
vercel-plugin-eval
โ 209by vercel-labs ยท part of vercel-labs/vercel-plugin
Run live eval sessions against the vercel-plugin to verify hook behavior, skill injection, dedup correctness, and coverage. Launches real Claude Code sessions via WezTerm, monitors debug logs, and produces a structured coverage report.
This is the playbook your agent receives when the skill activates โ you don't need to read it to use the skill, but it's here to audit before installing.
Plugin Eval
Launch real Claude Code sessions with the plugin installed, monitor debug logs in real-time, and verify every hook fires correctly with proper dedup.
DO NOT (Hard Rules)
- DO NOT use
claude --printor-pโ hooks don't fire, no files created - DO NOT use
--dangerously-skip-permissions - DO NOT create projects in
/tmp/โ always use~/dev/vercel-plugin-testing/ - DO NOT manually wire hooks or create
settings.local.jsonโ usenpx add-plugin - DO NOT set
CLAUDE_PLUGIN_ROOTmanually - DO NOT use
bash -cin WezTerm โ use/bin/zsh -ic - DO NOT use full path to claude โ use the
xalias - DO NOT write eval scripts โ do everything as Bash tool calls in the conversation
Copy the exact commands below. Do not improvise.
What to Monitor
Hook firing (all 8 registered hooks)
LOG=~/.claude/debug/<session-id>.txt
# SessionStart (3 hooks)
grep "SessionStart.*success" "$LOG"
# PreToolUse skill injection
grep -c "executePreToolHooks" "$LOG" # total calls
grep -c "provided additionalContext" "$LOG" # injections
# UserPromptSubmit
grep "UserPromptSubmit.*success" "$LOG"
# PostToolUse validate + shadcn font-fix
grep "posttooluse-validate.*provided" "$LOG"
grep "PostToolUse:Bash.*success" "$LOG"
# SessionEnd cleanup
grep "SessionEnd" "$LOG"Dedup correctness (the key metric)
TMPDIR=$(node -e "import {tmpdir} from 'os'; console.log(tmpdir())" --input-type=module)
CLAIMDIR="$TMPDIR/vercel-plugin-<session-id>-seen-skills.d"
# Claim files = one per skill, atomic O_EXCL
ls "$CLAIMDIR"
# Compare: injections should equal claims
inject_meta=$(grep -c "skillInjection:" "$LOG")
claims=$(ls "$CLAIMDIR" 2>/dev/null | wc -l | tr -d ' ')
echo "Injections: $((inject_meta / 3)) | Claims: $claims"skillInjection: appears 3x per actual injection in the debug log (initial check, parsed, success). Divide by 3.
PostToolUse validate quality
Look for real catches โ API key bypass, outdated models, wrong patterns:
grep "VALIDATION" "$LOG" | head -10Scenario Design
Describe products and features, never name specific technologies. Let the plugin infer which skills to inject. Always end prompts with: "Link the project to my vercel-labs team so we can deploy it later. Skip any planning and just build it. Get the dev server running."
Coverage targets by scenario type
| Scenario Type | Skills Exercised |
|---|---|
| AI chat app | ai-sdk, ai-gateway, nextjs, ai-elements |
| Durable workflow | workflow, ai-sdk, vercel-queues |
| Monorepo | turborepo, turbopack, nextjs |
| Edge auth + routing | routing-middleware, auth, sign-in-with-vercel |
| Chat bot (multi-platform) | chat-sdk, ai-sdk, vercel-storage |
| Feature flags + CRM | vercel-flags, vercel-queues, ai-sdk |
| Email pipeline | email, satori, ai-sdk, vercel-storage |
| Marketplace/payments | payments, marketplace, cms |
| Kitchen sink | micro, ncc, all niche skills |
Hard-to-trigger skills (8 of 44)
These need explicit technology references in the prompt because agents don't naturally reach for them:
ai-elementsโ say "use the AI Elements component registry"v0-devโ say "generate components with v0"vercel-firewallโ say "use Vercel Firewall for rate limiting"marketplaceโ say "publish to the Vercel Marketplace"geistโ say "install the geist font package"json-renderโ name filescomponents/chat-*.tsx
Coverage Report
Write results to .notes/COVERAGE.md with:
- Session index โ slug, session ID, unique skills, dedup status
- Hook coverage matrix โ which hooks fired in which sessions
- Skill injection table โ which of the 44 skills triggered
- Dedup stats โ injections vs claims per session
- Issues found โ bugs, pattern gaps, validation findings
Cleanup
rm -rf ~/dev/vercel-plugin-testingnpx skills add https://github.com/vercel-labs/vercel-plugin --skill vercel-plugin-evalRun this in your project โ your agent picks the skill up automatically.
Quick Start
Always append a timestamp to directory names so reruns don't overwrite old projects:
# 1. Create test dir & install plugin (with timestamp)
TS=$(date +%Y%m%d-%H%M)
SLUG="my-eval-$TS"
mkdir -p ~/dev/vercel-plugin-testing/$SLUG
cd ~/dev/vercel-plugin-testing/$SLUG
npx add-plugin https://github.com/vercel/vercel-plugin -s project -y
# 2. Launch session via WezTerm
wezterm cli spawn --cwd /Users/johnlindquist/dev/vercel-plugin-testing/$SLUG -- /bin/zsh -ic \
"unset CLAUDECODE; VERCEL_PLUGIN_LOG_LEVEL=debug x '<PROMPT>' --settings .claude/settings.json; exec zsh"
# 3. Find debug log (wait ~25s for session start)
find ~/.claude/debug -name "*.txt" -mmin -2 -exec grep -l "$SLUG" {} +No common issues documented yet. If you hit a problem, the repository's GitHub Issues page is the best place to look.