skills/trailofbits/skills/let-fate-decide

let-fate-decide

Installation
Summary

Draws 4 Tarot cards using cryptographic entropy to guide decisions when prompts are vague or ambiguous.

  • Triggers on explicit invocations ("let fate decide", "feeling lucky"), nonchalant delegation, Yu-Gi-Oh references, or genuinely ambiguous prompts where multiple approaches are equally valid
  • Uses a standard 78-card deck with Fisher-Yates shuffle and 50% reversal chance per card; outputs JSON with card meanings from markdown files
  • Interprets a 4-position spread (Context, Challenge, Guidance, Outcome) to synthesize abstract card meanings into concrete technical decisions
  • Explicitly avoids safety-critical decisions, overriding user requirements, or simulating draws when the script fails; one draw per decision point only
SKILL.md

Let Fate Decide

When the path forward is unclear, let the cards speak.

Quick Start

  1. Run the drawing script:

    uv run --no-config {baseDir}/scripts/draw_cards.py
    
  2. The script outputs JSON with 4 drawn cards, each with a file path relative to {baseDir}/

  3. Read each card's meaning file to understand the draw

  4. Interpret the spread using the guide at {baseDir}/references/INTERPRETATION_GUIDE.md

  5. Apply the interpretation to the task at hand

When to Use

  • Vague prompts: The user's request is ambiguous and multiple reasonable approaches exist
  • Explicit invocations: "I'm feeling lucky", "let fate decide", "dealer's choice", "surprise me", "whatever you think", "YOLO"
  • Casual delegation: "whatever", "up to you", "your call", "idk", "just do something", "wing it", "I trust you", "doesn't matter", "do what you want", "I don't care", "any approach works", "you pick"
  • Yu-Gi-Oh energy: "Heart of the cards", "I believe in the heart of the cards", "you've activated my trap card", "it's time to duel"
  • Shrug-like brevity: Very short prompts that fully delegate the decision without expressing a preference
  • Redraw requests: "Try again" or "draw again" when no actual system changes occurred (this means draw new cards, not re-run the same approach)
  • Tie-breaking: When you are about to arbitrarily pick between 2+ valid approaches, draw cards instead of silently choosing one

When NOT to Use

  • The user has given clear, specific instructions
  • The task has a single obvious correct approach
  • Safety-critical decisions (security, data integrity, production deployments)
  • The user explicitly asks you NOT to use Tarot
  • The user's tone is precision-seeking rather than casual -- use ask-questions-if-underspecified instead to gather actual requirements

How It Works

The Draw

The script uses secrets for cryptographic randomness:

  1. Builds a standard 78-card Tarot deck (22 Major Arcana + 56 Minor Arcana)
  2. Performs a Fisher-Yates shuffle via secrets.randbelow() (no modulo bias)
  3. Draws 4 cards from the top
  4. Each card independently has a 50% chance of being reversed

The Spread

The 4 card positions represent:

Position Represents Question It Answers
1 The Context What is the situation really about?
2 The Challenge What obstacle or tension exists?
3 The Guidance What approach should be taken?
4 The Outcome Where does this path lead?

Card Files

Each card's meaning is in its own markdown file under {baseDir}/cards/:

  • cards/major/ - 22 Major Arcana (archetypal forces)
  • cards/wands/ - 14 Wands (creativity, action, will)
  • cards/cups/ - 14 Cups (emotion, intuition, relationships)
  • cards/swords/ - 14 Swords (intellect, conflict, truth)
  • cards/pentacles/ - 14 Pentacles (material, practical, craft)

Interpretation

After drawing, read each card's file and synthesize meaning. See {baseDir}/references/INTERPRETATION_GUIDE.md for the full interpretation workflow.

Key rules:

  • Reversed cards invert or complicate the upright meaning
  • Major Arcana cards carry more weight than Minor Arcana
  • The spread tells a story across all 4 positions; don't interpret cards in isolation
  • Map abstract meanings to concrete technical decisions
  • Never output interpretation as a text-only turn. Include the interpretation alongside your next tool call (the action that implements the chosen option). Read all 4 cards in parallel if possible.

Example Session

User: "I dunno, just make it work somehow"

[Draw cards]
1. The Magician (upright) - Context: All tools are available
2. Five of Swords (reversed) - Challenge: Let go of a combative approach
3. The Star (upright) - Guidance: Follow the aspirational path
4. Ten of Pentacles (upright) - Outcome: Long-term stability

Interpretation: The cards suggest you have everything you need (Magician).
The challenge is avoiding overengineering or adversarial thinking about edge
cases (Five of Swords reversed). Follow the clean, hopeful approach (Star)
and build for lasting maintainability (Ten of Pentacles).

Approach: Implement the simplest correct solution with clear structure,
prioritizing long-term readability over clever optimizations.

Error Handling

If the drawing script fails:

  • Script crashes with traceback: Report the error to the user and skip the reading. Do not invent cards or simulate a draw — the whole point is real entropy.
  • Card file not found: Note the missing file, interpret the card from its name and suit alone, and continue with the reading.
  • Never fake entropy: If the script cannot run, do not simulate a draw using your own "randomness." Tell the user the draw failed.

Rationalizations to Reject

Rationalization Why Wrong
"The cards said to, so I must" Cards inform direction, they don't override safety or correctness
"This reading justifies my pre-existing preference" Be honest if the reading challenges your instinct
"The reversed card means do nothing" Reversed means a different angle, not inaction
"Major Arcana overrides user requirements" User requirements always take priority over card readings
"I'll keep drawing until I get what I want" One draw per decision point; accept the reading
Weekly Installs
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GitHub Stars
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First Seen
Feb 26, 2026
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