diff --git a/bin/omarchy-refresh-herdr b/bin/omarchy-refresh-herdr
new file mode 100755
index 0000000000..1e94f1bdc9
--- /dev/null
+++ b/bin/omarchy-refresh-herdr
@@ -0,0 +1,6 @@
+#!/bin/bash
+
+# omarchy:summary=Overwrite the user herdr config with the Omarchy default and reload herdr.
+
+omarchy-refresh-config herdr/config.toml
+omarchy-restart-herdr
diff --git a/bin/omarchy-restart-herdr b/bin/omarchy-restart-herdr
new file mode 100755
index 0000000000..1ca6d60159
--- /dev/null
+++ b/bin/omarchy-restart-herdr
@@ -0,0 +1,5 @@
+#!/bin/bash
+
+# omarchy:summary=Reload herdr if running with the latest configuration
+
+herdr server reload-config >/dev/null 2>&1 || true
diff --git a/config/herdr/config.toml b/config/herdr/config.toml
new file mode 100644
index 0000000000..323240af52
--- /dev/null
+++ b/config/herdr/config.toml
@@ -0,0 +1,94 @@
+# Mirrors the Omarchy tmux config in config/tmux/tmux.conf
+# tmux session -> herdr workspace, tmux window -> herdr tab, tmux pane -> herdr pane
+
+[theme]
+# tmux ran on the terminal's own palette (bg=default, fg=default, ANSI blue accents)
+name = "terminal"
+
+[theme.custom]
+# The active tab is drawn as panel_bg text on an accent background, so panel_bg
+# has to be dark for it to read - same colors as status-left's "#[fg=black,bg=blue]"
+panel_bg = "black"
+
+[terminal]
+# Matches -c "#{pane_current_path}" on every split, window, and session
+new_cwd = "follow"
+
+[keys]
+prefix = "ctrl+space"
+
+# Config and help
+reload_config = "prefix+q"
+help = "prefix+?"
+detach = "prefix+d"
+
+# Copy mode
+copy_mode = "prefix+["
+
+# Panes
+split_horizontal = ["prefix+h", "alt+enter"]
+split_vertical = ["prefix+v", "alt+shift+enter"]
+close_pane = ["prefix+x", "alt+esc"]
+zoom = "prefix+z"
+last_pane = "prefix+;"
+
+focus_pane_left = "ctrl+alt+left"
+focus_pane_down = "ctrl+alt+down"
+focus_pane_up = "ctrl+alt+up"
+focus_pane_right = "ctrl+alt+right"
+
+resize_mode = ["prefix+ctrl+left", "prefix+ctrl+down", "prefix+ctrl+up", "prefix+ctrl+right"]
+
+# No tmux equivalent; herdr's default prefix+shift+p is taken by previous session
+rename_pane = "prefix+shift+o"
+
+# Windows -> tabs
+new_tab = "prefix+c"
+rename_tab = "prefix+r"
+close_tab = "prefix+k"
+switch_tab = ["prefix+1..9", "alt+1..9"]
+previous_tab = ["prefix+p", "alt+left"]
+next_tab = ["prefix+n", "alt+right"]
+
+# Sessions -> workspaces
+new_workspace = "prefix+shift+c"
+rename_workspace = "prefix+shift+r"
+close_workspace = "prefix+shift+k"
+previous_workspace = ["prefix+shift+p", "alt+up"]
+next_workspace = ["prefix+shift+n", "alt+down"]
+
+# Resize by ~5 columns/rows, like resize-pane -L 5 on C-M-S-arrows
+[[keys.command]]
+key = "ctrl+alt+shift+left"
+type = "shell"
+command = "herdr pane resize --current --direction left --amount 0.03"
+
+[[keys.command]]
+key = "ctrl+alt+shift+down"
+type = "shell"
+command = "herdr pane resize --current --direction down --amount 0.03"
+
+[[keys.command]]
+key = "ctrl+alt+shift+up"
+type = "shell"
+command = "herdr pane resize --current --direction up --amount 0.03"
+
+[[keys.command]]
+key = "ctrl+alt+shift+right"
+type = "shell"
+command = "herdr pane resize --current --direction right --amount 0.03"
+
+[ui]
+accent = "blue"
+
+# tmux drew single-line dividers between adjacent panes
+pane_gaps = false
