VE

verifier-gui

Automates runtime verification of the Silo desktop app inside safe, throwaway workspaces.

Install

mkdir -p .claude/skills/verifier-gui && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/19013" && unzip -o skill.zip -d .claude/skills/verifier-gui && rm skill.zip

Installs to .claude/skills/verifier-gui

Activation

This is the description your AI agent reads to decide when to run this skill — the better it matches your request, the more reliably it fires.

Launch (or attach to) the Silo dev app and drive it for runtime verification through the dev automation RPC bridge — exec commands, eval DOM, capture screenshots, and create/activate/delete workspaces, terminals, editors. This is the repo's GUI evidence-capture handle for the `verify` skill. Use when verifying a change by running the real app and observing it. Always works inside a throwaway sandbox workspace, never the user's real workspaces.
447 chars✓ has a “when” triggerlonger than Claude Code's old 250-char listing cap (fine on current versions)
Advanced

Key capabilities

  • Launch or attach to the Silo dev app
  • Execute commands via RPC bridge
  • Evaluate DOM elements
  • Capture screenshots of the app
  • Create, activate, and delete sandbox workspaces

How it works

The skill launches or attaches to the Silo dev app and drives it using an RPC bridge to execute commands, evaluate the DOM, and capture screenshots, all within a temporary sandbox workspace.

Inputs & outputs

You give it
Commands or DOM expressions to execute within the Silo app
You get back
Screenshot images, command execution results, or DOM evaluation results

When to use verifier-gui

  • Verify UI behavior at runtime
  • Capture screenshots for documentation
  • Test desktop app workflows

About this skill

Silo GUI Verifier

The handle the verify skill looks for: how to get the running Silo app under control and capture evidence from it. Silo is a Tauri desktop app; its surface is pixels + a dev-only RPC bridge. This skill drives that bridge.

It does not judge. It launches, drives, captures. The verdict is verify's.

Golden rule 1: verify in a sandbox workspace, never the user's

The app may be the user's live session with real workspaces and terminals. Do all verification in a workspace you create from a temp dir, and delete it when done. Never openTerminal/deleteWorkspace/openFile against an existing workspace — you'd pollute or destroy real state. Create → activate → verify → delete. This also makes destructive paths (workspace delete, session kill) safe to exercise.

Golden rule 2: one turn, not one op per turn

The wall-clock cost here is agent turns, not the RPC bridge — each bridge call is ~milliseconds on localhost, but every separate Bash tool call is a full model round-trip (seconds). So issue a whole drive + capture sequence as a single Bash call. The silo() helper is just curl; bash variables (WS_ID, WS_DIR) persist within one invocation, so create → activate → drive → screenshot → decode all belong in one block (see §2). A 6-step flow then costs 2 turns, not 7.

Only split into a separate turn when you genuinely must:

  • The final Read /tmp/silo.pngRead is its own tool, so capture-in-one-turn then read-in-the-next is the floor (2 turns).
  • Branching on an observed result — if the next op depends on what you saw (a count, a tab list, a pass/fail), end the block, read the output, then decide. A fixed setup sequence has no such dependency — never split it.

Echo any state you'll need next turn (e.g. echo "WS_ID=$WS_ID") — bash vars die at the end of the Bash call.

1. Get the app up (attach or launch)

The bridge listens on 127.0.0.1:7878 (dev builds only — app:dev is built --features automation). Define the request helper first — the contract is strict: header X-Silo-Automation: 1 and a loopback Host, POST /, body {"op", "args"}.

silo(){ curl -s -m30 -X POST http://127.0.0.1:7878/ \
  -H 'X-Silo-Automation: 1' -H 'Content-Type: application/json' \
  --data "$1"; }

Attach if it's already running, else launch:

if [ "$(silo '{"op":"ping"}')" = '{"ok":true,"result":"pong"}' ]; then
  echo "attached to running dev app"
else
  pnpm dev >/tmp/silo-appdev.log 2>&1 &           # first run compiles Rust — slow
  for i in $(seq 1 120); do                       # poll up to ~4 min
    sleep 2
    [ "$(silo '{"op":"ping"}' 2>/dev/null)" = '{"ok":true,"result":"pong"}' ] && break
  done
fi

app:dev runs under the isolated "Silo Dev" identity (separate app data), so launching never touches the user's real Silo install — but if you attached to an already-running instance, the sandbox rule above still applies.

If you attached (ping succeeded on the first try), verify it's actually serving your code before doing anything else. A pong only proves some dev app is listening on 7878 — it can just as easily be a stale instance from a different checkout, a different branch, or a session someone else started hours ago, with none of the changes you're here to verify. Confirm the process identity, not just liveness:

ps aux | grep "target/debug/silo\b" | grep -v grep
# expect the binary path to start with YOUR working directory, e.g.:
#   /path/to/your/repo/apps/desktop/src-tauri/target/debug/silo
# a path pointing anywhere else means you're about to verify the wrong code —
# stop and either ask the user to close it or launch your own (a port conflict
# will make that obvious rather than silently reusing the wrong instance)

This check is cheap (one ps) against the cost of it going wrong: driving and debugging against the wrong checkout produces confident-looking PASS/FAIL results for code you didn't touch, and any oddity you hit sends you chasing a phantom bug in your own change instead of noticing the mismatch.

