GuestKit

io.github.zyvoraiPublished by GitHub account zyvoraiv1.2.9Updated Nov 1, 2026

Read-only evidence and boot-readiness tools for one VM disk image, offline.

VerifiedSTDIODesktop onlyCloud & InfrastructureFiles & StorageDeveloper Tools

Overview

AI-generated overview

GuestKit's MCP server exposes six read-only evidence tools that let an assistant inspect one offline VM disk image and judge whether it will boot.

What you can do
  • Inspect a single VM disk image while the guest is off, across qcow2, VMDK, VHDX, VHD, VDI and raw formats
  • Report OS identity and inventory counts from the disk
  • Score first-boot readiness from 0 to 100 with the blockers explained
  • Produce migration plans and cutover evidence for targets such as kvm, proxmox, qemu, kubevirt, aws, azure, gcp and hyperv
  • Stay read-only: repairs and other changes are not applied through these tools
When to use it
Useful when planning a hypervisor migration or cutover and you want an assistant to check a disk image's boot readiness and blockers before powering it on, or to gather evidence for a migration plan without booting the guest.
Requirements
Runs as a local stdio process started with the guestkit mcp-serve command against one image path, or from the published OCI image. The host needs Linux with qemu-img, losetup and qemu-nbd; opening a disk needs loop or NBD access, and the container must run as root with privileged access or SYS_ADMIN plus devices. No API keys or environment variables are declared.
Before you install
The tools are read-only, but the container needs root and privileged access to open disks, which is a broad grant on the host. Mount and repair paths may also require root. The bundled web stack is described as evaluation-only and unauthenticated, and some features are partial, such as in-process QCOW2 reads and shrink.

Installation

In SourceWeft

  1. Open GuestKit in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

GuestKit

[CI] [crates.io] [PyPI] [License: Apache 2.0] [Rust] [GHCR] [Docs]

[Book a demo] [30-day PoC] [Quickstart]

[GuestKit - Know it will boot. Before you power it on.]

Know it will boot. Before you power it on.

Offline VM intelligence and migration assurance. GuestKit reads a VM disk while the guest is off, scores first-boot readiness 0–100, repairs it through a plan you can read, and certifies cutover with a signed Passport.

6 disk formats · 0–100 boot score · 0 appliance daemons · 8 migration targets · Apache-2.0

Gallery · Docs · Product · Wiki · 30-day Enterprise trial

What's new

ReleaseWhat changed
Agent (1.2.6)Per-container eBPF network policy and BPF-LSM controls in the guest agent (guestkit.netpolicy / guestkit.lsm), off by default, audit first, enforce only under a time-bound lease
1.2.5Offline inject on run_migrate_repair: hostname, network, users, services, first-boot scripts, cloud-init, AD rejoin, Windows KMS and RDP, appended to the repair plan
1.2.5Online snapshots freeze the filesystem through the privileged helper, so KubeVirt snapshots of PVC-backed VMs work with the unprivileged agent
1.2.5Linux agent connects to the virtio channel on stock distros (udev rule shipped in DEB, RPM and tarball); concurrent NBD mounts no longer race
1.2.2Web Image Vault reaches TUI parity: inventory tabs, Assurance (plan, passport, repair preview and gated apply), Profiles and Files
1.2.0guestkit-qemu assured QEMU/VirtIO runtime, guestkit vm, virtctl-guestkit guestfs, the cutover bundle and guestkit shrink for oversized disks

Full history: CHANGELOG.md.

Why GuestKit

Every hypervisor exit fails the same way: you discover the disk was broken at 2am, in the cutover window, after power-on. GuestKit reads the disk while the guest is off — qcow2, VMDK, VHDX, VHD, VDI or raw — through its own pure-Rust engine (NBD or loop mount). There is no appliance daemon and no "power it on and see".

When this happens…GuestKit gives you…
"Will it boot?" is answered at power-onAn offline doctor score (0–100) with a root-cause chain for each blocker
Each migration relies on scripts and tribal knowledgeStructured plans in JSON/YAML and a CI gate on the same score
Cutover weekend is full of surprisesHypervisor-aware migrate-plan and day-0 packs, for 8 targets
There is no audit trail of what was checkedA signed Cutover Passport per disk
Repairs are hand edits inside a mounted imageFix plans you can read, applied with backups and rollback
Migration order is guessed by handfleet wave-plan: dependency-aware waves

Fixes are never implicit. Repairs go through a plan you can read, applied with backups and rollback, and the same score drives the CI gate, the signed Cutover Passport, and assured QEMU launch.

