| name | verify-with-prototype |
| description | Prototype-before-production workflow for risky host integrations (sudo, privileges, system config). Use when a feature touches the real OS, when behavior must be proven with a small script before full implementation, or when the user mentions prototype verification, POC script, or verify-with-prototype. Run after investigate/followup and before doctest-TDD integration. |
You guide the agent through prototype verification before full implementation
and integration. The goal is to learn failure modes cheaply (false positives,
session caches, TTY requirements) in a throwaway script, then encode lessons in
a real package with fakes-based tests.
When to use
- Host or privilege integration:
sudo, /etc/sudoers.d, TUN, networksetup, etc.
- Persistent state vs session cache can be confused (
sudo -n, timestamp cache)
- Production mistakes are hard to undo or dangerous to test in CI
- User wants "setup once, then never password again" or similar UX proofs
When not to use
- Pure documentation or config-only changes
- Behavior already covered by isolated unit tests with no OS side effects
- User only wants root-cause explanation → use
investigate instead
Required workflow
Phase 0 — Understand (often already done)
- Symptom, expected behavior, and constraints from
investigate / followup
- Identify the stand-in for the expensive dependency (e.g.
hello.sh instead of sing-box)
Phase 1 — POC script
Create script/<feature>-poc/ (Go preferred) with small command surface:
| Command | Purpose |
|---|
detect | Report persistent state vs cache vs "works right now" separately |
auto-setup | One-time install path (may prompt on TTY) |
remove-* | Tear down + invalidate session cache if relevant |
Document a manual test matrix in the script header:
remove → auto-setup (password once) → auto-setup (no password) → remove → auto-setup (password again)
POC rules
- Do not infer persistent install from
sudo -n alone — use drop-in file + local manifest (or equivalent)
- On remove, flush sudo timestamp cache (
sudo -k) when testing "prompt again" behavior
- Distinguish stdin vs stdout TTY when password is required
Phase 2 — Manual verification
User (or agent with user) runs the matrix in a real terminal. Capture lessons:
- False positives (e.g. warm cache after
remove-sudo)
- Missing non-TTY guard
- Wrong detection signal
Fix the POC until the matrix passes. Do not proceed to production until manual proof succeeds.
Phase 3 — Requirement doc
Write REQUIREMENT-DESIGN-<slug>.md with:
- Data model (
Config, Rule, manifest paths, sudoers drop-in name)
- Approved scope (package only vs integration)
- Test tree outline (doctests with injectable
FS + Runner, no real /etc or sudo)
Get explicit user approval before TDD implementation.
Phase 4 — Extract package + TDD
- Extract core logic to
pkgs/<name>/ with injectable FS and Runner
- Doctest tree with fakes only — no real system modification in CI
- Thin CLIs: POC script + production caller(s) share the package
- Guards:
- Under
go test, panic if FS/Runner nil (production deps would touch the OS)
- Before interactive
sudo, error if stdin is not a TTY (already-installed path may skip)
Phase 5 — Integration
- Wire production entrypoints (flags like
--no-setup-sudo for opt-out of auto-setup)
- Hook layer in existing packages for test injection
- Bump /
replace module deps as needed
Response shape
- Risk summary — what can go wrong on the real system
- POC plan — commands, stand-in, manual matrix
- Detection model — persistent vs cache vs live probe (table)
- After manual proof — package API sketch + test groups
- Stop — do not implement production code until POC matrix passes and user approves REQUIREMENT-DESIGN
Case study (this repo)
VPN passwordless sudo (master-2026-07-06-vpn-no-password work):
- POC:
script/sudo-nopasswd-poc (detect, auto-setup, remove-sudo)
- Lesson:
sudo -n after remove-sudo succeeded via timestamp cache, not NOPASSWD
- Fix: manifest +
/etc/sudoers.d stat for IsInstalled; sudo -k on remove
- Package:
pkgs/sudosetup with fake FS/Runner doctests
- Integration:
ws-proxy vpn auto-setup + --no-setup-sudo
- Guards: test-time production-deps panic; stdin-TTY check before first setup
Related commands
agent-pro skill investigate show
agent-pro skill followup show
agent-pro skill verify-with-prototype show
Install locally:
agent-pro skill verify-with-prototype install
