persona_class
-    end
-
     options = {}
     force_tool_use = []
 
@@ -180,6 +170,16 @@ class AiPersona < ActiveRecord::Base
         klass
       end
 
+    persona_class = DiscourseAi::AiBot::Personas::Persona.system_personas_by_id[self.id]
+    if persona_class
+      instance_attributes.each do |key, value|
+        # description/name are localized
+        persona_class.define_singleton_method(key) { value } if key != :description && key != :name
+      end
+      persona_class.define_method(:options) { options }
+      return persona_class
+    end
+
     ai_persona_id = self.id
 
     Class.new(DiscourseAi::AiBot::Personas::Persona) do
@@ -264,9 +264,19 @@ class AiPersona < ActiveRecord::Base
   end
 
   def system_persona_unchangeable
-    if top_p_changed? || temperature_changed? || system_prompt_changed? || tools_changed? ||
-         name_changed? || description_changed?
+    if top_p_changed? || temperature_changed? || system_prompt_changed? || name_changed? ||
+         description_changed?
       errors.add(:base, I18n.t("discourse_ai.ai_bot.personas.cannot_edit_system_persona"))
+    elsif tools_changed?
+      old_tools = tools_change[0]
+      new_tools = tools_change[1]
+
+      old_tool_names = old_tools.map { |t| t.is_a?(Array) ? t[0] : t }.to_set
+      new_tool_names = new_tools.map { |t| t.is_a?(Array) ? t[0] : t }.to_set
+
+      if old_tool_names != new_tool_names
+        errors.add(:base, I18n.t("discourse_ai.ai_bot.personas.cannot_edit_system_persona"))
+      end
     end
   end
 

app/serializers/ai_tool_serializer.rb

@@ -22,11 +22,14 @@ class AiToolSerializer < ApplicationSerializer
   def options
     options = {}
     object.accepted_options.each do |option|
-      options[option.name] = {
+      processed_option = {
         name: option.localized_name,
         description: option.localized_description,
         type: option.type,
       }
+      processed_option[:values] = option.values if option.values.present?
+      processed_option[:default] = option.default if option.default.present?
+      options[option.name] = processed_option
     end
     options
   end

assets/javascripts/discourse/admin/models/ai-persona.js

@@ -41,6 +41,7 @@ const SYSTEM_ATTRIBUTES = [
   "enabled",
   "system",
   "priority",
+  "tools",
   "user_id",
   "default_llm",
   "force_default_llm",

assets/javascripts/discourse/components/ai-llm-selector.js

@@ -15,10 +15,12 @@ export default class AiLlmSelector extends ComboBox {
 
   @computed
   get content() {
+    const blankName =
+      this.attrs.blankName || i18n("discourse_ai.ai_persona.no_llm_selected");
     return [
       {
         id: "blank",
-        name: i18n("discourse_ai.ai_persona.no_llm_selected"),
+        name: blankName,
       },
     ].concat(this.llms);
   }

assets/javascripts/discourse/components/ai-persona-editor.gjs

@@ -420,13 +420,12 @@ export default class PersonaEditor extends Component {
           </div>
         {{/if}}
       {{/if}}
-      {{#unless this.editingModel.system}}
-        <AiPersonaToolOptions
-          @persona={{this.editingModel}}
-          @tools={{this.selectedToolNames}}
-          @allTools={{@personas.resultSetMeta.tools}}
-        />
-      {{/unless}}
+      <AiPersonaToolOptions
+        @persona={{this.editingModel}}
+        @tools={{this.selectedToolNames}}
+        @llms={{@personas.resultSetMeta.llms}}
+        @allTools={{@personas.resultSetMeta.tools}}
+      />
       <div class="control-group">
         <label>{{i18n "discourse_ai.ai_persona.allowed_groups"}}</label>
         <GroupChooser

assets/javascripts/discourse/components/ai-persona-tool-option-editor.gjs

@@ -2,28 +2,75 @@ import Component from "@glimmer/component";
 import { Input } from "@ember/component";
 import { on } from "@ember/modifier";
 import { action } from "@ember/object";
+import { eq } from "truth-helpers";
+import { i18n } from "discourse-i18n";
+import AiLlmSelector from "./ai-llm-selector";
 
 export default class AiPersonaToolOptionEditor extends Component {
   get isBoolean() {
     return this.args.option.type === "boolean";
   }
 
+  get isEnum() {
+    return this.args.option.type === "enum";
+  }
+
+  get isLlm() {
+    return this.args.option.type === "llm";
+  }
+
   get selectedValue() {
     return this.args.option.value.value === "true";
   }
 
+  get selectedLlm() {
+    if (this.args.option.value.value) {
+      return `custom:${this.args.option.value.value}`;
+    } else {
+      return "blank";
+    }
+  }
+
+  set selectedLlm(value) {
+    if (value === "blank") {
+      this.args.option.value.value = null;
+    } else {
+      this.args.option.value.value = value.replace("custom:", "");
+    }
+  }
+
   @action
   onCheckboxChange(event) {
     this.args.option.value.value = event.target.checked ? "true" : "false";
   }
 
+  @action
+  onSelectOption(event) {
+    this.args.option.value.value = event.target.value;
+  }
+
   <template>
     <div class="control-group ai-persona-tool-option-editor">
       <label>
         {{@option.name}}
       </label>
       <div class="">
-        {{#if this.isBoolean}}
+        {{#if this.isEnum}}
+          <select name="input" {{on "change" this.onSelectOption}}>
+            {{#each @option.values as |value|}}
+              <option value={{value}} selected={{eq value @option.value.value}}>
+                {{value}}
+              </option>
+            {{/each}}
+          </select>
+        {{else if this.isLlm}}
+          <AiLlmSelector
+            class="ai-persona-tool-option-editor__llms"
+            @value={{this.selectedLlm}}
+            @llms={{@llms}}
+            @blankName={{i18n "discourse_ai.ai_persona.use_parent_llm"}}
+          />
+        {{else if this.isBoolean}}
           <input
             type="checkbox"
             checked={{this.selectedValue}}

assets/javascripts/discourse/components/ai-persona-tool-options.gjs

@@ -67,7 +67,10 @@ export default class AiPersonaToolOptions extends Component {
               </div>
               <div class="ai-persona-editor__tool-option-options">
                 {{#each toolOption.options as |option|}}
-                  <AiPersonaToolOptionEditor @option={{option}} />
+                  <AiPersonaToolOptionEditor
+                    @option={{option}}
+                    @llms={{@llms}}
+                  />
                 {{/each}}
               </div>
             </div>

config/locales/client.en.yml

@@ -213,6 +213,7 @@ en:
         edit: "Edit"
         description: "Description"
         no_llm_selected: "No language model selected"
+        use_parent_llm: "Use personas language model"
         max_context_posts: "Max context posts"
         max_context_posts_help: "The maximum number of posts to use as context for the AI when responding to a user. (empty for default)"
         vision_enabled: Vision enabled

config/locales/server.en.yml

@@ -199,6 +199,7 @@ en:
       link: "Show Artifact in new tab"
       view_source: "View Source"
       view_changes: "View Changes"
+      change_description: "Change Description"
     unknown_model: "Unknown AI model"
 
     tools:
@@ -293,6 +294,20 @@ en:
       summarizing: "Summarizing topic"
       searching: "Searching for: '%{query}'"
       tool_options:
+        create_artifact:
+          creator_llm:
+            name: "LLM"
+            description: "Language model to use for artifact creation"
+        update_artifact:
+          editor_llm:
+            name: "LLM"
+            description: "Language model to use for artifact edits"
+          update_algorithm:
+            name: "Update Algorithm"
+            description: "Ask LLM to fully replace, or use diff to update"
+          do_not_echo_artifact:
+            name: "Do Not Echo Artifact"
+            description: "Will limit costs however effectiveness of Artifact updates will be reduced"
         google:
           base_query:
             name: "Base Search Query"
@@ -312,6 +327,7 @@ en:
             name: "Base Search Query"
             description: "Base query to use when searching. Example: '#urgent' will prepend '#urgent' to the search query and only include topics with the urgent category or tag."
       tool_summary:
+        read_artifact: "Read a web artifact"
         update_artifact: "Update a web artifact"
         create_artifact: "Create web artifact"
         web_browser: "Browse Web"
@@ -335,6 +351,7 @@ en:
         search_meta_discourse: "Search Meta Discourse"
         javascript_evaluator: "Evaluate JavaScript"
       tool_help:
+        read_artifact: "Read a web artifact using the AI Bot"
         update_artifact: "Update a web artifact using the AI Bot"
         create_artifact: "Create a web artifact using the AI Bot"
         web_browser: "Browse web page using the AI Bot"
@@ -358,8 +375,9 @@ en:
         search_meta_discourse: "Search Meta Discourse"
         javascript_evaluator: "Evaluate JavaScript"
       tool_description:
+        read_artifact: "Read a web artifact using the AI Bot"
         update_artifact: "Updated a web artifact using the AI Bot"
-        create_artifact: "Created a web artifact using the AI Bot"
+        create_artifact: "Created a web artifact: %{name} - %{specification}"
         web_browser: "Reading <a href='%{url}'>%{url}</a>"
         github_search_files: "Searched for '%{keywords}' in %{repo}/%{branch}"
         github_search_code: "Searched for '%{query}' in %{repo}"

db/fixtures/ai_bot/603_bot_ai_personas.rb

@@ -37,7 +37,19 @@ DiscourseAi::AiBot::Personas::Persona.system_personas.each do |persona_class, id
 
   persona.system = true
   instance = persona_class.new
-  persona.tools = instance.tools.map { |tool| tool.to_s.split("::").last }
+  tools = {}
+  instance.tools.map { |tool| tool.to_s.split("::").last }.each { |name| tools[name] = nil }
+  existing_tools = persona.tools || []
+
+  existing_tools.each do |tool|
+    if tool.is_a?(Array)
+      name, value = tool
+      tools[name] = value if tools.key?(name)
+    end
+  end
+
+  persona.tools = tools.map { |name, value| [name, value] }
+
   persona.system_prompt = instance.system_prompt
   persona.top_p = instance.top_p
   persona.temperature = instance.temperature

lib/ai_bot/artifact_update_strategies/base.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+module DiscourseAi
+  module AiBot
+    module ArtifactUpdateStrategies
+      class InvalidFormatError < StandardError
+      end
+      class Base
+        attr_reader :post, :user, :artifact, :artifact_version, :instructions, :llm
+
+        def initialize(llm:, post:, user:, artifact:, artifact_version:, instructions:)
+          @llm = llm
+          @post = post
+          @user = user
+          @artifact = artifact
+          @artifact_version = artifact_version
+          @instructions = instructions
+        end
+
+        def apply(&progress)
+          changes = generate_changes(&progress)
+          parsed_changes = parse_changes(changes)
+          apply_changes(parsed_changes)
+        end
+
+        private
+
+        def generate_changes(&progress)
+          response = +""
+          llm.generate(build_prompt, user: user) do |partial|
+            progress.call(partial) if progress
+            response << partial
+          end
+          response
+        end
+
+        def build_prompt
+          # To be implemented by subclasses
+          raise NotImplementedError
+        end
+
+        def parse_changes(response)
+          # To be implemented by subclasses
+          raise NotImplementedError
+        end
+
+        def apply_changes(changes)
+          # To be implemented by subclasses
+          raise NotImplementedError
+        end
+      end
+    end
+  end
+end

