Add "Copy for LLM" button for error occurrences

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## [Unreleased]
 
+- Add a "Copy for LLM" button that copies an occurrence as an LLM-ready prompt, served from `/errors/:error_id/occurrences/:id.md` ([@bvalentino](https://github.com/fractaledmind/solid_errors/pull/97))
 - Fix `undefined method 'bootstrap_svg'` crash on the error page when an error has no occurrences
 
 ## [0.7.0] - 2025-06-11

app/controllers/solid_errors/occurrences_controller.rb

@@ -0,0 +1,18 @@
+module SolidErrors
+  class OccurrencesController < ApplicationController
+    # GET /errors/1/occurrences/1
+    #
+    # Always renders the markdown prompt, whether or not the URL carried the
+    # `.md` extension. Served as text/plain so browsers display it inline
+    # instead of downloading it.
+    def show
+      @occurrence = Occurrence.find_by!(id: params[:id], error_id: params[:error_id])
+      @error = @occurrence.error
+
+      # Rendered as `text` rather than `md` so ActionView's ERB handler skips
+      # HTML escaping (its escape_ignore_list covers text/plain), which would
+      # otherwise mangle backtraces and exception messages.
+      render "show", formats: [:text], content_type: "text/plain", layout: false
+    end
+  end
+end

app/views/layouts/solid_errors/application.html.erb

@@ -51,6 +51,29 @@
       document.querySelectorAll('[data-controller="fade"]').forEach(element => {
         fadeOut(element);
       });
+
+      // Copy links fetch their own href and put the body on the clipboard. If the
+      // clipboard is unavailable (non-secure origin) we never preventDefault, so
+      // the browser follows the link to the plain text instead.
+      document.addEventListener('click', event => {
+        const link = event.target.closest('[data-copy]')
+        if (!link || !navigator.clipboard) return
+
+        event.preventDefault()
+        event.stopPropagation()
+
+        const label = link.querySelector('span')
+        const original = label.textContent
+
+        fetch(link.href)
+          .then(response => response.text())
+          .then(text => navigator.clipboard.writeText(text))
+          .then(() => {
+            label.textContent = 'Copied!'
+            setTimeout(() => { label.textContent = original }, 2000)
+          })
+          .catch(() => { window.location = link.href })
+      });
     </script>
   </body>
 </html>

app/views/solid_errors/errors/_actions.html.erb

@@ -5,6 +5,10 @@
     </svg>
     <span>Back to errors</span>
   <% end %>
+  <% if (latest_occurrence = error.occurrences.order(created_at: :desc).first) %>
+    <%= render "solid_errors/errors/copy_button",
+          url: error_occurrence_path(error, latest_occurrence) %>
+  <% end %>
   <% if error.resolved? %>
     <%= render 'solid_errors/errors/delete_button', error: error %>
   <% else %>

app/views/solid_errors/errors/_copy_button.html.erb

@@ -0,0 +1,10 @@
+<%# locals: (url:, classes: "inline-flex items-center justify-center gap-2 font-medium cursor-pointer border rounded-lg py-3 px-5 bg-gray-100 text-initial border-gray-300 hover:ring-gray-200 hover:ring-8") -%>
+<%# Deliberately an <a>: when the clipboard API is unavailable (any non-secure
+    origin) or JS fails, the browser just follows the link to the plain text. -%>
+<%= link_to url, class: classes, data: {copy: true} do %>
+  <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-clipboard" viewBox="0 0 16 16">
+    <path d="M4 1.5H3a2 2 0 0 0-2 2V14a2 2 0 0 0 2 2h10a2 2 0 0 0 2-2V3.5a2 2 0 0 0-2-2h-1v1h1a1 1 0 0 1 1 1V14a1 1 0 0 1-1 1H3a1 1 0 0 1-1-1V3.5a1 1 0 0 1 1-1h1z"/>
+    <path d="M9.5 1a.5.5 0 0 1 .5.5v1a.5.5 0 0 1-.5.5h-3a.5.5 0 0 1-.5-.5v-1a.5.5 0 0 1 .5-.5zm-3-1A1.5 1.5 0 0 0 5 1.5v1A1.5 1.5 0 0 0 6.5 4h3A1.5 1.5 0 0 0 11 2.5v-1A1.5 1.5 0 0 0 9.5 0z"/>
+  </svg>
+  <span>Copy for LLM</span>
+<% end %>

app/views/solid_errors/occurrences/_occurrence.html.erb

@@ -4,9 +4,14 @@
 
 <%= tag.section id: dom_id(occurrence), class: "" do %>
   <%= tag.details open: open do %>
-    <summary class="hover:bg-gray-50 p-2 rounded cursor-pointer">
-      <%= time_tag seen_at, seen_at %>
-      (<em><%= time_ago_in_words(seen_at) %> ago</em>)
+    <summary class="hover:bg-gray-50 p-2 rounded cursor-pointer flex items-center gap-3">
+      <span>
+        <%= time_tag seen_at, seen_at %>
+        (<em><%= time_ago_in_words(seen_at) %> ago</em>)
+      </span>
+      <%= render "solid_errors/errors/copy_button",
+            url: error_occurrence_path(occurrence.error_id, occurrence),
+            classes: "inline-flex items-center gap-1 text-sm font-medium cursor-pointer border rounded-lg py-1 px-2 bg-gray-100 text-initial border-gray-300 hover:ring-gray-200 hover:ring-4" %>
     </summary>
     <div class="">
       <dl class="ml-6">

