system-designer-mcp: Instructions file for Codex

AGENTS.md

system-designer-mcp AGENTS.md is an instructions file for Codex, OpenCode from chevyphillip/system-designer-mcp. It costs 648 tokens per session, scanned A, original, MIT.

Repository instructions for system-designer-mcp, including its TypeScript structure, Bun commands, coding conventions, tests, and deployment steps.

In plain words
What is it for?
They guide development, testing, linting, formatting, building, running the MCP server, and deploying its Cloudflare Worker.
Why use it?
They give an agent the project’s expected layout and checks, which helps it make changes consistently.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md.

This is chevyphillip/system-designer-mcp's own configuration. It tells Codex and OpenCode how to work on system-designer-mcp itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything system-designer-mcp configures →

Reuse

Borrowing it

Nothing to install: this file belongs to chevyphillip/system-designer-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/chevyphillip/system-designer-mcp/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/chevyphillip/system-designer-mcp

Made for: Codex, OpenCode.

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 system-designer-mcp AGENTS.md

README.md
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Your own site
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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 system-designer-mcp AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/chevyphillip/system-designer-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/chevyphillip/system-designer-mcp/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 648 This file is loaded in full into every session.
When invoked 648 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00648 $0.00648
Opus 5.5 $0.00259 $0.00259
Sonnet 5.5 $0.00130 $0.00130
Haiku 4.5 $0.00065 $0.00065

Measured 2mo ago against content hash 42a3e4dfed10, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

system-designer-mcp 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 2mo 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 · 26 lines

How it starts

The opening of the file, as written. The whole thing — 26 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Repository Guidelines

Project Structure & Module Organization

Source lives in src/ organised into types.ts (model contracts), schemas.ts, tools.ts, integration/, transformers/, validators/. CLI at src/cli.ts, worker entry src/worker.ts, local server src/index.ts. Tests under test/ mirroring source directories with *.test.ts. Docs in docs/, runnable examples in examples/, automation in scripts/, compiled assets emitted to dist/.

Build, Test, and Development Commands

Use Bun for everything. bun install seeds dependencies. bun run dev launches the stdio MCP server with watch reload. bun run dev:worker spins up Wrangler for the Cloudflare Worker. bun run build emits Node targets to dist/; bun run build:worker creates the browser bundle consumed by Workers. bun test runs the Bun test suite (bun test --watch for rapid feedback). Quality gates: bun run lint, bun run lint:fix, bun run format, and bun run format:check. Deploy the worker with bun run deploy.

Coding Style & Naming Conventions

TypeScript strictness is enforced via ESLint + @typescript-eslint (see eslint.config.js). Follow Prettier defaults: 2-space indentation, semicolons, single quotes, 100-char line width, trailing commas where valid. Prefer named exports and keep files cohesive to their domain (transformers, validators, integration). Branch prefixes mirror change intent (feature/*, fix/*, docs/*). Use descriptive entity IDs and tool names aligned with the MCP schema.

Testing Guidelines

Place tests in test/ mirroring the source path (e.g., src/validators/system-runtime.ts → test/validators/system-runtime.test.ts). Write Bun tests with describe/test from bun:test, favouring behaviour-focused descriptions. Target ≥95% coverage for new logic and include regression assertions for model/system runtime conversions. Run bun test before PRs and bun run dev:worker when touching Worker paths to confirm SSE behaviour.

Read the full file on GitHub · 26 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. 2mo ago First seen · 26 lines · 648 tokens per session scan A 42a3e4dfed10

Subscribe to this mod's changes

system-designer-mcp AGENTS.md is an instructions file published in the GitHub repository chevyphillip/system-designer-mcp (2 stars, last pushed 1y ago), licensed MIT. It adds 648 tokens to every session, about $0.0026 per session on Opus 5.5. 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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