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+# Landlord override frontend — in-flight design notes
+
+**Status:** Paused mid-grilling (2026-05-27)
+**Branch:** `feautre/additional_walltypes`
+**Author:** Jun-te (with Claude, via `/grill-me`)
+
+This is a *design-in-progress* document, not an ADR. It captures decisions made
+so far on the landlord-override frontend plan so the conversation can resume
+without re-litigating settled questions. Promote to an ADR once the trigger
+mechanism (Q4) is resolved — that's the decision worth permanent recording.
+
+## Goal
+
+Build the front-end e2e for `landlord_description_override`, starting from the
+`bulk_upload` flow. Backend lives at `/workspaces/home/github/Model`.
+
+## Backstory
+
+- Four landlord override tables exist in Drizzle
+  ([src/app/db/schema/landlord_overrides.ts](../../src/app/db/schema/landlord_overrides.ts)):
+  `landlord_property_type_overrides`, `landlord_built_form_type_overrides`,
+  `landlord_wall_type_overrides`, `landlord_roof_type_overrides`. Schema
+  rationale in [ADR-0002](../adr/0002-landlord-override-vocabulary.md).
+- Nothing in Next.js reads or writes them yet.
+- The Python lambda at
+  `/workspaces/home/github/Model/applications/landlord_description_overrides/handler.py`
+  is **not deployed** and **not wired** into the BulkUpload pipeline. It
+  hardcodes its trigger params (`portfolio_id`, `s3_uri`) and its source column
+  names (`"Property Type"`, `"Walls"`, `"Roofs"`).
+- Note: ADR-0002 says writes come from Next.js POST, but the current backend
+  writes direct to Postgres. This drift may need to be revisited under Q4.
+
+## Decided so far
+
+### Q1 — Scope
+
+**Trigger + Review/Edit, with classifier non-blocking for address matching.**
+Restated by user as: extend the column-mapping UI with optional
+landlord-description slots → persist the mapping on the upload → pass mapping
+to the lambda → lambda needs edits to work when deployed.
+
+### Q2 — Categories
+
+**All four classifier categories** get independent optional slots in
+[`INTERNAL_FIELDS`](../../src/app/portfolio/[slug]/(portfolio)/bulk-upload/[uploadId]/map-columns/MapColumnsClient.tsx#L14-L21):
+`property_type`, `built_form_type`, `wall_type`, `roof_type`.
+
+Rejected alternatives: (a) start with only PT+BF — wasted plumbing churn for
+the same migration cost; (c) collapse PT+BF into one UI slot — bakes a
+backend coincidence (they read the same CSV column today) into the
+user-facing model.
+
+### Q2.1 — No `autoDetect` for the new slots
+
+The four new slots default to `"skip"`. The user must explicitly map them.
+`autoDetect()` regex patterns are for required address-ish fields only.
+
+**Why:** Address headers are unambiguous and required, so guessing is safe and
+useful. Landlord-description columns are ambiguous (a "type" column could be
+PropertyType or BuiltFormType or something else) and they are optional —
+auto-detecting them would silently opt the landlord into classifier runs they
+didn't intend.
+
+## Open — resume here
+
+### Q3 (in flight) — Uniqueness validation on the mapping
+
+Today validation only checks required fields exist
+([MapColumnsClient.tsx:67-68](../../src/app/portfolio/[slug]/(portfolio)/bulk-upload/[uploadId]/map-columns/MapColumnsClient.tsx#L67-L68));
+two CSV headers can both map to `address_1` silently.
+
+- (a) Leave it alone — backend last-wins.
+- (b) Enforce uniqueness only on the four new slots.
+- (c) Enforce uniqueness everywhere except `skip`. **Recommended.**
+
+### Q4 (queued — biggest) — Trigger mechanism
+
+How does Next.js invoke the lambda once mapping is complete? SQS message?
+Direct lambda invoke? HTTP endpoint? And what's the state-machine integration —
+new `BulkUpload` status, or runs orthogonally to address matching?
+
+This drives both the deployment work and the lambda edits. Likely worth its
+own ADR once decided.
+
+### Q5 (queued) — Persistence of the extended mapping
+
+Current `bulkAddressUploads.columnMapping` is a `Record<string, string>` and
+naturally accommodates the new slots. Confirm no separate table is needed.
+
+### Q6 (queued) — Lambda edits
+
+Handler hardcodes `source_column="Property Type" / "Walls" / "Roofs"`; needs
+to read the mapping from the trigger body.
+`LandlordDescriptionOverridesTriggerBody` already exists — check what fields
+it has vs needs.
+
+### Q7 (queued) — Review/Edit UI for classified mappings
+
+Is the per-row review/edit surface in scope for this iteration, or deferred?
+User has not addressed yet. ADR-0002 calls this "the future override
+frontend" and treats it as deferred work — but "front end e2e from
+bulk_upload" could reasonably include it.
+
+## Resuming
+
+Re-read this file, then ask Q3. Don't re-litigate Q1/Q2 unless the user
+reopens them.