@actantdb/mastra

Wrap a Mastra agent. Capture every model call, tool call, context manifest, approval, and effect result. Replay from any decision point.

You keep Mastra. You add Actant.

Install

npm install @actantdb/mastra

Use

import { withActant } from "@actantdb/mastra";
import { myMastraAgent } from "./agent";

export const agent = withActant(myMastraAgent, {
  project: "prod-support-agent",
  replay: true,
  approvals: true,
});

Then open Studio:

npx actant studio

What gets captured

| Event | What it records | | --------------------------- | ---------------------------------------------------- | | agent.run.started | run id, agent name, initiating message | | model.call | model + provider + redacted prompt hash + response hash + tokens + latency | | tool.call.requested | tool name + arguments (with secret redaction) + risk class | | guard.verdict | allow / constrain / require_approval / block / halt + policy snapshot | | approval.required | approval request id + summary + reversibility | | approval.decision | approver + scope (once / session / etc) + decision | | tool.call.completed | result ref + duration + exit / status | | context.build | manifest hash + included / blocked counts + per-item visibility decision | | effect.observed | structured observation (when the tool emits one) |

Captured locally to ~/.actant/<project>/events.sqlite. No remote backend required. No data leaves your machine unless you opt in.

Approval API

In Studio: click the pending approval, choose allow, constrain (rewrites the arguments), or deny.

Or from the CLI:

actant approve <tool_call_id>
actant approve <tool_call_id> --scope session
actant deny    <tool_call_id> --reason "policy mismatch"

Replay

actant replay run <event_id> --without-memory mem_42
actant replay run <event_id> --policy strict
actant replay diff <run_a> <run_b>

Replay does NOT re-execute real side effects in v0.1. Recorded tool results are reused. To re-invoke models or tools, opt into experimental mode (v0.2).

Status

Pre-alpha. See /PIVOT.md for the project's current shape, and /CHANGELOG.md for the day-by-day milestone.

The Gate-1 target is 2026-06-30: this package wraps a Mastra agent, Studio renders the timeline, approval works, basic replay checkpoint works, 3 non-Wes developers have run it on a real agent.

License

Apache 2.0.