What can you do with this server?

The ERDL MCP Server provides deterministic rule enforcement for AI agents, ensuring consistent, compliant behavior through mathematical condition matching rather than relying on LLM prompts. * Evaluate/Guard tool calls (erdl_evaluate): Intercept and check any planned tool call against loaded rules before execution, returning decisions like ALLOW, DENY, CORRECT, REQUEST_HUMAN, or EMERGENCY_HALT. * List active rules (erdl_list_rules): View all currently loaded rules, optionally filtered by category (coding, engineering, writing, design, security, performance, testing, compliance, accessibility, or custom). * Create rules from natural language (erdl_create_rule): Turn plain-language instructions (e.g., "Never use any in TypeScript") into persistent YAML rules saved to ~/.openoba/rules/, taking effect immediately. * Simulate rules before creating them (erdl_simulate): Test a proposed rule against 3 auto-generated scenarios to validate it works as intended before committing. * Explain decisions (erdl_explain): Get a full decision trail showing every rule checked and why a particular decision was made. * Access rules as resources: Query erdl://rules/list for all rules as JSON, or erdl://status for the server's runtime status. * Use 30 built-in preset rules across coding, engineering, writing, and design categories — active immediately with no configuration. * Integrate with any MCP-compatible client: Works with Claude Desktop, Cursor, OpenClaw, VS Code/GitHub Copilot, and more. * Pro/Enterprise features (with license): Includes advanced execution rings (ESCALATE, ROLLBACK, QUARANTINE), Guardian Agent Role, Audit Export (OCSF/OTLP), Team Rules, a Dashboard, and compliance packs for standards like NIST and EU AI Act.

Which integrations are available for this server?

Integrates with GitHub Copilot via VS Code MCP configuration, allowing Copilot to follow enforced rules.

How do I use ERDL MCP Server?

1. Click on "Install Server". 2. Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state. 3. In the chat, type @ followed by the MCP server name and your instructions, e.g., "@ERDL MCP Server Create a rule that bans console.log in TypeScript files" That's it! The server will respond to your query, and you can continue using it as needed. Here is a step-by-step guide with screenshots.

ERDL MCP Server

by OpenOBA

Overview Schema Related Servers Score Discussions

TypeScript

Local

ERDL MCP Server

Deterministic rules for AI Agents. Say it once. Never repeat.

npm version npm downloads license tests

📖 中文版

ERDL (Entity-Rule Definition Language) gives your Agent deterministic rules. 30 built-in rules across 6 categories. Unlimited personal rules. Free forever.

Why ERDL?

Without ERDL	With ERDL
"Don't use `any`" — forgotten in 5 turns	Rules enforced deterministically, every tool call
"Write shorter sentences" — ignored	Writing rules fire before every output
"Confirm before adding deps" — skipped	Blocked until you confirm
"Why did you do that?" — no answer	`erdl_explain` shows the full decision trail

Related MCP server: PolicyGuard

Quick Start

# Start MCP Server (5 tools, 30 rules — all MCP clients)
npx -y @openoba-ai/erdl-mcp

# Or: install OpenClaw Plugin for hardware enforcement
openclaw plugins install @openoba-ai/erdl-openclaw

30 rules active immediately. No account. No configuration. No API key.

中文用户：

npx -y @openoba-ai/erdl-mcp --lang zh

Free vs Pro

	Free	Pro
5 MCP Tools	✅	✅
30 Preset Rules	✅	✅
Unlimited Personal Rules	✅	✅
Chinese / English	✅	✅
All 11 Operators	✅	✅
MIT Open Source	✅	✅
Execution Rings 1–2 (REQUEST_HUMAN, ESCALATE, ROLLBACK, QUARANTINE)	—	✅
Guardian Agent Role (监管者模式)	—	✅
Audit Export (OCSF / OTLP)	—	✅
Team Rules (组织级规则共享)	—	✅
Dashboard (规则命中统计)	—	✅
Enterprise Compliance Packs (GB/Z 185, NIST, EU AI Act)	—	Enterprise

Get a Pro License →

One-command Install

# macOS / Linux
curl -fsSL https://raw.githubusercontent.com/OpenOBA/erdl-mcp-server/master/scripts/install.sh | bash

# Windows (PowerShell)
iwr https://raw.githubusercontent.com/OpenOBA/erdl-mcp-server/master/scripts/install.ps1 | iex

Why ERDL vs SKILL.md / Prompt Rules?

	Prompt-Based Rules	ERDL MCP Server
Execution	LLM "tries" to follow	Deterministic engine — guaranteed
Visibility	Invisible, can't tell if it worked	`erdl_explain` shows every decision
Reliability	LLM may ignore or forget	Zero hallucination — condition match is mathematical
Testing	Manual	`erdl_simulate` with 3 auto-scenarios
Portability	Single platform	All MCP-compatible Agents

ERDL rules don't suggest. They don't hope. They enforce.

