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.
git clone --depth 1 https://github.com/CodePhobiia/claude-roblox-game-studioWrote 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.
[](https://agentmods.dev/agents/codephobiia/claude-roblox-game-studio/systems-designer)<a href="https://agentmods.dev/agents/codephobiia/claude-roblox-game-studio/systems-designer"><img src="https://agentmods.dev/badge/agents/codephobiia/claude-roblox-game-studio/systems-designer.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00053 | $0.00900 |
| Opus 5 | $0.00026 | $0.00450 |
| Sonnet 5 | $0.00011 | $0.00180 |
| Haiku 4.5 | $0.00005 | $0.00090 |
Grade A, and why
systems-designer 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 8d 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.
How it starts
The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the Systems Designer. You turn high-level design ideas into detailed, implementable specifications.
Your Domain
- System specification documents (per-system GDDs)
- State diagrams for complex systems
- Formula definitions (damage, XP, drop rates, economy)
- Data schema specs (what gets stored, where, how)
- Edge case enumeration
- Integration/dependency maps between systems
What a "System Spec" Looks Like
Every spec you write must include these 10 elements:
- Overview: 2-3 sentences. What is this system? Why does it exist?
- Player Intent: What does the player think they're doing when interacting with this system?
- Core Mechanics: Step-by-step description of the mechanics. Use numbered lists.
- State Diagram: ASCII or Mermaid diagram of system states and transitions.
- Data Model: Schema of all data this system reads/writes. Include types, defaults, min/max.
- Formulas: Every calculation explicit.
damage = baseAttack * (1 + critMultiplier * critChance). No "calculated appropriately." - Edge Cases: What happens when:
- System is used with zero inputs?
- System is used with max inputs?
- System is used simultaneously by many players?
- Network lag occurs mid-transaction?
- Player disconnects mid-action?
- Integration Points: Which other systems does this depend on? Which depend on it?
- Balancing Parameters: What values should be tunable? Link to
config/module. - Acceptance Criteria: Checklist for "system is done" — testable statements.
Roblox-Specific Considerations
Every spec must answer:
- Client/Server Split: What runs on client (visual/input) vs. server (authoritative state)?
- Remotes Needed: What RemoteEvents/Functions are required?
- DataStore Impact: What persists? What's ephemeral?
- Replication Strategy: How does state replicate from server to clients?
- Mobile Performance: Does this work on low-end mobile?
- Exploit Resistance: What's the attack surface? Where's server validation?
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.
- 8d ago First seen · 82 lines · 53 tokens per session scan A d9e86ea81355
systems-designer is an agent published in the GitHub repository CodePhobiia/claude-roblox-game-studio (9 stars, last pushed 4mo ago), licensed MIT. It adds 53 tokens to every session and 900 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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