Interactive JSON Form — decision/survey pages with a client-side JSON round-trip

Self-Evolving Skill: This skill improves through use. If instructions are wrong, parameters drifted, or a workaround was needed — fix this file immediately, don't defer. Only update for real, reproducible issues.

A single self-contained .html file that presents extensive explanations, lets a small known audience (e.g. a CEO + data scientists) pick options, rank them, and comment, then hands their input back as a downloadable / copyable / re-importable JSON — with no server, no submit endpoint, and no tracking. Published privately on your own host behind a noindex header + an unguessable path, so it is reachable by whoever has the linkTelus-direct door) but blocked from crawlers/indexing.

When to use this skill

You need a few named humans to make structured choices + free-form comments on a set of options, and you want their answers back as machine-readable JSON you ingest directly.
Mobile-friendly, re-openable (import a prior JSON to resume), zero tooling for the responder, and no backend to stand up.
The audience is small and known → a downloadable JSON they send you beats a hosted collector; a public form would over-expose.

When NOT to use it

Anonymous mass surveys / thousands of respondents (use a real survey backend).
You need server-side aggregation in real time (add a collector, or use Lark Base — see ../../lark-automation for the Base decision-harness alternative).
Multi-page sitemap sites with no JS → use the sibling page-template skill.

Why this over Lark Base / Forms / cards (decided by research 2026-07-13)

Lark Base grids truncate long text (row-height/width are NOT API-settable), Forms are read-only after submit with no create API, and cards are one-shot with a 30-day window + a callback webhook. A self-contained HTML page has none of those limits: full text wraps natively, edits are unlimited, and the JSON round-trip is pure client-side. The cost is that responses come back as files, not a live table — acceptable for a small known audience.

The pattern (what makes it work)

Data-driven options. An OPTIONS array at the top of the inline <script> is the single source of truth; the DOM is generated from it. To reskin for a new decision, edit that array only.
collect() → JSON. Reads every control (respondent, per-option vote/rank/ comment, overall) into a versioned object {schema, respondent, role, firstPick, overallComment, choices:[{id,title,vote,rank,comment}]}.
Three return paths, all client-side:
- Download: Blob + URL.createObjectURL + a[download] → a .json file.
- Copy: navigator.clipboard.writeText (with execCommand fallback).
- Import: <input type=file> → FileReader → hydrate() repopulates the form. Import→export is byte-identical (resumable editing) — assert this.
schema version string on every payload so the ingester can evolve.
beforeunload guard warns on unsaved edits.
Self-contained: inline <style> + <script>, no external requests, no fonts/CDN, <meta name="robots" content="noindex, nofollow, noarchive, nosnippet">, <meta name="referrer" content="no-referrer">.

Start from templates/index.html in this skill — it is the working page (built for the ODB × time-bar decision) with the mechanism intact; swap the OPTIONS array + the two intro .note blocks and you have a new page.

Verify before you ship (headless, local)

Render + exercise the JS with Playwright against file:// (no login needed): fill the form via page.evaluate (the radios are visually hidden labels — set .checked + dispatch change rather than page.check), call collect(), then reload a fresh page, hydrate() the JSON, collect() again, and assert the two JSON strings are identical. Screenshot fullPage:false and eyeball it. See the local-shot.mjs pattern.

Publish privately on your own host (no web-server config change, no restart)

The pattern, not a particular server: point a hostname at a static docroot behind a web server that already emits header X-Robots-Tag "noindex, nofollow, noarchive, nosnippet" globally. A static file dropped into a subdirectory is then served instantly with noindex over the existing TLS chain — no config edit, no reload, so co-hosted services on the same door are untouched.

Substitute your own values for $SITE_HOST (the public hostname), $SSH_HOST (its ssh alias), $DOCROOT (the server's static root) and $WEB_USER (the account the web server runs as).

# 1. upload the built page
scp -q your-page.html "$SSH_HOST:/tmp/page.html"
# 2. drop it at an UNGUESSABLE path (docroot is usually server-owned → sudo)
ssh "$SSH_HOST" 'set -e
  P="<slug>-$(openssl rand -hex 16)"                          # unguessable path segment
  D="'"$DOCROOT"'/$P"
  sudo mkdir -p "$D"; sudo cp /tmp/page.html "$D/index.html"
  sudo chown -R '"$WEB_USER:$WEB_USER"' "$D"; rm -f /tmp/page.html
  echo "URL: https://'"$SITE_HOST"'/$P/"'
# 3. TRUE external reachability. An on-LAN 200 does NOT prove the WAN chain when
#    split-DNS short-circuits the hostname to a LAN address — verify from a host
#    that is genuinely outside your network.
ssh <some-external-host> 'curl -sS -o /dev/null -w "EXTERNAL %{http_code} TLS=%{ssl_verify_result}\n" https://'"$SITE_HOST"'/<PATH>/'

Crawler-blocking layers (this skill's default): (a) global X-Robots-Tag noindex header (already on the door), (b) page <meta robots noindex>, (c) an unguessable path with no inbound links. A 4th layer — User-Agent blocking — needs a Caddy @bots matcher in the edge-route registry (edge-routes.toml + generate-edge-config.py); it is a production config change, so treat it as optional hardening, not default.

If your edge config is generated from a registry rather than hand-edited, change the registry and regenerate — that is the durable path, and it keeps the door reproducible.

Ingesting responses

The JSON is exactly collect()'s output. Consume it directly; key on schema for versioning and respondent/role to attribute. Merge multiple respondents' files by choices[].id.

Hard rules

One file, no external network requests, no tracking, noindex in <meta>.
Never a real submit/collector endpoint unless the user explicitly opts in (it turns a private artifact into a hosted service + a data-handling duty).
Never publish to the door by hand-editing the live web-server config — drop a static file into the docroot (config-free) or change the registry + regen.
Always verify the import→export round-trip is byte-identical before shipping.

Post-Execution Reflection

After this skill completes, reflect before closing the task:

Locate yourself. — Find this SKILL.md's canonical path before editing.
What failed? — Fix the instruction. If the deploy recipe drifted (docroot, header, sudo), fix it here AND cross-check edge-routes.toml.
What worked better than expected? — If a new control type (multi-select, drag-rank) recurs, fold it into templates/index.html.
What drifted? — Keep the JSON schema, the deploy commands, and the crawler-block layers aligned with reality.
Log it. — Evolution-log entry with trigger, fix, evidence.

Do NOT defer. The next invocation inherits whatever you leave behind.

interactive-json-form