arc-relay AGENTS.md

arc-relay AGENTS.md is an instructions file for Codex, OpenCode from comma-compliance/arc-relay. It costs 1,305 tokens per session, scanned A, original, MIT.

A contributor guide for Arc Relay, an open-source service that controls, filters, and archives AI tool calls made through MCP, a standard connection method for AI assistants and external tools.

In plain words
What is it for?
It helps agents build and test Arc Relay, work on authentication and policy controls, redact personal data, limit responses, send alerts, archive traffic, and manage Docker services.
Why use it?
It explains what the project does and how its Go server, command-line tools, middleware, storage, and web interface fit together.

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/comma-compliance/arc-relay/agents-md
Clone the repo
git clone --depth 1 https://github.com/comma-compliance/arc-relay

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 arc-relay AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/comma-compliance/arc-relay/agents-md.svg)](https://agentmods.dev/instructions/comma-compliance/arc-relay/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/comma-compliance/arc-relay/agents-md"><img src="https://agentmods.dev/badge/instructions/comma-compliance/arc-relay/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 1,305 This file is loaded in full into every session.
When invoked 1,305 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 $0.01305 $0.01305
Opus 5 $0.00652 $0.00652
Sonnet 5 $0.00261 $0.00261
Haiku 4.5 $0.00130 $0.00130

Measured 5d ago against content hash 7e4398a3d460, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

arc-relay 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 · 142 lines

How it starts

The opening of the file, as written. The whole thing — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Arc Relay - AI Contributor Guide

This file provides context for AI coding tools (Claude Code, Cursor, Copilot) working on Arc Relay.

What is Arc Relay?

An open-source MCP (Model Context Protocol) control plane. Not just a proxy - it provides auth, user management, middleware-based policy controls, traffic interception, and archiving for AI tool calls. Built in Go with SQLite storage and a server-rendered web UI.

Project Structure

cmd/
  arc-relay/          Server binary (CGO required - SQLite)
  arc-sync/           CLI tool (pure Go, no CGO)
internal/
  config/             TOML config parsing + env var overrides
  docker/             Docker container lifecycle management
  mcp/                MCP protocol types and endpoint classification
  middleware/          Bidirectional middleware pipeline
    archive.go         Archive middleware (observe-only, sends to webhook)
    archive_dispatcher.go  Durable delivery with retry + circuit breaker
    archive_encrypt.go     NaCl Box payload encryption
    sanitizer.go       Pattern-based PII redaction/blocking
    sizer.go           Response size enforcement
    alerter.go         Pattern + size alerting (log/webhook)
    middleware.go      Pipeline core, registry, factory pattern
  proxy/               MCP proxy backends
    proxy.go           Server manager, lifecycle, enumeration
    stdio_bridge.go    Docker stdin/stdout bridge
    http_proxy.go      HTTP forward proxy
    remote_proxy.go    Remote servers with OAuth
    sse.go             SSE response parsing
    health.go          Health monitoring + auto-recovery
  store/               SQLite persistence
    db.go              Connection, migrations, backups
    users.go           Users, passwords (bcrypt), API keys (SHA-256)
    sessions.go        Web sessions
    crypto.go          AES-256-GCM config encryption
    middleware.go      Middleware config + events
    archive_queue.go   Durable delivery queue
    access.go          Endpoint access tiers
    request_logs.go    Audit logging
  web/                 HTTP handlers + templates
    handlers.go        All route handlers
    templates/         Server-rendered HTML (13 templates)
    oauth_provider.go  OAuth 2.1 authorization server
    device_auth.go     Device code flow for CLI auth
  cli/                 CLI shared packages
    config/            arc-sync config (~/.config/arc-sync/)
    sync/              .mcp.json sync logic
    relay/             HTTP client for Arc Relay API
    project/           Project detection (Claude Code, Cursor)
    safety/            Git safety checks
  oauth/               OAuth 2.1 client (PKCE, auto-discovery)
  auth/                Auth utilities
  catalog/             MCP server registry
migrations/            Embedded SQL migrations (001-012)
skills/arc-sync/       Claude Code skill definition

Read the full file on GitHub · 142 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 · 142 lines · 1,305 tokens per session scan A 7e4398a3d460

Subscribe to this mod's changes

arc-relay AGENTS.md is an instructions file published in the GitHub repository comma-compliance/arc-relay (57 stars, last pushed 5d ago), licensed MIT. It adds 1,305 tokens to every session, about $0.0065 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.