AI coding agent rules (AGENTS.md, Cursor, Claude)

Quick install via terminal (1-liner commands)

Add SadaSend instructions to your repository with a single terminal command. Compatible with all modern coding assistants.

BASH

# 1. Universal Standard (AGENTS.md - Linux Foundation & Supabase standard)
curl -fsSL https://www.sadasend.com/AGENTS.md >> AGENTS.md

# 2. Claude Code CLI (CLAUDE.md)
curl -fsSL https://www.sadasend.com/CLAUDE.md >> CLAUDE.md

# 3. Cursor IDE (.cursorrules)
curl -fsSL https://www.sadasend.com/.cursorrules >> .cursorrules

File naming across tools and platforms

Different tools recognize different instruction files. SadaSend provides unified guidance for all of them:

Tool / Platform	Standard File Path	How It Works
Universal / Linux Foundation	AGENTS.md	Root instruction file adopted by multi-agent frameworks, Supabase, and CI bots
Google Antigravity	AGENTS.md or GEMINI.md or .agents/rules/*.md	Hierarchical rule discovery and MCP tool bindings across Antigravity IDE and CLI
Cursor IDE	.cursorrules or .cursor/rules/*.mdc	Injected into Cursor Composer and Chat context for code completions
Cline (VS Code)	.clinerules	Custom system instructions read by the Cline autonomous agent in VS Code
Anthropic Claude Code	CLAUDE.md	Read automatically by the Claude Code CLI at the start of every session
Windsurf (Codeium)	.windsurfrules	Root configuration for Windsurf Cascade agent workflows
OpenCode CLI	AGENTS.md or opencode.json	Agent guidelines and tool permissions for OpenCode terminal sessions
GitHub Copilot	.github/copilot-instructions.md	Official repository-wide instructions for GitHub Copilot Chat
Hosted MCP Connection	mcp_config.json or .cursor/mcp.json or cline_mcp_settings.json	Direct connection to SadaSend hosted MCP tools (https://mcp.sadasend.com)

Universal rule template (Copy & Paste)

If you prefer to manually configure your rules, place the following content in your repository:

MARKDOWN

# SadaSend Email Integration Rules

1. Environment & Credentials:
   - Read from `process.env.SADASEND_API_KEY` and `process.env.SADASEND_FROM_EMAIL`. Never hardcode keys.
   - Use scoped keys (`[send]`, `[read]`) and recipient allowlists (`*@yourcompany.com`) during local development.

2. API Standards:
   - Primary Endpoint: `POST https://api.sadasend.com/v1/emails`
   - SMTP Gateway: `smtp.sadasend.com:587` (STARTTLS), User: `sadasend`, Pass: `$SADASEND_API_KEY`
   - Always include an `Idempotency-Key` UUID header on transactional sends to prevent duplicate delivery.

3. Error Handling:
   - 400: Syntax or burner address invalid.
   - 401: Invalid API key.
   - 403: Allowlist or permission scope refusal. Requires human configuration.
   - 422: Domain missing verified SPF/DKIM DNS records.
   - 429: Rate limit hit. Back off exponentially.

Connecting the hosted MCP server

To equip AI coding agents with direct email preview and diagnostic tools without giving them your entire account, connect to the hosted MCP server:

JSON

{
  "mcpServers": {
    "sadasend": {
      "url": "https://mcp.sadasend.com",
      "headers": {
        "Authorization": "Bearer YOUR_SADASEND_API_KEY"
      }
    }
  }
}

Verification command

An agent can run this command in your terminal to verify that credentials and domain verification are active before generating application code:

BASH

curl -s -w "\nStatus: %{http_code}\n" \
  https://api.sadasend.com/v1/domains \
  -H "Authorization: Bearer $SADASEND_API_KEY"