Secure Script Runner (Zero‑Exposure Sandbox)

Zero‑exposure script execution using MGC Blackbox. Store scripts encrypted, execute locally, AI never sees plaintext. Supports MCP/API/WebUI execution, internal credential calls, and script sealing.

Overview

Secure Script Runner is a documentation skill that teaches how to execute scripts with zero plaintext exposure using MGC Blackbox.

This skill enables:

• Store scripts encrypted in local MGC
• Execute scripts locally (AI sees results only)
• Three execution modes: MCP, API, WebUI
• Scripts can call internal MGC credentials
• Script sealing for cross‑node delegation

This skill contains no executable code and is safe for automatic approval.

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What This Skill Enables

After reading this documentation, an AI agent will understand how to:

• Store scripts securely in MGC Blackbox
• Execute scripts via MCP (AI), API (script), or WebUI (human)
• Call MGC internal credentials from scripts
• Seal scripts using node public key
• Build zero‑exposure workflows

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Prerequisites

1. Install MGC Blackbox: pip install mgc-blackbox
2. Start MGC service: mgc (runs at http://127.0.0.1:57219)
3. MCP tools available: Use mgc_save, mgc_get, mgc_seal
4. Token file: ~/.mgc/database/mgc_black_box/.mgc_token

Important: For AI agents, use MCP tools. CLI may have port conflicts in some environments.

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Zero‑Exposure Execution

Core Concept

text

Script (plaintext) → MGC Encryption → Encrypted Storage
                                              ↓
                              Local Execution (MGC)
                                              ↓
                              AI receives result only

AI executes but never sees script plaintext.

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Three Execution Modes

Mode	Interface	Use Case
MCP	mgc_get	AI agents
REST API	/api/mgc/sensitive/get	System scripts
WebUI	http://127.0.0.1:57218	Human operators

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Storing Scripts

Step 1: Prepare Script

Store a script with execution metadata:

python

# Via MCP tool
mgc_save(
    info_type="script",
    info_owner="my_script",
    ext01="python",           # Startup command
    ext02="script.py arg1",  # Default runtime args
    content="print('Hello from zero‑exposure!')"
)

Parameters

Parameter	Required	Description
info_type	Yes	Must be "script"
info_owner	Yes	Unique script identifier
ext01	Yes	Startup command (python, node, etc.)
ext02	No	Default runtime arguments
content	Yes	Script plaintext (encrypted at rest)

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Executing Scripts

Mode 1: Via MCP (AI)

python

# Execute via MCP tool
result = mgc_get(
    info_type="script",
    info_owner="my_script",
    action="run"
)
# AI receives execution result only

Mode 2: Via REST API (Script)

bash

curl -X POST http://127.0.0.1:57219/api/mgc/sensitive/get \
  -H "Content-Type: application/json" \
  -H "X-MGC-Token: $(cat ~/.mgc/database/mgc_black_box/.mgc_token)" \
  -d '{
    "info_type": "script",
    "info_owner": "my_script",
    "action": "run"
  }'

Mode 3: Via WebUI (Human)

1. Open WebUI: http://127.0.0.1:57218
2. Navigate to Get page
3. Find your script
4. Click "Run" button

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Calling MGC Credentials

Scripts can call MGC internal credentials using the internal API:

python

# Example: Call MGC credential from script
import urllib.request
import json

def get_mgc_credential(info_type, info_owner):
    data = json.dumps({
        "info_type": info_type,
        "info_owner": info_owner
    }).encode("utf-8")

    req = urllib.request.Request(
        "http://127.0.0.1:57219/api/mgc/sensitive/get",
        data=data,
        headers={
            "Content-Type": "application/json",
            "X-MGC-Token": open("/path/to/token").read()
        },
        method="POST"
    )

    with urllib.request.urlopen(req) as resp:
        return json.loads(resp.read().decode())["data"]

Note: Credentials are retrieved locally, script executes locally, AI never sees plaintext.

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Script Sealing (Advanced)

For cross‑node delegation, scripts can be sealed using the node's public key:

Step 1: Get Node Public Key

python

# Via MCP tool
node_pub = mgc_get(
    info_type="__NODE_PUB__",
    info_owner="__NODE_PUB__"
)

Step 2: Seal Script

python

# Via MCP tool
sealed = mgc_seal(
    info_type="script",
    info_owner="my_script",
    ext04=node_pub  # Target node public key
)

Step 3: Store Sealed Script

python

# Store sealed version
mgc_save(
    info_type="script",
    info_owner="my_script_sealed",
    ext01="python",
    content=sealed
)

Sealed scripts are encrypted and can only be executed by the target node.

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MCP Tools Reference

mgc_save

Arguments:

json

{
  "info_type": "script",
  "info_owner": "unique identifier",
  "ext01": "startup command (python, node, etc.)",
  "ext02": "default runtime arguments",
  "content": "script plaintext"
}

mgc_get

Arguments:

json

{
  "info_type": "script",
  "info_owner": "script identifier",
  "action": "get | run"
}

Returns: Script content or execution result

mgc_seal

Arguments:

json

{
  "info_type": "script",
  "info_owner": "script identifier",
  "ext04": "target node RSA public key"
}

Returns: Sealed script (encrypted with target node key)

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Security Notes

1. Zero‑exposure: Script executes locally, AI receives result only
2. Encrypted storage: All scripts encrypted at rest
3. No plaintext leakage: AI never sees script content
4. Script sealing: Cross‑node scripts stay encrypted

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Links

• Main Repository: https://github.com/zkeviny/MGC-Blackbox
• Issues: https://github.com/zkeviny/MGC-Blackbox/issues
• Contact: [e-mail]