Ladder Pick Development Plan

March 2, 2026

Ladder Pick — ChatGPT App Development Plan#

Project name: ted-mcp-servers
App name (App Directory display): Ladder Pick
App language: English first (UI / tool description / privacy policy all in English; only the plan document is in Korean)

Build a “Ladder Pick” app that can be listed on the ChatGPT App Directory.
Enable the complete flow — entering participants / items → generating a ladder (random matching) → revealing results — through an interactive widget (iframe) within a chat.
After testing with ChatGPT Developer Mode, the ultimate goal is App Directory submission / approval / Publish.

MVP: Interactive widget (iframe UI) + MCP tool-based. The widget provides core interactions such as entering participants / items, displaying results, and reshuffling.
Out of scope (initial): Login / payments, real-time multiplayer, complex animations, external data integration.
No authentication required: Since there is no external service integration, we start without OAuth / authentication flows.
Safety / Policy: No write operations to external systems. Tool hint annotations:
- readOnlyHint: false — Not true because internal state is created / modified
- destructiveHint: false — No irreversible external impact
- openWorldHint: false — No public internet state changes

The user types @Ladder Pick or something like “play a ladder game.”
ChatGPT calls the create_game tool, and the Ladder Pick widget is displayed in an iframe.
Within the widget:
- Players list: Add / remove participant names (default 4)
- Items list: Add / remove result items (prizes / roles)
- Options: Reveal mode (All at once / One by one), Seed (auto / custom)
- Click the “Pick!” button → Generate matching results
Results area:
- All at once: Display the full matching table immediately
- One by one: Reveal one person at a time with the “Reveal Next” button
- “Reshuffle” button: Reshuffle with a new seed
- “Export” button: Copy results as text

Even without the widget, ChatGPT can display tool call results as text (table).
Example: “Ladder Pick, match A,B,C,D with 1st,2nd,3rd,4th” → Text table response

Fewer than 2 participants → Error message: “At least 2 players are required.”
Item count ≠ participant count → Error message: “Number of items must match number of players. You have {n} players and {m} items.”
Items list empty → Error message: “Items list cannot be empty.”

Participant list (Players): 2–20 people
Result items (Items): Must be exactly the same count as participants (error returned on mismatch)
Options
- Reveal mode: all | one-by-one
- Seed: Auto-generated or user-specified (for reproducibility)

Matching results: Player ↔ Item 1:1 mapping
Ladder visualization: Canvas-based visual ladder (vertical lines + horizontal rungs + color-coded path animations)

Module-level Map<gameId, GameState> for in-process in-memory management
Unique ID issued on game creation; subsequent reshuffle / reveal_next lookups use that ID
No persistent storage (resets on server restart; this is sufficient for the initial version)

ChatGPT Apps consist of two components: