A Kakoune / Neovim inspired editor, written in Rust.

The editing model is very heavily based on Kakoune; during development I found myself agreeing with most of Kakoune's design decisions.

For more information, see the website or documentation.

All shortcuts/keymaps can be found in the documentation on the website.

Troubleshooting

Features

• Vim-like modal editing
• Multiple selections
• Built-in language server support
• Smart, incremental syntax highlighting and code editing via tree-sitter

Although it's primarily a terminal-based editor, I am interested in exploring a custom renderer (similar to Emacs) using wgpu.

Note: Only certain languages have indentation definitions at the moment. Check runtime/queries/<lang>/ for indents.scm.

Installation

Installation documentation.

This fork

This is a personal fork that adds two things on top of upstream Helix:

• Steel plugin system. Merged from the upstream steel-engine work. See STEEL.md and steel-docs.md.
• Claude Code bridge. Lets Claude Code read live editor state and drive the editor through Unix-socket RPC. Design spec: docs/specs/2026-05-12-helix-claude-mcp-bridge-design.md. Bridge crate readme: helix-claude-mcp/README.md.

Building

Build the editor and the MCP bridge binary, both with target-cpu=native:

cargo install \
  --profile opt \
  --config 'build.rustflags="-C target-cpu=native"' \
  --path helix-term \
  --locked

cargo install \
  --profile opt \
  --config 'build.rustflags="-C target-cpu=native"' \
  --path helix-claude-mcp \
  --locked

That places hx and helix-claude-mcp in ~/.cargo/bin. Restart any running Helix sessions and Claude Code sessions after a rebuild — both cache the spawned process per session.

Helix configuration

In ~/.config/helix/config.toml:

[editor.context-logger]
enabled = true                              # writes <workspace>/.helix/context.json on focus loss
include-selection-text = true               # default — current selection appears in the snapshot
include-buffer-text = false                 # default — flip on for full buffer dumps (large)
max-selection-bytes = 8192                  # default — truncates long selections

[editor.control-socket]
enabled = true                              # binds <workspace>/.helix/control-<pid>.sock for the MCP bridge

Both default to enabled = false, so opting in is explicit. With both enabled:

• A JSON snapshot of editor state is written to .helix/context.json whenever the terminal loses focus (or when you run :write-context manually).
• A per-process Unix socket appears at .helix/control-<pid>.sock, mode 0600, listening for control RPC from the bridge.

Claude Code MCP server

Tell Claude Code about the bridge. Either project-scoped (committed to the repo) in <workspace>/.mcp.json:

{
  "mcpServers": {
    "helix": {
      "command": "helix-claude-mcp",
      "args": ["serve"]
    }
  }
}

…or globally in ~/.claude.json under the same "mcpServers" key. Claude Code spawns the binary per session and sets CLAUDE_PROJECT_DIR automatically.

Claude Code hooks (passive context injection)

The bridge also ships a hook subcommand that injects a <helix-editor-context> block into each prompt. In ~/.claude/settings.json:

{
  "hooks": {
    "UserPromptSubmit": [
      {
        "hooks": [
          { "type": "command", "command": "helix-claude-mcp hook", "timeout": 5 }
        ]
      }
    ],
    "PostCompact": [
      {
        "hooks": [
          { "type": "command", "command": "helix-claude-mcp hook --reset-marker" }
        ]
      }
    ],
    "SessionStart": [
      {
        "matcher": "compact",
        "hooks": [
          { "type": "command", "command": "helix-claude-mcp hook --reset-marker" }
        ]
      }
    ]
  }
}

The UserPromptSubmit hook injects the current snapshot into every prompt (dedup'd per session and per snapshot mtime). The PostCompact and SessionStart matcher=compact hooks clear the dedup marker so the snapshot re-injects after Claude Code compacts the conversation.

What Claude can do once it's wired up

Resources (read-only, cheap):

• helix://state/current — active buffer, cursor, selection, mode
• helix://state/buffers — list of open buffers
• helix://state/snapshot — the full snapshot

Tools (live RPC to the editor):

Tool	What it does
helix_open_file	Open a file in Helix and focus it.
helix_goto_line	Move cursor to a 1-indexed line/column.
helix_select	Select a range from (start_line, start_column) to (end_line, end_column); view recenters.
helix_get_diagnostics	LSP diagnostics for a buffer.
helix_get_hover	LSP hover at a position.
helix_get_definition	LSP goto-definition.
helix_get_references	LSP find-references.
helix_get_workspace_symbols	LSP workspace symbol search.
helix_format_document	Format a buffer via its LSP formatter.
helix_run_command	Execute any Helix typable command. Powerful — can :write, :reload, :run-shell-command, etc. See spec §10b.

Tools refuse cleanly with a structured error when Helix isn't running; resources still serve the last-written snapshot via the file path so passive context survives a closed editor.

Contributing

Contributing guidelines can be found here.

Getting help

Your question might already be answered on the FAQ.

Discuss the project on the community Matrix Space (make sure to join #helix-editor:matrix.org if you're on a client that doesn't support Matrix Spaces yet).

Credits

Thanks to @jakenvac for designing the logo!