# Configuration

[README](../README.md)

Startup configuration, preferences, bindings, and opt-in native language servers. See the [example configuration](../examples/config.rb) and [plugin API](plugins.md).

By default, vamp loads `$XDG_CONFIG_HOME/vamp/config.rb`, or `~/.config/vamp/config.rb` when that environment variable is unset. `--config path` selects a file explicitly; `--no-config` bypasses Ruby entirely. Set `VAMP_RUBY` to select a different Ruby executable.

Rejected configuration opens a centered floating **Configuration error** window, sized like the floating file explorer. It shows the selected config path, full failure reason, and explains that default settings and bindings are in use. The diagnostic remains visible even if background messages arrive; editing keys and paste are ignored until **Enter** or **Escape** dismisses it. Use arrows (or Ctrl+h/j/k/l) to scroll long paths/reasons horizontally or vertically, and **Home** to reset the view. Correct the config and restart vamp to apply it. Invalid individual preferences/bindings that do not reject the whole configuration still report ordinary notices.

```ruby
# @param config [Vamp::Config]
Vamp.configure do |config|
  config.leader = "space"
  config.clipboard_mode = "system"
  config.file_explorer_side = "right"
  config.file_explorer_view = "tree"
  config.file_picker_view = "tree"
  config.bind "ctrl+h", config.core.left, mode: config.modes.tree
  config.bind "ctrl+l", config.core.right, mode: config.modes.tree
  config.plugin "plugins/greeting.rb"
  config.bind "g", "greet"
  config.bind "leader g", "greet"
  config.bind "ctrl+r", config.core.redo
  config.bind "shift+j", config.core.join_lines
  config.bind "ctrl+c", config.core.normal, mode: config.modes.insert
  config.bind "ctrl+f", config.core.search
  config.bind "ctrl+c", config.core.normal, mode: config.modes.search
  config.bind "ctrl+v", config.core.select
  config.bind "ctrl+c", config.core.copy, mode: config.modes.visual
  config.bind "ctrl+x", config.core.cut, mode: config.modes.visual
  config.bind "ctrl+r", config.core.change, mode: config.modes.visual
end
```

## Preferences

Plugin paths resolve relative to the config file, not the shell's working directory. `config.bind key, target, mode: config.modes.normal` overrides one key or leader-prefixed sequence; editing modes are `config.modes.normal`, `config.modes.insert`, `config.modes.command`, `config.modes.search`, and `config.modes.visual`. `config.modes.selection` configures shared list navigation; `config.modes.tree` overrides it in tree browsing. Omitting `mode` selects Normal. The leader defaults to `"space"` and is applied before configured bindings.
`config.file_explorer_side` defaults to `"right"`; other choices are `"left"`, `"top"`, and `"bottom"`. Independent `file_explorer_view` / `file_picker_view` preferences both default to `"tree"` and accept `"list"` as an alternative. Invalid preference strings report notices and retain defaults while valid bindings still install. Non-string/empty values disable the whole configuration like other Ruby type errors.
`config.clipboard_mode` accepts `"system"` (default) or `"separate"`. An invalid policy string reports a notice and retains System while valid bindings still install; non-string/empty values reject the whole Ruby configuration.

## Actions and modes

`config.core` exposes the built-in actions below as immutable `Action` values; `config.modes` exposes immutable `Mode` values. Misspelled methods fail during configuration evaluation, and `bind` rejects the wrong value type. Built-in action strings and mode strings are not accepted. Registered Ex/plugin commands still use exact string names (`"w"`, `"greet"`, etc., without `:` or arguments) and can only be bound in Normal mode. Ruby provides runtime checks, not compile-time checking; the editor still validates action/mode compatibility.

Registered command names may contain dot-separated segments, each starting with an ASCII letter followed by ASCII letters/digits/underscores/hyphens, plus one optional trailing `!`. Names cannot contain whitespace, empty segments, or leading/trailing dots. This grammar applies to core and plugin commands alike.

