---

name: document description: | Document canvas for displaying and editing markdown content. Use when showing documents, emails, or when users need to select text for editing.

Document Canvas

Display markdown documents with optional text selection and diff highlighting.

Example Prompts

Try asking Claude:

• "Draft an email to the marketing team about the Q1 product launch"
• "Help me edit this blog post - show it so I can highlight the parts to revise"
• "Write a project proposal and let me review it"
• "Show me the README so I can select sections to update"
• "Compose a response to this customer complaint"

Scenarios

display (default)

Read-only document view with markdown rendering. User can scroll but cannot select text.

Copycanvas_spawn({
  kind: "document",
  scenario: "display",
  config: JSON.stringify({
    content: "# Hello World\n\nThis is **markdown** content.",
    title: "My Document"
  })
})

edit

Interactive document view with text selection. User can click and drag to select text, which is sent via IPC in real-time.

• Renders markdown with syntax highlighting (headers, bold, italic, code, links, lists, blockquotes)
• Diff highlighting: green background for additions, red for deletions
• Click and drag to select text
• Selection automatically sent via IPC

Copycanvas_spawn({
  kind: "document",
  scenario: "edit",
  config: JSON.stringify({
    content: "# My Blog Post\n\nThis is the **introduction** to my post.\n\n## Section One\n\n- Point one\n- Point two",
    title: "Blog Post Draft",
    diffs: [
      {startOffset: 50, endOffset: 62, type: "add"}
    ]
  })
})

email-preview

Specialized view for email content display.

Copycanvas_spawn({
  kind: "document",
  scenario: "email-preview",
  config: JSON.stringify({
    content: "Dear Team,\n\nPlease review the attached document.\n\nBest regards,\nAlice",
    title: "RE: Project Update"
  })
})

Configuration

Copyinterface DocumentConfig {
  content: string;        // Markdown content
  title?: string;         // Document title (shown in header)
  diffs?: DocumentDiff[]; // Optional diff markers for highlighting
  readOnly?: boolean;     // Disable selection (default: false for edit)
}

interface DocumentDiff {
  startOffset: number;    // Character offset in content
  endOffset: number;
  type: "add" | "delete";
}

Markdown Rendering

Supported markdown features:

• Headers (# H1, ## H2, etc.)
• Bold (**text**)
• Italic (*text*)
• Code (`inline` and fenced blocks)
• Links ([text](url))
• Lists (- or * bullets)
• Blockquotes (>)

Selection Result

Copyinterface DocumentSelection {
  selectedText: string;   // The selected text
  startOffset: number;    // Start character offset
  endOffset: number;      // End character offset
  startLine: number;      // Line number (1-based)
  endLine: number;
  startColumn: number;    // Column in start line
  endColumn: number;
}

Controls

• Mouse click and drag: Select text (edit scenario)
• Up/Down or scroll: Navigate document
• q or Esc: Close/cancel

API Usage

Copy// Display read-only document
canvas_spawn({
  kind: "document",
  scenario: "display",
  config: JSON.stringify({
    content: "# My Document\n\nContent here.",
    title: "View Mode",
  })
});

// Interactive editing with selection
canvas_spawn({
  kind: "document",
  scenario: "edit",
  config: JSON.stringify({
    content: "# My Document\n\nSelect some **text** here.",
    title: "Edit Mode",
    diffs: [{ startOffset: 20, endOffset: 30, type: "add" }],
  })
});

// Get current selection from a running canvas
canvas_selection({ id: "document-1234567890-abc123" });
// Returns: { success: true, selection: { selectedText: "text", startOffset: 30, endOffset: 34 } }