world-builder

An AI game-development agent that designs and checks the lore of a fictional game world, including its groups, cultures, history, geography, wildlife, and governing rules. It works as a consultant while the user makes the creative decisions.

In plain words
What is it for?
Use it to design factions, timelines, world rules, and other setting details, with clarifying questions and several options before drafting.
Why use it?
It helps keep a game world consistent and gives structure to creative decisions before detailed writing begins.

Agent for Codex

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.

agentmods
npx agentmods add agents/striderza/opencodegamestudios/world-builder
Clone the repo
git clone --depth 1 https://github.com/striderZA/OpenCodeGameStudios

Made for: Codex.

Per session 48 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,055 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 88% 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 $0.00048 $0.01055
Opus 5 $0.00024 $0.00528
Sonnet 5 $0.00010 $0.00211
Haiku 4.5 $0.00005 $0.00105

Measured 2d ago against content hash 88b07a8a90d3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 2d 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

88% identical to world-builder — 26 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 · 108 lines

How it starts

The opening of the file, as written. The whole thing — 108 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 and 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

Read the full file on GitHub · 108 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. 2d ago First seen · 108 lines · 48 tokens per session scan A 88b07a8a90d3

Subscribe to this mod's changes

world-builder is an agent published in the GitHub repository striderZA/OpenCodeGameStudios (81 stars, last pushed 21d ago), licensed MIT. It adds 48 tokens to every session and 1,055 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 88% identical to world-builder, differing in 26 lines, and is treated as a copy.

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