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Let Fate Decide

Free

Inject randomness into decision-making with Tarot.

by trailofbits6.5k stars on trailofbits/skills
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Updated Aug 10, 2026
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Free · Opens the source repo

What Let Fate Decide does

Let Fate Decide is a unique skill designed for developers and designers who find themselves facing ambiguous prompts or casual decision-making scenarios. By utilizing a Tarot card spread based on the 12 Houses of the Zodiac, this skill introduces an element of randomness to help guide next steps when the path forward is unclear. The skill is particularly useful when users express nonchalant attitudes or delegate decisions without specific preferences, allowing for a creative approach to problem-solving.

The skill operates by running a Python script that draws cards from both Major and Minor Arcana decks, creating a spread that provides insights into various aspects of a task. Each house in the spread corresponds to a different area of focus, such as self, resources, communication, and creativity. The output is delivered in JSON format, which can be easily interpreted using accompanying guides. This makes it accessible for users who may not be familiar with Tarot but are looking for a novel way to approach decision-making.

Let Fate Decide is ideal for situations where traditional decision-making methods may lead to analysis paralysis or when a more playful, less rigid approach is desired. It encourages users to embrace uncertainty and explore different angles of a problem, thereby fostering creativity and innovation. However, it is important to note that this skill should not be used in contexts requiring precise instructions or where safety is a concern, as it is not a substitute for thorough analysis or critical thinking.

In summary, Let Fate Decide is a tool for those looking to break free from conventional decision-making processes. By allowing the cards to guide them, users can discover new perspectives and solutions, making it a valuable addition to any developer or designer's toolkit.

When to use it

Use this skill when the user expresses casual delegation or when multiple reasonable approaches exist.

When not to use it

Avoid using this skill when clear instructions are provided or in safety-critical scenarios.

What you can build with it

Casual Decision-Making

When a user says 'just do something' or 'I trust you', use this skill to draw cards and guide your approach.

Breaking Analysis Paralysis

In scenarios where multiple valid options exist, let the cards help choose a direction instead of getting stuck.

Creative Exploration

Use the Tarot spread to inspire new ideas and perspectives during brainstorming sessions.

How to install Let Fate Decide

View source

1. Install with the skills CLI

npx skills add trailofbits/skills/let-fate-decide --agent claude-code

2. Or install it manually

Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.

Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs

Inside SKILL.md

Written by trailofbits

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 for the default 12 Houses of the Zodiac spread: 12 houses, each with 1 Major Arcana card and 2 Minor Arcana cards. Each house and card includes a file path relative to {baseDir}/

  3. Read each house file and each card's meaning file to understand the draw. For faster reads, use --content to include house and card text directly in the JSON:

    uv run --no-config {baseDir}/scripts/draw_cards.py --content
    
  4. Interpret the spread using the guide at {baseDir}/references/INTERPRETATION_GUIDE.md

  5. When the task belongs to a specialized technical workflow, use {baseDir}/references/TECHNICAL_CONTEXT_LENSES.md to translate the reading into an audit, verification, domain, failure-class, or stakeholder lens

  6. 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
  • As the deciding authority for safety-critical work (security, data integrity, production deployments, release approval, incident response)
  • The user explicitly asks you NOT to use Tarot
  • The user's tone is precision-seeking rather than casual -- ask clarifying questions instead to gather actual requirements

Security and Correctness Use

This skill may be used inside a security, audit, or correctness pipeline as a creative lens for discovery: choosing which angle to inspect next, breaking analysis paralysis, generating hypotheses, or surfacing blind spots.

It is never sufficient by itself. In security and correctness contexts, the reading must be followed by ordinary engineering evidence: source review, tests, proofs, traces, reproduction steps, exploitability analysis, or other domain-appropriate verification. Do not treat a favorable card as permission to ship, suppress a finding, skip validation, or overrule a concrete risk.

How It Works

The Draw

The script uses secrets for cryptographic randomness:

  1. Builds separate Major Arcana (22 cards) and Minor Arcana (56 cards) decks
  2. Performs Fisher-Yates shuffles via secrets.randbelow() (no modulo bias)
  3. Deals the default 12 Houses of the Zodiac spread
  4. Each house receives 1 Major Arcana card followed by 2 Minor Arcana cards
  5. Each of the 36 cards independently has a 50% chance of being reversed

The default spread records a conservative unordered-card entropy budget exceeding 100 bits: roughly log2(C(22,12)) bits from Major Arcana selection, log2(C(56,24)) bits from Minor Arcana selection (assuming secrets.randbelow() is cryptographically secure), plus 36 reversal bits. The exact values are computed and reported in the JSON output under entropy_bits. The actual ordered assignment of cards to houses contains more entropy.

The Spread

The default spread is 12 Houses of the Zodiac:

HouseRepresentsQuestion It Answers
1SelfHow should this work begin?
2ResourcesWhat values, assets, or constraints matter?
3CommunicationWhat needs to be clarified or connected?
4FoundationsWhat context or dependency anchors the task?
5CreativityWhere should experimentation or delight shape the work?
6PracticeWhat quality, maintenance, or execution concern matters?
7PartnershipWho or what must this integrate with?
8TransformationWhat risk, shared state, or deep change is present?
9ExplorationWhat principle or broader strategy guides the path?
10CallingWhat delivery or long-term outcome is being served?
11CommunityWhat system, network, or shared aspiration is involved?
12The HiddenWhat blind spot, ending, or unconscious factor matters?

Within each house, the Major Arcana card sets the archetypal theme and the two Minor Arcana cards provide practical detail.

For compatibility with older workflows, draw_cards.py --legacy returns the previous 4-card hand, and draw_cards.py --legacy <count> returns a custom hand of 1-78 cards. A positional count without --legacy is rejected, because the new default spread has a fixed shape.

Reference Files

Each house's meaning is in its own markdown file under {baseDir}/houses/. House files describe how the house applies across technical contexts including building new projects, vulnerability discovery, correctness verification, and common audit, verification, domain, failure-class, and stakeholder workflows.

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 house file and each card file, then synthesize meaning. See {baseDir}/references/INTERPRETATION_GUIDE.md for the full interpretation workflow. For cross-domain translation, see {baseDir}/references/TECHNICAL_CONTEXT_LENSES.md.

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 12 houses; don't interpret cards in isolation
  • Map abstract meanings to concrete technical decisions
  • In security, audit, and correctness work, use the reading to choose an investigation path, then require evidence before accepting or dismissing any risk
  • Never output interpretation as a text-only turn. Include the interpretation alongside your next tool call (the action that implements the chosen option). Prefer --content so all 36 card meanings and all 12 house meanings are available from the draw output.

Example Session (House-Level Fragment)

A real reading synthesizes all 12 houses; the fragment below shows only what one house contributes so the format is clear. Do not stop after one house in actual use.

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

[Draw cards]
1st House (Self): The Magician (upright), Five of Swords (reversed),
                  Ten of Pentacles (upright)

House contribution: The starting stance is resourceful and tool-rich
(Magician), but the practical details warn against combative edge-case work
(Five of Swords reversed) while still favoring maintainable craft
(Ten of Pentacles). This is one input into the overall reading; combine with
the remaining 11 houses before deciding on an approach.

The named draw agent returns a more compact form for portent questions: 3 concise bullets covering the dominant theme, the main risk or blind spot, and the recommended next action.

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

RationalizationWhy 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
"The reading says the risk is fine"Cards can suggest what to inspect; only evidence can dismiss a security or correctness concern

Frequently asked questions about Let Fate Decide

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