Memory System
The Memory System is what gives Isekaigen its long-term coherence. Without it, the AI would only “remember” whatever fits in the visible recent history — roughly the last 10–20 turns. With the Memory System, important events from turn 1 can still surface and influence your story at turn 200.
The problem it solves
Section titled “The problem it solves”AI models have a context window — a maximum amount of text they can process at once. In a long-running game, your full story history quickly exceeds this limit. If the system simply kept appending turns, the oldest parts of the story would drop out of the AI’s view, and it would start contradicting earlier events.
The Memory System solves this by compressing important events into standalone memory entries that can be retrieved and injected into any turn’s context, even if the original conversation is long gone from the visible history.
How memories are created
Section titled “How memories are created”After each story turn, the AI evaluates what just happened. If the turn contains a meaningful event — a revelation, a significant character moment, a decision with lasting consequences, or important new information — it automatically creates a Memory Book entry.
A memory entry is a concise prose summary of what happened, stored for future retrieval.
📝 Note: Not every turn creates a memory. The system is selective — small actions, routine dialogue, and minor events don’t generate entries. Only genuinely significant moments do.
Semantic retrieval
Section titled “Semantic retrieval”When a memory is stored, it is also processed for semantic search — meaning the system understands the meaning of each memory, not just the words.
At the start of each turn:
- The system takes your current input
- Finds the memories most semantically relevant to what you’re doing
- Injects those memories into the AI’s context for this turn
The result is that the AI always has access to the memories most relevant to whatever you’re currently doing. If you mention a character by name, memories involving that character rise to the top. If you’re in a specific location, memories tied to that place become relevant.
This is fundamentally different from just showing recent history — it’s smart search applied to your personal story archive.
The Memory Book UI
Section titled “The Memory Book UI”View and manage your memories by clicking the Brain icon (🧠) in the input box toolbar. The Memory Book shows all your game’s memories, ordered from most recent to oldest.
From the Memory Book you can:
- Read all stored memories
- Edit a memory entry — useful if the AI misunderstood something
- Delete a memory entry — useful if it’s redundant or incorrect
- See which turn each memory was created on
💡 Tip: Editing memories is powerful. If the AI wrote a memory that mischaracterizes something important, correcting it will fix the AI’s “understanding” of that event for all future turns.
Lore Book vs Memory Book
Section titled “Lore Book vs Memory Book”Isekaigen has two separate knowledge stores:
| Memory Book | Lore Book | |
|---|---|---|
| What goes in it | Story events (what happened) | World facts (what exists) |
| Created by | AI automatically each turn | You manually, or AI during turns |
| Content | Narrative summaries of events | Encyclopedia-style world entries |
| Scope | Your specific game’s history | World knowledge — people, places, rules |
Both are retrieved contextually each turn. Lore Book tells the AI what the world is; Memory Book tells it what has happened to you personally in that world.
Disabling the Memory System
Section titled “Disabling the Memory System”The Memory System can be turned off in game settings. When disabled, no new memories are created and none are retrieved — the AI relies entirely on visible history. This is rarely needed but useful for very short sessions.
Tips for a better Memory System
Section titled “Tips for a better Memory System”- Play longer games — the Memory System becomes more valuable the longer your game runs. Early on, most of your history fits in context anyway.
- Don’t edit memories carelessly — they influence the AI. Editing to “correct” the story toward what you wished happened (rather than what actually happened) can cause contradictions with the visible chat history.
- Check memories when the AI forgets something — if the AI contradicts an earlier event, check the Memory Book. The relevant memory might not exist, or might be slightly inaccurate.
- Use the Lore Book for things that must never be forgotten — key character facts, world rules, major plot reveals.