2. Drive & capture — one block, one turn

Per golden rule 2, do the whole sandbox setup, drive steps, and screenshot in a single Bash call. Bash variables persist within the invocation, so the workspace id flows from one op to the next with no agent round-trip. End the block with the screenshot + decode; the only follow-up turn is Read /tmp/silo.png.

# ── ONE Bash call = ONE turn ──────────────────────────────────────────────
WS_DIR=$(mktemp -d /tmp/silo-verify.XXXXXX)
WS_ID=$(silo "{\"op\":\"openWorkspace\",\"args\":{\"folder\":\"$WS_DIR\",\"name\":\"verify-sandbox\"}}" \
  | python3 -c 'import json,sys; print(json.load(sys.stdin)["result"]["id"])')
silo "{\"op\":\"activateWorkspace\",\"args\":{\"id\":\"$WS_ID\"}}"

# ── drive steps (add as many as the check needs) ──
silo '{"op":"exec","args":{"command":"core.newTerminal"}}'
# silo "{\"op\":\"openFile\",\"args\":{\"path\":\"$WS_DIR/README.md\"}}"
# silo '{"op":"eval","args":{"expr":"document.querySelectorAll(\".xterm\").length"}}'

# ── capture as the LAST step in the same block ──
silo '{"op":"screenshot"}' > /tmp/shot.json
python3 -c "import json,base64;d=json.load(open('/tmp/shot.json'));r=d['result'];open('/tmp/silo.png','wb').write(base64.b64decode(r['png_base64']));print('shot',r['width'],r['height'])"

echo "WS_ID=$WS_ID"   # surface state needed for next-turn cleanup

Next turn: Read /tmp/silo.png. The capture can be slow (a few seconds), especially the first call — keep the timeout ≥30s and retry once if it returns empty. No OS permission setup is required.

A single-folder workspace also means core.newTerminal won't pop the folder picker (which automation can't click) — it resolves the lone folder directly.

Reading evidence without a screenshot — for structure/counts, an inline eval in the same block is cheaper than a picture: document.querySelectorAll('.xterm').length (terminal count), [...document.querySelectorAll('.dv-tab')].map(t=>t.textContent) (open tabs), document.body.innerText.includes('Session ended') (spawn failure). WebGL caveat: terminals render to a canvas (WebGL addon) — .xterm has no DOM text, so to read what a shell printed you need a screenshot, not textContent.

Op catalog

exec runs a registered command (the real ctx path); eval runs JS in the webview global scope (note: app modules like store are not in scope — use the dedicated ops for state). The full, authoritative list is the switch (op) in apps/desktop/src/automation/bridge.tsread it when in doubt; this table mirrors it. eval is the escape hatch, but for Monaco state prefer the dedicated editor ops below — monaco is not a page global, so eval can't reach it.

Core / liveness

OpArgsReturns / use
pingpong — liveness
execcommandrun a command id (menu/keybinding dispatch) → {ran}
evalexprevaluate JS in the page; awaits a returned promise
screenshothost-side window capture → {png_base64,width,height}

Workspaces / panels (sandbox only — never point at real workspaces)

OpArgsReturns / use
listWorkspaces{active, workspaces[{id,name,folder}]}
openWorkspacefolder,namecreate + activate (use a temp dir) → {id}
activateWorkspaceidswitch active → {active}
addFolderid,folderattach a folder, bypassing the native OS picker ("Add Folder…" in Workspace Properties) → {extraFolders}
deleteWorkspaceidreap terminals + remove → {deleted,active}
splitActivePanelposition? (l/r/top/bottom)split center group → {groups}
activatePanelpanelIdfocus a dock panel → {activated}
showSidePanelidexpand slot + activate its tab → {shown,slot}

Editors / terminals

OpArgsReturns / use
openFilepathopen an editor tab → {editorId,panelId}
openDiffpath,providerId,args?,title?,preview?open a diff tab via a content provider → {diffId,panelId}
listEditorsworkspaceId?{previewEditorId, editors[{id,filePath,title,isPreview,mode,providerId}]}
openTerminalcwd?ctx.terminals.create{terminalId,panelId}
`listTerminals

Content truncated.

When not to use it

  • When verifying a change that does not involve running the real app
  • When the verification does not require observing the app's GUI
  • When the app is not a Tauri desktop app with a dev-only RPC bridge

Limitations

  • Requires the Silo app to be a dev build with `--features automation`.
  • Verification must occur in a sandbox workspace, not the user's real workspaces.
  • RPC `eval` operations have a hard 5-second reply timeout.

How it compares

This skill provides a programmatic and sandboxed way to interact with and verify the Silo GUI, ensuring state safety and repeatable testing, unlike manual interaction or non-GUI-based verification.

Compared to similar skills

verifier-gui side by side with the closest alternatives in the catalog.

SkillInstallsUpdatedSafetyDifficulty
verifier-gui (this skill)015dReviewAdvanced
wp-testing-core68moReviewIntermediate
bats-testing-patterns22moReviewIntermediate
orchardcore-tester15moReviewIntermediate

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