| name | living-ui-modify |
| description | Modify an existing Living UI application (PocketBase + React kit) — add features, change design, fix bugs — then re-validate and relaunch it. |
| action-sets | ["file_operations","code_execution","living_ui"] |
Living UI Modify
You are changing an EXISTING app. Everything in the living-ui-creator skill
applies (ownership rule, schema/verbs/UI order, kit usage, honesty rule) —
this skill covers only what differs.
Step 0: Locate and understand
- Find the project: read
agent_file_system/workspace/living_ui_projects.json
or use the project id/path given in your instruction.
- Read the project's
LIVING_UI.md (current plan/entities/ops) and
reference/requirements.md. Read manifest.json for authMode and port.
- If something broke, read the logs FIRST:
{project_path}/logs/frontend_console.log and
{project_path}/logs/pocketbase.log.
- If the request is ambiguous, ask 1 batch of clarifying questions
(a FINAL
send_message (continue_work=false — the reply wakes the session)).
- Record the request in the spec BEFORE editing code: append a dated
entry to
reference/requirements.md under a ## Changes section (create
the section if absent):
- 2026-08-05: <the user's request, stated as a checkable capability>.
NEVER rewrite the existing sections — they are the delivered contract;
## Changes is append-only. The verifier checks every entry there, so an
unrecorded change is an unverified change (and a recorded one can never
be silently dropped by a later modify).
SUPERSESSION — the one permitted edit to old entries: when the new
request REVERSES or REPLACES an earlier ## Changes entry (the user
changed their mind, or the old entry demanded an approach the platform
now rejects), wrap the stale entry in ~~strikethrough~~ — do not delete
it (it stays as history) and do not leave it live (the verifier enforces
every unstruck line, and contradictory live entries make the spec
unsatisfiable: an app once went STUCK three times because old entries
demanded a handler the validation gate forbids while the new entry
forbade it — no code could satisfy both). Strike ONLY entries the new
request genuinely contradicts, never entries you merely failed to build.
Rules for changing a live app
- Ownership is unchanged: edit only
frontend/src/app/, pb/pb_migrations/
(NEW files only — never edit, rename, or delete an applied migration: the
filename is its identity in the live DB, and a renamed one makes the app
unable to boot), pb/pb_hooks/ops.pb.js (+ new *.pb.js / *.js helper
modules), operations.json (non-system), triggers.json, LIVING_UI.md.
Adding/changing an agent trigger (app fires the agent): declare it in
triggers.json first — see the creator skill's references/TRIGGERS.md;
the gate re-derives capabilities.triggers on relaunch, and fires of
undeclared names are refused in-app.
- Schema changes are additive migrations. The user's data lives in
pb/pb_data/ — never delete it, never drop-and-recreate collections that
hold data. To alter a collection, write a new migration that loads and
updates it (app.findCollectionByNameOrId(...) → modify → app.save(...)).
- Relation fields need the target collection's ID —
app.findCollectionByNameOrId('<name>').id, never the name.
- Record the delta in
LIVING_UI.md (what changed, new entities/ops).
Finish
living_ui_notify_ready(project_id="<PROJECT_ID>") # gate + boot DEV env
living_ui_walk_verify(project_id="<PROJECT_ID>") # verify dev + PROMOTE
These run in the dev environment: notify_ready gates and boots a
disposable copy of your new CODE on a hidden port with a FRESH, EMPTY
database — migrations replay at boot, so only data your migrations seed
exists. The user's live app keeps running the previous version, untouched,
and its data is NEVER cloned into dev. Test freely against the dev URL it
returns (create whatever test records you need — they are thrown away).
walk_verify drives the dev instance in a real (headless) browser; a clean
verdict is what PROMOTES your change to the live app (new migrations apply
to the real data at its boot) and announces it.
- The dev DB starts empty every time. If a feature needs data to be
visible, either seed it in a migration (survives promote) or create test
records through the app/API after
notify_ready (dev-only, disposable).
- Never run
lui validate or lui dev against the real project dir —
the build overwrites the served frontend in place and blanks the user's
live UI. notify_ready gates the dev copy for you.
- Never write test data to the live app (its DB is the user's real
data; agent test writes outside the dev env are refused). Do all testing
after
notify_ready, against the dev URL. GET /api/_a2app answers
env: "dev" or env: "live" if you need to confirm which instance a
port is.
HONESTY RULE: the change is live only when living_ui_walk_verify returns
status: success — never tell the user a change is live when the relaunch,
verification or deploy failed. On failure the user's app still runs the
previous working version.