Boot-readiness scoring
First-boot probability 0–100, the blockers explained, and a reviewable fix plan.
The cutover problem 		Offline repair
Repairs go through a plan you can read, applied with backups and rollback.
What you can do 		Migration assurance
The same score drives the CI gate, the signed Cutover Passport and assured QEMU launch.
Quick start
Engine and formats
A pure-Rust engine over qcow2, VMDK, VHDX, VHD, VDI and raw, through NBD or loop mount.
Platform layout 		Suite hand-offs
Export with Transiva, convert and deploy with h2kvm, assure with GuestKit, operate on Zorvia or Zeus OS.
Who does what 		CLI, TUI, web, CI
CLI, TUI, QEMU, Python, web console, in-guest agent and a GitHub Action.
Run the web stack

70+ commands · 6 disk formats · 0 appliance daemons · 8 migration targets · Apache-2.0

[Capabilities at a glance: Assure, Repair, Certify, Surfaces]

The full comparison has more rows, including fleet drift, the Carbon TUI with the in-guest agent, and guestkit qga as a drop-in for virsh qemu-agent-command.

GuestKit vs libguestfs + virt-v2v

[GuestKit vs libguestfs + virt-v2v: not just convert it, prove it will boot]

GuestKitlibguestfs + virt-v2v
Disk accessRust engine; guest files reached through qemu-nbd or loop mounts on the hostLaunches a small appliance VM to read and edit the disk
Boot readinessdoctor: a 0–100 first-boot score per target, with blockers explainedInspection and conversion; no readiness score
Migration planmigrate-plan per target (kvm, proxmox, qemu, kubevirt, aws, azure, gcp, hyperv)virt-v2v converts a guest to run on KVM
RepairFix plans with backups and rollback; rescue for SSH, GRUB and passwordsvirt-customize, virt-rescue and guestfish for scripted edits
Cutover evidenceSigned Cutover Passport and a GitHub Action that fails below a scoreNot part of the toolkit
InterfacesCLI, TUI, Python, web console, in-guest agent, GitHub ActionCLI tools and language bindings
Choose libguestfs whenYou need its broad filesystem and OS coverage, or virt-v2v's end-to-end conversion, and have no need for a score or a cutover record

GuestKit sits next to conversion tools rather than replacing all of them: h2kvm converts and deploys, and calls GuestKit for the offline fixes.

See it live

[GuestKit web console — Assurance panel showing a boot score of 78 with ranked findings]

Assurance: doctor score 78, a REVIEW decision, and ranked findings with a fix command each.

[GuestKit web console — Summary with OS identity and inventory counts]

Summary: OS identity and inventory counts from inspect.

[GuestKit web console — Image Vault landing page]

Image Vault: import a disk, or try the offline demo.

The bundled OSS web console rendering its offline demo data, not a live deployment. Demo videos are in the gallery.

How it fits together

[Read the disk offline; decide before power-on]

text
  disk.qcow2 / .vmdk / .vhdx / .vhd / .vdi / .raw                    │                    ▼         ┌──────────────────────┐         │  Pure-Rust engine    │──►  doctor 0–100 + blockers         │  NBD / loop mount    │──►  migrate-plan YAML         └──────────────────────┘──►  Passport · repair · CI gate                    │                 guestkit-qemu (assured launch)      CLI · TUI · QEMU · Python · Web · Agent · GitHub Action

Export with Transiva (Apache-2.0) → convert & deploy with h2kvm (Zyvor Production License) → assure with GuestKit (Apache-2.0) → operate on Zorvia or Zeus OS. Run and manage VMs with FluxVM. Who does what · h2kvm integration

Architecture in depth: docs/architecture/overview.md.

Quickstart

bash
# v1.2.6 GitHub Release — crates.io `guestkit` is still 0.3.2curl -fsSL -O https://github.com/zyvorai/zyvor-guestkit/releases/download/v1.2.6/guestkit-1.2.6-linux-amd64.tar.gz
guestkit doctor vm.qcow2 --target proxmox --explainguestkit migrate-plan vm.vmdk --target kvm --export plan.yamlguestkit passport emit vm.qcow2 --target kvm -o passport.jsonguestctl tui vm.qcow2           # Assurance · preview · exportguestkit-qemu plan vm.qcow2 --json   # assurance → QEMU definition

CI gate — same score, no CLI install step:

yaml
- uses: zyvorai/guestkit@v1  with:    disk: vm.qcow2    target: kvm    fail-below: '80'

Targets: kvm · proxmox · qemu · kubevirt · aws · azure · gcp · hyperv. Host needs: Linux with qemu-img, losetup, and qemu-nbd (mount/repair may need root).

