forge-llm/README.org

#+TITLE: forge-llm
#+AUTHOR: Roger Gonzalez
#+EMAIL: roger@rogs.me

* forge-llm
:PROPERTIES:
:ID:       81db1fd1-a5db-4201-9113-72889f7c7829
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[[https://melpa.org/#/forge-llm][file:https://melpa.org/packages/forge-llm-badge.svg]]
[[https://gitlab.com/rogs/forge-llm/badges/master/pipeline.svg]]

Generate Pull Request descriptions for Forge using LLM providers through the [[https://github.com/ahyatt/llm][llm]] package.

[[https://gitlab.com/uploads/-/system/project/avatar/67959042/logo.png]]

** Overview
:PROPERTIES:
:ID:       e5e5a1d0-cf5a-4f45-8d4c-f2f75339bf9a
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~forge-llm~ is an Emacs package that integrates Large Language Models (LLMs) with Forge, a Magit interface to GitHub and GitLab forges. This package helps you generate high-quality Pull Request descriptions based on your git diff and repository PR templates.

Main features:
- Automatically finds and uses your repository's PR template
- Generates PR descriptions based on git diffs between branches
- Seamless integration with Forge's PR creation workflow
- Supports any LLM provider supported by the ~llm~ package
- Stream LLM responses in real-time

** Dependencies
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:ID:       f30fedc1-a24a-4308-bc78-6f9c01857c18
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- [[https://magit.vc/][Magit]] and [[https://github.com/magit/forge][Forge]]
- [[https://github.com/ahyatt/llm][llm]]
- Emacs 25.1+

** Installation
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*** Using MELPA (Recommended)
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:ID:       0e561e53-10f6-4a0b-90e3-46094124aeb2
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The easiest way to install ~forge-llm~ is via MELPA. Ensure you have MELPA configured in your Emacs setup (it's included by default in many distributions like Doom Emacs and Spacemacs).

#+begin_src emacs-lisp
(use-package forge-llm
  :ensure t
  :after forge
  :config
  (forge-llm-setup))
#+end_src

*** Using straight.el with use-package
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:ID:       0c4a74cd-f752-4b3f-a729-0cc5a34f3d38
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If you use ~straight.el~ to manage your packages, it can install ~forge-llm~ directly from MELPA. Ensure MELPA is included in your ~straight-recipe-repositories~ or ~straight-recipe-sources~.

#+begin_src emacs-lisp
(use-package forge-llm
  ;; straight.el will fetch this from MELPA if :ensure t is used
  ;; and straight.el is configured as the handler for use-package.
  :ensure t
  :after forge
  :config
  (forge-llm-setup))
#+end_src

*** Using Doom Emacs
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**** Basic Setup
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1. Add the following to your ~packages.el~ (ensure MELPA is enabled in your Doom configuration, which is usually the default):

#+begin_src emacs-lisp
(package! forge-llm)
(package! llm)  ; Dependency
#+end_src

2. Add somewhere in your ~config.el~:

#+begin_src emacs-lisp
;; Load and setup forge-llm after forge is loaded
(after! forge
  (require 'forge-llm)
  (forge-llm-setup))

;; Configure your LLM provider (example using OpenAI)
;; Place this somewhere appropriate in your config.el
(require 'llm-openai)  ; Or your preferred LLM provider
(setq forge-llm-llm-provider (make-llm-openai :key "YOUR-OPENAI-KEY")) ; Replace with your key/provider setup
#+end_src

3. Run ~doom sync~ to install the package.

**** Keybindings
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The package automatically sets up Doom Emacs keybindings when Doom is detected:

- ~SPC m g~ - Generate PR description in a separate buffer
- ~SPC m p~ - Generate PR description at point
- ~SPC m t~ - Insert PR template at point

No additional configuration is needed for these keybindings to work.

*** Manual installation
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:ID:       b91cfecf-04a3-43c8-96d3-dea082e5ed6e
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Clone the repository:

#+begin_src shell
git clone https://gitlab.com/rogs/forge-llm.git ~/.emacs.d/site-lisp/forge-llm
#+end_src

Add to your Emacs configuration:

#+begin_src emacs-lisp
(add-to-list 'load-path "~/.emacs.d/site-lisp/forge-llm")
(require 'forge-llm)
(forge-llm-setup)
#+end_src

** Setting up LLM providers
:PROPERTIES:
:ID:       842282e1-4760-4687-96a1-4c15adb9a13d
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~forge-llm~ depends on the [[https://github.com/ahyatt/llm][llm]] package for LLM integration. You'll need to set up at least one LLM provider. Please refer to the [[https://github.com/ahyatt/llm?tab=readme-ov-file#setting-up-providers][llm documentation]] for detailed instructions.

