---
summary: "Operator runbook for Mantis Slack desktop QA: GitHub dispatch, local CLI, warm VNC leases, hydrate modes, timing interpretation, artifacts, and failure handling."
read_when:
  - Running Mantis Slack desktop QA from GitHub or locally
  - Debugging slow Mantis Slack desktop runs
  - Choosing source, prehydrated, or warm-lease mode
  - Posting screenshot and video evidence to a PR
title: "Mantis Slack desktop runbook"
---

Mantis Slack desktop QA is the real-UI lane for Slack-class bugs that need a
Linux desktop, VNC rescue, Slack Web, a real Mnemo gateway, screenshots,
videos, and a PR evidence comment.

Use it when unit tests or the headless Slack live lane cannot prove the bug.

## Storage model

Mantis uses three different storage layers:

- Provider image: owned by Crabbox and stored in the cloud provider account.
  It contains machine capabilities such as Chrome/Chromium, ffmpeg, scrot,
  Node/corepack/pnpm, native build tools, and empty cache directories.
- Warm lease state: owned by the current operator session. It can contain a
  logged-in browser profile, `/var/cache/crabbox/pnpm`, and a prepared source
  checkout while the lease is alive.
- Mantis artifacts: owned by the Mnemo run. They live under
  `.artifacts/qa-e2e/mantis/...`, then GitHub Actions uploads them and the
  Mantis GitHub App comments inline evidence on the PR.

Never put secrets, browser cookies, Slack login state, repository checkouts,
`node_modules`, or `dist/` into a prebaked provider image.

## GitHub dispatch

Run the workflow from `main`:

```bash
gh workflow run mantis-slack-desktop-smoke.yml \
  --ref main \
  -f candidate_ref=<trusted-ref-or-sha> \
  -f pr_number=<pr-number> \
  -f scenario_id=slack-canary \
  -f crabbox_provider=aws \
  -f keep_vm=false \
  -f hydrate_mode=source
```

Allowed `candidate_ref` values are intentionally narrow because the workflow
uses live credentials: current `main` ancestry, release tags, or an open PR head
from `mnemo/mnemo`.

The workflow writes:

- uploaded artifact: `mantis-slack-desktop-smoke-<run-id>-<attempt>`;
- inline PR comment from the Mantis GitHub App;
- `slack-desktop-smoke.png`;
- `slack-desktop-smoke.mp4`;
- `slack-desktop-smoke-preview.gif`;
- `slack-desktop-smoke-change.mp4`;
- `mantis-slack-desktop-smoke-summary.json`;
- `mantis-slack-desktop-smoke-report.md`;
- remote logs such as `slack-desktop-command.log`, `mnemo-gateway.log`,
  `chrome.log`, and `ffmpeg.log`.

The PR comment is updated in place by the hidden
`<!-- mantis-slack-desktop-smoke -->` marker.

## Local CLI

Cold source proof:

```bash
pnpm mnemo qa mantis slack-desktop-smoke \
  --provider aws \
  --class standard \
  --gateway-setup \
  --credential-source convex \
  --credential-role maintainer \
  --provider-mode live-frontier \
  --model openai/gpt-5.4 \
  --alt-model openai/gpt-5.4 \
  --scenario slack-canary \
  --hydrate-mode source
```

Keep the VM for VNC rescue:

```bash
pnpm mnemo qa mantis slack-desktop-smoke \
  --provider aws \
  --class standard \
  --gateway-setup \
  --scenario slack-canary \
  --keep-lease
```

Open VNC:

```bash
crabbox vnc --provider aws --id <cbx_id> --open
```

Reuse a warm lease:

```bash
pnpm mnemo qa mantis slack-desktop-smoke \
  --provider aws \
  --lease-id <cbx_id-or-slug> \
  --gateway-setup \
  --scenario slack-canary \
  --hydrate-mode source
```

Use `--hydrate-mode prehydrated` only when the reused remote workspace already
has `node_modules` and a built `dist/`. Mantis fails closed if those are
missing.