Python (v1.1.0+), on PyPI: pip install zyvor-guestkit, then guestkit.run_doctor("vm.qcow2", target="kvm", explain=True). The full quick start, shrink and Python examples: docs/quick-start.md.

MCP server — guestkit mcp-serve <image> [--target kvm] is a stdio MCP server exposing six read-only evidence tools for one disk image. Build with cargo build --release --features mcp. Registry name io.github.zyvorai/guestkit; OCI image ghcr.io/zyvorai/guestkit-mcp. Opening a disk needs loop/NBD, so the container must run as root with --privileged (or SYS_ADMIN plus devices) despite its nonroot default user. See docs/guides/MCP.md and DOCKER.md.

Documentation

GoalDocument
Docs sitezyvorai.github.io/zyvor-guestkit
Docs homedocs/README.md · INDEX
DevOps runbooksdocs/devops
Feature guideguestkit-user-feature-guide.md
h2kvm integrationh2kvm integration
QEMU / VirtIO runtimeqemu-runtime.md
Dump virsh → GuestKitvirsh-to-guestkit.md
Architectureoverview

The complete map, with the changelog and roadmap, is in docs/documentation-map.md.

Go deeper

Open source, Enterprise

Open source — free under Apache-2.0. This repo · personal, lab, and commercial production. Full offline doctor, migrate-plan, repair, fleet, policy · CLI · TUI · Python · self-hosted web/workers.

Enterprise — buy for programs. Same engine — not a locked doctor. Command Center · Portfolio · Assurance · Migration Factory · Passport Authority · OIDC / RBAC / audit · SLA · air-gap · hypervisor exit workshops.

Open source vs Enterprise · Full feature matrix · 30-day Enterprise trial · Pricing

Trial expired or want a guided evaluation? Book a demo or start a 30-day PoC — no email needed. [email protected] remains as a fallback.

Maturity

GuestKit is at v1.2.6 (GitHub Release; PyPI zyvor-guestkit; crates.io guestkit is still 0.3.2). The architecture overview states the engine's scope plainly:

AreaStatus
Pure-Rust parsing: partition tables, filesystem signatures, evidence schema, boot engine, assurance APIsShipped
Web UI (deploy/ui: inventory, Assurance, Profiles, Files), GHCR zyvor-uiShipped
In-process QCOW2 readPartial: format detection and selective reads; full cluster walk defers to qemu-nbd
File access inside guestsThrough loop devices / qemu-nbd and a host mount, not in-process ext4/NTFS parsers
guestkit shrinkNarrow by design: a single/last ext2/3/4 partition, MBR or GPT, no LVM/LUKS; other layouts are reported and left untouched
GHCR web stack (deploy/docker-compose.ghcr.yml)Eval only: unauthenticated, do not expose beyond localhost
Guest-agent eBPF policy and LSMOpt-in: gated by capabilities.ebpf, off by default

Part of the Zyvor stack

ProductRole next to GuestKit
GuestKitOffline VM assurance: boot score, repair, Cutover Passport
TransivaExports VMs out of the source hypervisor, upstream of GuestKit
h2kvmConverts and deploys to KVM; uses the GuestKit Python package for offline fixes
ZorviaKubeVirt VM platform to operate the migrated VMs
FluxVMRuns and manages VMs; production run, network and TTL sit there, not in guestkit vm

→ zyvor.dev

Support

Free under Apache-2.0. If it helps you, you can donate any amount you like: https://payments.cashfree.com/forms/zyvor-donate. A donation is voluntary and supports development and maintenance. It is not a purchase: it buys no support, SLA, features, priority or license, and it is not tax-deductible (Zyvor AI Labs Private Limited is a company, not a charity). Zyvor Enterprise (supported releases, SLAs, a named contact and enterprise features) is separate: [email protected].

License

GuestKit is free and open source under the Apache License, Version 2.0. You may use, modify, and run it for personal, lab, and commercial production use at no charge, subject to Apache-2.0 (preserve notices / NOTICE where required). See NOTICE and docs/legal/ where applicable. That does not change.

Zyvor Enterprise adds what production teams ask for: supported releases, deployment and upgrade guidance, priority incident triage, a named technical contact and 24x7 critical intake. Production support, SLAs, and Zyvor Enterprise products are licensed separately. Plans and terms: docs/SUBSCRIPTION-MODEL.md · Pricing · [email protected].

Report vulnerabilities privately per SECURITY.md. More at zyvor.dev/guestkit · docs · blog.

Know every disk will boot before cutover weekend

[Book a demo] [30-day PoC] [Pricing] [Contact sales] [Star on GitHub]

Source: README.md at commit bf4c4e9

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

2
  1. v1.2.9LatestOct 18, 2026
  2. v1.2.8Oct 18, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts