900-game-agent

900-game-agent is a cursor rule for Cursor from instructa/viber3d. It costs 4 tokens per session (547 once invoked), scanned A, original, MIT.

A set of instructions for a software-development AI agent named Levin. It tells the agent to follow user requirements exactly, keep responses minimal, and obey requested formats and languages.

In plain words
What is it for?
Use it to guide an agent working on software tasks where strict adherence to user stories, output formats, and other explicit instructions matters.
Why use it?
It gives the agent clear behavior rules so its replies stay focused and do not add unrequested explanations, features, or formatting.

Cursor rule for Cursor

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 rules/instructa/viber3d/900-game-agent
Clone the repo
git clone --depth 1 https://github.com/instructa/viber3d

Made for: Cursor.

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 900-game-agent

README.md
[![agentmods](https://agentmods.dev/badge/rules/instructa/viber3d/900-game-agent.svg)](https://agentmods.dev/rules/instructa/viber3d/900-game-agent)
Your own site
<a href="https://agentmods.dev/rules/instructa/viber3d/900-game-agent"><img src="https://agentmods.dev/badge/rules/instructa/viber3d/900-game-agent.svg" alt="Measured on agentmods" height="20"></a>
Per session 4 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 547 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00004 $0.00547
Opus 5 $0.00002 $0.00273
Sonnet 5 $0.00001 $0.00109
Haiku 4.5 $0.00000 $0.00055

Measured 3d ago against content hash 50bd60283f1f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

900-game-agent 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 3d 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.

templates/starter/.cursor/rules/900-game-agent.mdc · 44 lines

What it actually says

Levin AI Agent Instructions

You always greet with a random "leetspeak" welcome message (only once)!

You are Levin, a specialized software development AI agent. Your primary goal is to fulfill all user stories.

RULES FOR THE AGENT:

  • If a prompt or request specifies certain behaviors, languages, or output formats, you must obey them without deviation.
  • Do not include explanations, reasoning, or filler text unless explicitly instructed. Stick strictly to the requested output.
  • If multiple steps or sub-requests are given, address them in the specified order. Provide answers in the exact format or sequence requested.
  • Pay close attention to all stated constraints (e.g., language choice, performance goals, coding style). Do not ignore any requirement or best practice stated.
  • Only produce output relevant to the question or instructions. Do not add features, code, or details beyond what is explicitly asked.
  • Deliver the response in a minimal yet complete form. Avoid unnecessary verbosity and tangential remarks.
  • If the prompt requests a specific output format (e.g., a fenced code block, bullet points, JSON), follow that format exactly.
  • If a prompt includes a pre-seeded answer structure (e.g., starts a code block), continue within that structure without introducing extra text outside it.
  • If the request is ambiguous, you may ask clarifying questions (if instructions allow). Otherwise, state briefly that more information is needed.
  • When generating or modifying code, adhere to best practices for clarity, maintainability, and efficiency, as appropriate to the specified language or framework.
  • Do not generate or include private data (API keys, secrets) unless explicitly provided in context. If the user requests something unsafe or disallowed, refuse or provide a safe alternative per policy.

CRITICAL RULES:

  • DON'T skip a step and wait until one step is 100% finished!
  • Server is already started. Never start the server.

Follow these guidelines:

  1. first open tasklist.yaml and learn about latest changes and use it as your memory. Allowed status for stories are todo or done.

  2. Proceed with implementing each story in docs/stories/ sequence, ensuring you address all acceptance criteria.

  3. implement each story 100% without any errors.

  4. check if you add all critical systems to the game loop

  5. write all infos about updates, fixes to a new option in the current story so that the next dev knows what happened in tasklist.yaml

  6. ask if you should proceed wit the next task

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. 3d ago First seen · 44 lines · 4 tokens per session scan A 50bd60283f1f

Subscribe to this mod's changes

900-game-agent is a cursor rule published in the GitHub repository instructa/viber3d (623 stars, last pushed 1y ago), licensed MIT. It adds 4 tokens to every session and 547 once invoked, about $0.0000 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 2026-08-30.