What MCP-AQL is, why it exists, and what to read first

What plain MCP leaves open

MCP standardizes how tools register and how calls are made, but it does not encode what an operation means. A harmless query and a destructive deletion share the same structural shape, so the only signal about intent is free-text description.

{
  "name": "get_user",
  "description": "Return a user record"
}

{
  "name": "drop_database",
  "description": "Delete the production database"
}

What MCP-AQL adds

MCP-AQL makes intent structural. Routing an operation through READ declares it side-effect-free. Routing through DELETE declares it destructive. That makes safety classification available to clients, LLMs, and policy systems without parsing descriptions or guessing from naming conventions.

• READ means safe query semantics
• DELETE means destructive intent is explicit
• EXECUTE means lifecycle or side-effectful runtime flow

Discover operations

{
  "operation": "introspect",
  "params": { "query": "operations" }
}

Call a discovered operation

{
  "operation": "create_user",
  "params": {
    "email": "alice@example.com",
    "name": "Alice"
  }
}

1. Discover operations

{
  "operation": "introspect",
  "params": { "query": "operations" }
}

{
  "success": true,
  "data": {
    "operations": [
      { "name": "get_user", "endpoint": "read" },
      { "name": "create_user", "endpoint": "create" },
      { "name": "delete_user", "endpoint": "delete" }
    ]
  }
}

2. Read safely

{
  "operation": "get_user",
  "params": { "user_id": "user_123" }
}

{
  "success": true,
  "data": {
    "id": "user_123",
    "email": "alice@example.com",
    "name": "Alice"
  }
}

3. Create state

{
  "operation": "create_user",
  "params": {
    "email": "alice@example.com",
    "name": "Alice"
  }
}

{
  "success": true,
  "data": {
    "id": "user_123",
    "created": true
  }
}

4. Handle malformed input

{
  "operation": "get_user",
  "params": {}
}

{
  "success": false,
  "error": {
    "code": "VALIDATION_MISSING_PARAM",
    "message": "Missing required parameter 'user_id'",
    "details": {
      "param_name": "user_id"
    }
  }
}

5. Ask for confirmation before delete

{
  "operation": "delete_user",
  "params": { "user_id": "user_123" }
}

{
  "success": false,
  "error": {
    "code": "CONFIRMATION_REQUIRED",
    "message": "This operation requires confirmation",
    "details": {
      "danger_level": "destructive",
      "confirmation_token": "conf_abc123xyz"
    }
  }
}

6. Retry with the confirmation token

{
  "operation": "delete_user",
  "params": {
    "user_id": "user_123",
    "_confirmation": "conf_abc123xyz"
  }
}

{
  "success": true,
  "data": {
    "deleted": true
  }
}