diff --git a/docs/ROADMAP.md b/docs/ROADMAP.md
index 4682d38..c683cf2 100644
--- a/docs/ROADMAP.md
+++ b/docs/ROADMAP.md
@@ -32,7 +32,7 @@ Each app is independently containerized (its own Dockerfile + port). `shared/*`
 | # | Name | Goal | Status |
 |---|------|------|--------|
 | **M1** | Foundation + `trip-cluster` | Stand up the monorepo, shared packages (`shared/ai` deferred to M3), SQLite store, Immich ingest, and the `trip-cluster` app end-to-end. Validate on a **hard, GPS-poor sample against a quantified acceptance bar** (not the easy last trip) before widening. **This is the POC that proves the foundation.** | **Shipped** — implemented, reviewed, merged to `main` (2026-06-27); 66 tests green. Validation-gate run on a hard sample still pending. |
-| **M1.5** | Visual similarity | Trip-level CLIP clustering over Immich's pgvector embeddings (whose readability M1's spike verifies) — the rescue signal for the GPS-poor old library where timestamp/GPS signals are weakest. | Not started (dependency spike in M1) |
+| **M1.5** | Visual similarity | Trip-level CLIP clustering over Immich's pgvector embeddings (readability/shape verified by the pgvector spike — see findings) — the rescue signal for the GPS-poor old library where timestamp/GPS signals are weakest. | Not started; dependency spike **done** (2026-06-27, embeddings readable + joinable — see findings spec) |
 | **M2** | `tag-verify` | Verify/normalize existing tags, dedupe the tag vocabulary, find outliers — on the proven foundation. | Not started |
 | **M3** | `enrich` | Geocode existing location tags ("Kiev" → coordinates) and backfill GPS into Immich to improve future trip detection; AI captioning; content tags; noise detection. | Not started |
 | **M4** | Migrate `image-rater` | Move the existing app onto the shared packages (+ optional SQLite). Largely mechanical (delete local copies, import shared). | Not started |
@@ -58,9 +58,11 @@ These apply across all milestones (decided during the 2026-06-27 brainstorm):
 
 ## Enablement notes (things to set up to unlock later milestones)
 
-- **Visual similarity (M1.5; dependency verified in M1):** Immich's REST API doesn't cleanly expose CLIP embeddings. Viable path = **read-only access to Immich's Postgres pgvector** embeddings. **M1 runs a read-only feasibility spike** (confirm embeddings are readable; pin table/column shape + DB access against the live version); the trip-level clustering itself is **M1.5**. User can provide DB access and is re-running CLIP with a stronger model — both pure upside, especially for the GPS-poor old library.
+- **Visual similarity (M1.5; dependency verified by the pgvector spike, 2026-06-27):** Immich's REST API doesn't cleanly expose CLIP embeddings. Viable path = **read-only access to Immich's Postgres pgvector** embeddings. A read-only feasibility spike (`scripts/pgvector_spike.py`, tracked separately from M1 — *not* run inside M1) **confirmed** embeddings are readable and pinned the shape against the live DB: `smart_search.embedding`, 1152-dim, cosine `<=>`, `assetId → asset.id` join clean. See the findings spec for the version-pinned contract. The trip-level clustering itself is **M1.5**. User provides DB access (`IMMICH_DB_URL`) and is re-running CLIP with a stronger model — both pure upside, especially for the GPS-poor old library.
 - **GPS facts:** Immich's reverse-geocoding only *labels* coordinates a photo already has; it does **not** invent GPS, and Immich cannot infer GPS from image content. For GPS-less old photos, coordinates come from manual map placement or the **M3 `enrich`** step (geocode location tags → write back as GPS). Reverse-geocoding + metadata-extraction jobs can be run anytime to strengthen location anchors for the GPS-having subset.
 
 ## Related specs
 
 - M1: `docs/superpowers/specs/2026-06-27-immich-photo-flow-design.md`
+- M1.5 pgvector spike — design: `docs/superpowers/specs/2026-06-27-pgvector-embedding-spike-design.md`
+- M1.5 pgvector spike — findings (M1.5's contract): `docs/superpowers/specs/2026-06-27-pgvector-embedding-findings.md`