Prove native Slack approval UI:

```bash
pnpm mnemo qa mantis slack-desktop-smoke \
  --provider aws \
  --class standard \
  --approval-checkpoints \
  --credential-source convex \
  --credential-role maintainer \
  --hydrate-mode source
```

Approval checkpoint mode is mutually exclusive with `--gateway-setup`. It runs
the opt-in `slack-approval-exec-native` and `slack-approval-plugin-native`
scenarios unless you pass explicit approval checkpoint `--scenario` flags; other
Slack scenarios are rejected before the VM starts. The Slack QA runner writes
each checkpoint JSON file from the real Slack API message it observed, then the
remote watcher renders that message snapshot into
`approval-checkpoints/<scenario>-pending.png` and
`approval-checkpoints/<scenario>-resolved.png`. The run fails if any checkpoint
JSON, message evidence, ack JSON, or rendered screenshot is missing or empty.

Cold GitHub Actions leases do not have Slack Web cookies, so their browser
capture can land on Slack sign-in. For approval checkpoint proof, trust the
rendered checkpoint images and Slack QA artifacts rather than
`slack-desktop-smoke.png`. Use a kept warm lease with a manually logged-in Slack
Web profile only when the browser screenshot itself must show Slack Web.

## Hydrate modes

| Mode          | Use when                                  | Remote behavior                                                                       | Tradeoff                                                 |
| ------------- | ----------------------------------------- | ------------------------------------------------------------------------------------- | -------------------------------------------------------- |
| `source`      | Normal PR proof, cold machines, CI        | Runs `pnpm install --frozen-lockfile --prefer-offline` and `pnpm build` inside the VM | Slowest, strongest source-checkout proof                 |
| `prehydrated` | You intentionally prepared a reused lease | Requires existing `node_modules` and `dist/`; skips install/build                     | Fast, but only valid for operator-controlled warm leases |

GitHub Actions always prepares the candidate checkout before the VM run. Its
pnpm store is cached by OS, Node version, and lockfile. The VM source run also
uses `/var/cache/crabbox/pnpm` when present.

## Timing interpretation

`mantis-slack-desktop-smoke-report.md` includes phase timings:

- `crabbox.warmup`: cloud provider boot, desktop/browser readiness, and SSH.
- `crabbox.inspect`: lease metadata lookup.
- `credentials.prepare`: Convex credential lease acquisition.
- `crabbox.remote_run`: sync, browser launch, Mnemo install/build or
  hydrate validation, gateway startup, screenshot, and video capture.
- `artifacts.copy`: rsync back from the VM.

`crabbox.remote_run` can be marked `accepted` when Crabbox returns a non-zero
remote status after Mantis has copied metadata proving that either the Mnemo
gateway setup completed or the Slack QA command itself exited successfully.
Treat `accepted` as pass-with-explanation, not a failed scenario.

If the run is slow:

- warmup dominates: prebake or promote a better Crabbox provider image;
- remote_run dominates in `source`: use a warm lease, improve pnpm store reuse,
  or move machine prerequisites into the provider image;
- remote_run dominates in `prehydrated`: the remote workspace was not actually
  ready, or the gateway/browser/Slack setup is slow;
- artifact copy dominates: inspect video size and artifact directory contents.

## Evidence checklist

A good PR comment should show:

- scenario id and candidate SHA;
- GitHub Actions run URL;
- artifact URL;
- inline approval checkpoint screenshot, or a Slack Web screenshot from a
  logged-in warm lease;
- inline animated preview when available;
- full MP4 and trimmed MP4 links;
- pass/fail status;
- timing summary in the attached report.

Do not commit screenshots or videos into the repository. Keep them in GitHub
Actions artifacts or the PR comment.

## Failure handling

If the workflow fails before the VM run, inspect the Actions job first. Typical
causes are untrusted `candidate_ref`, missing environment secrets, or candidate
install/build failure.

If the VM run fails but screenshots were copied back, inspect:

```bash
cat mantis-slack-desktop-smoke-report.md
cat mantis-slack-desktop-smoke-summary.json
cat slack-desktop-command.log
cat mnemo-gateway.log
cat chrome.log
cat ffmpeg.log
```

If the run kept the lease, open VNC with the report's `crabbox vnc ...` command.
Stop the lease when done:

```bash
crabbox stop --provider aws <cbx_id-or-slug>
```

If Slack login expired, repair it in VNC on a kept lease and rerun with
`--lease-id`. Do not bake that browser profile into a provider image.

## Related

- [QA overview](/concepts/qa-e2e-automation)
- [Slack channel](/channels/slack)
- [Testing](/help/testing)