app/views/solid_errors/occurrences/show.text.erb

@@ -0,0 +1,40 @@
+<%- backtrace = @occurrence.parsed_backtrace -%>
+Fix this error from the <%= Rails.application.class.module_parent_name %> application, reported by Solid Errors:
+
+<fault id="<%= @error.id %>" environment="<%= Rails.env %>">
+<class><%= @error.exception_class %></class>
+<message><%= @error.message %></message>
+<severity><%= @error.severity %></severity>
+<source><%= @error.source %></source>
+<occurred-at><%= @occurrence.created_at.utc.iso8601 %></occurred-at>
+<occurrence-count><%= @error.occurrences.count %></occurrence-count>
+<project-root><%= SolidErrors::BacktraceLine::RAILS_ROOT %></project-root>
+<backtrace>
+<%- backtrace.lines.each do |line| -%>
+<%= line.filtered_method ? line.to_s : line.unparsed_line %>
+<%- end -%>
+</backtrace>
+<%- if backtrace.application_lines.any? -%>
+<source-context>
+<%- backtrace.application_lines.each do |line| -%>
+<file path="<%= line.filtered_file %>" line="<%= line.filtered_number %>">
+<%- line.source.each do |number, code| -%>
+<%= number %>: <%= code.chomp %>
+<%- end -%>
+</file>
+<%- end -%>
+</source-context>
+<%- end -%>
+<%- if @occurrence.context.present? -%>
+<context>
+<%= JSON.pretty_generate(@occurrence.context) %>
+</context>
+<%- end -%>
+</fault>
+
+Investigate and fix the root cause of this error:
+
+1. Use the backtrace and source context to locate where the error was raised in this codebase.
+2. Check the request context for the conditions that triggered it.
+3. Implement a fix that addresses the root cause, following the conventions of the surrounding code.
+4. Add or update tests covering the failure case where applicable.

config/routes.rb

@@ -1,5 +1,7 @@
 SolidErrors::Engine.routes.draw do
   get "/", to: "errors#index", as: :root
 
-  resources :errors, only: [:index, :show, :update, :destroy], path: ""
+  resources :errors, only: [:index, :show, :update, :destroy], path: "" do
+    resources :occurrences, only: [:show]
+  end
 end

lib/solid_errors/engine.rb

@@ -17,6 +17,10 @@ class Engine < ::Rails::Engine
       end
     end
 
+    initializer "solid_errors.mime_types" do
+      Mime::Type.register "text/markdown", :md unless Mime[:md]
+    end
+
     initializer "solid_errors.active_record.error_subscriber" do
       Rails.error.subscribe(SolidErrors::Subscriber.new)
     end

test/dummy/config/routes.rb

@@ -7,4 +7,6 @@
 
   # Defines the root path route ("/")
   # root "posts#index"
+
+  mount SolidErrors::Engine => "/solid_errors"
 end

test/integration/solid_errors/markdown_test.rb

@@ -0,0 +1,45 @@
+require "test_helper"
+
+class SolidErrors::MarkdownTest < ActionDispatch::IntegrationTest
+  setup do
+    begin
+      raise StandardError, "Something <went> wrong"
+    rescue => exception
+      Rails.error.report(exception, context: {controller: "UsersController", action: "show"})
+    end
+
+    @error = SolidErrors::Error.last
+    @occurrence = @error.occurrences.last
+  end
+
+  test "renders the occurrence as a plain text prompt" do
+    get "/solid_errors/#{@error.id}/occurrences/#{@occurrence.id}.md"
+
+    assert_response :success
+    assert_equal "text/plain", response.media_type
+
+    assert_includes response.body, "Investigate and fix the root cause of this error:"
+    assert_includes response.body, "<class>StandardError</class>"
+    assert_includes response.body, "<backtrace>"
+    assert_includes response.body, "\"controller\": \"UsersController\""
+    # Not HTML escaped: the exception message survives verbatim.
+    assert_includes response.body, "<message>Something <went> wrong</message>"
+  end
+
+  test "404s when the occurrence does not belong to the error" do
+    other = SolidErrors::Error.create!(exception_class: "Other", message: "other",
+      severity: "error", fingerprint: "other")
+
+    get "/solid_errors/#{other.id}/occurrences/#{@occurrence.id}.md"
+
+    assert_response :not_found
+  end
+
+  test "the error page links to the copy prompt" do
+    get "/solid_errors/#{@error.id}"
+
+    assert_response :success
+    assert_includes response.body, "Copy for LLM"
+    assert_includes response.body, "/solid_errors/#{@error.id}/occurrences/#{@occurrence.id}"
+  end
+end