lib/ai_bot/artifact_update_strategies/diff.rb

@@ -0,0 +1,183 @@
+# frozen_string_literal: true
+module DiscourseAi
+  module AiBot
+    module ArtifactUpdateStrategies
+      class Diff < Base
+        private
+
+        def build_prompt
+          DiscourseAi::Completions::Prompt.new(
+            system_prompt,
+            messages: [{ type: :user, content: user_prompt }],
+            post_id: post.id,
+            topic_id: post.topic_id,
+          )
+        end
+
+        def parse_changes(response)
+          sections = { html: nil, css: nil, javascript: nil }
+          current_section = nil
+          lines = []
+
+          response.each_line do |line|
+            case line
+            when /^\[(HTML|CSS|JavaScript)\]$/
+              sections[current_section] = lines.join if current_section && !lines.empty?
+              current_section = line.match(/^\[(.+)\]$/)[1].downcase.to_sym
+              lines = []
+            when %r{^\[/(?:HTML|CSS|JavaScript)\]$}
+              sections[current_section] = lines.join if current_section && !lines.empty?
+              current_section = nil
+            else
+              lines << line if current_section
+            end
+          end
+
+          sections.each do |section, content|
+            sections[section] = extract_search_replace_blocks(content)
+          end
+
+          sections
+        end
+
+        def apply_changes(changes)
+          source = artifact_version || artifact
+          updated_content = { js: source.js, html: source.html, css: source.css }
+
+          %i[html css javascript].each do |section|
+            blocks = changes[section]
+            next unless blocks
+
+            content = source.public_send(section == :javascript ? :js : section)
+            blocks.each do |block|
+              begin
+                content =
+                  DiscourseAi::Utils::DiffUtils::SimpleDiff.apply(
+                    content,
+                    block[:search],
+                    block[:replace],
+                  )
+              rescue DiscourseAi::Utils::DiffUtils::SimpleDiff::NoMatchError
+                # TODO, we may need to inform caller here, LLM made a mistake which it
+                # should correct
+              end
+            end
+            updated_content[section == :javascript ? :js : section] = content
+          end
+
+          artifact.create_new_version(
+            html: updated_content[:html],
+            css: updated_content[:css],
+            js: updated_content[:js],
+            change_description: instructions,
+          )
+        end
+
+        private
+
+        def extract_search_replace_blocks(content)
+          return nil if content.blank?
+
+          blocks = []
+          remaining = content
+
+          pattern = /<<+\s*SEARCH\s*\n(.*?)\n=+\s*\n(.*?)\n>>+\s*REPLACE/m
+          while remaining =~ pattern
+            blocks << { search: $1.strip, replace: $2.strip }
+            remaining = $'
+          end
+
+          blocks.empty? ? nil : blocks
+        end
+
+        def system_prompt
+          <<~PROMPT
+            You are a web development expert generating precise search/replace changes for updating HTML, CSS, and JavaScript code.
+
+            Important rules:
+
+            1. Use EXACTLY this format for changes:
+               <<<<<<< SEARCH
+               (exact code to find)
+               =======
+               (replacement code)
+               >>>>>>> REPLACE
+            2. DO NOT modify the markers or add spaces around them
+            3. DO NOT add explanations or comments within sections
+            4. ONLY include [HTML], [CSS], and [JavaScript] sections if they have changes
+            5. Ensure search text matches EXACTLY - partial matches will fail
+            6. Keep changes minimal and focused
+            7. HTML should not include <html>, <head>, or <body> tags, it is injected into a template
+
+            JavaScript libraries must be sourced from the following CDNs, otherwise CSP will reject it:
+            #{AiArtifact::ALLOWED_CDN_SOURCES.join("\n")}
+
+            Reply Format:
+            [HTML]
+            (changes or empty if no changes)
+            [/HTML]
+            [CSS]
+            (changes or empty if no changes)
+            [/CSS]
+            [JavaScript]
+            (changes or empty if no changes)
+            [/JavaScript]
+
+            Example - Multiple changes in one file:
+
+            [JavaScript]
+            <<<<<<< SEARCH
+            console.log('old1');
+            =======
+            console.log('new1');
+            >>>>>>> REPLACE
+            <<<<<<< SEARCH
+            console.log('old2');
+            =======
+            console.log('new2');
+            >>>>>>> REPLACE
+            [/JavaScript]
+
+            Example - CSS with multiple blocks:
+
+            [CSS]
+            <<<<<<< SEARCH
+            .button { color: blue; }
+            =======
+            .button { color: red; }
+            >>>>>>> REPLACE
+            <<<<<<< SEARCH
+            .text { font-size: 12px; }
+            =======
+            .text { font-size: 16px; }
+            >>>>>>> REPLACE
+            [/CSS]
+          PROMPT
+        end
+
+        def user_prompt
+          source = artifact_version || artifact
+          <<~CONTENT
+            Artifact code:
+
+            [HTML]
+            #{source.html}
+            [/HTML]
+
+            [CSS]
+            #{source.css}
+            [/CSS]
+
+            [JavaScript]
+            #{source.js}
+            [/JavaScript]
+
+            Instructions:
+
+            #{instructions}
+          CONTENT
+        end
+      end
+    end
+  end
+end

lib/ai_bot/artifact_update_strategies/full.rb

@@ -0,0 +1,148 @@
+# frozen_string_literal: true
+module DiscourseAi
+  module AiBot
+    module ArtifactUpdateStrategies
+      class Full < Base
+        private
+
+        def build_prompt
+          DiscourseAi::Completions::Prompt.new(
+            system_prompt,
+            messages: [
+              { type: :user, content: "#{current_artifact_content}\n\n\n#{instructions}" },
+            ],
+            post_id: post.id,
+            topic_id: post.topic_id,
+          )
+        end
+
+        def parse_changes(response)
+          sections = { html: nil, css: nil, javascript: nil }
+          current_section = nil
+          lines = []
+
+          response.each_line do |line|
+            case line
+            when /^\[(HTML|CSS|JavaScript)\]$/
+              sections[current_section] = lines.join if current_section && !lines.empty?
+              current_section = line.match(/^\[(.+)\]$/)[1].downcase.to_sym
+              lines = []
+            when %r{^\[/(HTML|CSS|JavaScript)\]$}
+              sections[current_section] = lines.join if current_section && !lines.empty?
+              current_section = nil
+              lines = []
+            else
+              lines << line if current_section
+            end
+          end
+
+          sections
+        end
+
+        def apply_changes(changes)
+          source = artifact_version || artifact
+          updated_content = { js: source.js, html: source.html, css: source.css }
+
+          %i[html css javascript].each do |section|
+            content = changes[section]&.strip
+            next if content.blank?
+            updated_content[section == :javascript ? :js : section] = content
+          end
+
+          artifact.create_new_version(
+            html: updated_content[:html],
+            css: updated_content[:css],
+            js: updated_content[:js],
+            change_description: instructions,
+          )
+        end
+
+        private
+
+        def system_prompt
+          <<~PROMPT
+            You are a web development expert generating updated HTML, CSS, and JavaScript code.
+
+            Important rules:
+            1. Provide full source code for each changed section
+            2. Generate up to three sections: HTML, CSS, and JavaScript
+            3. Only include sections that need changes
+            4. Keep changes focused on the requirements
+            5. NEVER EVER BE LAZY, always include ALL the source code with any update you make. If you are lazy you will break the artifact.
+            6. Do not print out any reasoning, just the changed code, you will be parsed via a program.
+            7. Sections must start and end with exact tags: [HTML] [/HTML], [CSS] [/CSS], [JavaScript] [/JavaScript]
+            8. HTML should not include <html>, <head>, or <body> tags, it is injected into a template
+
+            JavaScript libraries must be sourced from the following CDNs, otherwise CSP will reject it:
+            #{AiArtifact::ALLOWED_CDN_SOURCES.join("\n")}
+
+            Always adhere to the format when replying:
+
+            [HTML]
+            complete html code, omit if no changes
+            [/HTML]
+
+            [CSS]
+            complete css code, omit if no changes
+            [/CSS]
+
+            [JavaScript]
+            complete js code, omit if no changes
+            [/JavaScript]
+
+            Examples:
+
+            Example 1 (HTML only change):
+            [HTML]
+            <div class="container">
+              <h1>Title</h1>
+            </div>
+            [/HTML]
+
+            Example 2 (CSS and JavaScript changes):
+            [CSS]
+            .container { padding: 20px; }
+            .title { color: blue; }
+            [/CSS]
+            [JavaScript]
+            function init() {
+              console.log("loaded");
+            }
+            [/JavaScript]
+
+            Example 3 (All sections):
+            [HTML]
+            <div id="app"></div>
+            [/HTML]
+            [CSS]
+            #app { margin: 0; }
+            [/CSS]
+            [JavaScript]
+            const app = document.getElementById("app");
+            [/JavaScript]
+
+          PROMPT
+        end
+
+        def current_artifact_content
+          source = artifact_version || artifact
+          <<~CONTENT
+            Current artifact code:
+
+            [HTML]
+            #{source.html}
+            [/HTML]
+
+            [CSS]
+            #{source.css}
+            [/CSS]
+
+            [JavaScript]
+            #{source.js}
+            [/JavaScript]
+          CONTENT
+        end
+      end
+    end
+  end
+end

lib/ai_bot/bot.rb

@@ -220,8 +220,11 @@ module DiscourseAi
         update_blk.call("", cancel, build_placeholder(tool.summary, "")) if show_placeholder
 
         result =
-          tool.invoke do |progress|
-            if show_placeholder
+          tool.invoke do |progress, render_raw|
+            if render_raw
+              update_blk.call("", cancel, tool.custom_raw, :partial_invoke)
+              show_placeholder = false
+            elsif show_placeholder
               placeholder = build_placeholder(tool.summary, progress)
               update_blk.call("", cancel, placeholder)
             end

lib/ai_bot/personas/persona.rb

@@ -102,6 +102,7 @@ module DiscourseAi
             if SiteSetting.ai_artifact_security.in?(%w[lax strict])
               tools << Tools::CreateArtifact
               tools << Tools::UpdateArtifact
+              tools << Tools::ReadArtifact
             end
 
             tools << Tools::GithubSearchCode if SiteSetting.ai_bot_github_access_token.present?
@@ -201,7 +202,9 @@ module DiscourseAi
 
           prompt.max_pixels = self.class.vision_max_pixels if self.class.vision_enabled
           prompt.tools = available_tools.map(&:signature) if available_tools
-
+          available_tools.each do |tool|
+            tool.inject_prompt(prompt: prompt, context: context, persona: self)
+          end
           prompt
         end
 

lib/ai_bot/personas/web_artifact_creator.rb

@@ -5,11 +5,11 @@ module DiscourseAi
     module Personas
       class WebArtifactCreator < Persona
         def tools
-          [Tools::CreateArtifact, Tools::UpdateArtifact]
+          [Tools::CreateArtifact, Tools::UpdateArtifact, Tools::ReadArtifact]
         end
 
         def required_tools
-          [Tools::CreateArtifact, Tools::UpdateArtifact]
+          [Tools::CreateArtifact, Tools::UpdateArtifact, Tools::ReadArtifact]
         end
 
         def system_prompt

lib/ai_bot/playground.rb

@@ -479,7 +479,9 @@ module DiscourseAi
             raw = reply.dup
             raw << "\n\n" << placeholder if placeholder.present?
 
