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justinandClaude Opus 5 5a75876f9f docs: tagged checkpoints do work on cloud-protected VPGs

The repo said, in four places, that a tagged checkpoint cannot be inserted
when the protected site is Azure or AWS. That came from the 9.0 API
reference. It is wrong on 10.9.10.

Measured against the lab: both an AWS-protected and an Azure-protected VPG
accepted the insert, the Zerto task reached Completed, and the checkpoint
appeared in the journal. This is the second doc claim this repo carried
that live 10.9 contradicts, after the VPG status enum.

What actually differs is latency and granularity, and both are set by the
PROTECTED site, not the recovery site:

  protected at   journal gap   tag visible after
  vSphere        5s            ~4s
  Azure          60s           ~34s
  AWS            630s          ~128s

There is a sharper consequence than slowness. The tagged checkpoint is
stamped about 30s AFTER the insert request, so on a cloud-protected VPG an
agent that mutates promptly puts its change inside the checkpoint that was
supposed to precede it. Recovering from that tag would restore the broken
state. The docs now say to use the newest checkpoint that already existed
when the guard ran.

Two of the four were message text, not prose. wait_for_tag's timeout
message asserted the insert was unsupported when the real cause was its own
45s budget being far too short for a VPG that checkpoints every 630s, so it
told operators the wrong thing at exactly the wrong moment. It now says to
check the Zerto task before concluding the insert failed.

The 45s timeout itself is still wrong for cloud sources and needs to become
cadence-aware. That is a behaviour change, so it is not in this commit.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_016yVfC5nvZowoLFnEGWhLGn

2026-09-22 18:04:47 -04:00

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zerto-ai-rewind

PoC MCP that makes an agent pin a Zerto tagged checkpoint before it changes a VM, then pull a file back from that tag.

If the loop works, these tools are the delta to add to official ZVM MCP (ZVM.MCP, 10.9). This repo is one MCP process for the demo. It is not a second full ZVM catalog.

What it does

zerto_check_tool — before running anything against a VM: read_only (go), mutating (guard first), or unknown (ask the human whether to checkpoint).
zerto_find_protection — VM name, hostname, or vmIdentifier to exactly one VM and every VPG. Zero or two-plus VMs: stop.
zerto_create_tagged_checkpoint / zerto_guard_before_mutate — same tag on every protecting VPG, wait until listed. The name records which agent and what it is doing: ai:<agent> | <action> | vm=<vm> | change=<id> | <utc>.
zerto_recover_file — FLR after a human sets confirmed=true. Linux and Windows guest paths. Locally replicated VPGs only: FLR runs at the VPG's recovery site. Reports its own unmount; zerto_list_flr_sessions / zerto_end_flr_session find and reap a mount orphaned by a crashed recovery.
Two catalogs — mutating_tools (guard first) and read_only_tools (safe). Both cover Linux (ssh, ansible) and Windows (winrm, powershell, smb), and both are illustrative, not exhaustive. A tool in neither is unknown, not safe: ask the human.

Official ZVM MCP already has inventory and failover test. It does not insert tagged checkpoints or run FLR.

Setup

Python 3.12+.

python3 -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"
cp config.example.json config.json
# edit zerto_url, username, password

Keycloak password-grant, client_id zerto-client on 10.x. Appliance certs are self-signed; verify_tls defaults to false.

stdio MCP (Claude Desktop, VS Code, Cursor, OpenCode):

{
  "mcpServers": {
    "zerto-rewind": {
      "command": "zerto-rewind-mcp",
      "env": {
        "ZERTO_REWIND_CONFIG": "/absolute/path/to/config.json"
      }
    }
  }
}

Copy skills/zerto-rewind/SKILL.md into the client's skill path.

pytest

Demo

Protected app VM. Agent is about to edit a guest config file.

Guard: discover VPG set, insert tagged checkpoint, wait.
Agent writes the bad config.
Human confirms.
zerto_recover_file from that tag.

Git never had the file. RPO is the journal, not last night's backup.

Certified for this PoC

vSphere ZVM 10.x and ZCA on AWS/Azure, same REST paths. HVM is out (separate swagger). Failover Live is not a tool.

Tagged checkpoints do work when the protected site is Azure or AWS. The 9.0 API reference says they cannot be inserted; that is wrong on 10.9.10, where both were accepted and the task reached Completed.

What differs is latency and granularity, both set by the protected site:

protected at	journal gap	tag visible after
vSphere	5s	~4s
Azure	60s	~34s
AWS	630s	~128s

The tagged checkpoint is also stamped about 30s after the insert request, so on a cloud-protected VPG a prompt mutation can land inside the checkpoint meant to precede it. Recover from the newest checkpoint that already existed when the guard ran, not from the tag.

Not this product

Moholo Agent Rewind snapshots the agent's laptop tools. This server uses the Zerto journal as the snapshot store. Do not copy their file blobs.

Upstream

Ask Zerto engineering to add to ZVM.MCP: find-by-unique-VM-with-all-VPGs, tagged checkpoint insert that waits, FLR. Keep VPG settings CRUD where it already is.

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