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/create-modal

Create declarative modals using the modal library API. Covers modal types (confirm, input, select, form), sections (Text, Buttons, Input, Textarea, Checkbox, List, When, Custom), rendering with OverlayModal, and keyboard/mouse handling. Use when adding modals or dialogs to the

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sidecar
1k17 skills
Install
$ npx -y skills add marcus/sidecar --skill create-modal --agent claude-code

How it fires

How this skill gets triggered: by you, by Claude, or both.

  • Fires itselfAuto-invocation. Claude auto-loads it when your prompt matches the work.Auto-invocation is when the right skill fires by itself at the right moment, driven by a FLOW.md router and a hook, instead of you invoking it by name. It is the difference between a skill being installed and a skill actually getting used.Read the full definition →
  • You can call itInvoke it directly when you want it.
  • Slash command/create-modal

Context preview

The summary Claude sees to decide when to auto-load this skill.

Create declarative modals using the modal library API. Covers modal types (confirm, input, select, form), sections (Text, Buttons, Input, Textarea, Checkbox, List, When, Custom), rendering with OverlayModal, and keyboard/mouse handling. Use when adding modals or dialogs to the

SKILL.md

create-modal.SKILL.md
name: create-modal
description: Create declarative modals using the modal library API. Covers modal types (confirm, input, select, form), sections (Text, Buttons, Input, Textarea, Checkbox, List, When, Custom), rendering with OverlayModal, and keyboard/mouse handling. Use when adding modals or dialogs to the application.

Creating Declarative Modals

Use the `internal/modal` package. The library handles keyboard navigation, mouse hit regions, hover states, and scrolling automatically.

Quick Start

import "github.com/marcus/sidecar/internal/modal"

// 1. Create the modal
m := modal.New("Delete Worktree?",
    modal.WithWidth(58),
    modal.WithVariant(modal.VariantDanger),
    modal.WithPrimaryAction("delete"),
).
    AddSection(modal.Text("Name: " + wt.Name)).
    AddSection(modal.Spacer()).
    AddSection(modal.Buttons(
        modal.Btn(" Delete ", "delete", modal.BtnDanger()),
        modal.Btn(" Cancel ", "cancel"),
    ))

// 2. Render in View
func (p *Plugin) View(width, height int) string {
    background := p.renderListView(width, height)
    rendered := p.myModal.Render(width, height, p.mouseHandler)
    return ui.OverlayModal(background, rendered, width, height)
}

// 3. Handle input in Update
case tea.KeyMsg:
    action, cmd := p.myModal.HandleKey(msg)
    if action != "" {
        return p.handleAction(action) // "delete", "cancel", etc.
    }
    return p, cmd

case tea.MouseMsg:
    action := p.myModal.HandleMouse(msg, p.mouseHandler)
    if action != "" {
        return p.handleAction(action)
    }
    return p, nil

Critical: Modal Initialization Pattern

The modal must exist before input handling. Create an `ensure` function called in **both** View and Update:

func (p *Plugin) ensureMyModal() {
    if p.targetItem == nil {
        return // Required state missing
    }

    modalW := 50
    if modalW > p.width-4 {
        modalW = p.width - 4
    }
    if modalW < 20 {
        modalW = 20
    }

    // Only rebuild if needed
    if p.myModal != nil && p.myModalWidthCache == modalW {
        return
    }
    p.myModalWidthCache = modalW

    p.myModal = modal.New("Title", modal.WithWidth(modalW), ...).
        AddSection(...)
}

**Call `ensureModal()` before the nil check in key handlers:**

func (p *Plugin) handleMyModalKeys(msg tea.KeyMsg) tea.Cmd {
    p.ensureMyModal()  // CRITICAL: Before nil check
    if p.myModal == nil {
        return nil
    }
    action, cmd := p.myModal.HandleKey(msg)
    // ...
}

Without this, the first keypress after opening drops because View runs after Update in bubbletea.

Constructor and Options

m := modal.New(title string, opts ...Option)

| Option | Description | Default | |--------|-------------|---------| | `WithWidth(int)` | Modal width in characters | 50 | | `WithVariant(Variant)` | Visual style | `VariantDefault` | | `WithPrimaryAction(string)` | Action ID for Enter on inputs | "" | | `WithHints(bool)` | Show "Tab to switch..." hint | true | | `WithCloseOnBackdropClick(bool)` | Backdrop click returns "cancel" | true |

**Variants:** `VariantDefault`, `VariantDanger` (red), `VariantWarning` (yellow), `VariantInfo` (blue)

Built-in Sections

Text and Spacer

modal.Text("Static text with auto line wrapping")
modal.Spacer()  // Single blank line

Buttons

modal.Buttons(
    modal.Btn(" Save ", "save"),              // Standard button
    modal.Btn(" Delete ", "delete", modal.BtnDanger()),  // Red
    modal.Btn(" Submit ", "submit", modal.BtnPrimary()), // Primary
    modal.Btn(" Cancel ", "cancel"),
)
  • Include padding in labels: `" Save "` not `"Save"`
  • Button IDs are returned as actions
  • Tab/Shift+Tab cycles focus

Input

var nameInput textinput.Model
modal.Input("name-input", &nameInput)
modal.InputWithLabel("name-input", "Name:", &nameInput)
modal.Input("name-input", &nameInput,
    modal.WithSubmitOnEnter(true),       // Default: true
    modal.WithSubmitAction("submit"),    // Override primary action
)

Textarea

var msgArea textarea.Model
modal.Textarea("message", &msgArea, 5)          // height in lines
modal.TextareaWithLabel("message", "Label:", &msgArea, 5)
  • Enter inserts newlines (never submits)

Checkbox

var includeFiles bool
modal.Checkbox("include-files", "Include untracked files", &includeFiles)
  • Enter or Space toggles

List

items := []modal.ListItem{
    {ID: "item-1", Label: "First item", Data: someValue},
    {ID: "item-2", Label: "Second item"},
}
var selectedIdx int
modal.List("my-list", items, &selectedIdx, modal.WithMaxVisible(5))
  • j/k or up/down moves selection; Enter returns selected item's ID

When (Conditional)

modal.When(func() bool { return showWarning },
    modal.Text("Warning: This action is irreversible!"),
)

Custom

modal.Custom(
    func(contentWidth int, focusID, hoverID string) modal.RenderedSection {
        return modal.RenderedSection{
            Content: content,
            Focusables: []modal.FocusableInfo{
                {ID: "custom-btn", OffsetX: 0, OffsetY: 2, Width: 10, Height: 1},
            },
        }
    },
    func(msg tea.Msg, focusID string) (string, tea.Cmd) {
        return "", nil  // can be nil if no custom input handling
    },
)

Handling Input

Keyboard

action, cmd := m.HandleKey(msg)

| Key | Behavior | |-----|----------| | Tab | Focus next element | | Shift+Tab | Focus previous element | | Enter | Return focused element's ID (or primaryAction for inputs) | | Esc | Return "cancel" | | Other | Forwarded to focused section |

Mouse

action := m.HandleMouse(msg, p.mouseHandler)

| Event | Behavior | |-------|----------| | Click backdrop | Return "cancel" (if enabled) | | Click button/checkbox | Return element ID | | Hover element | Update hover state | | Scroll on modal | Scroll content |

Modal Methods

m.FocusedID() string   // Currently focused element
Read more
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24m ago
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Repo: marcus/sidecar

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