-            blk.call(partial) if blk && type != :tool_details && type != :partial_tool
+            if blk && type != :tool_details && type != :partial_tool && type != :partial_invoke
+              blk.call(partial)
+            end
 
             if stream_reply && !Discourse.redis.get(redis_stream_key)
               cancel&.call

lib/ai_bot/tools/create_artifact.rb

@@ -8,38 +8,49 @@ module DiscourseAi
           "create_artifact"
         end
 
-        def self.js_dependency_tip
-          <<~TIP
-            If you need to include a JavaScript library, you may include assets from:
-            - unpkg.com
-            - cdnjs.com
-            - jsdelivr.com
-            - ajax.googleapis.com
+        def self.specification_description
+          <<~DESC
+            A detailed description of the web artifact you want to create. Your specification should include:
 
-            To include them ensure they are the last tag in your HTML body.
-            Example: <script crossorigin src="https://cdn.jsdelivr.net/npm/vue@2.6.14/dist/vue.min.js"></script>
-          TIP
-        end
+            1. Purpose and functionality
+            2. Visual design requirements
+            3. Interactive elements and behavior
+            4. Data handling (if applicable)
+            5. Specific requirements or constraints
+            6. DO NOT include full source code of the artifact, just very clear requirements
 
-        def self.js_script_tag_tip
-          <<~TIP
-            if you need a custom script tag, you can use the following format:
+            Good specification examples:
 
-            <script type="module">
-              // your script here
-            </script>
+            Example: (Calculator):
+            "Create a modern calculator with a dark theme. It should:
+            - Have a large display area showing current and previous calculations
+            - Include buttons for numbers 0-9, basic operations (+,-,*,/), and clear
+            - Use a grid layout with subtle hover effects on buttons
+            - Show button press animations
+            - Keep calculation history visible above current input
+            - Use a monospace font for numbers
+            - Support keyboard input for numbers and operations"
 
-            If you only need a regular script tag, you can use the following format:
+            Poor specification example:
+            "Make a website that looks nice and does cool stuff"
+            (Too vague, lacks specific requirements and functionality details)
 
-            // your script here
-          TIP
+            Tips for good specifications:
+            - Be specific about layout and design preferences
+            - Describe all interactive elements and their behavior
+            - Include any specific visual effects or animations
+            - Mention responsive design requirements if needed
+            - List any specific libraries or frameworks to use/avoid
+            - Describe error states and edge cases
+            - Include accessibility requirements
+            - Include code snippets to help ground the specification
+          DESC
         end
 
         def self.signature
           {
             name: "create_artifact",
-            description:
-              "Creates a web artifact with HTML, CSS, and JavaScript that can be displayed in an iframe",
+            description: "Creates a web artifact based on a specification",
             parameters: [
               {
                 name: "name",
@@ -48,121 +59,243 @@ module DiscourseAi
                 required: true,
               },
               {
-                name: "html_body",
-                description:
-                  "The HTML content for the BODY tag (do not include the BODY tag). #{js_dependency_tip}",
+                name: "specification",
                 type: "string",
+                description: specification_description,
                 required: true,
               },
-              { name: "css", description: "Optional CSS styles for the artifact", type: "string" },
-              {
-                name: "js",
-                description:
-                  "Optional
-              JavaScript code for the artifact, this will be the last <script> tag in the BODY. #{js_script_tag_tip}",
-                type: "string",
-              },
             ],
           }
         end
 
+        def self.accepted_options
+          [option(:creator_llm, type: :llm)]
+        end
+
         def self.allow_partial_tool_calls?
           true
         end
 
         def partial_invoke
-          @selected_tab = :html_body
-          if @prev_parameters
-            @selected_tab = parameters.keys.find { |k| @prev_parameters[k] != parameters[k] }
+          if parameters[:specification].present?
+            in_progress(specification: parameters[:specification])
           end
-          update_custom_html
-          @prev_parameters = parameters.dup
+        end
+
+        def in_progress(specification:, source: nil)
+          source = (<<~HTML) if source.present?
+            ### Source
+
+            ````
+            #{source}
+            ````
+          HTML
+
+          self.custom_raw = <<~HTML
+            <details>
+              <summary>Thinking...</summary>
+
+
+            ### Specification
+            ````
+            #{specification}
+            ````
+
+            #{source}
+
+            </details>
+          HTML
         end
 
         def invoke
-          yield parameters[:name] || "Web Artifact"
-          # Get the current post from context
           post = Post.find_by(id: context[:post_id])
           return error_response("No post context found") unless post
 
-          html = parameters[:html_body].to_s
-          css = parameters[:css].to_s
-          js = parameters[:js].to_s
+          partial_response = +""
+          artifact_code =
+            generate_artifact_code(post: post, user: post.user) do |partial|
+              partial_response << partial
+              in_progress(specification: parameters[:specification], source: partial_response)
+              yield nil, true
+            end
+          return error_response(artifact_code[:error]) if artifact_code[:error]
 
-          # Create the artifact
-          artifact =
-            AiArtifact.new(
-              user_id: bot_user.id,
-              post_id: post.id,
-              name: parameters[:name].to_s[0...255],
-              html: html,
-              css: css,
-              js: js,
-              metadata: parameters[:metadata],
-            )
+          artifact = create_artifact(post, artifact_code)
 
           if artifact.save
             update_custom_html(artifact)
             success_response(artifact)
           else
+            self.custom_raw = self.custom_raw + "\n\n###Error creating artifact..."
             error_response(artifact.errors.full_messages.join(", "))
           end
         end
 
         def chain_next_response?
-          @chain_next_response
+          false
+        end
+
+        def description_args
+          { name: parameters[:name], specification: parameters[:specification] }
         end
 
         private
 
-        def update_custom_html(artifact = nil)
-          html = parameters[:html_body].to_s
-          css = parameters[:css].to_s
-          js = parameters[:js].to_s
+        def generate_artifact_code(post:, user:)
+          prompt = build_artifact_prompt(post: post)
+          response = +""
 
-          artifact_div =
-            "<div class=\"ai-artifact\" data-ai-artifact-id=\"#{artifact.id}\"></div>" if artifact
+          llm =
+            (
+              options[:creator_llm].present? &&
+                LlmModel.find_by(id: options[:creator_llm].to_i)&.to_llm
+            ) || self.llm
 
-          content = []
-
-          content << [:html_body, "### HTML\n\n```html\n#{html}\n```"] if html.present?
-
-          content << [:css, "### CSS\n\n```css\n#{css}\n```"] if css.present?
-
-          content << [:js, "### JavaScript\n\n```javascript\n#{js}\n```"] if js.present?
-
-          content.sort_by! { |c| c[0] === @selected_tab ? 1 : 0 } if !artifact
-
-          if artifact
-            content.unshift([nil, "[details='#{I18n.t("discourse_ai.ai_artifact.view_source")}']"])
-            content << [nil, "[/details]"]
+          llm.generate(prompt, user: user, feature_name: "create_artifact") do |partial_response|
+            response << partial_response
+            yield partial_response
           end
 
-          content << [:preview, "### Preview\n\n#{artifact_div}"] if artifact_div
-          self.custom_raw = content.map { |c| c[1] }.join("\n\n")
+          sections = parse_sections(response)
+
+          if valid_sections?(sections)
+            html, css, js = sections
+            { html: html, css: css, js: js }
+          else
+            { error: "Failed to generate valid artifact code", response: response }
+          end
+        end
+
+        def build_artifact_prompt(post:)
+          DiscourseAi::Completions::Prompt.new(
+            artifact_system_prompt,
+            messages: [{ type: :user, content: parameters[:specification] }],
+            post_id: post.id,
+            topic_id: post.topic_id,
+          )
+        end
+
+        def parse_sections(response)
+          sections = { html: nil, css: nil, javascript: nil }
+          current_section = nil
+          lines = []
+
+          response.each_line do |line|
+            case line
+            when /^\[(HTML|CSS|JavaScript)\]$/
+              current_section = line.match(/^\[(.+)\]$/)[1].downcase.to_sym
+              lines = []
+            when %r{^\[/(HTML|CSS|JavaScript)\]$}
+              sections[current_section] = lines.join if current_section
+              current_section = nil
+              lines = []
+            else
+              lines << line if current_section
+            end
+          end
+
+          [sections[:html].to_s.strip, sections[:css].to_s.strip, sections[:javascript].to_s.strip]
+        end
+
+        def valid_sections?(sections)
+          return false if sections.empty?
+
+          # Basic validation of sections
+          has_html = sections[0].include?("<") && sections[0].include?(">")
+          has_css = sections[1].include?("{") && sections[1].include?("}")
+          has_js = sections[2].present?
+
+          has_html || has_css || has_js
+        end
+
+        def create_artifact(post, code)
+          AiArtifact.new(
+            user_id: bot_user.id,
+            post_id: post.id,
+            name: parameters[:name].to_s[0...255],
+            html: code[:html],
+            css: code[:css],
+            js: code[:js],
+            metadata: {
+              specification: parameters[:specification],
+            },
+          )
+        end
+
+        def artifact_system_prompt
+          <<~PROMPT
+            You are a web development expert creating HTML, CSS, and JavaScript code.
+            Follow these instructions precisely:
+
+            1. Provide complete source code for all three required sections: HTML, CSS, and JavaScript
+            2. Use exact section tags: [HTML]/[/HTML], [CSS]/[/CSS], [JavaScript]/[/JavaScript]
+            3. Format requirements:
+               - HTML: No <html>, <head>, or <body> tags
+               - CSS: Valid CSS rules
+               - JavaScript: Clean, working code
+            4. NEVER USE SHORTCUTS - generate complete code for each section. No placeholders.
+            5. If you need to source ANY 3rd party libraries, use the following CDNs:
+            #{AiArtifact::ALLOWED_CDN_SOURCES.join("\n")}
+
+            6. When sourcing libraries, include them in the [HTML] section, for example: <script src="https://cdn.jsdelivr.net/...."></script>
+
+            Required response format:
+
+            [HTML]
+            <div id="app"><!-- Your complete HTML here --></div>
+            [/HTML]
+
+            [CSS]
+            #app { /* Your complete CSS here */ }
+            [/CSS]
+
+            [JavaScript]
+            // Your complete JavaScript here
+            [/JavaScript]
+
+            Important:
+            - All three sections are required
+            - Sections must use exact tags shown above
+            - Focus on simplicity and reliability
+            - Include basic error handling
+            - Follow accessibility guidelines
+            - No explanatory text, only code
+          PROMPT
+        end
+
+        def update_custom_html(artifact)
+          html_preview = <<~MD
+            [details="View Source"]
+            ### HTML
+            ```html
+            #{artifact.html}
+            ```
+
+            ### CSS
+            ```css
+            #{artifact.css}
+            ```
+
+            ### JavaScript
+            ```javascript
+            #{artifact.js}
+            ```
+            [/details]
+
+            ### Preview
+            <div class="ai-artifact" data-ai-artifact-id="#{artifact.id}"></div>
+          MD
+
+          self.custom_raw = html_preview
         end
 
         def success_response(artifact)
-          @chain_next_response = false
-
-          {
-            status: "success",
-            artifact_id: artifact.id,
-            message: "Artifact created successfully and rendered to user.",
-          }
+          { status: "success", artifact_id: artifact.id, message: "Artifact created successfully." }
         end
 
         def error_response(message)
-          @chain_next_response = false
-
           { status: "error", error: message }
         end
-
-        def help
-          "Creates a web artifact with HTML, CSS, and JavaScript that can be displayed in an iframe. " \
-            "Requires a name and HTML content. CSS and JavaScript are optional. " \
-            "The artifact will be associated with the current post and can be displayed using an iframe."
-        end
       end
     end
   end

lib/ai_bot/tools/option.rb

@@ -4,12 +4,14 @@ module DiscourseAi
   module AiBot
     module Tools
       class Option
-        attr_reader :tool, :name, :type
+        attr_reader :tool, :name, :type, :values, :default
 
-        def initialize(tool:, name:, type:)
+        def initialize(tool:, name:, type:, values: nil, default: nil)
           @tool = tool
           @name = name.to_s
           @type = type
+          @values = values
+          @default = default
         end
 