## Key notation

Key notation follows [Herdr's readable style](https://herdr.dev/docs/configuration/#keybindings). Literal non-control Unicode characters are case-sensitive (`n`, `J`, `+`); named keys and modifiers are case-insensitive:

- Named keys: `esc`, `enter`, `backspace`, `delete`, `left`, `right`, `up`, `down`, `home`, `end`, `tab`, `space`.
- Modifiers: `ctrl+a` through `ctrl+z`, and `shift+a` through `shift+z`. `shift+j` and `J` address the same key.
- Named punctuation: `minus`, `comma`, `ampersand`, `plus`, `backtick`. Each addresses the same binding as its literal character.

`ctrl+i` aliases `tab`, and `ctrl+m` aliases `enter`, including inside leader sequences. Ctrl+h and Ctrl+j are distinct control keys, not Backspace/Enter aliases. Only a single modifier on an ASCII letter is supported. Arbitrary non-leader key sequences, Alt/Cmd/Super, combined modifiers, modified special keys, and Vim-style angle-bracket notation are rejected rather than silently treated as another key.

Normal mode binds `ctrl+o` to `config.core.jump_back` and `ctrl+i`/`tab` to `config.core.jump_forward`. Insert-mode Tab remains literal text. Override or disable these keys with the ordinary per-mode binding interface; both jump actions also appear in the command palette.

The built-in `gt`/`gb` sequences move to the first/last line in Normal and Visual; `gf` follows Markdown file links in Normal only. This is not a configurable general sequence prefix: bind `config.core.document_start`, `config.core.document_end`, or `config.core.follow_link` to a single key or leader sequence to add another route. A configured or disabled `g` overrides the built-in prefix in that binding mode; choosing `g` as the leader overrides it in both modes.

## Action reference

| Available modes | Methods on `config.core` |
| --- | --- |
| Normal | `insert`, `append`, `open_below`, `open_above` |
| Normal, Visual | `insert_first_nonblank`, `append_line_end`, `clone_above`, `clone_below` |
| Normal | `join_lines`, `undo`, `redo`, `command` |
| Normal | `follow_link` |
| Normal | `jump_back`, `jump_forward` |
| Normal | `lsp.definition`, `lsp.diagnostics`, `lsp.hover` |
| Normal | `search`, `paste_before`, `paste_after` |
| Normal | `paste_system_before`, `paste_system_after` |
| Normal, Visual | `select`, `select_linewise`, `search_next`, `search_previous` |
| Normal, Visual | `repeat_last_edit` |
| Normal, Visual | `file_picker`, `file_explorer` |
| Normal, Visual | `document_start`, `document_end` |
| Normal, Insert, Visual | `line_start`, `line_end` |
| Normal, Insert, Visual, Tree | `left`, `right` |
| Normal, Insert, Visual, Selection, Tree | `down`, `up` |
| Normal, Insert, Visual | `word_next`, `word_previous`, `word_end`, `big_word_next`, `big_word_previous`, `big_word_end` |
| Normal, Insert | `delete` |
| Visual | `copy`, `cut`, `change`, `select_lines`, `select_next`, `skip_occurrence`, `select_all` |
| Visual | `copy_system` |
| Normal, Insert, Command, Search, Visual | `normal`, `palette` |
| Insert, Command, Search | `backspace` |
| Insert | `newline` |
| Command, Search | `submit` |

`core.select` (`v`) and `core.select_linewise` (`V`) select characterwise and whole-row Visual shapes. Switching selectors retains endpoints; pressing the active shape's selector again cancels. Both use `config.modes.visual`; there is no separate linewise binding mode. `core.select_lines` (Visual Ctrl+l) still splits touched rows into Normal carets.

## Binding overrides and failures

Adding a binding keeps the original key. Pass `nil` to disable a key, including literal typing in Insert/Command mode:

```ruby
Vamp.configure do |config|
  config.bind "n", config.core.insert
  config.bind "i", nil
  config.bind "space", config.core.command
  config.bind ":", nil
end
```

The last valid declaration for a key/mode wins. Invalid keys, incompatible action/mode pairs, ambiguous leader prefixes, or unknown command names leave that binding unchanged and appear in the status message; other valid bindings still load. An invalid leader key reports a notice and retains Space, while valid bindings still install. Ruby syntax errors, unknown methods, and type errors—including non-string or empty leader values—disable the entire configuration and fall back to defaults. One plugin's load failure does not prevent other plugins loading. Disabling a plugin removes its single-key and leader bindings, without restoring any default keys they replaced.

