Case Forge - Mystery Case Generator

• A sealed room with a body inside (locked room)
• A death time that contradicts testimony (time paradox)
• A behavior that defies logic (cognitive misdirection)
• An alibi that seems impossible to break

The anomaly is the heart of the puzzle — it's what makes players think "wait, that can't be right."

Progressive Disclosure

Information comes in layers:

• Surface: What players see first (the narrative)
• Hidden: What the GM knows (true cause, timeline, culprit)
• Triggered: Clues revealed only when players ask specific questions

Output Structure

ALWAYS generate all 6 sections in this exact order:

1. Background (Narrative)

Format: Novel-style third-person narrative, 800-1500 words Purpose: Immersive story that presents the anomaly without explaining it

Writing Requirements:

• Third person POV
• Sensory details (environment, sounds, textures)
• Natural dialogue (not exposition dumps)
• Show, don't tell
• At least 3 characters appear naturally through action/dialogue

Must Include:

• Time + Location + Atmosphere establishment
• Event progression (gradually leads to the death)
• The "anomaly" presented (but NOT explained)
• Multiple small details (items, traces, times)

FORBIDDEN:

• Using words like "case", "clue", "suspect", "investigation"
• Explaining the anomaly's mechanism
• Asking questions like a puzzle prompt
• Summarizing or interpreting events

Style: Think detective novel opening, not case file summary.

2. Case Archive (Hidden Information)

Format: Structured list Purpose: GM reference — the truth behind the mystery

Include:

• Deceased: Name
• Cause of Death (real)
• Actual Death Time
• Discovery Time
• Core Anomaly Type: e.g., time paradox / sealed space / cognitive misdirection
• Anomaly Explanation (abstract description of mechanism, no operational details)
• Time Misdirection? Yes/No + how

Safety Note: Describe mechanisms abstractly — focus on the "why it works" not "step-by-step how to do it."

3. Suspect Profiles

Format: List, minimum 3 suspects Purpose: Create plausible alternatives to the real culprit

For each suspect:

• Identity
• Relationship to deceased
• Surface Motive (apparent reason to want them dead)
• Hidden Information (secrets, true relationship)
• Lying? (Yes/No + what they're concealing)

Key: Every suspect should seem guilty. The real culprit hides among them.

4. Clue System (Three Tiers)

Format: Structured entries

For each clue use this format:

Key Point: [What this clue reveals]
Trigger: When player asks about [specific topic]
Presentation: Dialogue / Description / Report
Description: [The actual clue content]
Purpose: Advances reasoning by [specific step]

Organize into three levels:

Tier 1 - Basic Clues (understanding the scene):

• Players get these easily
• Establish the basic situation
• Example: "What does the locked door look like?"

Tier 2 - Critical Clues (pointing to the anomaly):

• Reveal the impossibility
• Require targeted questions
• Example: "Why is the death time inconsistent with the witness testimony?"

Tier 3 - Decisive Clues (locking in the truth):

• Directly identify the culprit or mechanism
• Require precise investigation
• Example: "Is there evidence the time of death was manipulated?"

Important: Clues should be discovered through player curiosity, not GM exposition.

5. Misdirection Design

Format: Lists

Irrelevant Items (minimum 2):

• Objects that attract attention but mean nothing
• Example: A broken phone, an unopened coffee bag

Misleading Details:

• Time-related: Clocks showing wrong times
• Behavioral: Characters acting strangely for innocent reasons
• Physical: Evidence that points to wrong conclusions

False Lead Directions:

• Where might players incorrectly deduce?
• What seems like a clue but is actually a red herring?

6. Complete Solution (Answer Key)

Format: Detailed explanation

Must include all 5 parts:

① True Timeline:

• Minute-by-minute account of what actually happened
• When death occurred vs. when it was discovered
• What each character was really doing

② Anomaly Explanation (abstract):

• How the "impossible" situation was created
• Focus on the logical mechanism, not operational steps
• Example: "Through a time-delayed mechanism, the door appeared locked from inside after the culprit left" (abstract) NOT "Use a fishing line to..." (operational)

③ Culprit Identity:

• State the name clearly
• Explain why this person specifically

④ Motive:

• Specific, personal, believable
• Not generic "they wanted money"
• Connect to character backstory

⑤ Evidence Chain:

• Step-by-step deduction path
• Which clues lead to which conclusions
• How to eliminate other suspects
• Final proof

Quality Check: The solution should feel inevitable in hindsight — all the pieces were there, players just needed to assemble them correctly.

Design Philosophy

Start with the Anomaly

Before writing anything else, decide:

1. What seems impossible?
2. How is it actually possible?
3. Why doesn't everyone immediately see the solution?

The anomaly is your foundation — everything else supports it.

Create Human Characters

Suspects aren't puzzle pieces — they're people with:

• Genuinely held beliefs about what happened
• Personal reasons to conceal information (even if innocent)
• Relationships that complicate the situation
• Flaws that make them act irrationally

Layer the Mystery

A good case has multiple "aha moments":

1. "Wait, that's weird" (noticing the anomaly)
2. "Oh, I see what's really happening" (understanding the mechanism)
3. "So it was YOU" (identifying the culprit)
4. "And here's why" (understanding the motive)

Each revelation should feel earned.

Respect the Player

• Don't withhold information just to be tricky
• Don't create arbitrary complexity
• Don't rely on obscure knowledge
• DO reward careful observation and logical thinking

Safety Constraints

DO NOT provide:

• Reproducible criminal methods (operational steps)
• Real-world crime tutorials
• Specific techniques that could be copied

DO provide:

• Abstract descriptions of mechanisms ("a time-delayed system")
• Logical explanations ("because X, therefore Y")
• Fair play puzzle design (players have equal information)

When in doubt, focus on the logic of the crime, not the mechanics.

Example Usage

When generating a case, you'll naturally work through:

1. Choose your anomaly: "I'll make a sealed room case where the door appears locked from inside"
2. Design the mechanism: "The lock was manipulated remotely using a simple mechanical system"
3. Create characters: "The victim, the caregiver who found them, the estranged sibling, the neighbor"
4. Plant clues: "Scratches on the doorframe, lubricant residue, inconsistent timeline"
5. Add misdirection: "A mysterious phone call that seems important but isn't, a dropped item that's just careless"
6. Write the narrative: "The sea fog crept in that evening, thick enough to hide..."

The narrative comes last because it needs to naturally contain all the other elements.

Quality Checklist

Before finalizing, verify:

✅ The anomaly is genuinely puzzling (not obvious) ✅ The solution is logically sound (no holes) ✅ All clues are accessible to players ✅ At least 3 suspects exist with plausible motives ✅ The culprit appears in the narrative ✅ The narrative avoids "case/clue/suspect" terminology ✅ Misdirection exists but doesn't make the case unsolvable ✅ The solution explains everything without introducing new elements ✅ No reproducible criminal methods are included ✅ The case feels fair — solvers will think "I could have gotten that"

Remember

You're not just creating a puzzle — you're creating an experience. The best mystery cases:

• Respect the solver's intelligence
• Create genuine surprise in the reveal
• Feel satisfying to solve
• Make players want to immediately try another one

References

This skill includes additional reference materials in the references/ directory:

• generator_prompt.txt - Original detailed prompt template used to design this skill
• game_prompt.txt - Game master prompt for interactive gameplay
• PROJECT_SUMMARY.md - Complete project background and design history

These files are available for deeper understanding but are not loaded by default to keep the skill lightweight.