How bindings work

A binding maps a key to one or more steps. This page explains what a step can be, which binding answers a key, and what happens when a step fails. Key names, modifiers and the default tables are in the configuration reference.

Where bindings live

Table	Answers keys
[hotkeys]	While idle. Inside a mode, for Ctrl/Alt/Cmd chords the mode does not bind itself
[<mode>.hotkeys]	While that mode is open
[[app_configs]], [[<mode>.app_configs]]	While the named app is focused, merged over the table they override

Mode tables also accept multi-key sequences such as gg, with 500 ms allowed between keys.

What a step can be

A binding’s value is one step, or an array of steps run in order:

[hotkeys]
"Primary+Shift+D" = ["hints", "exec echo 'hints activated'"]
"PageUp"          = ["action go_top", "action page_down"]

Each step is one of:

• a mode command, such as hints or grid --toggle
• idle, which leaves the current mode
• action <name>, from the action names
• macro <name> [args...], from [macros]
• mode <name>, for a mode declared under [modes]
• a config command such as config set, as on the command line
• a runtime toggle: toggle-cursor-follow-selection, toggle-scroll-invert or toggle-screen-share
• run <step>..., a nested sequence
• exec <command>, which runs a shell command through general.exec_shell, such as "Primary+T" = "exec open -a Terminal"

Apart from exec, each step is the command you would type after neru in a shell, with the same flags, so you can try a binding from a terminal first.

Sequences

An array of steps is a sequence. A hotkey binding, a macro, a mode’s --on-exit steps and neru run all run sequences the same way.

• Neru logs a failed step and runs the next one.
• End a step with --bail-on-error, as its last word, to stop the sequence there if that step fails. See Failure policy.
• action wait_for_mode_exit pauses until the current mode exits. With --bail, the sequence stops if the mode was canceled, such as with Escape.
• A sequence can start another, through run or a macro. The nested one counts as one step to its caller. The depth limit is under neru run.

Which binding wins

While idle, [hotkeys] answers, merged with the focused app’s [[app_configs]] entry.

Inside a mode, Neru checks in this order:

1. A sticky modifier tap.
2. The mode’s table, [<mode>.hotkeys] merged with [[<mode>.app_configs]].
3. The mode’s own keys, such as hint labels or grid keys.
4. For a Ctrl, Alt or Cmd chord, [hotkeys].

So a mode binding beats a global binding for the same chord. For example, "Cmd+Shift+F" = "recursive_grid" in [hints.hotkeys] replaces a global "Cmd+Shift+F" = "hints" while hints are open.

The fallback to [hotkeys] is what lets a global "Super+;" = "recursive_grid --toggle" also close the mode from inside it. Bare keys and Shift-only chords never fall back, because they are labels and grid keys. In a mode table, "__disabled__" hands the chord back to the global binding rather than silencing it.

Neru rebuilds the merged tables when a mode opens, when the focused app changes, and when the config is reloaded. Switching apps while a mode is open applies the new app’s overrides from your next key.

Per-app overrides

An app_configs entry changes bindings while one app has focus. [[app_configs]] overrides [hotkeys], and [[hints.app_configs]] overrides [hints.hotkeys], and so on for each mode. The syntax is in Per-app hotkey overrides.

The entry merges over the base table under the same rules as a config table merges over the defaults. bundle_id means a different thing on each platform, see App identity.

Mistakes are caught at load

Neru checks every binding and macro when the config loads, so a typo fails neru config validate instead of doing nothing when you press the key.

In a binding	Result
A flag no mode has (hints --serach), or a value no flag takes (--strategy=nonsense)	The config fails to load and Neru runs on defaults
A flag the named mode does not accept (grid --search)	Loads, and neru config validate warns
A flag whose partner is missing (hints --repeat with no --action)	Loads, and neru config validate warns

A key whose binding loaded with a warning refuses that step when pressed, with the same message the CLI gives. Steps nested in a run or --on-exit, and macro steps with a $1 placeholder, have their command checked at load and their flags checked when they run.