What's Included

30 Built-in Rules (8 Categories)

Category	Rules	Scope
`coding`	10	TypeScript quality, Git discipline, dependency hygiene
`engineering`	24	Workflow discipline, pipeline gates, session memory, self-verify
`writing`	7	Tone, formatting, clarity
`design`	3	Tailwind-first, responsive, accessible
`security`	6	SQL injection, eval, hardcoded secrets, input validation
`testing`	11	Coverage, boundary conditions, flaky tests, TDD workflow
`performance`	3	N+1 queries, pagination, measure before optimize
`observability`	3	Structured logging, health checks, no secrets in logs

5 MCP Tools

Tool	Purpose
`erdl_evaluate`	Action Guard — check rules before every tool call
`erdl_simulate`	Test a rule against 3 scenarios before creating
`erdl_create_rule`	Create a rule from natural language
`erdl_list_rules`	List all active rules
`erdl_explain`	Full decision trail for any action

MCP Resources

Resource	Content
`erdl://rules/list`	All rules as JSON
`erdl://status`	Server runtime status

Installation

Any MCP Client

{
  "mcpServers": {
    "erdl": {
      "command": "npx",
      "args": ["-y", "@openoba-ai/erdl-mcp@latest"]
    }
  }
}

Or let ERDL generate the config for your client:

npx @openoba-ai/erdl-mcp@latest --setup

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or the equivalent path on your OS.

Cursor

Add to .cursor/mcp.json in your project root.

OpenClaw

# MCP Server (all MCP clients)
openclaw mcp set erdl '{"command":"npx","args":["-y","@openoba-ai/erdl-mcp@latest"]}'

# OpenClaw Plugin (hard enforcement via before_tool_call)
openclaw plugins install @openoba-ai/erdl-openclaw

Plugin vs MCP Server: The MCP Server gives your Agent ERDL tools. The Plugin adds deterministic tool call interception — rules run BEFORE every exec/write/search, no relying on LLM self-discipline. Install both for maximum protection.

VS Code / GitHub Copilot

Add to .vscode/mcp.json or the Copilot MCP configuration.

Creating Your First Rule

You: "Never use `any` in TypeScript."

Agent: 1. erdl_simulate → tests the rule against 3 scenarios
       2. erdl_create_rule → saves to ~/.openoba/rules/
       3. Rule is now active. Next `any` will be blocked.

You: "Why did you reject my code?"
Agent: erdl_explain → shows every rule that fired

Or create rules manually in ~/.openoba/rules/ (ERDL SPEC §5 format):

protocol: "erdl/v1"
version: "1.0.0"

rules:
  - name: "no_console_log"
    description: "Don't commit console.log statements"
    priority: 10
    when:
      logic: AND
      conditions:
        - field: "tool.name"
          operator: in
          value: ["write", "edit", "apply_patch"]
        - field: "tool.args"
          operator: match
          value: "console\\.log"
    then: DENY
    message: "Remove console.log before committing"

📚 Full tutorial: Create Your First ERDL Rule → (English)

📖 Complete Rule Reference (all 30 rules with modification guides) → (English)

CLI Reference

npx @openoba-ai/erdl-mcp@latest          # Start MCP server (always latest)
npx @openoba-ai/erdl-mcp@latest --lang zh # Chinese mode
npx @openoba-ai/erdl-mcp@latest --pro-key sk-xxx  # Activate Pro license
npx @openoba-ai/erdl-mcp@latest --upgrade  # Upgrade to latest
npx @openoba-ai/erdl-mcp@latest --uninstall  # Clean removal
npx @openoba-ai/erdl-mcp@latest --help     # Full usage

Upgrading from v1.0.x? You MUST update your MCP config:
Remove old local-path config:
openclaw mcp remove erdl  # or remove "erdl" from mcp.servers in config
Re-add with npx (auto-latest):
openclaw mcp set erdl "{\"command\":\"npx\",\"args\":[\"-y\",\"@openoba-ai/erdl-mcp@latest\"]}"
Or manually in ~/.openclaw/openclaw.json → mcp.servers.erdl:
{ "command": "npx", "args": ["-y", "@openoba-ai/erdl-mcp@latest"] }
npm cache clearing (if --version shows an older release):
npm cache clean --force

Run from Source

git clone https://github.com/OpenOBA/erdl-mcp-server.git
cd erdl-mcp-server
npm install
npm run build
node bin/erdl-mcp.js --version

License

MIT · OpenOBA · @OpenOBA

Built by AI + Human. Deterministic architecture, not prompt engineering.

Install Server

license - permissive license

quality

maintenance

How are these scores calculated?

Maintenance

–Maintainers

–Response time

–Release cycle

–Releases (12mo)

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