ActGate

Local IntentLedger and MCP stdio proxy: propose a tool action, approve or deny in an append-only hash-chained ledger, then let an identical tools/call reach one upstream MCP server.

This is not a SaaS. The ledger path stays on disk. dry-run and approve record decisions only; they do not execute tools. The MCP proxy is what executes, and only after approve.

Install

pip install actgate

Dev:

pip install -e .[dev]

CLI quickstart

actgate init
actgate propose --tool shell.exec --args '{"cmd":"ls"}' --blast-tags fs.read
actgate pending
actgate dry-run <intent_id>
actgate approve <intent_id>
actgate verify
actgate list

MCP proxy

Point your MCP client at ActGate instead of the upstream server:

actgate init
actgate mcp --upstream python -m some_mcp_server

Use the same --root (or the same working directory) for init, approve/deny, and mcp, so they share one ledger.

Flow:

1. Client tools/list is forwarded to upstream. Only tools/call is gated; other methods are forwarded.
2. First tools/call for a tool+args writes a propose event and returns ACTGATE_PENDING intent_id=... (upstream is not called).
3. Human: actgate approve <intent_id> (or actgate deny <intent_id>).
4. Identical subsequent tools/call (same tool and args) runs upstream once and appends an execute event. A third call returns already-executed.
5. Denied intents never hit upstream.

Bare verify checks hash-chain integrity only. Set ACTGATE_SEAL_KEY for optional HMAC seals, or pass verify --require-seal.

Human loop (HITL)

Typical MCP approval loop:

1. Client hits actgate mcp --upstream ... and gets ACTGATE_PENDING.
2. Human: actgate pending (or actgate pending --watch) to see undecided proposes.
3. actgate approve <intent_id> or actgate deny <intent_id>.
4. Client retries the same tools/call; proxy executes once.

pending is the propose-without-decision queue. --watch polls (default 1s) and prints newly pending intents as JSON until Ctrl-C (clean exit 0).

Exit codes

Intent shape

{
  "tool": "shell.exec",
  "args": {"cmd": "ls"},
  "args_hash": null,
  "blast_tags": ["fs.read"],
  "requested_mode": "execute",
  "created_at": "2026-09-06T00:00:00+00:00"
}

What this is not

• Not a hosted approval product
• Not a policy DSL
• No network calls in the ledger core path (the MCP proxy talks to a local upstream process)

Development

pip install -e .[dev]
pytest