+
+# kill-window and kill-session never asked
+confirm_close = false
+
+# automatic-rename gave windows a name without prompting
+prompt_new_tab_name = false
+
+# set -g mouse on
+mouse_capture = true
diff --git a/default/bash/aliases b/default/bash/aliases
index 7433541e41..9212c9d6dd 100644
--- a/default/bash/aliases
+++ b/default/bash/aliases
@@ -49,6 +49,7 @@ alias cy='codex -s danger-full-access -a never'
 alias d='docker'
 alias r='rails'
 alias t='tmux attach || tmux new -s Work'
+alias h='herdr'
 alias ic='tdl c'
 alias ix='tdl cx'
 alias icx='tdl c cx'
diff --git a/default/bash/fns/herdr b/default/bash/fns/herdr
new file mode 100644
index 0000000000..45788e3726
--- /dev/null
+++ b/default/bash/fns/herdr
@@ -0,0 +1,142 @@
+# Echo a split ratio as a float
+# Usage: hratio <numerator> <denominator>
+hratio() {
+  awk -v a="$1" -v b="$2" 'BEGIN { printf "%.4f", a / b }'
+}
+
+# Split a herdr pane and echo the id of the new pane
+# Usage: hsplit <pane_id> <right|down> <ratio> <cwd>
+hsplit() {
+  herdr pane split "$1" --direction "$2" --ratio "$3" --cwd "$4" --no-focus |
+    jq -r '.result.pane.pane_id'
+}
+
+# Create a Herdr Dev Layout with editor, ai, and terminal
+# Usage: hdl <c|cx|codex|other_ai> [<second_ai>]
+hdl() {
+  [[ -z $1 ]] && { echo "Usage: hdl <c|cx|codex|other_ai> [<second_ai>]"; return 1; }
+  [[ -z $HERDR_PANE_ID ]] && { echo "You must start herdr to use hdl."; return 1; }
+
+  local current_dir="${PWD}"
+  local editor_pane ai_pane ai2_pane
+  local ai="$1"
+  local ai2="$2"
+
+  # Use HERDR_PANE_ID for the pane we're running in (stable even if focus moves)
+  editor_pane="$HERDR_PANE_ID"
+
+  # Name the current tab after the base directory name
+  herdr tab rename "$HERDR_TAB_ID" "$(basename "$current_dir")" >/dev/null
+
+  # Split tab vertically - top 85%, bottom 15%
+  hsplit "$editor_pane" down 0.85 "$current_dir" >/dev/null
+
+  # Split editor pane horizontally - AI on right 30%
+  ai_pane=$(hsplit "$editor_pane" right 0.7 "$current_dir")
+
+  # If second AI provided, split the AI pane vertically
+  if [[ -n $ai2 ]]; then
+    ai2_pane=$(hsplit "$ai_pane" down 0.5 "$current_dir")
+    herdr pane run "$ai2_pane" "$ai2" >/dev/null
+  fi
+
+  # Run ai in the right pane
+  herdr pane run "$ai_pane" "$ai" >/dev/null
+
+  # Run nvim in the left pane
+  herdr pane run "$editor_pane" "$EDITOR ." >/dev/null
+}
+
+# Create a Herdr Dev Square layout with editor, diff watch, terminal, and opencode
+# Usage: hds
+hds() {
+  [[ -n $1 ]] && { echo "Usage: hds"; return 1; }
+  [[ -z $HERDR_PANE_ID ]] && { echo "You must start herdr to use hds."; return 1; }
+
+  local current_dir="${PWD}"
+  local editor_pane diff_pane terminal_pane opencode_pane
+
+  editor_pane="$HERDR_PANE_ID"
+
+  herdr tab rename "$HERDR_TAB_ID" "$(basename "$current_dir")" >/dev/null
+
+  terminal_pane=$(hsplit "$editor_pane" down 0.5 "$current_dir")
+  diff_pane=$(hsplit "$editor_pane" right 0.5 "$current_dir")
+  opencode_pane=$(hsplit "$terminal_pane" right 0.5 "$current_dir")
+
+  herdr pane run "$editor_pane" "nvim ." >/dev/null
+  herdr pane run "$diff_pane" "hunk diff --watch" >/dev/null
+  herdr pane run "$opencode_pane" "opencode" >/dev/null
+}
+
+# Create multiple hdl tabs with one per subdirectory in the current directory