Bindings are resolved inside the editor module, not the terminal adapter. Bracketed paste remains literal and bypasses keybindings. If configuration disables your keys for leaving Insert/Command/Search/Visual mode or entering commands, restart with `--no-config` to restore defaults.

## Selection-list bindings

The palette, floating file picker, and focused docked explorer share `config.modes.selection`. It is a binding context, not a buffer editing mode. `config.core.down` moves to the next list item; `config.core.up` moves to the previous. Defaults are Ctrl+j/Down/Ctrl+n for next and Ctrl+k/Up for previous. Remap or disable any single key:

```ruby
config.bind "ctrl+f", config.core.down, mode: config.modes.selection
config.bind "ctrl+b", config.core.up, mode: config.modes.selection
config.bind "ctrl+j", nil, mode: config.modes.selection
```

Selection bindings take precedence while a file or command list is focused. Unbound printable keys filter in List/explorer INSERT, but not explorer NORMAL; a disabled key is consumed without filtering or moving. Only `up`, `down`, and `nil` are accepted—no leader sequences, edits, or plugin commands. Invalid declarations leave existing routes unchanged. Navigation does not change text, carets, history, or the buffer mode. Both list footers show effective keys, including remaps and disabled directions.

Tree views use `config.modes.tree`, accepting `up`, `down`, `left`, `right`, or `nil`. Explorer NORMAL defaults to h/j/k/l for parent/next/previous/child, with the existing control/arrow routes retained. Tree routes override shared selection routes. In explorer INSERT, printable tree keys are not intercepted: h/j/k/l become query text, while control/special-key tree routes still navigate. Ctrl+h/l select visible parents/children in the filtered projection without changing the query or saved folder expansion. Unmatched keys inherit shared selection bindings. Cached hints prioritize plain keys in NORMAL and omit them in INSERT. For example:

```ruby
config.bind "ctrl+f", config.core.right, mode: config.modes.tree
config.bind "ctrl+h", nil, mode: config.modes.tree
```

Ctrl+h is **not** a Backspace alias or default deletion key in any mode. Raw Ctrl+h (0x08) and Backspace (DEL/0x7f) are distinct, as are CSI-u events. In the tree it navigates in NORMAL and INSERT without deleting query text; it never deletes file-buffer Insert text by default. Explicit `config.core.backspace` bindings remain available if desired.

Ctrl+j is distinct from Enter: in the TUI's raw mode, LF is Ctrl+j and CR is Enter; CSI-u control events also work. No enhanced-terminal negotiation is required. Ctrl+m remains an Enter alias. Outside lists, existing editing bindings are unchanged: Ctrl+k still clones above in Normal/Visual, and explicit Ctrl+j defaults insert a newline in Insert or submit Command/Search prompts. Enter and Ctrl+j can now be rebound independently.

## Leader key

Space starts a leader sequence in Normal/Visual when it has no direct binding in that mode. Leader bindings use `leader` followed by whitespace-separated single-key names, for example `config.bind "leader b n", "bnext"`. Nested prefixes wait for the next key without a timeout. The status bar shows the actual pending sequence before the file path; the palette advertises effective sequences alongside ordinary bindings.

Set `config.leader = ","` to change the trigger for every default and configured leader route. Suffix keys stay unchanged: the default palette binding becomes comma then Space, save becomes comma then `w`, and buffer-next becomes comma then `b` then `n`. Choose an unused single key in the existing notation; Escape, ASCII digits, malformed keys, and a new trigger already directly bound in Normal/Visual are rejected without replacing the current choice. A direct binding on the current trigger—including `nil`—takes precedence per mode and hides unreachable leader routes from the palette.

Esc cancels a pending sequence and count without leaving Visual or collapsing carets. Unknown suffixes consume the key and cancel safely, never falling through to an edit. Paste, external command execution, buffer switching, and binding/leader changes clear pending state. A count before a leader motion applies normally; digits inside a sequence are literal suffix keys. Plugins execute once. Outside Normal/Visual, the leader has no prefix behavior, so Space still types normally in Insert and prompts.