Some of the providers supported by the ~llm~ package include:
- OpenAI
- Anthropic (Claude)
- Google (Gemini, Vertex AI)
- Azure OpenAI
- GitHub Models
- Ollama (for local models like Llama, Mistral, etc.)
- GPT4All (for local models)
- llama.cpp (via OpenAI compatible endpoint)
- Deepseek
- Generic OpenAI-compatible endpoints

See the [[https://github.com/ahyatt/llm?tab=readme-ov-file#setting-up-providers][llm documentation]] for the complete list and specific setup steps.

*** Example: OpenAI provider
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First, create an [[https://platform.openai.com/account/api-keys][OpenAI API key]]. Then configure the ~llm~ OpenAI provider:

#+begin_src emacs-lisp
(require 'llm-openai)
(setq forge-llm-llm-provider (make-llm-openai :key "YOUR-OPENAI-KEY"))
#+end_src

*** Example: Anthropic provider
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:ID:       b9728ac5-f5c0-4d6b-8d3e-a4b7c3d9e1f0
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To use Claude models from Anthropic:

#+begin_src emacs-lisp
(require 'llm-claude)
(setq forge-llm-llm-provider (make-llm-claude :key "YOUR-ANTHROPIC-KEY" :chat-model "claude-3-7-sonnet-20250219"))
#+end_src

*** Using auth-source for API keys (recommended)
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:ID:       59f84b84-ce44-4208-8531-56992cae847e
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For better security, use Emacs ~auth-source~ to store your API keys:

#+begin_src emacs-lisp
(use-package llm
  :ensure t
  :config
  (setq llm-warn-on-nonfree nil))

(require 'llm-openai)

(use-package forge-llm
  :ensure t
  :after (forge llm)
  :custom
  (forge-llm-llm-provider
   (make-llm-openai
    :key (auth-source-pick-first-password
           :host "api.openai.com"
           :user "apikey")))
  :config
  (forge-llm-setup))
#+end_src

Content of ~.authinfo~ or ~.authinfo.gpg~:
#+begin_src
machine api.openai.com login apikey password YOUR-API-KEY-HERE
#+end_src

** Usage
:PROPERTIES:
:ID:       e6753914-01ee-41e9-bcdf-f3d6e75ee451
:END:

After setting up ~forge-llm~, the following commands will be available in Forge's pull request creation buffer:

| Key binding            | Command                                    | Description                                           |
|------------------------+--------------------------------------------+-------------------------------------------------------|
| C-c C-l g              | forge-llm-generate-pr-description          | Generate a PR description (output to separate buffer) |
| C-c C-l p              | forge-llm-generate-pr-description-at-point | Generate a PR description at the current point        |
| C-c C-l t              | forge-llm-insert-template-at-point         | Insert the PR template at the current point           |
| SPC m g (Doom Emacs)   | forge-llm-generate-pr-description          | Generate a PR description (output to separate buffer) |
| SPC m p (Doom Emacs)   | forge-llm-generate-pr-description-at-point | Generate a PR description at the current point        |
| SPC m t (Doom Emacs)   | forge-llm-insert-template-at-point         | Insert the PR template at the current point           |

*** Demo: Generate PR description in a new buffer
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Pressing ~C-c C-l g~ will generate a PR description and display it in a separate buffer:

[[https://gitlab.com/-/project/67959042/uploads/3eed67e0b188d040906d30b6b6cc3ec6/generate-pr-desc.gif][file:https://gitlab.com/-/project/67959042/uploads/3eed67e0b188d040906d30b6b6cc3ec6/generate-pr-desc.gif]]

/Click the image to view in full screen/

*** Demo: Generate PR description at point
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:ID:       9e5d4f8b-4eab-8798-9e5d-4f8b4eab8798
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Pressing ~C-c C-l p~ will generate a PR description and insert it directly at the cursor position:

[[https://gitlab.com/-/project/67959042/uploads/9e5d4f8b4eab87989eafca9f58baa467/generate-pr-at-point.gif][file:https://gitlab.com/-/project/67959042/uploads/9e5d4f8b4eab87989eafca9f58baa467/generate-pr-at-point.gif]]

/Click the image to view in full screen/

*** Workflow:
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:ID:       d745d788-793a-4847-95d7-4f5105bc654d
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1. Create a PR using Forge as normal (~forge-create-pullreq~)
2. In the PR creation buffer, position your cursor where you want to insert the PR description
3. Press ~C-c C-l p~ to generate and insert a PR description based on your changes
4. Edit the description as needed and submit the PR

*** Canceling Generation:
:PROPERTIES:
:ID:       7ddfeaab-31a3-4476-b770-7c9751566d88
:END:
If you need to cancel an in-progress LLM request:
- ~M-x forge-llm-cancel-request~