         def localized_name

lib/ai_bot/tools/read_artifact.rb

@@ -0,0 +1,211 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module AiBot
+    module Tools
+      class ReadArtifact < Tool
+        MAX_HTML_SIZE = 30.kilobytes
+        MAX_CSS_FILES = 5
+
+        def self.name
+          "read_artifact"
+        end
+
+        def self.signature
+          {
+            name: "read_artifact",
+            description: "Read an artifact from a URL and convert to a local artifact",
+            parameters: [
+              {
+                name: "url",
+                type: "string",
+                description: "URL of the artifact to read",
+                required: true,
+              },
+            ],
+          }
+        end
+
+        def invoke
+          return error_response("Unknown context, feature only works in PMs") if !post
+
+          uri = URI.parse(parameters[:url])
+          return error_response("Invalid URL") unless uri.is_a?(URI::HTTP)
+
+          if discourse_artifact?(uri)
+            handle_discourse_artifact(uri)
+          else
+            handle_external_page(uri)
+          end
+        end
+
+        def chain_next_response?
+          @chain_next_response
+        end
+
+        private
+
+        def error_response(message)
+          @chain_next_response = true
+          { status: "error", error: message }
+        end
+
+        def success_response(artifact)
+          { status: "success", artifact_id: artifact.id, message: "Artifact created successfully." }
+        end
+
+        def discourse_artifact?(uri)
+          uri.path.include?("/discourse-ai/ai-bot/artifacts/")
+        end
+
+        def post
+          @post ||= Post.find_by(id: context[:post_id])
+        end
+
+        def handle_discourse_artifact(uri)
+          if uri.path =~ %r{/discourse-ai/ai-bot/artifacts/(\d+)(?:/(\d+))?}
+            artifact_id = $1.to_i
+            version = $2&.to_i
+          else
+            return error_response("Invalid artifact URL format")
+          end
+
+          if uri.host == Discourse.current_hostname
+            source_artifact = AiArtifact.find_by(id: artifact_id)
+            return error_response("Artifact not found") if !source_artifact
+
+            if !source_artifact.public? && !Guardian.new(post.user).can_see?(source_artifact.post)
+              return error_response("Access denied")
+            end
+            new_artifact = clone_artifact(source_artifact, version)
+          else
+            response = fetch_page(uri)
+            return error_response("Failed to fetch artifact") unless response
+
+            html, css, js = extract_discourse_artifact(response.body)
+            return error_response("Invalid artifact format") unless html
+
+            new_artifact =
+              create_artifact_from_web(
+                html: html,
+                css: css,
+                js: js,
+                name: "Imported Discourse Artifact",
+              )
+          end
+
+          if new_artifact&.persisted?
+            update_custom_html(new_artifact)
+            success_response(new_artifact)
+          else
+            error_response(
+              new_artifact&.errors&.full_messages&.join(", ") || "Failed to create artifact",
+            )
+          end
+        end
+
+        def extract_discourse_artifact(html)
+          doc = Nokogiri.HTML(html)
+          iframe = doc.at_css("body > iframe")
+          return nil unless iframe
+
+          # parse srcdoc attribute of iframe
+          iframe_doc = Nokogiri.HTML(iframe["srcdoc"])
+          return nil unless iframe_doc
+
+          body = iframe_doc.at_css("body")
+          last_script_tag = body&.at_css("script:last-of-type")
+          script = last_script_tag&.content.to_s[0...MAX_HTML_SIZE]
+          last_script_tag.remove if last_script_tag
+          content = body&.inner_html.to_s[0...MAX_HTML_SIZE]
+          style = iframe_doc.at_css("style")&.content.to_s[0...MAX_HTML_SIZE]
+
+          [content, style, script]
+        end
+
+        def handle_external_page(uri)
+          response = fetch_page(uri)
+          return error_response("Failed to fetch page") unless response
+
+          html, css, js = extract_content(response, uri)
+          new_artifact =
+            create_artifact_from_web(html: html, css: css, js: js, name: "external artifact")
+
+          if new_artifact&.persisted?
+            update_custom_html(new_artifact)
+            success_response(new_artifact)
+          else
+            error_response(
+              new_artifact&.errors&.full_messages&.join(", ") || "Failed to create artifact",
+            )
+          end
+        end
+
+        def extract_content(response, uri)
+          doc = Nokogiri.HTML(response.body)
+
+          html = doc.at_css("body").to_html.to_s[0...MAX_HTML_SIZE]
+
+          css_files =
+            doc
+              .css('link[rel="stylesheet"]')
+              .map { |link| URI.join(uri, link["href"]).to_s }
+              .first(MAX_CSS_FILES)
+          css = download_css_files(css_files).to_s[0...MAX_HTML_SIZE]
+
+          js = doc.css("script:not([src])").map(&:content).join("\n").to_s[0...MAX_HTML_SIZE]
+
+          [html, css, js]
+        end
+
+        def clone_artifact(source, version = nil)
+          source_version = version ? source.versions.find_by(version_number: version) : nil
+          content = source_version || source
+
+          AiArtifact.create!(
+            user: post.user,
+            post: post,
+            name: source.name,
+            html: content.html,
+            css: content.css,
+            js: content.js,
+            metadata: {
+              cloned_from: source.id,
+              cloned_version: source_version&.version_number,
+            },
+          )
+        end
+
+        def create_artifact_from_web(html:, css:, js:, name:)
+          AiArtifact.create(
+            user: post.user,
+            post: post,
+            name: name,
+            html: html,
+            css: css,
+            js: js,
+            metadata: {
+              imported_from: parameters[:url],
+            },
+          )
+        end
+
+        def update_custom_html(artifact)
+          self.custom_raw = <<~HTML
+            ### Artifact created successfully
+
+            <div class="ai-artifact" data-ai-artifact-id="#{artifact.id}"></div>
+          HTML
+        end
+
+        def fetch_page(uri)
+          send_http_request(uri.to_s) { |response| response if response.code == "200" }
+        end
+
+        def download_css_files(urls)
+          urls.map { |url| fetch_page(URI.parse(url)).body }.join("\n")
+        end
+      end
+    end
+  end
+end

lib/ai_bot/tools/tool.rb

@@ -27,8 +27,8 @@ module DiscourseAi
             []
           end
 
-          def option(name, type:)
-            Option.new(tool: self, name: name, type: type)
+          def option(name, type:, values: nil, default: nil)
+            Option.new(tool: self, name: name, type: type, values: values, default: default)
           end
 
           def help
@@ -42,6 +42,9 @@ module DiscourseAi
           def allow_partial_tool_calls?
             false
           end
+
+          def inject_prompt(prompt:, context:, persona:)
+          end
         end
 
         attr_accessor :custom_raw, :parameters
@@ -89,8 +92,13 @@ module DiscourseAi
                 val = (val.to_s == "true")
               when :integer
                 val = val.to_i
+              when :enum
+                val = val.to_s
+                val = option.default if option.values && !option.values.include?(val)
               end
               result[option.name] = val
+            elsif val.nil?
+              result[option.name] = option.default
             end
           end
           result

lib/ai_bot/tools/update_artifact.rb

@@ -8,50 +8,10 @@ module DiscourseAi
           "update_artifact"
         end
 
-        # this is not working that well, we support it, but I am leaving it dormant for now
-        def self.unified_diff_tip
-          <<~TIP
-            When updating and artifact in diff mode unified diffs can be applied:
-
-            If editing:
-
-            <div>
-              <p>Some text</p>
-            </div>
-
-            You can provide a diff like:
-
-            <div>
-            - <p>Some text</p>
-            + <p>Some new text</p>
-            </div>
-
-            This will result in:
-
-            <div>
-              <p>Some new text</p>
-            </div>
-
-            If you need to supply multiple hunks for a diff use a @@ separator, for example:
-
-            @@ -1,3 +1,3 @@
-            - <p>Some text</p>
-            + <p>Some new text</p>
-            @@ -5,3 +5,3 @@
-            - </div>
-            + <p>more text</p>
-            </div>
-
-            If you supply text without @@ seperators or + and - prefixes, the entire text will be appended to the artifact section.
-
-          TIP
-        end
-
         def self.signature
           {
             name: "update_artifact",
-            description:
-              "Updates an existing web artifact with new HTML, CSS, or JavaScript content. Note either html, css, or js MUST be provided. You may provide all three if desired.",
+            description: "Updates an existing web artifact",
             parameters: [
               {
                 name: "artifact_id",
@@ -59,138 +19,241 @@ module DiscourseAi
                 type: "integer",
                 required: true,
               },
-              { name: "html", description: "new HTML content for the artifact", type: "string" },
-              { name: "css", description: "new CSS content for the artifact", type: "string" },
               {
-                name: "js",
-                description: "new JavaScript content for the artifact",
+                name: "instructions",
+                description: "Clear instructions on what changes need to be made to the artifact.",
                 type: "string",
+                required: true,
               },
               {
-                name: "change_description",
+                name: "version",
                 description:
-                  "A brief description of the changes being made. Note: This only documents the change - you must provide the actual content in html/css/js parameters to make changes.",
-                type: "string",
+                  "The version number of the artifact to update, if not supplied latest version will be updated",
+                type: "integer",
+                required: false,
               },
             ],
           }
         end
 
+        def self.inject_prompt(prompt:, context:, persona:)
+          return if persona.options["do_not_echo_artifact"].to_s == "true"
+          # we inject the current artifact content into the last user message
+          if topic_id = context[:topic_id]
+            posts = Post.where(topic_id: topic_id)
+            artifact = AiArtifact.order("id desc").where(post: posts).first
+            if artifact
+              latest_version = artifact.versions.order(version_number: :desc).first
+              current = latest_version || artifact
+
+              artifact_source = <<~MSG
+                Current Artifact:
+
+                ### HTML
+                ```html
+                #{current.html}
+                ```
+
+                ### CSS
+                ```css
+                #{current.css}
+                ```
+
+                ### JavaScript
+                ```javascript
+                #{current.js}
+                ```
+
+              MSG
+
+              last_message = prompt.messages.last
+              last_message[:content] = "#{artifact_source}\n\n#{last_message[:content]}"
+            end
+          end
+        end
+
+        def self.accepted_options
+          [
+            option(:editor_llm, type: :llm),
+            option(:update_algorithm, type: :enum, values: %w[diff full], default: "diff"),
+            option(:do_not_echo_artifact, type: :boolean, default: true),
+          ]
+        end
+
         def self.allow_partial_tool_calls?
           true
         end
 
-        def chain_next_response?
-          @chain_next_response
+        def partial_invoke
+          in_progress(instructions: parameters[:instructions]) if parameters[:instructions].present?
         end
 
-        def partial_invoke
-          @selected_tab = :html
-          if @prev_parameters
-            @selected_tab = parameters.keys.find { |k| @prev_parameters[k] != parameters[k] }
-          end
-          update_custom_html
-          @prev_parameters = parameters.dup
+        def in_progress(instructions:, source: nil)
+          source = (<<~HTML) if source.present?
+            ### Source
+
+            ````
+            #{source}
+            ````
+          HTML
+
+          self.custom_raw = <<~HTML
+            <details>
+              <summary>Thinking...</summary>
+
+              ### Instructions
+              ````
+              #{instructions}
+              ````
+
+              #{source}
+
+            </details>
+          HTML
         end
 
         def invoke
-          yield "Updating Artifact"
-
           post = Post.find_by(id: context[:post_id])
           return error_response("No post context found") unless post
 
           artifact = AiArtifact.find_by(id: parameters[:artifact_id])
           return error_response("Artifact not found") unless artifact
 
+          artifact_version = nil
+          if version = parameters[:version]
+            artifact_version = artifact.versions.find_by(version_number: version)
+            # we could tell llm it is confused here if artifact version is not there
+            # but let's just fix it transparently which saves an llm call
+          end
+
+          artifact_version ||= artifact.versions.order(version_number: :desc).first
+
           if artifact.post.topic.id != post.topic.id
             return error_response("Attempting to update an artifact you are not allowed to")
           end
 
-          last_version = artifact.versions.order(version_number: :desc).first
+          llm =
+            (
+              options[:editor_llm].present? &&
+                LlmModel.find_by(id: options[:editor_llm].to_i)&.to_llm
+            ) || self.llm
+
+          strategy =
+            (
+              if options[:update_algorithm] == "diff"
+                ArtifactUpdateStrategies::Diff
+              else
+                ArtifactUpdateStrategies::Full
+              end
+            )
 
           begin
-            version =
-              artifact.create_new_version(
-                html: parameters[:html] || last_version&.html || artifact.html,
-                css: parameters[:css] || last_version&.css || artifact.css,
-                js: parameters[:js] || last_version&.js || artifact.js,
-                change_description: parameters[:change_description].to_s,
-              )
+            instructions = parameters[:instructions]
+            partial_response = +""
+            new_version =
+              strategy
+                .new(
+                  llm: llm,
+                  post: post,
+                  user: post.user,
+                  artifact: artifact,
+                  artifact_version: artifact_version,
+                  instructions: instructions,
+                )
+                .apply do |progress|
+                  partial_response << progress
+                  in_progress(instructions: instructions, source: partial_response)
+                  # force in progress to render
+                  yield nil, true
+                end
 
-            update_custom_html(artifact, version)
-            success_response(artifact, version)
-          rescue DiscourseAi::Utils::DiffUtils::DiffError => e
-            error_response(e.to_llm_message)
-          rescue => e
+            update_custom_html(
+              artifact: artifact,
+              artifact_version: artifact_version,
+              new_version: new_version,
+            )
+            success_response(artifact, new_version)
+          rescue StandardError => e
             error_response(e.message)
           end
         end
 
+        def chain_next_response?
+          false
+        end
+
         private
 
