Add the ability to set OpenRouter headers

Author: sirwolfgang

docs/configuration.md

@@ -54,6 +54,10 @@ RubyLLM.configure do |config|
   config.openrouter_api_key = ENV.fetch('OPENROUTER_API_KEY', nil)
   config.ollama_api_base = ENV.fetch('OLLAMA_API_BASE', nil)
 
+  # --- Open Router Configuration ---
+  config.openrouter_referer = 'https://rubyllm.com'
+  config.openrouter_title   = 'RubyLLM'
+
   # --- AWS Bedrock Credentials ---
   # Uses standard AWS credential chain (environment, shared config, IAM role)
   # if these specific keys aren't set. Region is required if using Bedrock.
@@ -224,4 +228,3 @@ default_response = default_chat.ask("Query using global production settings...")
 *   **Thread Safety:** Each context is independent, making them safe for use across different threads.
 
 Contexts provide a clean and safe mechanism for managing diverse configuration needs within a single application.
-

lib/ruby_llm/configuration.rb

@@ -23,6 +23,8 @@ class Configuration
                   :bedrock_region,
                   :bedrock_session_token,
                   :openrouter_api_key,
+                  :openrouter_referer,
+                  :openrouter_title,
                   :ollama_api_base,
                   # Default models
                   :default_model,

lib/ruby_llm/providers/openrouter.rb

@@ -14,10 +14,13 @@ def api_base(_config)
         'https://openrouter.ai/api/v1'
       end
 
+      # @see https://openrouter.ai/docs/api-reference/overview#headers
       def headers(config)
         {
-          'Authorization' => "Bearer #{config.openrouter_api_key}"
-        }
+          'Authorization' => "Bearer #{config.openrouter_api_key}",
+          'HTTP-Referer' => config.openrouter_referer, # Optional: Site URL for rankings on openrouter.ai.
+          'X-Title' => config.openrouter_title         # Optional: Site title for rankings on openrouter.ai.
+        }.compact
       end
 
       def slug