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MGC Blackbox

A local encrypted vault and sealed-script runner for agents — secrets stay AES-256 encrypted on the device, the agent can use them but never reads plaintext.

by zkeviny ↗Identity, Access, Secrets & EncryptionCommunity

LABSCO SUMMARY

The agent can use the key without seeing it.

The claim is narrow and checkable: secrets live in an AES-256 encrypted store on your own device, an agent calls them by name, and plaintext never enters the conversation or the logs. Sealing extends the same idea to scripts — a capsule the recipient executes but cannot read. Two things to plan around: deletion is manual rather than a tool call, and the licence is the project's own rather than a standard open-source one.

What it is

A local encrypted execution layer that sits between an agent and your secrets. API keys, credentials and configs go into an encrypted store; scripts can be sealed into capsules that only a target node can decrypt and run. Everything decrypts on-device, and MGC is the boundary rather than an agent itself.

What you get

  • Store a secret under a name, encrypted locally — mgc_save
  • Retrieve a stored item for use without the plaintext entering the conversation — mgc_get
  • List what is stored, metadata only — mgc_list
  • Seal a script into an execution capsule that only the target node can decrypt and run — even the sender cannot read it back — mgc_seal
  • Open the local web UI for the parts meant for a human: initialization, manual storage, metadata inspection, audit and deletion — mgc_open_webui
  • A REST path alongside MCP, so system scripts can fetch encrypted items at runtime with the access token

Requirements

pip install mgc-blackbox, into the same Python environment your MCP agent runs in. mgc starts it as a local service; for MCP, configure command mgc with args ["--mcp"]. The web UI is at http://127.0.0.1:57218, stepping down to 57217, 57216 and onwards if the port is taken — the startup output prints the address it actually used. An access token is generated on first run at ~/.mgc/database/mgc_black_box/.mgc_token and is required for every REST call. There is no delete function: removal is a manual database operation from the web UI's audit view. Integration into third-party products is free but the project asks for authorization first.

Setup effort

One command — pip install mgc-blackbox

See installation options