#+title: GPTel: A simple ChatGPT client for Emacs

[[https://melpa.org/#/gptel][file:https://melpa.org/packages/gptel-badge.svg]]

GPTel is a simple, no-frills ChatGPT client for Emacs.

https://user-images.githubusercontent.com/8607532/230516812-86510a09-a2fb-4cbd-b53f-cc2522d05a13.mp4

https://user-images.githubusercontent.com/8607532/230516816-ae4a613a-4d01-4073-ad3f-b66fa73c6e45.mp4

- Requires an [[https://platform.openai.com/account/api-keys][OpenAI API key]].
- It's async and fast, streams responses.
- Interact with ChatGPT from anywhere in Emacs (any buffer, shell, minibuffer, wherever)
- ChatGPT's responses are in Markdown or Org markup.
- Supports conversations and multiple independent sessions.
- You can go back and edit your previous prompts, or even ChatGPT's previous responses when continuing a conversation. These will be fed back to ChatGPT.

GPTel uses Curl if available, but falls back to url-retrieve to work without external dependencies.

** Breaking Changes
1. =gptel-api-key-from-auth-source= search the API KEY using the =gptel-host=, i.e., "api.openai.com" instead of the original "openai.com". You need to update your =~/.authinfo=.

** Installation

GPTel is on MELPA. Install it with =M-x package-install⏎= =gptel=.

(Optional: Install =markdown-mode=.)

**** Straight
#+begin_src emacs-lisp
  (straight-use-package 'gptel)
#+end_src

Installing the =markdown-mode= package is optional.

**** Manual
Clone or download this repository and run =M-x package-install-file⏎= on the repository directory.

Installing the =markdown-mode= package is optional.

**** Doom Emacs
In =packages.el=
#+begin_src emacs-lisp
(package! gptel)
#+end_src

In =config.el=
#+begin_src emacs-lisp
(use-package! gptel
 :config
 (setq! gptel-api-key "your key"))
#+end_src

**** Spacemacs
After installation with =M-x package-install⏎= =gptel=

- Add =gptel= to =dotspacemacs-additional-packages=
- Add =(require 'gptel)= to =dotspacemacs/user-config=

** Usage

Procure an [[https://platform.openai.com/account/api-keys][OpenAI API key]].

Optional: Set =gptel-api-key= to the key. Alternatively, you may choose a more secure method such as:

- Storing in =~/.authinfo=. By default, "api.openai.com" is used as HOST and "apikey" as USER.
  #+begin_src authinfo
machine api.openai.com login apikey password TOKEN
  #+end_src
- Setting it to a function that returns the key.

*** In any buffer:

1. Select a region of text and call =M-x gptel-send=. The response will be inserted below your region.

2. You can select both the original prompt and the response and call =M-x gptel-send= again to continue the conversation.

3. Call =M-x gptel-send= with a prefix argument to
- set chat parameters (GPT model, directives etc) for this buffer,
- to read the prompt from elsewhere or redirect the response elsewhere,
- or to replace the prompt with the response.

[[https://user-images.githubusercontent.com/8607532/230770018-9ce87644-6c17-44af-bd39-8c899303dce1.png]]

With a region selected, you can also rewrite prose or refactor code from here:

*Code*:

[[https://user-images.githubusercontent.com/8607532/230770162-1a5a496c-ee57-4a67-9c95-d45f238544ae.png]]

*Prose*:

[[https://user-images.githubusercontent.com/8607532/230770352-ee6f45a3-a083-4cf0-b13c-619f7710e9ba.png]]

*** In a dedicated chat buffer:

1. Run =M-x gptel= to start or switch to the ChatGPT buffer. It will ask you for the key if you skipped the previous step. Run it with a prefix-arg (=C-u M-x gptel=) to start a new session.

2. In the gptel buffer, send your prompt with =M-x gptel-send=, bound to =C-c RET=.

3. Set chat parameters (GPT model, directives etc) for the session by calling =gptel-send= with a prefix argument (=C-u C-c RET=):

[[https://user-images.githubusercontent.com/8607532/224946059-9b918810-ab8b-46a6-b917-549d50c908f2.png]]

That's it. You can go back and edit previous prompts and responses if you want.

The default mode is =markdown-mode= if available, else =text-mode=.  You can set =gptel-default-mode= to =org-mode= if desired.

** Using it your way

GPTel's default usage pattern is simple, and will stay this way: Read input in any buffer and insert the response below it.

If you want custom behavior, such as
- reading input from or output to the echo area,
- or in pop-up windows,
- sending the current line only, etc,

GPTel provides a general =gptel-request= function that accepts a custom prompt and a callback to act on the response. You can use this to build custom workflows not supported by =gptel-send=.  See the documentation of =gptel-request=, and the [[https://github.com/karthink/gptel/wiki][wiki]] for examples.

*** Extensions using GPTel

These are packages that depend on GPTel to provide additional functionality

- [[https://github.com/kamushadenes/gptel-extensions.el][gptel-extensions]]: Extra utility functions for GPTel.
- [[https://github.com/kamushadenes/ai-blog.el][ai-blog.el]]: Streamline generation of blog posts in Hugo.

** Additional Configuration

- =gptel-host=: Overrides the OpenAI API host.  This is useful for those who transform Azure API into OpenAI API format, utilize reverse proxy, or employ third-party proxy services for the OpenAI API.

- =gptel-proxy=: Path to a proxy to use for GPTel interactions. This is passed to Curl via the =--proxy= argument.

** Why another ChatGPT client?

Other Emacs clients for ChatGPT prescribe the format of the interaction (a comint shell, org-babel blocks, etc).  I wanted:

1. Something that is as free-form as possible: query ChatGPT using any text in any buffer, and redirect the response as required.  Using a dedicated =gptel= buffer just adds some visual flair to the interaction.
2. Integration with org-mode, not using a walled-off org-babel block, but as regular text.  This way ChatGPT can generate code blocks that I can run.

** Will you add feature X?

Maybe, I'd like to experiment a bit more first.  Features added since the inception of this package include
- Curl support (=gptel-use-curl=)
- Streaming responses (=gptel-stream=)
- Cancelling requests in progress (=gptel-abort=)
- General API for writing your own commands (=gptel-request=, [[https://github.com/karthink/gptel/wiki][wiki]])
- Dispatch menus using Transient (=gptel-send= with a prefix arg)
- Specifying the conversation context size
- GPT-4 support
- Response redirection (to the echo area, another buffer, etc)
- A built-in refactor/rewrite prompt

Features being considered or in the pipeline:
- Limiting conversation context to Org headings using properties (#58)
- Stateless design (#17)

** Alternatives

Other Emacs clients for ChatGPT include

- [[https://github.com/xenodium/chatgpt-shell][chatgpt-shell]]: comint-shell based interaction with ChatGPT.  Also supports DALL-E, executable code blocks in the responses, and more.
- [[https://github.com/rksm/org-ai][org-ai]]: Interaction through special =#+begin_ai ... #+end_ai= Org-mode blocks.  Also supports DALL-E, querying ChatGPT with the contents of project files, and more.

There are several more: [[https://github.com/CarlQLange/chatgpt-arcana.el][chatgpt-arcana]], [[https://github.com/MichaelBurge/leafy-mode][leafy-mode]], [[https://github.com/iwahbe/chat.el][chat.el]]

** Acknowledgments

- [[https://github.com/algal][Alexis Gallagher]] and [[https://github.com/d1egoaz][Diego Alvarez]] for fixing a nasty multi-byte bug with =url-retrieve=.
- [[https://github.com/tarsius][Jonas Bernoulli]] for the Transient library.