-        def update_custom_html(artifact = nil, version = nil)
+        def line_based_markdown_diff(before, after)
+          # Split into lines
+          before_lines = before.split("\n")
+          after_lines = after.split("\n")
+
+          # Use ONPDiff for line-level comparison
+          diff = ONPDiff.new(before_lines, after_lines).diff
+
+          # Build markdown output
+          result = ["```diff"]
+
+          diff.each do |line, status|
+            case status
+            when :common
+              result << " #{line}"
+            when :delete
+              result << "-#{line}"
+            when :add
+              result << "+#{line}"
+            end
+          end
+
+          result << "```"
+          result.join("\n")
+        end
+
+        def update_custom_html(artifact:, artifact_version:, new_version:)
           content = []
 
-          if parameters[:html].present?
-            content << [:html, "### HTML Changes\n\n```html\n#{parameters[:html]}\n```"]
-          end
-
-          if parameters[:css].present?
-            content << [:css, "### CSS Changes\n\n```css\n#{parameters[:css]}\n```"]
-          end
-
-          if parameters[:js].present?
-            content << [:js, "### JavaScript Changes\n\n```javascript\n#{parameters[:js]}\n```"]
-          end
-
-          if parameters[:change_description].present?
-            content.unshift(
-              [:description, "### Change Description\n\n#{parameters[:change_description]}"],
-            )
-          end
-
-          content.sort_by! { |c| c[0] === @selected_tab ? 1 : 0 } if !artifact
-
-          if artifact
-            content.unshift([nil, "[details='#{I18n.t("discourse_ai.ai_artifact.view_changes")}']"])
-            content << [nil, "[/details]"]
+          if new_version.change_description.present?
             content << [
-              :preview,
-              "### Preview\n\n<div class=\"ai-artifact\" data-ai-artifact-version=\"#{version.version_number}\" data-ai-artifact-id=\"#{artifact.id}\"></div>",
+              :description,
+              "[details='#{I18n.t("discourse_ai.ai_artifact.change_description")}']\n\n````\n#{new_version.change_description}\n````\n\n[/details]",
             ]
           end
+          content << [nil, "[details='#{I18n.t("discourse_ai.ai_artifact.view_changes")}']"]
 
-          content.unshift("\n\n")
+          %w[html css js].each do |type|
+            source = artifact_version || artifact
+            old_content = source.public_send(type)
+            new_content = new_version.public_send(type)
+
+            if old_content != new_content
+              diff = line_based_markdown_diff(old_content, new_content)
+              content << [nil, "### #{type.upcase} Changes\n#{diff}"]
+            end
+          end
+
+          content << [nil, "[/details]"]
+          content << [
+            :preview,
+            "### Preview\n\n<div class=\"ai-artifact\" data-ai-artifact-version=\"#{new_version.version_number}\" data-ai-artifact-id=\"#{artifact.id}\"></div>",
+          ]
 
           self.custom_raw = content.map { |c| c[1] }.join("\n\n")
         end
 
         def success_response(artifact, version)
-          @chain_next_response = false
-
-          hash = {
+          {
             status: "success",
             artifact_id: artifact.id,
             version: version.version_number,
             message: "Artifact updated successfully and rendered to user.",
           }
-
-          hash
         end
 
         def error_response(message)
-          @chain_next_response = true
           self.custom_raw = ""
-
           { status: "error", error: message }
         end
-
-        def help
-          "Updates an existing web artifact with changes to its HTML, CSS, or JavaScript content. " \
-            "Requires the artifact ID and at least one change diff. " \
-            "Changes are applied using unified diff format. " \
-            "A description of the changes is required for version history."
-        end
       end
     end
   end

lib/completions/endpoints/base.rb

@@ -87,10 +87,11 @@ module DiscourseAi
                 partial_tool_calls: partial_tool_calls,
               )
 
-            result = [result] if !result.is_a?(Array)
+            wrapped = result
+            wrapped = [result] if !result.is_a?(Array)
             cancelled_by_caller = false
             cancel_proc = -> { cancelled_by_caller = true }
-            result.each do |partial|
+            wrapped.each do |partial|
               blk.call(partial, cancel_proc)
               break if cancelled_by_caller
             end

lib/completions/endpoints/open_ai.rb

@@ -132,7 +132,7 @@ module DiscourseAi
         end
 
         def decode_chunk_finish
-          @processor.finish
+          processor.finish
         end
 
         def xml_tools_enabled?

lib/utils/diff_utils.rb

@@ -1,184 +0,0 @@
-# frozen_string_literal: true
-# Inspired by Aider https://github.com/Aider-AI/aider
-
-module DiscourseAi
-  module Utils
-    module DiffUtils
-      # Custom errors with detailed information for LLM feedback
-      class DiffError < StandardError
-        attr_reader :original_text, :diff_text, :context
-
-        def initialize(message, original_text:, diff_text:, context: {})
-          @original_text = original_text
-          @diff_text = diff_text
-          @context = context
-          super(message)
-        end
-
-        def to_llm_message
-          original_text = @original_text
-          original_text = @original_text[0..1000] + "..." if @original_text.length > 1000
-
-          <<~MESSAGE
-            #{message}
-
-            Original text:
-            ```
-            #{original_text}
-            ```
-
-            Attempted diff:
-            ```
-            #{diff_text}
-            ```
-
-            #{context_message}
-
-            Please provide a corrected diff that:
-            1. Has the correct context lines
-            2. Contains all necessary removals (-) and additions (+)
-          MESSAGE
-        end
-
-        private
-
-        def context_message
-          return "" if context.empty?
-
-          context.map { |key, value| "#{key}: #{value}" }.join("\n")
-        end
-      end
-
-      class NoMatchingContextError < DiffError
-        def initialize(original_text:, diff_text:)
-          super(
-            "Could not find the context lines in the original text",
-            original_text: original_text,
-            diff_text: diff_text,
-          )
-        end
-      end
-
-      class AmbiguousMatchError < DiffError
-        def initialize(original_text:, diff_text:)
-          super(
-            "Found multiple possible locations for this change",
-            original_text: original_text,
-            diff_text: diff_text,
-          )
-        end
-      end
-
-      class MalformedDiffError < DiffError
-        def initialize(original_text:, diff_text:, issue:)
-          super(
-            "The diff format is invalid",
-            original_text: original_text,
-            diff_text: diff_text,
-            context: {
-              "Issue" => issue,
-            },
-          )
-        end
-      end
-
-      def self.apply_hunk(text, diff)
-        # we need to handle multiple hunks just in case
-        if diff.match?(/^\@\@.*\@\@$\n/)
-          hunks = diff.split(/^\@\@.*\@\@$\n/)
-          if hunks.present?
-            hunks.each do |hunk|
-              next if hunk.blank?
-              text = apply_hunk(text, hunk)
-            end
-            return text
-          end
-        end
-
-        text = text.encode(universal_newline: true)
-        diff = diff.encode(universal_newline: true)
-        # we need this for matching
-        text = text + "\n" unless text.end_with?("\n")
-
-        diff_lines = parse_diff_lines(diff, text)
-
-        validate_diff_format!(text, diff, diff_lines)
-
-        return text.strip + "\n" + diff.strip if diff_lines.all? { |marker, _| marker == " " }
-
-        lines_to_match = diff_lines.select { |marker, _| ["-", " "].include?(marker) }.map(&:last)
-        match_start, match_end = find_unique_match(text, lines_to_match, diff)
-        new_hunk = diff_lines.select { |marker, _| ["+", " "].include?(marker) }.map(&:last).join
-
-        new_hunk = +""
-
-        diff_lines_index = 0
-        text[match_start..match_end].lines.each do |line|
-          diff_marker, diff_content = diff_lines[diff_lines_index]
-
-          while diff_marker == "+"
-            new_hunk << diff_content
-            diff_lines_index += 1
-            diff_marker, diff_content = diff_lines[diff_lines_index]
-          end
-
-          new_hunk << line if diff_marker == " "
-
-          diff_lines_index += 1
-        end
-
-        # leftover additions
-        diff_marker, diff_content = diff_lines[diff_lines_index]
-        while diff_marker == "+"
-          diff_lines_index += 1
-          new_hunk << diff_content
-          diff_marker, diff_content = diff_lines[diff_lines_index]
-        end
-
-        (text[0...match_start].to_s + new_hunk + text[match_end..-1].to_s).strip
-      end
-
-      private_class_method def self.parse_diff_lines(diff, text)
-        diff.lines.map do |line|
-          marker = line[0]
-          content = line[1..]
-
-          if !["-", "+", " "].include?(marker)
-            marker = " "
-            content = line
-          end
-
-          [marker, content]
-        end
-      end
-
-      private_class_method def self.validate_diff_format!(text, diff, diff_lines)
-        if diff_lines.empty?
-          raise MalformedDiffError.new(original_text: text, diff_text: diff, issue: "Diff is empty")
-        end
-      end
-
-      private_class_method def self.find_unique_match(text, context_lines, diff)
-        return 0 if context_lines.empty? && removals.empty?
-
-        pattern = context_lines.map { |line| "^\\s*" + Regexp.escape(line.strip) + "\s*$\n" }.join
-        matches =
-          text
-            .enum_for(:scan, /#{pattern}/m)
-            .map do
-              match = Regexp.last_match
-              [match.begin(0), match.end(0)]
-            end
-
-        case matches.length
-        when 0
-          raise NoMatchingContextError.new(original_text: text, diff_text: diff)
-        when 1
-          matches.first
-        else
-          raise AmbiguousMatchError.new(original_text: text, diff_text: diff)
-        end
-      end
-    end
-  end
-end

