AgentRules AGENTS.md

Project instructions for coding agents that emphasize thinking through requirements, keeping changes simple, preserving the existing architecture, and making focused edits.

In plain words
What is it for?
Use them to guide planning, clarify acceptance criteria, choose a minimal implementation, and review whether a code change fits the existing system.
Why use it?
They reduce assumptions, unnecessary features, and changes that conflict with how the project is already structured.

Instructions file for CodexOpenCode

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 instructions/learnaihubc/agentrules/agents-md
Clone the repo
git clone --depth 1 https://github.com/LearnAIHubC/AgentRules

Made for: Codex, OpenCode.

Per session 1,280 This file is loaded in full into every session.
When invoked 1,280 The same file — it is already loaded in full.
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 $0.01280 $0.01280
Opus 5 $0.00640 $0.00640
Sonnet 5 $0.00256 $0.00256
Haiku 4.5 $0.00128 $0.00128

Measured 2d ago against content hash f0f88d9d0b6e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

AgentRules AGENTS.md 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.

AGENTS.md · 115 lines

How it starts

The opening of the file, as written. The whole thing — 115 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

Behavioral guidelines to reduce common LLM coding mistakes. Merge with project-specific instructions as needed.

Tradeoff: These guidelines bias toward caution over speed. For trivial tasks, use judgment.

1. Think Before Coding

Don't assume. Don't hide confusion. Surface tradeoffs.

Before implementing:

  • Turn the request into 2-5 concrete, verifiable acceptance criteria.
  • State your assumptions explicitly. If uncertain, ask.
  • If multiple interpretations exist, present them - don't pick silently.
  • If a simpler approach exists, say so. Push back when warranted.
  • If something is unclear, stop. Name what's confusing. Ask.

2. Simplicity First

Minimum code that solves the problem. Nothing speculative.

  • No features beyond what was asked.
  • No abstractions for single-use code.
  • No "flexibility" or "configurability" that wasn't requested.
  • No error handling for impossible scenarios.
  • If you write 200 lines and it could be 50, rewrite it.

Ask yourself: "Would a senior engineer say this is overcomplicated?" If yes, simplify.

3. Preserve Existing Architecture and Framework Boundaries

Understand the system before extending it. Preserve the guarantees already in place.

When creating or extending a project:

  • If a codebase, scaffold, template, architecture, dependency set, or framework has already been selected, inspect its structure, conventions, dependency graph, existing patterns, and supported extension points before designing or coding.
  • Prefer the project's established abstractions and integration paths when they cover the need. Do not introduce a parallel architecture or replace or bypass a dependency or framework without explicit justification.
  • Keep feature logic modular, but integrate it through the lifecycle and control boundaries of the adopted architecture and frameworks, such as dependency injection, routing, state management, persistence, middleware, and configuration.
  • Do not make a feature work by bypassing those boundaries in a way that disables framework hooks, guarantees, cross-cutting behavior, or existing functionality.
  • If the requirement does not fit the current boundaries, explain the mismatch and tradeoffs before changing the architecture or introducing or replacing dependencies.
  • Verify the feature through the project's normal entry points and regression tests, confirming that the existing architecture and framework behavior remains effective.

Read the full file on GitHub · 115 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 · 115 lines · 1,280 tokens per session scan A f0f88d9d0b6e

Subscribe to this mod's changes

AgentRules AGENTS.md is an instructions file published in the GitHub repository LearnAIHubC/AgentRules (17 stars, last pushed 20d ago), licensed MIT. It adds 1,280 tokens to every session, about $0.0064 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.