Leader bindings require Normal/Visual and the target's existing mode eligibility; Ex/plugin targets remain Normal-only. A sequence cannot be both a complete binding and another binding's prefix: ambiguous declarations are refused atomically. Disabled leaves remain reserved. Only leader-prefixed sequences are supported—not arbitrary multi-key mappings, timers, or macros.

## Native LSP

LSP runs in Rust, independently of Ruby plugin hosts. **Every language server is disabled by default.** Ruby evaluates configuration only at startup; no LSP plugin needs loading. Install a trusted server yourself and explicitly opt in:

```ruby
Vamp.configure do |config|
  config.lsp["rust"] = true # rust-analyzer, extensions: ["rs"]
  config.lsp["ruby"] = true # solargraph stdio, extensions: ["rb"]
  config.lsp["python"] = true # ty server + ruff server, extensions: ["py"]

  config.lsp["my-language"] = {
    command: ["my-language-server", "--stdio"],
    extensions: ["myl"],
    initialization_options: {},
    settings: { "my-language-server" => { "exampleOption" => true } }
  }
  config.bind "leader d", config.core.lsp.definition
  config.bind "leader D", config.core.lsp.diagnostics
  config.bind "K", config.core.lsp.hover
end
```

Keys are arbitrary nonempty strings, used as the protocol's `languageId`; they need no Tree-sitter grammar or hardcoded language enum. Absent/`false` entries are disabled. `true` enables a built-in preset: `"rust"` uses `rust-analyzer`/`rs`, `"python"` uses `ty server` plus `ruff server`/`py`, and `"ruby"` uses `solargraph stdio`/`rb`. Unknown keys need a configuration object with nonempty `command` argv or a `servers` list, plus `extensions` (without leading dots). Objects also explicitly enable servers; known presets supply omitted command/extensions. An explicit `command` replaces the entire preset with one server: `config.lsp["rust"] = { command: ["/custom/path/rust-analyzer"] }` retains `rs`, while a Python command override does not also launch Ruff.

Only `command`, `extensions`, `initialization_options`, `settings`, and `servers` are accepted. Options/settings must be JSON-compatible objects. Without an explicit command/list, options apply to every default server; explicit `initialization_options` replaces preset defaults. `servers` must be a nonempty ordered list of objects with explicit `command` and optional per-server `initialization_options`/`settings`; it shares language-level extensions and cannot be combined with top-level command/options/settings. Invalid declarations reject configuration with a notice rather than activating a guessed server. Commands are executable/argument arrays, never shell commands; use an absolute path if the executable is not on PATH. No server installation or restart is automatic.

Install Solargraph yourself with `gem install solargraph` in the project's Ruby environment. The Ruby preset launches `["solargraph", "stdio"]`, following [Solargraph's stdio integration](https://solargraph.org/guides/language-server), and uses [YARD annotations](https://solargraph.org/guides/yard) for type information. Explicit `command` overrides replace the entire argv: for a bundled installation, use `config.lsp["ruby"] = { command: ["bundle", "exec", "solargraph", "stdio"] }`; Vamp retains the `rb` extension but does not append `stdio` to your override.

**Python (Astral):** install [ty](https://docs.astral.sh/ty/editors/) and [Ruff](https://docs.astral.sh/ruff/editors/setup/) yourself, for example with `uv tool install ty` and `uv tool install ruff`. The Python preset sends the same documents to both servers, uses ty for hover/definition, and merges type errors with Ruff lint diagnostics. Clearing or losing one server preserves the other's diagnostics. Formatting and code actions remain unsupported by Vamp.

Use `servers` to customize the stack independently; order selects the hover/definition server:

```ruby
config.lsp["python"] = {
  servers: [
    {
      command: ["ty", "server"],
      initialization_options: { experimental: { useUv: "off" } }
    },
    {
      command: ["ruff", "server"],
      initialization_options: { settings: { lint: { extendSelect: ["I"] } } }
    }
  ]
}
```

**uv remains optional project tooling.** Run project setup/synchronization yourself; [ty discovers an existing `.venv`](https://docs.astral.sh/ty/reference/configuration/#python) without a uv launcher. Vamp neither runs `uv sync` nor changes dependencies/lockfiles. The default ty preset sets `experimental.useUv: "off"` so inherited `TY_UV` cannot enable ty's [experimental environment-management integration](https://docs.astral.sh/ty/reference/editor-settings/). Ruff's initialization options default to `{}`. When replacing ty's initialization options, retain that flag if you want the same policy.