lib/utils/diff_utils/hunk_diff.rb

@@ -0,0 +1,228 @@
+# frozen_string_literal: true
+# Inspired by Aider https://github.com/Aider-AI/aider
+
+module DiscourseAi
+  module Utils
+    module DiffUtils
+      class HunkDiff
+        class DiffError < StandardError
+          attr_reader :original_text, :diff_text, :context
+
+          def initialize(message, original_text:, diff_text:, context: {})
+            @original_text = original_text
+            @diff_text = diff_text
+            @context = context
+            super(message)
+          end
+
+          def to_llm_message
+            original_text = @original_text
+            original_text = @original_text[0..1000] + "..." if @original_text.length > 1000
+
+            <<~MESSAGE
+            #{message}
+
+            Original text:
+            ```
+            #{original_text}
+            ```
+
+            Attempted diff:
+            ```
+            #{diff_text}
+            ```
+
+            #{context_message}
+
+            Please provide a corrected diff that:
+            1. Has the correct context lines
+            2. Contains all necessary removals (-) and additions (+)
+          MESSAGE
+          end
+
+          private
+
+          def context_message
+            return "" if context.empty?
+
+            context.map { |key, value| "#{key}: #{value}" }.join("\n")
+          end
+        end
+
+        class NoMatchingContextError < DiffError
+          def initialize(original_text:, diff_text:)
+            super(
+              "Could not find the context lines in the original text",
+              original_text: original_text,
+              diff_text: diff_text,
+            )
+          end
+        end
+
+        class AmbiguousMatchError < DiffError
+          def initialize(original_text:, diff_text:)
+            super(
+              "Found multiple possible locations for this change",
+              original_text: original_text,
+              diff_text: diff_text,
+            )
+          end
+        end
+
+        class MalformedDiffError < DiffError
+          def initialize(original_text:, diff_text:, issue:)
+            super(
+              "The diff format is invalid",
+              original_text: original_text,
+              diff_text: diff_text,
+              context: {
+                "Issue" => issue,
+              },
+            )
+          end
+        end
+
+        def self.apply(text, diff)
+          new(text, diff).apply
+        end
+
+        def initialize(text, diff)
+          @text = text.encode(universal_newline: true)
+          @diff = diff.encode(universal_newline: true)
+          @text = @text + "\n" unless @text.end_with?("\n")
+        end
+
+        def apply
+          if multiple_hunks?
+            apply_multiple_hunks
+          else
+            apply_single_hunk
+          end
+        end
+
+        private
+
+        attr_reader :text, :diff
+
+        def multiple_hunks?
+          diff.match?(/^\@\@.*\@\@$\n/)
+        end
+
+        def apply_multiple_hunks
+          result = text
+          hunks = diff.split(/^\@\@.*\@\@$\n/)
+
+          hunks.each do |hunk|
+            next if hunk.blank?
+            result = self.class.new(result, hunk).apply
+          end
+
+          result
+        end
+
+        def apply_single_hunk
+          diff_lines = parse_diff_lines
+          validate_diff_format!(diff_lines)
+
+          return text.strip + "\n" + diff.strip if context_only?(diff_lines)
+
+          lines_to_match = extract_context_lines(diff_lines)
+          match_start, match_end = find_unique_match(lines_to_match)
+
+          build_result(match_start, match_end, diff_lines)
+        end
+
+        def parse_diff_lines
+          diff.lines.map do |line|
+            marker = line[0]
+            content = line[1..]
+
+            if !["-", "+", " "].include?(marker)
+              marker = " "
+              content = line
+            end
+
+            [marker, content]
+          end
+        end
+
+        def validate_diff_format!(diff_lines)
+          if diff_lines.empty?
+            raise MalformedDiffError.new(
+                    original_text: text,
+                    diff_text: diff,
+                    issue: "Diff is empty",
+                  )
+          end
+        end
+
+        def context_only?(diff_lines)
+          diff_lines.all? { |marker, _| marker == " " }
+        end
+
+        def extract_context_lines(diff_lines)
+          diff_lines.select { |marker, _| ["-", " "].include?(marker) }.map(&:last)
+        end
+
+        def find_unique_match(context_lines)
+          return 0, 0 if context_lines.empty?
+
+          pattern = context_lines.map { |line| "^\\s*" + Regexp.escape(line.strip) + "\s*$\n" }.join
+          matches =
+            text
+              .enum_for(:scan, /#{pattern}/m)
+              .map do
+                match = Regexp.last_match
+                [match.begin(0), match.end(0)]
+              end
+
+          case matches.length
+          when 0
+            raise NoMatchingContextError.new(original_text: text, diff_text: diff)
+          when 1
+            matches.first
+          else
+            raise AmbiguousMatchError.new(original_text: text, diff_text: diff)
+          end
+        end
+
+        def build_result(match_start, match_end, diff_lines)
+          new_hunk = +""
+          diff_lines_index = 0
+
+          text[match_start..match_end].lines.each do |line|
+            diff_marker, diff_content = diff_lines[diff_lines_index]
+
+            while diff_marker == "+"
+              new_hunk << diff_content
+              diff_lines_index += 1
+              diff_marker, diff_content = diff_lines[diff_lines_index]
+            end
+
+            new_hunk << line if diff_marker == " "
+
+            diff_lines_index += 1
+          end
+
+          # Handle any remaining additions
+          append_remaining_additions(new_hunk, diff_lines, diff_lines_index)
+
+          combine_result(match_start, match_end, new_hunk)
+        end
+
+        def append_remaining_additions(new_hunk, diff_lines, diff_lines_index)
+          diff_marker, diff_content = diff_lines[diff_lines_index]
+          while diff_marker == "+"
+            diff_lines_index += 1
+            new_hunk << diff_content
+            diff_marker, diff_content = diff_lines[diff_lines_index]
+          end
+        end
+
+        def combine_result(match_start, match_end, new_hunk)
+          (text[0...match_start].to_s + new_hunk + text[match_end..-1].to_s).strip
+        end
+      end
+    end
+  end
+end

lib/utils/diff_utils/simple_diff.rb

@@ -0,0 +1,178 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module Utils
+    module DiffUtils
+      class SimpleDiff
+        LEVENSHTEIN_THRESHOLD = 2
+
+        class Error < StandardError
+        end
+        class NoMatchError < Error
+        end
+
+        def self.apply(content, search, replace)
+          new.apply(content, search, replace)
+        end
+
+        def apply(content, search, replace)
+          raise ArgumentError, "content cannot be nil" if content.nil?
+          raise ArgumentError, "search cannot be nil" if search.nil?
+          raise ArgumentError, "replace cannot be nil" if replace.nil?
+
+          lines = content.split("\n")
+          search_lines = search.split("\n")
+
+          # 1. Try exact matching
+          match_positions =
+            find_matches(lines, search_lines) { |line, search_line| line == search_line }
+
+          # 2. Try stripped matching
+          if match_positions.empty?
+            match_positions =
+              find_matches(lines, search_lines) do |line, search_line|
+                line.strip == search_line.strip
+              end
+          end
+
+          # 3. Try fuzzy matching
+          if match_positions.empty?
+            match_positions =
+              find_matches(lines, search_lines) do |line, search_line|
+                fuzzy_match?(line, search_line)
+              end
+          end
+
+          # 4. Try block matching as last resort
+          if match_positions.empty?
+            if block_matches = find_block_matches(content, search)
+              return replace_blocks(content, block_matches, replace)
+            end
+          end
+
+          if match_positions.empty?
+            raise NoMatchError, "Could not find a match for the search content"
+          end
+
+          # Replace matches in reverse order
+          match_positions.sort.reverse.each do |pos|
+            lines.slice!(pos, search_lines.length)
+            lines.insert(pos, *replace.split("\n"))
+          end
+
+          lines.join("\n")
+        end
+
+        private
+
+        def find_matches(lines, search_lines)
+          matches = []
+          max_index = lines.length - search_lines.length
+
+          (0..max_index).each do |i|
+            if (0...search_lines.length).all? { |j| yield(lines[i + j], search_lines[j]) }
+              matches << i
+            end
+          end
+
+          matches
+        end
+
+        def fuzzy_match?(line, search_line)
+          return true if line.strip == search_line.strip
+          s1 = line.lstrip
+          s2 = search_line.lstrip
+          levenshtein_distance(s1, s2) <= LEVENSHTEIN_THRESHOLD
+        end
+
+        def levenshtein_distance(s1, s2)
+          m = s1.length
+          n = s2.length
+          d = Array.new(m + 1) { Array.new(n + 1, 0) }
+
+          (0..m).each { |i| d[i][0] = i }
+          (0..n).each { |j| d[0][j] = j }
+
+          (1..m).each do |i|
+            (1..n).each do |j|
+              cost = s1[i - 1] == s2[j - 1] ? 0 : 1
+              d[i][j] = [d[i - 1][j] + 1, d[i][j - 1] + 1, d[i - 1][j - 1] + cost].min
+            end
+          end
+
+          d[m][n]
+        end
+
+        def find_block_matches(content, search)
+          content_blocks = extract_blocks(content)
+          search_blocks = extract_blocks(search)
+
+          return nil if content_blocks.empty? || search_blocks.empty?
+
+          matches = []
+          search_blocks.each do |search_block|
+            content_blocks.each do |content_block|
+              matches << content_block if content_block[:text] == search_block[:text]
+            end
+          end
+
+          matches.empty? ? nil : matches
+        end
+
+        def extract_blocks(text)
+          lines = text.split("\n")
+          blocks = []
+          current_block = []
+          block_start = nil
+
+          lines.each_with_index do |line, index|
+            if line =~ /^[^\s]/
+              # Save previous block if exists
+              if !current_block.empty?
+                current_block << line
+                blocks << {
+                  start: block_start,
+                  length: current_block.length,
+                  text: current_block.join("\n").strip,
+                }
+                current_block = []
+              else
+                current_block = [line]
+                block_start = index
+              end
+            else
+              # Continue current block
+              current_block << line if current_block.any?
+            end
+          end
+
+          # Add final block
+          if !current_block.empty?
+            blocks << {
+              start: block_start,
+              length: current_block.length,
+              text: current_block.join("\n").strip,
+            }
+          end
+
+          blocks
+        end
+
+        def replace_blocks(content, blocks, replace)
+          lines = content.split("\n")
+
+          # Sort blocks in reverse order to maintain correct positions
+          blocks
+            .sort_by { |b| -b[:start] }
+            .each_with_index do |block, index|
+              replacement = index.zero? ? replace : ""
+              lines.slice!(block[:start], block[:length])
+              lines.insert(block[:start], *replacement.split("\n"))
+            end
+
+          lines.join("\n")
+        end
+      end
+    end
+  end
+end

spec/lib/modules/ai_bot/tools/create_artifact_spec.rb

@@ -2,7 +2,6 @@
 
 RSpec.describe DiscourseAi::AiBot::Tools::CreateArtifact do
   fab!(:llm_model)
-  let(:bot_user) { DiscourseAi::AiBot::EntryPoint.find_user_from_model(llm_model.name) }
   let(:llm) { DiscourseAi::Completions::Llm.proxy("custom:#{llm_model.id}") }
   fab!(:post)
 
@@ -10,61 +9,70 @@ RSpec.describe DiscourseAi::AiBot::Tools::CreateArtifact do
 
   describe "#process" do
     it "correctly adds details block on final invoke" do
-      tool =
-        described_class.new(
-          { html_body: "hello" },
-          bot_user: Fabricate(:user),
-          llm: llm,
-          context: {
-            post_id: post.id,
-          },
-        )
+      responses = [<<~TXT.strip]
+          [HTML]
+          <div>
+            hello
+          </div>
+          [/HTML]
+          [CSS]
+          .hello {
+            color: red;
+          }
+          [/CSS]
+          [JavaScript]
+          console.log("hello");
+          console.log("world");
+          [/JavaScript]
+        TXT
 
-      tool.parameters = { html_body: "hello" }
+      tool = nil
 
-      tool.invoke {}
+      DiscourseAi::Completions::Llm.with_prepared_responses(responses) do
+        tool =
+          described_class.new(
+            { html_body: "hello" },
+            bot_user: Fabricate(:user),
+            llm: llm,
+            context: {
+              post_id: post.id,
+            },
+          )
+
+        tool.parameters = { name: "hello", specification: "hello spec" }
+
+        tool.invoke {}
+      end
 