** Customization
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You can customize various aspects of ~forge-llm~ through the following variables:

*** PR Template Configuration
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:ID:       ccb75625-c64d-47ad-adbe-77862b4ebbb5
:END:

- ~forge-llm-pr-template-paths~ - List of possible paths for PR/MR templates relative to repo root
  #+begin_src emacs-lisp
  (setq forge-llm-pr-template-paths
        '(".github/PULL_REQUEST_TEMPLATE.md"
          ".github/pull_request_template.md"
          "docs/pull_request_template.md"
          ".gitlab/merge_request_templates/default.md"))
  #+end_src

- ~forge-llm-default-pr-template~ - Default PR template to use when no template is found in the repository

*** LLM Provider Configuration
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- ~forge-llm-llm-provider~ - LLM provider to use. Can be a provider object or a function that returns a provider object
  (See the [[https://github.com/ahyatt/llm][llm package]] documentation for how to create provider objects).
  #+begin_src emacs-lisp
  (setq forge-llm-llm-provider (make-llm-openai :key "YOUR-API-KEY"))
  #+end_src

- ~forge-llm-temperature~ - Temperature for LLM responses (nil for provider default)
  #+begin_src emacs-lisp
  (setq forge-llm-temperature 0.7)
  #+end_src

- ~forge-llm-max-tokens~ - Maximum number of tokens for LLM responses (nil for provider default)
  #+begin_src emacs-lisp
  (setq forge-llm-max-tokens 1024)
  #+end_src

- ~forge-llm-max-diff-size~ - Maximum size in characters for git diffs sent to the LLM (nil for no truncation)
  #+begin_src emacs-lisp
  ;; Default is 50000, set to nil to disable truncation
  (setq forge-llm-max-diff-size 100000)  ; Increase to 100K characters
  ;; Or disable truncation completely
  (setq forge-llm-max-diff-size nil)
  #+end_src

*** Prompt Configuration
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- ~forge-llm-pr-description-prompt~ - Prompt used to generate a PR description with the LLM. This prompt is formatted with the PR template and git diff.

  You can customize this prompt to match your project's PR description style:

  #+begin_src emacs-lisp
  (setq forge-llm-pr-description-prompt
        "Generate a PR description for the following changes.
  PR template:
  %s

  Git diff:
  ```
  %s
  ```

  Please generate a PR description that follows our team's style.")
  #+end_src

** Troubleshooting
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:ID:       30489ac7-98ed-4820-a780-83c239e427f6
:END:

- If you're having issues with the LLM provider, you can enable debug logging for ~llm~ by setting ~llm-log~ to ~t~.
- Check the ~*forge-llm-debug-prompt*~ buffer to see the exact prompt being sent to the LLM.
- Check the ~*forge-llm-output*~ buffer to see the raw output from the LLM.

*** Common Issues:
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- *Error: "No LLM provider configured"*
  - Make sure you've set ~forge-llm-llm-provider~ to a valid provider object.
  - Ensure your API key is correct.

- *Error: "Failed to generate git diff"*
  - Ensure you're in a repository with valid head and base branches.
  - Check if the current directory is within a git repository.

- *PR Generation is too slow*
  - Consider using a faster model (like GPT-3.5-turbo instead of GPT-4).
  - Reduce ~forge-llm-max-tokens~ to limit the response size.

- *PR template not found*
  - Check if your PR template is in one of the paths listed in ~forge-llm-pr-template-paths~.
  - Add your custom template path if needed.

** TO-DO:
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:ID:       97dad50e-0d25-42aa-9fe6-5e6402256454
:END:
- Add more examples and use cases

** Contributing
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:ID:       398ecc9e-30c2-4af4-afc5-c793ab3bedaa
:END:

Contributions are welcome! Please feel free to submit a Merge Request.

*** Development Setup
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:ID:       237ac5d2-d323-4b7d-9c51-54760a3ccc53
:END:

1. Clone the repository:
   #+begin_src shell
   git clone https://gitlab.com/rogs/forge-llm.git
   cd forge-llm
   #+end_src

2. Install dependencies for development:
   - Ensure you have forge and llm packages

** Acknowledgments
:PROPERTIES:
:ID:       b5d4c3e2-f1a0-4b9c-8d7e-6f5a4b3c2d1e
:END:

This project was heavily inspired by [[https://github.com/douo/magit-gptcommit][magit-gptcommit]]. Check it out! This package works very well with forge-llm.

Another huge inspiration was [[https://github.com/xenodium][xenodium]], with their Emacs package [[https://github.com/xenodium/chatgpt-shell][chatgpt-shell]].

** License
:PROPERTIES:
:ID:       14189649-a22f-4cf8-9850-9a8bb62456d3
:END:

This project is licensed under the GNU General Public License version 3 - see the LICENSE file for details.