docs for openrouter

docs/faq.md

@@ -4,6 +4,7 @@
 - [How does aider use git?](#how-does-aider-use-git)
 - [GPT-4 vs GPT-3.5](#gpt-4-vs-gpt-35)
 - [Aider isn't editing my files?](#aider-isnt-editing-my-files)
+- [Accessing other LLMs with OpenRouter](#accessing-other-llms-with-openrouter)
 - [Can I use aider with other LLMs, local LLMs, etc?](#can-i-use-aider-with-other-llms-local-llms-etc)
 - [Can I change the system prompts that aider uses?](#can-i-change-the-system-prompts-that-aider-uses)
 - [Can I run aider in Google Colab?](#can-i-run-aider-in-google-colab)
@@ -112,6 +113,19 @@ In these cases, here are some things you might try:
   - Use `/drop` to remove files from the chat session which aren't needed for the task at hand. This will reduce distractions and may help GPT produce properly formatted edits.
   - Use `/clear` to remove the conversation history, again to help GPT focus.
 
+## Accessing other LLMs with OpenRouter
+
+[OpenRouter](https://openrouter.ai) provide an interface to [many models](https://openrouter.ai/docs) which are not widely accessible, in particular gpt-4-32k and claude-2.
+
+To access the openrouter models simply
+
+- register for an account, purchase some credits and generate an api key
+- set --openai-api-base to https://openrouter.ai/api/v1
+- set --openai-api-key to your openrouter key
+- set --model to the model of your choice (openai/gpt-4-32k, anthropic/claude-2 etc.)
+
+Some of the models weren't very functional and each llm has its own quirks. The anthropic models work ok, but the llama-2 ones in particular will need more work to play friendly with aider.
+
 ## Can I use aider with other LLMs, local LLMs, etc?
 
 Aider only has experimental support for LLMs other than OpenAI's GPT-3.5 and GPT-4. This is for two reasons: