Fix Openrouter Error Parser to Handle Detailed Error Messages

lib/ruby_llm/providers/openrouter.rb

@@ -16,6 +16,35 @@ def headers
         }
       end
 
+      def parse_error(response)
+        return if response.body.empty?
+
+        body = try_parse_json(response.body)
+        case body
+        when Hash
+          parse_error_part_message body
+        when Array
+          body.map do |part|
+            parse_error_part_message part
+          end.join('. ')
+        else
+          body
+        end
+      end
+
+      private
+
+      def parse_error_part_message(part)
+        message = part.dig('error', 'message')
+        raw = try_parse_json(part.dig('error', 'metadata', 'raw'))
+        return message unless raw.is_a?(Hash)
+
+        raw_message = raw.dig('error', 'message')
+        return [message, raw_message].join(' - ') if raw_message
+
+        message
+      end
+
       class << self
         def configuration_requirements
           %i[openrouter_api_key]

spec/ruby_llm/providers/openrouter/parse_error_spec.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe RubyLLM::Providers::OpenRouter do # rubocop:disable RSpec/SpecFilePathFormat
+  describe '#parse_error' do
+    model = 'openai/o3-mini'
+    provider = 'openrouter'
+    context "with #{provider}/#{model}" do
+      let(:chat) { RubyLLM.chat(model: model, provider: provider) }
+
+      before do
+        RubyLLM.config.openrouter_api_key = 'sk-or-v1-sk-or-v1-mocked-key'
+      end
+
+      it 'raises detailed error' do
+        expect { chat.ask('Hello') }.to raise_error do |error|
+          expect(error).to be_a(RubyLLM::Error)
+          expect(error.message).to eq 'Provider returned error - Country, region, or territory not supported'
+        end
+      end
+    end
+  end
+end