create-a-tic-tac-toe-game/environment.md

1. Concept Paragraph

Concept Overview:
Tic-Tac-Trail is a deterministic, turn-based tactical puzzle inspired by grid conquest—completely unrelated to negotiation or trade mechanics. Two explorers, Team Sun and Team Moon, compete to claim paths on an ancient 3×3 stone map. Each tile can be marked with their emblem (Sun or Moon). The first expedition to align three of their emblems in a continuous line (horizontal, vertical, or diagonal) awakens the temple’s power and wins. Core player commands are expressed as [Mark:<row>,<col>], describing which grid position to claim, or [Pass] if no legal move remains. The environment tracks placement, board state, turn order, and victory conditions deterministically.

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2. Roles and Win Condition

• Players:

  • Player 1: Team Sun (symbol “S”)
  • Player 2: Team Moon (symbol “M”)

• Objective:
  Align three of one’s symbols (S or M) in a straight line (row, column, or diagonal) before the board fills.

• Decision Rules:

  • Win: First player to form an unbroken trio of their own emblem.
  • Loss: Opponent achieves a trio first.
  • Draw: All nine tiles filled without a winning alignment.
  • Once a win or draw occurs, the game becomes terminal and no further moves are accepted.

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3. Turn Structure and Determinism

• The game alternates turns strictly: Sun → Moon → Sun → Moon, and so on.
• Turn count begins at 1 and increments after each valid action.
• Maximum of nine turns (since there are nine cells).
• No random factors exist; the game is fully deterministic.
• Seed value (for reproducibility) is still stored in state, but unused—ensuring consistent replay.

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4. Action Grammar (Machine-Parseable)

Permitted Actions:

4.1 Mark a Tile

• Token Format: [Mark:<row>,<col>]
• Pattern (regex): ^\[Mark:(0|1|2),(0|1|2)\]$
• Semantics: Current player places their symbol on the specified cell (row, col) if it’s empty.

Examples:

• ✅ Valid: [Mark:0,2] — Player marks top-right cell.
• ❌ Invalid: [Mark:3,1] — Row "3" out of range (valid rows: 0–2).
• ❌ Invalid: [Mark:1-2] — Comma separator or keyword missing.

4.2 Pass

• Token Format: [Pass]
• Pattern (regex): ^\[Pass\]$
• Semantics: Used only if the player has no valid cell remaining (rare in tic-tac-toe).

Examples:

• ✅ Valid: [Pass] — Player skips turn.
• ❌ Invalid: [PASS] — Case-sensitive token must match exactly [Pass].

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5. Game State Schema

{
  "seed": 42,
  "turn_count": 1,
  "current_player": "Sun",
  "board_state": [
    ["_", "_", "_"],
    ["_", "_", "_"],
    ["_", "_", "_"]
  ],
  "player_symbols": {
    "Sun": "S",
    "Moon": "M"
  },
  "history": [
    {"player": "System", "message": "The ancient board awaits."}
  ],
  "winner": null,
  "status": "ongoing",
  "available_moves": [
    [0, 0], [0, 1], [0, 2],
    [1, 0], [1, 1], [1, 2],
    [2, 0], [2, 1], [2, 2]
  ],
  "scores": {
    "Sun": 0,
    "Moon": 0
  }
}

• Keys reflect a unique thematic world: the ancient “trail” board, emblems for “Sun” and “Moon,” and clear distinction from any negotiation-like schema.

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6. Initialization Rules

• When reset(seed) is called:
  1. The RNG is seeded (though unused for determinism) using seed.
  2. The board_state is filled with _ symbols representing empty stone tiles.
  3. The first turn is always Sun.
  4. The history log begins with a world description.
  5. available_moves includes all (row, col) pairs.
• Observation: Both players receive identical initial description and empty board visualization.

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7. Validation and Error Handling

• Extraction:
  The environment will extract content from within \boxed{{}} using _extract_answer_content(action).

• Validation Steps:

  1. Verify action string matches one of the two regex patterns.
  2. If [Mark:<r>,<c>], check:
     • 0 ≤ r,c ≤ 2
     • Corresponding cell is unoccupied ("_").
  3. If [Pass], ensure no playable cells remain; otherwise invalid.

• Invalid Reasons (examples):

  • "Invalid format — must be [Mark:r,c] or [Pass]."
  • "Chosen cell already occupied."
  • "Row or column index out of range."
  • "Cannot pass while moves still available."

If invalid, the system invokes set_invalid_move(reason) and forfeit logic may apply depending on higher-level controller.

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8. Terminal Conditions and Scoring

Checks performed after each valid move:

1. Win Check:
   If the current player owns three symbols aligned horizontally, vertically, or diagonally:

   • winner = current_player
   • status = "finished"
   • scores[current_player] = 1
   • Opponent receives 0.

2. Draw Check:
   If all cells filled and no winner:

   • winner = null
   • status = "draw"
   • Both scores = 0.5.

3. Continue Otherwise:

   • status = "ongoing"
   • Proceed to next player.

Tie-Break:
None beyond declared draw; equal scoring applies.

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9. Player Prompt Specification

Prompt Identity and Instructions:

Each turn’s prompt should contain:

1. A brief world intro:
   “You are an explorer representing Team Sun (or Team Moon) claiming tiles on the ancient Tic-Tac-Trail.”
2. The current board visualization (3×3 grid of _, S, M).
3. The list of allowed action formats:
   • [Mark:<row>,<col>] where <row> and <col> are integers 0–2.
   • [Pass] if no unclaimed tiles remain.
4. Reminder of victory condition: “Align three of your emblems in a straight line.”
5. Rule reminder: “All actions must be enclosed in \boxed{{}} at the end of your message.”

Few-shot examples:

Example valid response:
I should take the center stone before my rival.
\boxed{{[Mark:1,1]}}

Example invalid response (wrong format):
\boxed{{Mark:1,1}}   <-- Missing brackets [ ]

Example valid response (board full, passing):
No moves left, I will pass.
\boxed{{[Pass]}}

Extraction Function Notice:
_extract_answer_content(self, action: str) -> str will strip \boxed{{}} syntax and return internal content for validation.

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10. API Mapping Plan

Method	Purpose	Operations on Game State	Output
reset(seed)	Initialize the game	Sets all keys per schema, seed board, assign first player (Sun), populate available_moves, generate initial system message	Returns initial observations for both players
step(player_action)	Process one player's move	1. Extract content with _extract_answer_content 2. Validate grammar & legality 3. If valid, apply to board_state 4. Append to history 5. Update available_moves 6. Check win/draw conditions, adjust scores, and advance turn	Returns updated observations, reward info, done flag
_generate_player_prompt(player_id)	Builds textual context for that player	Uses the current board_state, turn_count, and list of legal actions. Demonstrates correct formatting.	Returns formatted prompt string instructing the player to end with a \boxed{{}} action

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11. Copy-Check Against the Example

This design is fully distinct from any negotiation or resource-trading environment.

• Theme: Archaeological puzzle arena (grid conquest), not negotiation.
• Objectives: Claim territory and form a line, not reach mutual agreements.
• Entities: Ancient stones, Sun and Moon symbols—not participants in a deal.
• Game State Keys: board_state, player_symbols, available_moves, and scores—entirely original.
• Prompt Text: References Tic-Tac-Trail and ancient exploration, not disputes or offers.

Therefore, this specification represents a fully self-contained original turn-based environment for a deterministic tic-tac-toe–style strategy challenge, compliant with TextArena architecture.

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