Servers start lazily only when a matching buffer opens. Extension matching is case-sensitive; if enabled languages overlap, the first language in sorted key order wins. All matching servers in that language run, and the first handles hover/definition, semantic highlighting, and the diagnostic-status command without fallback to sibling servers. Each server/project root gets one worker, with at most 16 configured servers and 16 server/project keys; Python uses two slots. Start vamp from your project root: its startup working directory is the workspace; automatic root discovery is not implemented.

See [native LSP architecture](architecture.md#native-lsp) for synchronization and worker behavior.

`:lsp.definition` or the configured Space d binding requests a definition at the primary caret, once regardless of selection count. Both Location and LocationLink results are supported; multiple results use the first. Local-file navigation reuses loaded buffers without overwriting unsaved text. LSP UTF-16 positions and percent-encoded file URIs are translated to validated grapheme coordinates. Navigation is ignored if its source buffer, revision, caret, or latest request has changed.

For programmatic bindings, `config.core.lsp` exposes immutable Normal-mode Action objects: `definition`, `diagnostics`, and `hover`. Each routes to the same native implementation as its Ex command; no LSP keys are bound by default. These actions are also available in the command palette. The namespace is distinct from `config.lsp[language_id]` server configuration.

Interactive LSP commands use dotted names (`:lsp.hover`, `:lsp.definition`, `:lsp.diagnostics`). The existing whitespace separator keeps the whole dotted name separate from arguments. Current LSP commands take no arguments.

Diagnostics appear as severity-colored gutter numbers and text underlines; the primary caret's diagnostic appears in the message row. `:lsp.diagnostics` reports the current document's server state. Older versioned diagnostics are discarded; unversioned diagnostics can only be associated with the arrival-time document revision. Editing clears previous annotations immediately. Server startup/transport failures are reported and clear that server's diagnostics; other servers and native editing remain available. There are no automatic restarts.

`:lsp.hover` or a configured hover action requests information at the primary caret once, regardless of count or selection count. The response opens a read-only floating popup: arrows/Ctrl+h/j/k/l scroll vertically/horizontally, Home/End select the first/last logical line, and Escape dismisses without collapsing carets. Other input dismisses and continues normal editing. Changes to the source buffer/revision/caret, intervening input, or newer requests prevent pending hover replies from reopening it.

Hover accepts plaintext/Markdown MarkupContent and string/code MarkedString forms, including arrays. The popup grows up to 100 columns and 24 rows, clamped to the available document workspace and content height. Multiline content and Markdown markers remain visible, with the same Markdown syntax colors as document buffers; named fenced code blocks use their language's bundled highlighter. Highlighting is cached across scrolling and redraws. Horizontal scrolling exposes long lines without splitting graphemes. Missing/unsupported/invalid hover results report a message without changing text, selections, or undo history. Content is bounded to 4 MiB and terminal controls are sanitized.

Semantic highlighting is **enabled automatically** when the first server advertises [LSP semantic tokens](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_semanticTokens). No additional configuration or binding is needed. Full-document requests are preferred; range-only servers receive a whole-document range request. Token colors override Tree-sitter where recognized; unsupported servers, unknown custom token types, missing tokens, and failed replies retain syntax highlighting. Text/path changes clear old semantic colors immediately, and stale replies cannot restore them. Same-text refreshes keep the current overlay until the replacement arrives.

rust-analyzer and ty support semantic tokens. Solargraph 0.61.0 and Ruff do not; Ruby therefore retains Tree-sitter colors with the Solargraph preset, while Python uses ty's tokens and Ruff's diagnostics. Declaration/definition modifiers use bold, deprecated symbols use strikethrough, and readonly variables/parameters/properties use italics without changing their role's color. Diagnostics, search, selections, and carets retain their existing styling precedence.

Native LSP currently provides synchronization, diagnostics, go-to-definition, hover, and semantic highlighting—not completion, rename, formatting, code actions, or workspace edits. Semantic token deltas, dynamic registration, and partial-result streaming are not implemented.