+# Usage: hdlm <c|cx|codex|other_ai> [<second_ai>]
+hdlm() {
+  [[ -z $1 ]] && { echo "Usage: hdlm <c|cx|codex|other_ai> [<second_ai>]"; return 1; }
+  [[ -z $HERDR_PANE_ID ]] && { echo "You must start herdr to use hdlm."; return 1; }
+
+  local ai="$1"
+  local ai2="$2"
+  local base_dir="$PWD"
+  local first=true
+
+  # Rename the workspace to the current directory name
+  herdr workspace rename "$HERDR_WORKSPACE_ID" "$(basename "$base_dir")" >/dev/null
+
+  for dir in "$base_dir"/*/; do
+    [[ -d $dir ]] || continue
+    local dirpath="${dir%/}"
+
+    if $first; then
+      # Reuse the current tab for the first project
+      herdr pane run "$HERDR_PANE_ID" "cd '$dirpath' && hdl $ai $ai2" >/dev/null
+      first=false
+    else
+      local pane_id
+      pane_id=$(herdr tab create --cwd "$dirpath" --no-focus | jq -r '.result.root_pane.pane_id')
+      herdr pane run "$pane_id" "hdl $ai $ai2" >/dev/null
+    fi
+  done
+}
+
+# Create a multi-pane swarm layout with the same command started in each pane (great for AI)
+# Usage: hsl <pane_count> <command>
+hsl() {
+  [[ -z $1 || -z $2 ]] && { echo "Usage: hsl <pane_count> <command>"; return 1; }
+  [[ -z $HERDR_PANE_ID ]] && { echo "You must start herdr to use hsl."; return 1; }
+
+  local count="$1"
+  local cmd="$2"
+  local current_dir="${PWD}"
+  local -a columns panes
+
+  herdr tab rename "$HERDR_TAB_ID" "$(basename "$current_dir")" >/dev/null
+
+  # Tile into a grid: ceil(sqrt(count)) columns, rows spread across them
+  local cols=1
+  while (( cols * cols < count )); do ((cols++)); done
+
+  # Even columns come from repeatedly splitting the first one at (n-k)/(n-k+1)
+  columns=("$HERDR_PANE_ID")
+  local k
+  for (( k = 1; k < cols; k++ )); do
+    columns+=("$(hsplit "${columns[0]}" right "$(hratio $((cols - k)) $((cols - k + 1)))" "$current_dir")")
+  done
+
+  # Split each column into its share of rows, again evenly
+  local col index rows j
+  for (( index = 0; index < cols; index++ )); do
+    col="${columns[index]}"
+    rows=$(( count / cols ))
+    (( index < count % cols )) && (( rows++ ))
+    panes+=("$col")
+    for (( j = 1; j < rows; j++ )); do
+      panes+=("$(hsplit "$col" down "$(hratio $((rows - j)) $((rows - j + 1)))" "$current_dir")")
+    done
+  done
+
+  local pane
+  for pane in "${panes[@]}"; do
+    herdr pane run "$pane" "$cmd" >/dev/null
+  done
+}
diff --git a/install/user/mise.sh b/install/user/mise.sh
index 9cab335f1a..e1952f23ce 100644
--- a/install/user/mise.sh
+++ b/install/user/mise.sh
@@ -4,6 +4,7 @@ omarchy-mise-install gemini
 omarchy-mise-install gh
 omarchy-mise-install copilot
 omarchy-mise-install opencode
+omarchy-mise-install herdr
 omarchy-mise-install npm:playwright playwright
 omarchy-mise-install pi
 omarchy-mise-install npm:@kitlangton/ghui ghui
diff --git a/migrations/1785191576.sh b/migrations/1785191576.sh
new file mode 100644
index 0000000000..0c2d7497ea
--- /dev/null
+++ b/migrations/1785191576.sh
@@ -0,0 +1,7 @@
+echo "Install herdr and seed its Omarchy config"
+
+omarchy-mise-install herdr
+
+# Only seed. A user who already has a herdr config keeps it; omarchy-refresh-herdr
+# is the explicit way to take the shipped defaults.
+[[ -f "$HOME/.config/herdr/config.toml" ]] || omarchy-refresh-config herdr/config.toml