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arthur-mcp: Instructions file for Codex

AGENTS.md

arthur-mcp AGENTS.md is an instructions file for Codex, OpenCode from alexmmatos/arthur-mcp. It costs 2,883 tokens per session, scanned A, original, MIT.

Project instructions that give coding agents shared context about Arthur MCP, including its product, code structure, technologies, and commands.

In plain words
What is it for?
Use them when an agent needs to understand the Arthur MCP repository, its React and NestJS parts, local setup, or development commands.
Why use it?
They reduce guesswork before code changes by telling an agent what the project contains and which guidance to read first.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: reads .claude/ paths; mentions Claude Code; mentions AGENTS.md.

This is alexmmatos/arthur-mcp's own configuration. It tells Codex and OpenCode how to work on arthur-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 arthur-mcp configures →

not rated 2repo 1mo ago A scan 2,883 tokens original MIT
View source ↗ alexmmatos/arthur-mcp arthurmcp.io
Reuse

Borrowing it

Nothing to install: this file belongs to alexmmatos/arthur-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/alexmmatos/arthur-mcp/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/alexmmatos/arthur-mcp

Made for: Codex, OpenCode.

Wrote this? Show the measurements

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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.

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Per session 2,883 This file is loaded in full into every session.
When invoked 2,883 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 $0.02883 $0.02883
Opus 5 $0.01442 $0.01442
Sonnet 5 $0.00577 $0.00577
Haiku 4.5 $0.00288 $0.00288

Measured 5d ago against content hash f2a8bc605230, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

arthur-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 5d 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 · 170 lines

How it starts

The opening of the file, as written. The whole thing — 170 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

This file is the shared project memory for Codex, Claude Code, and any other development agent. Before changing code, read this file, docs/ROADMAP.md, and docs/HANDOFF.md.

Product

Arthur MCP is a full-stack application for managing MCP servers/projects, importing API definitions, generating dynamic tools, handling prompts, secrets, logs, settings, sharing, and documentation.

Stack

  • Frontend: React 18, TypeScript, Vite, Material UI, React Router, Axios, react-i18next/i18next, Vitest.
  • The current frontend design is desktop-first, not mobile-first; responsive/mobile adaptation is pending work tracked in docs/ROADMAP.md. New UI should not make this worse, and mobile work goes through the mobile-first-expert specialist.
  • Backend: NestJS, TypeScript, TypeORM, local SQLite, Mongo/Mongoose in parts of the domain, JWT/Passport, Jest.
  • Local runtime: frontend at the repository root and API in api/.
  • Deploy/infra: Dockerfile, docker-compose.yml, nginx.conf, and render.yaml.

Structure

  • src/: React frontend.
  • src/pages/: main application screens.
  • src/components/: reusable components.
  • src/context/: React contexts, including auth, terminology, and server navigation.
  • src/i18n.ts: frontend i18next initialization and language detection.
  • src/locales/: frontend translation resources by locale and namespace.
  • src/theme/: theme and color mode.
  • api/src/: NestJS backend.
  • api/src/auth/: authentication, JWT, and password reset.
  • api/src/dynamic-mcp/: dynamic MCP tool generation/execution from APIs.
  • api/src/swagger/: Swagger/OpenAPI project import and persistence.
  • api/src/prompts/, api/src/secrets/, api/src/settings/, api/src/users/, api/src/roles/: domain modules.
  • api/src/audit-logs/ and api/src/execution-logs/: audit trails and execution history.
  • api/src/observability/: operational health checks, structured logging, Prometheus metrics, correlation IDs, and OpenTelemetry tracing.
  • observability/: local Prometheus, Grafana, and Tempo helper configuration.
  • docs/ENTITIES.md: backend domain entity reference across SQLite/TypeORM and MongoDB/Mongoose.
  • docs/DESIGN_PATTERNS.md: backend and frontend architecture/design pattern reference.
  • docs/FLOWS.md: user-facing workflow notes and API/UI behavior that affects journeys.

Read the full file on GitHub · 170 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. 5d ago First seen · 170 lines · 2,883 tokens per session scan A f2a8bc605230

Subscribe to this mod's changes

arthur-mcp AGENTS.md is an instructions file published in the GitHub repository alexmmatos/arthur-mcp (2 stars, last pushed 1mo ago), licensed MIT. It adds 2,883 tokens to every session, about $0.0144 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 2026-09-03.

Memory and contextmcpmcp-clientmcp-gatewaymcp-protocolmcp-securitymcp-server
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