       artifact_id = AiArtifact.order("id desc").limit(1).pluck(:id).first
 
       expected = <<~MD
-        [details='View Source']
-
+        [details="View Source"]
         ### HTML
-
         ```html
-        hello
+        <div>
+          hello
+        </div>
         ```
 
+        ### CSS
+        ```css
+        .hello {
+          color: red;
+        }
+        ```
+
+        ### JavaScript
+        ```javascript
+        console.log("hello");
+        console.log("world");
+        ```
         [/details]
 
         ### Preview
-
         <div class="ai-artifact" data-ai-artifact-id="#{artifact_id}"></div>
       MD
       expect(tool.custom_raw.strip).to eq(expected.strip)
     end
-
-    it "can correctly handle partial updates" do
-      tool = described_class.new({}, bot_user: bot_user, llm: llm)
-
-      tool.parameters = { css: "a { }" }
-      tool.partial_invoke
-
-      expect(tool.custom_raw).to eq("### CSS\n\n```css\na { }\n```")
-
-      tool.parameters = { css: "a { }", html_body: "hello" }
-      tool.partial_invoke
-
-      expect(tool.custom_raw).to eq(
-        "### CSS\n\n```css\na { }\n```\n\n### HTML\n\n```html\nhello\n```",
-      )
-
-      tool.parameters = { css: "a { }", html_body: "hello world" }
-      tool.partial_invoke
-
-      expect(tool.custom_raw).to eq(
-        "### CSS\n\n```css\na { }\n```\n\n### HTML\n\n```html\nhello world\n```",
-      )
-    end
   end
 end

spec/lib/modules/ai_bot/tools/read_artifact_spec.rb

@@ -0,0 +1,143 @@
+# frozen_string_literal: true
+
+RSpec.describe DiscourseAi::AiBot::Tools::ReadArtifact do
+  fab!(:llm_model)
+  let(:bot_user) { DiscourseAi::AiBot::EntryPoint.find_user_from_model(llm_model.name) }
+  fab!(:post)
+  fab!(:post2) { Fabricate(:post, user: post.user) }
+  fab!(:artifact) do
+    AiArtifact.create!(
+      user: post.user,
+      post: post,
+      name: "Test Artifact",
+      html: "<div>Test Content</div>",
+      css: ".test { color: blue; }",
+      js: "console.log('test');",
+    )
+  end
+
+  before { SiteSetting.ai_bot_enabled = true }
+
+  describe "#invoke" do
+    it "successfully reads a local artifact" do
+      tool =
+        described_class.new(
+          { url: "#{Discourse.base_url}/discourse-ai/ai-bot/artifacts/#{artifact.id}" },
+          bot_user: bot_user,
+          llm: llm_model.to_llm,
+          context: {
+            post_id: post2.id,
+          },
+        )
+
+      result = tool.invoke {}
+      expect(result[:status]).to eq("success")
+
+      new_artifact = AiArtifact.last
+      expect(new_artifact.html).to eq(artifact.html)
+      expect(new_artifact.css).to eq(artifact.css)
+      expect(new_artifact.js).to eq(artifact.js)
+      expect(new_artifact.metadata["cloned_from"]).to eq(artifact.id)
+    end
+
+    it "handles invalid URLs" do
+      tool =
+        described_class.new(
+          { url: "invalid-url" },
+          bot_user: bot_user,
+          llm: llm_model.to_llm,
+          context: {
+            post_id: post.id,
+          },
+        )
+
+      result = tool.invoke {}
+      expect(result[:status]).to eq("error")
+      expect(result[:error]).to eq("Invalid URL")
+    end
+
+    it "handles non-existent artifacts" do
+      tool =
+        described_class.new(
+          { url: "#{Discourse.base_url}/discourse-ai/ai-bot/artifacts/99999" },
+          bot_user: bot_user,
+          llm: llm_model.to_llm,
+          context: {
+            post_id: post.id,
+          },
+        )
+
+      result = tool.invoke {}
+      expect(result[:status]).to eq("error")
+      expect(result[:error]).to eq("Artifact not found")
+    end
+
+    it "handles external web pages" do
+      stub_request(:get, "https://example.com").to_return(status: 200, body: <<~HTML)
+            <html>
+              <head>
+                <link rel="stylesheet" href="/style.css">
+              </head>
+              <body>
+                <main>
+                  <div>External Content</div>
+                </main>
+                <script>console.log('test');</script>
+              </body>
+            </html>
+          HTML
+
+      stub_request(:get, "https://example.com/style.css").to_return(
+        status: 200,
+        body: ".external { color: red; }",
+      )
+
+      tool =
+        described_class.new(
+          { url: "https://example.com" },
+          bot_user: bot_user,
+          llm: llm_model.to_llm,
+          context: {
+            post_id: post.id,
+          },
+        )
+
+      result = tool.invoke {}
+      expect(result[:status]).to eq("success")
+
+      new_artifact = AiArtifact.last
+      expect(new_artifact.html).to include("<div>External Content</div>")
+      expect(new_artifact.css).to include(".external { color: red; }")
+      expect(new_artifact.js).to include("console.log('test');")
+      expect(new_artifact.metadata["imported_from"]).to eq("https://example.com")
+    end
+
+    it "respects MAX_HTML_SIZE limit" do
+      large_content = "x" * (described_class::MAX_HTML_SIZE + 1000)
+
+      stub_request(:get, "https://example.com").to_return(status: 200, body: <<~HTML)
+            <html>
+              <body>
+                <main>#{large_content}</main>
+              </body>
+            </html>
+          HTML
+
+      tool =
+        described_class.new(
+          { url: "https://example.com" },
+          bot_user: bot_user,
+          llm: llm_model.to_llm,
+          context: {
+            post_id: post.id,
+          },
+        )
+
+      result = tool.invoke {}
+      expect(result[:status]).to eq("success")
+
+      new_artifact = AiArtifact.last
+      expect(new_artifact.html.length).to be <= described_class::MAX_HTML_SIZE
+    end
+  end
+end

spec/lib/modules/ai_bot/tools/update_artifact_spec.rb

@@ -1,108 +1,140 @@
-# spec/lib/modules/ai_bot/tools/update_artifact_spec.rb
 # frozen_string_literal: true
 
 RSpec.describe DiscourseAi::AiBot::Tools::UpdateArtifact do
   fab!(:llm_model)
   let(:bot_user) { DiscourseAi::AiBot::EntryPoint.find_user_from_model(llm_model.name) }
-  let(:llm) { DiscourseAi::Completions::Llm.proxy("custom:#{llm_model.id}") }
   fab!(:post)
   fab!(:artifact) do
     AiArtifact.create!(
       user: Fabricate(:user),
       post: post,
       name: "Test Artifact",
-      html: "<div>\nOriginal\n</div>",
-      css: "div {\n color: blue; \n}",
-      js: "console.log('hello');",
+      html: "<div>Original</div>",
+      css: ".test { color: blue; }",
+      js: "console.log('original');\nconsole.log('world');\nconsole.log('hello');",
     )
   end
 
   before { SiteSetting.ai_bot_enabled = true }
 
   describe "#process" do
-    let(:html) { <<~DIFF }
-         <div>
-           Updated
-         </div>
-      DIFF
-
-    let(:css) { <<~DIFF }
-         div {
-          color: red;
-         }
-      DIFF
-
-    let(:js) { <<~DIFF }
+    it "correctly updates artifact using section markers" do
+      responses = [<<~TXT.strip]
+        [HTML]
+        <div>Updated</div>
+        [/HTML]
+        [CSS]
+        .test { color: red; }
+        [/CSS]
+        [JavaScript]
+        console.log('updated');
         console.log('world');
-      DIFF
+        console.log('updated2');
+        [/JavaScript]
+      TXT
 
-    it "updates artifact content when supplied" do
-      tool =
-        described_class.new(
-          {
-            artifact_id: artifact.id,
-            html: html,
-            css: css,
-            js: js,
-            change_description: "Updated colors and text",
-          },
-          bot_user: bot_user,
-          llm: llm,
-          context: {
-            post_id: post.id,
-          },
-        )
+      tool = nil
 
-      result = tool.invoke {}
+      DiscourseAi::Completions::Llm.with_prepared_responses(responses) do
+        tool =
+          described_class.new(
+            {
+              artifact_id: artifact.id,
+              instructions: "Change the text to Updated and color to red",
+            },
+            bot_user: bot_user,
+            llm: llm_model.to_llm,
+            persona_options: {
+              "update_algorithm" => "full",
+            },
+            context: {
+              post_id: post.id,
+            },
+          )
 
-      expect(result[:status]).to eq("success")
-      expect(result[:version]).to eq(1)
+        result = tool.invoke {}
+        expect(result[:status]).to eq("success")
+      end
 
-      version = artifact.versions.find_by(version_number: 1)
-      expect(version.html).to include("Updated")
-      expect(version.css).to include("color: red")
-      expect(version.js).to include("'world'")
-      expect(artifact.versions.count).to eq(1)
-      expect(version.change_description).to eq("Updated colors and text")
+      version = artifact.versions.order(:version_number).last
+      expect(version.html).to eq("<div>Updated</div>")
+      expect(version.css).to eq(".test { color: red; }")
+      expect(version.js).to eq(<<~JS.strip)
+        console.log('updated');
+        console.log('world');
+        console.log('updated2');
+      JS
 
-      # updating again should update the correct version
-      tool.parameters = {
-        artifact_id: artifact.id,
-        html: nil,
-        css: nil,
-        js: "updated",
-        change_description: "Updated colors and text again",
-      }
-
-      result = tool.invoke {}
-
-      version = artifact.versions.find_by(version_number: 2)
-
-      expect(result[:status]).to eq("success")
-      expect(result[:version]).to eq(2)
-
-      expect(version.html).to include("Updated")
-      expect(version.css).to include("color: red")
-      expect(version.js).to include("updated")
+      expect(tool.custom_raw).to include("Change Description")
+      expect(tool.custom_raw).to include("[details='View Changes']")
+      expect(tool.custom_raw).to include("### HTML Changes")
+      expect(tool.custom_raw).to include("### CSS Changes")
+      expect(tool.custom_raw).to include("### JS Changes")
+      expect(tool.custom_raw).to include("<div class=\"ai-artifact\"")
     end
 
-    it "handles partial updates correctly" do
-      tool = described_class.new({}, bot_user: bot_user, llm: llm)
+    it "handles partial updates with only some sections" do
+      responses = [<<~TXT.strip]
+        [JavaScript]
+        console.log('updated');
+        console.log('world');
+        console.log('hello');
+        [/JavaScript]
+      TXT
 
-      tool.parameters = { artifact_id: artifact.id, html: html, change_description: "Changed HTML" }
-      tool.partial_invoke
+      tool = nil
 
-      expect(tool.custom_raw).to include("### HTML Changes")
-      expect(tool.custom_raw).to include("### Change Description")
-      expect(tool.custom_raw).not_to include("### CSS Changes")
+      DiscourseAi::Completions::Llm.with_prepared_responses(responses) do
+        tool =
+          described_class.new(
+            { artifact_id: artifact.id, instructions: "Update only JavaScript" },
+            bot_user: bot_user,
+            llm: llm_model.to_llm,
+            persona_options: {
+              "update_algorithm" => "full",
+            },
+            context: {
+              post_id: post.id,
+            },
+          )
+
+        result = tool.invoke {}
+        expect(result[:status]).to eq("success")
+      end
+
+      version = artifact.versions.order(:version_number).last
+      expect(version.html).to eq("<div>Original</div>")
+      expect(version.css).to eq(".test { color: blue; }")
+      expect(version.js).to eq(
+        "console.log('updated');\nconsole.log('world');\nconsole.log('hello');",
+      )
+    end
+
+    it "handles invalid section format" do
+      responses = ["Invalid format without proper section markers"]
+
+      DiscourseAi::Completions::Llm.with_prepared_responses(responses) do
+        tool =
+          described_class.new(
+            { artifact_id: artifact.id, instructions: "Invalid update" },
+            bot_user: bot_user,
+            llm: llm_model.to_llm,
+            context: {
+              post_id: post.id,
+            },
+          )
+
+        result = tool.invoke {}
+        expect(result[:status]).to eq("success") # The strategy will just keep original content
+      end
     end
 
     it "handles invalid artifact ID" do
       tool =
         described_class.new(
-          { artifact_id: -1, html: html, change_description: "Test change" },
+          { artifact_id: -1, instructions: "Update something" },
           bot_user: bot_user,
-          llm: llm,
+          llm: llm_model.to_llm,
           context: {
             post_id: post.id,
           },
@@ -113,36 +145,233 @@ RSpec.describe DiscourseAi::AiBot::Tools::UpdateArtifact do
       expect(result[:error]).to eq("Artifact not found")
     end
 
-    it "requires at least one change" do
+    it "preserves unchanged sections in the diff output" do
+      responses = [<<~TXT.strip]
+        [HTML]
+        <div>Updated</div>
+        [/HTML]
+      TXT
+
+      tool = nil
+
+      DiscourseAi::Completions::Llm.with_prepared_responses(responses) do
+        tool =
+          described_class.new(
+            { artifact_id: artifact.id, instructions: "Just update the HTML" },
+            bot_user: bot_user,
+            llm: llm_model.to_llm,
+            persona_options: {
+              "update_algorithm" => "full",
+            },
+            context: {
+              post_id: post.id,
+            },
+          )
+
