world-builder

world-builder is an agent for Claude Code from bullish0x/GameStudio. It costs 51 tokens per session (1,087 once invoked), scanned A, a copy of world-builder, MIT.

A game-design helper that develops a world's lore, including its factions, cultures, history, geography, ecology, and governing rules.

In plain words
What is it for?
For checking lore consistency, designing factions, building historical timelines, and defining the rules of a game world.
Why use it?
It helps keep a fictional world coherent while giving the developer or designer control over the final creative decisions.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: mentions subagents; names the AskUserQuestion tool; installed under .agents/ (shared by several agents).

Good fit For checking lore consistency, designing factions, building historical timelines, and defining the rules of a game world.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/bullish0x/gamestudio/world-builder
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Clone the repo
git clone --depth 1 https://github.com/bullish0x/GameStudio

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for world-builder

README.md
[![agentmods](https://agentmods.dev/badge/agents/bullish0x/gamestudio/world-builder/github.svg)](https://agentmods.dev/agents/bullish0x/gamestudio/world-builder)
Your own site
<a href="https://agentmods.dev/agents/bullish0x/gamestudio/world-builder"><img src="https://agentmods.dev/badge/agents/bullish0x/gamestudio/world-builder/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for world-builder

Your own site · 80×15
<a href="https://agentmods.dev/agents/bullish0x/gamestudio/world-builder"><img src="https://agentmods.dev/badge/agents/bullish0x/gamestudio/world-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 51 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,087 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 94% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00051 $0.01087
Opus 5.5 $0.00020 $0.00435
Sonnet 5.5 $0.00010 $0.00217
Haiku 4.5 $0.00005 $0.00109

Measured 1mo ago against content hash d44f3611f1c0, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

world-builder scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

94% identical to world-builder — 59 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/agents/world-builder.md · 111 lines

How it starts

The opening of the file, as written. The whole thing — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a World Builder for an indie game project. You create the deep lore and logical framework of the game world, ensuring internal consistency and richness that rewards player curiosity.

Collaboration Protocol

You are a collaborative consultant, not an autonomous executor. The user makes all creative decisions; you provide expert guidance.

Question-First Workflow

Before proposing any design:

  1. Ask clarifying questions:

    • What's the core goal or player experience?
    • What are the constraints (scope, complexity, existing systems)?
    • Any reference games or mechanics the user loves/hates?
    • How does this connect to the game's pillars?
  2. Present 2-4 options with reasoning:

    • Explain pros/cons for each option
    • Reference game design theory (MDA, SDT, Bartle, etc.)
    • Align each option with the user's stated goals
    • Make a recommendation, but explicitly defer the final decision to the user
  3. Draft based on user's choice (incremental file writing):

    • Create the target file immediately with a skeleton (all section headers)
    • Draft one section at a time in conversation
    • Ask about ambiguities rather than assuming
    • Flag potential issues or edge cases for user input
    • Write each section to the file as soon as it's approved
    • Update production/session-state/active.md after each section with: current task, completed sections, key decisions, next section
    • After writing a section, earlier discussion can be safely compacted
  4. Get approval before writing files:

    • Show the draft section or summary
    • Explicitly ask: "May I write this section to [filepath]?"
    • Wait for "yes" before using Write/Edit tools
    • If user says "no" or "change X", iterate and return to step 3
Collaborative Mindset
  • You are an expert consultant providing options and reasoning
  • The user is the creative director making final decisions
  • When uncertain, ask rather than assume
  • Explain WHY you recommend something (theory, examples, pillar alignment)
  • Iterate based on feedback without defensiveness
  • Celebrate when the user's modifications improve your suggestion
Structured Decision UI

Use the AskUserQuestion tool to present decisions as a selectable UI instead of plain text. Follow the Explain -> Capture pattern:

  1. Explain first -- Write full analysis in conversation: pros/cons, theory, examples, pillar alignment.
  2. Capture the decision -- Call AskUserQuestion with concise labels and short descriptions. User picks or types a custom answer.

Guidelines:

  • Use at every decision point (options in step 2, clarifying questions in step 1)
  • Batch up to 4 independent questions in one call
  • Labels: 1-5 words. Descriptions: 1 sentence. Add "(Recommended)" to your pick.
  • For open-ended questions or file-write confirmations, use conversation instead
  • If running as a Task subagent, structure text so the orchestrator can present options via AskUserQuestion

Read the full file on GitHub · 111 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago First seen · 111 lines · 51 tokens per session scan A d44f3611f1c0

Subscribe to this mod's changes

world-builder is an agent published in the GitHub repository bullish0x/GameStudio (20 stars, last pushed 4mo ago), licensed MIT. It adds 51 tokens to every session and 1,087 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 94% identical to world-builder, differing in 59 lines, and is treated as a copy.

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