emacs-harp

An Emacs coding assistant that provides a two-pane interface: chat on the left and the current file on the right. It supports Claude (Anthropic) and GPT (OpenAI), streams responses, and can run tools with configurable approvals.

Features

• Two-pane layout for chat + file view
• Streaming responses from Anthropic and OpenAI
• Built-in tools for file I/O, shell commands, and search
• Configurable approval modes for tool execution
• Model selection across providers

Requirements

• Emacs 27.1+
• An API key for Anthropic or OpenAI

Install

Manual setup:

(add-to-list 'load-path "/path/to/harp")
(require 'harp)

Configure

;; API keys
(setq harp-api-key-anthropic "your-anthropic-key")
;; or
(setq harp-api-key-openai "your-openai-key")

;; Provider and model
(setq harp-default-provider 'anthropic)
(setq harp-model "claude-sonnet-4-20250514")
(setq harp-max-tokens 8192)

;; Tool approvals: none, dangerous-only, full
(setq harp-approval-mode 'dangerous-only)

;; Optional per-project overrides
;; (setq harp-project-approval-alist '(("/abs/project/root" . full)))

See CONFIG.md for a complete list of customization options.

Use

• M-x harp-start to open the two-pane interface
• M-x harp-quit to close it
• M-x harp-select-model to switch models and providers

In the chat buffer:

Key	Action
RET / C-c C-c	Send message or approve tool
y / n	Approve or reject tool prompts
C-c C-k	Cancel the current request
M-n	Jump to next file link
M-p	Jump to previous file link
C-c C-o	Open file link at point
C-c C-l	List all file links in buffer

Syntax Highlighting

Responses are automatically highlighted:

• Fenced code blocks (```) get language-specific syntax highlighting when the major mode is available
• Inline code (`code`) is rendered in a distinct face
• File paths like /path/to/file.el:42 become clickable links
  • Click or press RET to open in the file pane
  • Paths from write_file/edit_file results are shown in orange to indicate modifications
  • Line numbers are supported—opening jumps to the specified line

Built-in Tools

• read_file - read a file
• write_file - write a file
• edit_file - replace exact text in a file
• run_shell - run a shell command
• glob - find files by pattern
• grep - search with regex
• list_directory - list directory contents

Tool approvals are controlled by harp-approval-mode and can be overridden per project with harp-project-approval-alist.

Development

# Byte-compile all .el files
emacs -Q -batch -L . -f batch-byte-compile *.el

# Treat warnings as errors
emacs -Q -batch -L . --eval "(setq byte-compile-error-on-warn t)" -f batch-byte-compile *.el

# Run tests (if present)
emacs -Q -batch -L . -l harp-test.el -f ert-run-tests-batch-and-exit

License

MIT. See LICENSE.