+        tool.invoke {}
+      end
+
+      version = artifact.versions.order(:version_number).last
+      expect(version.css).to eq(artifact.css)
+      expect(version.js).to eq(artifact.js)
+      expect(tool.custom_raw).to include("### HTML Changes")
+      expect(tool.custom_raw).not_to include("### CSS Changes")
+      expect(tool.custom_raw).not_to include("### JavaScript Changes")
+    end
+
+    it "handles updates to specific versions" do
+      # Create first version
+      responses = [<<~TXT.strip]
+        [HTML]
+        <div>Version 1</div>
+        [/HTML]
+      TXT
+
+      DiscourseAi::Completions::Llm.with_prepared_responses(responses) do
+        described_class
+          .new(
+            { artifact_id: artifact.id, instructions: "Update to version 1" },
+            bot_user: bot_user,
+            llm: llm_model.to_llm,
+            persona_options: {
+              "update_algorithm" => "full",
+            },
+            context: {
+              post_id: post.id,
+            },
+          )
+          .invoke {}
+      end
+
+      first_version = artifact.versions.order(:version_number).last
+
+      responses = [<<~TXT.strip]
+        [HTML]
+        <div>Updated from version 1</div>
+        [/HTML]
+      TXT
+
+      DiscourseAi::Completions::Llm.with_prepared_responses(responses) do
+        tool =
+          described_class.new(
+            {
+              artifact_id: artifact.id,
+              version: first_version.version_number,
+              instructions: "Update from version 1",
+            },
+            bot_user: bot_user,
+            llm: llm_model.to_llm,
+            persona_options: {
+              "update_algorithm" => "full",
+            },
+            context: {
+              post_id: post.id,
+            },
+          )
+
+        result = tool.invoke {}
+        expect(result[:status]).to eq("success")
+      end
+
+      latest_version = artifact.versions.order(:version_number).last
+      expect(latest_version.html).to eq("<div>Updated from version 1</div>")
+    end
+  end
+
+  it "correctly updates artifact using diff strategy (partial diff)" do
+    responses = [<<~TXT.strip]
+
+    [HTML]
+    nonsense
+    <<<<<<< SEARCH
+    <div>Original</div>
+    =======
+    <div>Updated</div>
+    >>>>>>> REPLACE
+    garbage llm injects
+    [/HTML]
+
+    [CSS]
+    garbage llm injects
+    <<<<<<< SEARCH
+    .test { color: blue; }
+    =======
+    .test { color: red; }
+    >>>>>>> REPLACE
+    nonsense
+    [/CSS]
+
+    [JavaScript]
+    nothing to do
+    [/JavaScript]
+
+    LLMs like to say nonsense that we can ignore here as well
+  TXT
+
+    tool = nil
+
+    DiscourseAi::Completions::Llm.with_prepared_responses(responses) do
       tool =
         described_class.new(
-          { artifact_id: artifact.id, change_description: "No changes" },
+          { artifact_id: artifact.id, instructions: "Change the text to Updated and color to red" },
           bot_user: bot_user,
-          llm: llm,
+          llm: llm_model.to_llm,
           context: {
             post_id: post.id,
           },
+          persona_options: {
+            "update_algorithm" => "diff",
+          },
         )
 
       result = tool.invoke {}
       expect(result[:status]).to eq("success")
-      expect(artifact.versions.count).to eq(1)
     end
 
-    it "correctly renders changes in message" do
+    version = artifact.versions.order(:version_number).last
+    expect(version.html).to eq("<div>Updated</div>")
+    expect(version.css).to eq(".test { color: red; }")
+    expect(version.js).to eq(<<~JS.strip)
+    console.log('original');
+    console.log('world');
+    console.log('hello');
+  JS
+
+    expect(tool.custom_raw).to include("Change Description")
+    expect(tool.custom_raw).to include("[details='View Changes']")
+    expect(tool.custom_raw).to include("### HTML Changes")
+    expect(tool.custom_raw).to include("### CSS Changes")
+    expect(tool.custom_raw).to include("<div class=\"ai-artifact\"")
+  end
+
+  it "correctly updates artifact using diff strategy" do
+    responses = [<<~TXT.strip]
+
+    [HTML]
+    <<<<<<< SEARCH
+    <div>Original</div>
+    =======
+    <div>Updated</div>
+    >>>>>>> REPLACE
+    [/HTML]
+
+    [CSS]
+    <<<<<<< SEARCH
+    .test { color: blue; }
+    =======
+    .test { color: red; }
+    >>>>>>> REPLACE
+    [/CSS]
+
+    [JavaScript]
+    <<<<<<< SEARCH
+    console.log('original');
+    console.log('world');
+    console.log('hello');
+    =======
+    console.log('updated');
+    console.log('world');
+    console.log('updated sam');
+    >>>>>>> REPLACE
+    [/JavaScript]
+
+    LLMs like to say nonsense that we can ignore here
+  TXT
+
+    tool = nil
+
+    DiscourseAi::Completions::Llm.with_prepared_responses(responses) do
       tool =
         described_class.new(
-          { artifact_id: artifact.id, html: html, change_description: "Updated content" },
+          { artifact_id: artifact.id, instructions: "Change the text to Updated and color to red" },
           bot_user: bot_user,
-          llm: llm,
+          llm: llm_model.to_llm,
           context: {
             post_id: post.id,
           },
+          persona_options: {
+            "update_algorithm" => "diff",
+          },
         )
 
-      tool.invoke {}
-
-      expect(tool.custom_raw.strip).to include(html.strip)
+      result = tool.invoke {}
+      expect(result[:status]).to eq("success")
     end
+
+    version = artifact.versions.order(:version_number).last
+    expect(version.html).to eq("<div>Updated</div>")
+    expect(version.css).to eq(".test { color: red; }")
+    expect(version.js).to eq(<<~JS.strip)
+    console.log('updated');
+    console.log('world');
+    console.log('updated sam');
+  JS
+
+    expect(tool.custom_raw).to include("Change Description")
+    expect(tool.custom_raw).to include("[details='View Changes']")
+    expect(tool.custom_raw).to include("### HTML Changes")
+    expect(tool.custom_raw).to include("### CSS Changes")
+    expect(tool.custom_raw).to include("### JS Changes")
+    expect(tool.custom_raw).to include("<div class=\"ai-artifact\"")
   end
 end

spec/lib/utils/diff_utils/hunk_diff_spec.rb

@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
-RSpec.describe DiscourseAi::Utils::DiffUtils do
+RSpec.describe DiscourseAi::Utils::DiffUtils::HunkDiff do
   describe ".apply_hunk" do
-    subject(:apply_hunk) { described_class.apply_hunk(original_text, diff) }
+    subject(:apply_hunk) { described_class.apply(original_text, diff) }
 
     context "with HTML content" do
       let(:original_text) { <<~HTML }
@@ -140,7 +140,7 @@ RSpec.describe DiscourseAi::Utils::DiffUtils do
 
         it "raises an AmbiguousMatchError" do
           expect { apply_hunk }.to raise_error(
-            DiscourseAi::Utils::DiffUtils::AmbiguousMatchError,
+            DiscourseAi::Utils::DiffUtils::HunkDiff::AmbiguousMatchError,
           ) do |error|
             expect(error.to_llm_message).to include("Found multiple possible locations")
           end
@@ -156,7 +156,7 @@ RSpec.describe DiscourseAi::Utils::DiffUtils do
 
         it "raises a NoMatchingContextError" do
           expect { apply_hunk }.to raise_error(
-            DiscourseAi::Utils::DiffUtils::NoMatchingContextError,
+            DiscourseAi::Utils::DiffUtils::HunkDiff::NoMatchingContextError,
           ) do |error|
             expect(error.to_llm_message).to include("Could not find the context lines")
           end
@@ -169,7 +169,7 @@ RSpec.describe DiscourseAi::Utils::DiffUtils do
 
           it "raises a MalformedDiffError" do
             expect { apply_hunk }.to raise_error(
-              DiscourseAi::Utils::DiffUtils::MalformedDiffError,
+              DiscourseAi::Utils::DiffUtils::HunkDiff::MalformedDiffError,
             ) do |error|
               expect(error.context["Issue"]).to eq("Diff is empty")
             end

spec/lib/utils/diff_utils/simple_diff_spec.rb

@@ -0,0 +1,168 @@
+# frozen_string_literal: true
+
+RSpec.describe DiscourseAi::Utils::DiffUtils::SimpleDiff do
+  subject { described_class }
+
+  describe ".apply" do
+    it "raises error for nil inputs" do
+      expect { subject.apply(nil, "search", "replace") }.to raise_error(ArgumentError)
+      expect { subject.apply("content", nil, "replace") }.to raise_error(ArgumentError)
+      expect { subject.apply("content", "search", nil) }.to raise_error(ArgumentError)
+    end
+
+    it "prioritizes exact matches over all fuzzy matches" do
+      content = <<~TEXT
+        line 1
+          line 1
+        lin 1
+      TEXT
+
+      search = "  line 1"
+      replace = "  new_line"
+      expected = <<~TEXT
+        line 1
+          new_line
+        lin 1
+      TEXT
+
+      expect(subject.apply(content, search, replace)).to eq(expected.strip)
+    end
+
+    it "raises error when no match is found" do
+      content = "line1\ncompletely_different\nline3"
+      search = "nothing_like_this"
+      replace = "new_line"
+      expect { subject.apply(content, search, replace) }.to raise_error(
+        DiscourseAi::Utils::DiffUtils::SimpleDiff::NoMatchError,
+      )
+    end
+
+    it "replaces all matching occurrences" do
+      content = "line1\nline2\nmiddle\nline2\nend"
+      search = "line2"
+      replace = "new_line2"
+      expect(subject.apply(content, search, replace)).to eq(
+        "line1\nnew_line2\nmiddle\nnew_line2\nend",
+      )
+    end
+
+    it "replaces exact matches" do
+      content = "line1\nline2\nline3"
+      search = "line2"
+      replace = "new_line2"
+      expect(subject.apply(content, search, replace)).to eq("line1\nnew_line2\nline3")
+    end
+
+    it "handles multi-line replacements" do
+      content = "start\nline1\nline2\nend"
+      search = "line1\nline2"
+      replace = "new_line"
+      expect(subject.apply(content, search, replace)).to eq("start\nnew_line\nend")
+    end
+
+    it "is forgiving of whitespace differences" do
+      content = "line1\n  line2\nline3"
+      search = "line2"
+      replace = "new_line2"
+      expect(subject.apply(content, search, replace)).to eq("line1\nnew_line2\nline3")
+    end
+
+    it "is forgiving of small character differences" do
+      content = "line one one one\nlin2\nline three three" # Notice 'lin2' instead of 'line2'
+      search = "line2"
+      replace = "new_line2"
+      expect(subject.apply(content, search, replace)).to eq(
+        "line one one one\nnew_line2\nline three three",
+      )
+    end
+
+    it "is forgiving in multi-line blocks with indentation differences" do
+      content = "def method\n    line1\n  line2\nend"
+      search = "line1\nline2"
+      replace = "new_content"
+      expect(subject.apply(content, search, replace)).to eq("def method\nnew_content\nend")
+    end
+
+    it "handles CSS blocks in different orders" do
+      content = <<~CSS
+        .first {
+          color: red;
+          padding: 10px;
+        }
+        .second {
+          color: blue;
+          margin: 20px;
+        }
+      CSS
+
+      search = <<~CSS
+        .second {
+          color: blue;
+          margin: 20px;
+        }
+        .first {
+          color: red;
+          padding: 10px;
+        }
+      CSS
+
+      replace = <<~CSS
+        .new-block {
+          color: green;
+        }
+      CSS
+
+      expected = <<~CSS
+        .new-block {
+          color: green;
+        }
+      CSS
+
+      expect(subject.apply(content, search, replace)).to eq(expected.strip)
+    end
+
+    it "handles JavaScript blocks in different orders" do
+      content = <<~JS
+        function first() {
+          const x = 1;
+          return x + 2;
+        }
+
+        function second() {
+          if (true) {
+            return 42;
+          }
+          return 0;
+        }
+      JS
+
+      search = <<~JS
+        function second() {
+          if (true) {
+            return 42;
+          }
+          return 0;
+        }
+
+        function first() {
+          const x = 1;
+          return x + 2;
+        }
+      JS
+
+      replace = <<~JS
+        function replacement() {
+          return 'new';
+        }
+      JS
+
+      expected = <<~JS
+        function replacement() {
+          return 'new';
+        }
+      JS
+
+      expect(subject.apply(content, search, replace).strip).to eq(expected.strip)
+    end
+  end
+end

spec/models/ai_persona_spec.rb

@@ -210,4 +210,32 @@ RSpec.describe AiPersona do
     RailsMultisite::ConnectionManagement.stubs(:current_db) { "abc" }
     expect(AiPersona.persona_cache[:value]).to eq(nil)
   end
+
+  describe "system persona validations" do
+    let(:system_persona) do
+      AiPersona.create!(
+        name: "system_persona",
+        description: "system persona",
+        system_prompt: "system persona",
+        tools: %w[Search Time],
+        system: true,
+      )
+    end
+
+    context "when modifying a system persona" do
+      it "allows changing tool options without allowing tool additions/removals" do
+        tools = [["Search", { "base_query" => "abc" }], ["Time"]]
+        system_persona.update!(tools: tools)
+
+        system_persona.reload
+        expect(system_persona.tools).to eq(tools)
+
+        invalid_tools = ["Time"]
+        system_persona.update(tools: invalid_tools)
+        expect(system_persona.errors[:base]).to include(
+          I18n.t("discourse_ai.ai_bot.personas.cannot_edit_system_persona"),
+        )
+      end
+    end
+  end
 end