fix(recommendation): Songs-like gets its own profile so it stops wandering

Operator, 2026-09-10: "when I play it I'm expecting to get a consistent
sound and style from the experience... I was getting a seeming wide variety
of music from each one when I was hoping to stay in a certain neighborhood."

Songs-like shared the `daily_mix` weight profile with For-You, and that
sharing WAS the bug. The two surfaces want opposite things: For-You answers
"what will they enjoy today" and is supposed to roam; Songs-like answers
"what sounds like THIS". Under one profile the broad answer wins.

The arithmetic, from the shared weights:

    unrelated track, liked, not played recently → 1.0 + 2.0 + 1.0 = 4.0
    PERFECT similarity match, not liked         → 1.0 + 1.5       = 2.5

Liking something outranked sounding like the seed, because LikeBoost (2.0)
exceeded SimilarityWeight's whole range (1.5) and TasteWeight (1.5, and
seed-INDEPENDENT) matched it outright. Under the new profile the same pair
scores 5.00 vs 2.00.

Two levers, because either alone leaves the other's failure intact:

POOL. Songs-like now takes its own CandidateSourceLimits. The default gave
~29% of candidates a sim_score of literally zero — `taste_overlap` and
`random_fill` are both `0.0::float8` in recommendation.sql, seed-independent
by construction. Same total pool size; composition shifts to arms that
measure distance from the seed, LBSimilar doubled.

WEIGHTS. A third profile beside radio and daily_mix, DB-backed and live per
rule 25, with the property that similarity's range exceeds the combined
range of every seed-independent differentiator — so a closer match cannot
be beaten on likes, freshness and taste alone, while tracks within ~0.39
similarity of each other still get ordered by what the user likes.

Rule 131 changed the pool design mid-way and for the better. Zeroing the
two seed-independent arms was the first instinct and is exactly the
vanish-or-nothing shape that rule forbids: a seed with thin ListenBrainz
coverage would yield a short mix or none. They are the tier-3 FLOOR — cut
hard, never removed — and the weights keep them at the bottom of the
ranking rather than out of the pool. "A few tracks further from the seed
than we'd like" beats "no playlist".

Caught while wiring it: switching only pickTopN's final Score would have
been nearly INERT. scoreAndSortCandidates does the selection sort, and the
caller caps and truncates in that order — so the playlist would still have
been chosen by daily_mix and merely relabelled with songs_like numbers. It
now takes the profile as a parameter, and each surface passes its own.

Also corrects the daily_mix card's blurb, which claimed Songs-like as one
of its surfaces and no longer is.

Guards pin behaviour rather than the numbers, since numbers get retuned:
that similarity beats an unrelated liked track, that daily_mix still
DOESN'T (or the split buys nothing), that the tier-3 floor is non-zero,
and that the UI card shows its own values rather than falling back. Each
falsified against its named regression first.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SQ31KQpYbStyK5y58UmPLH

.dockerignore

@@ -6,9 +6,20 @@
 **/build
 web/build
 
-# Flutter mobile client — built separately on developer machines / Flutter CI.
-# Including it in the Go build context wastes ~70 files and invalidates the
-# `COPY . .` layer cache on every Flutter-only change.
+# The Android client — built by its own job, never from this context. The APK
+# reaches the image through client/, downloaded as a CI artifact, so nothing
+# here reads android/ sources.
+#
+# This block named `flutter_client/` until 2026-09-10 and lost its PATTERN when
+# that tree was deleted, leaving a comment describing an exclusion that was no
+# longer happening. android/ never took its place, so 4.1 MB of Gradle project
+# has been entering the context and busting the `COPY . .` layer on every
+# Android-only change.
+android/
+
+# Local `make build` output — an 18 MB binary the image never uses, since the
+# builder stage compiles its own.
+bin/
 
 # Docs and IDE noise
 docs/
@@ -26,5 +37,8 @@ docs/
 !.env.example
 
 # CI workflow files don't need to ship in the image.
-.forgejo/
-.github/
+#
+# This said `.forgejo/` and `.github/` — neither of which this repo has. Gitea
+# Actions reads `.gitea/`, so the one directory that actually exists was the
+# one not excluded, and every workflow edit invalidated the context.
+.gitea/

.gitea/workflows/android.yml

@@ -80,15 +80,12 @@ jobs:
 
       - name: Upload debug APK
         if: github.event_name == 'push' && github.ref == 'refs/heads/main'
-        # Mirrored action, never actions/upload-artifact. @v4+ throws
-        # GHESNotSupportedError client-side on the hostname (no server setting
-        # reaches that check), and @v3 is worse — it reports success while Gitea
-        # serves artifacts back only through the v4 API, so the upload is stored
-        # and invisible to every retrieval path. @v3 is what left 72 unreachable
-        # artifacts on this repo. Pinned by SHA because the mirror auto-syncs;
-        # full URL because DEFAULT_ACTIONS_URL sends bare owner/repo to github.com.
-        # See Scribe issues 2255 / 2270.
-        uses: https://git.fabledsword.com/bvandeusen/upload-artifact@cb8afe72b42edc798abfb8fcb556cf660d894245
+        # Stock action: it works on this forge since the runner moved to
+        # gitea/runner 3.x, which edits upload-artifact's client-side GHES refusal
+        # out of the action bundle (Scribe snippet #2271). Never @v3 — it reports
+        # success while Gitea serves artifacts back only through the v4 API, and
+        # it is what left 72 unreachable artifacts on this repo (Scribe 2270).
+        uses: actions/upload-artifact@v7
         with:
           name: minstrel-android-debug-${{ github.sha }}
           path: android/app/build/outputs/apk/debug/app-debug.apk

.gitea/workflows/release.yml

@@ -3,10 +3,30 @@ name: release
 # Builds and pushes the minstrel container image to the Gitea registry.
 #
 #   push to dev                  → :dev            (freshly-built dev APK bundled)
-#   push to main                 → :main and :latest (latest-release APK bundled)
-#   push tag vYYYY.MM.DD.HHMM    → :vYYYY.MM.DD.HHMM and :latest (fresh APK bundled)
+#   push to main                 → :latest + :<sha> (latest-release APK bundled)
+#   push tag vYYYY.MM.DD.HHMM    → :latest          (fresh APK bundled)
 #   workflow_dispatch            → manual trigger (same rules based on the ref)
 #
+# That is the whole tag map, and it is family rule 145 + 147 as written.
+#
+# :<sha> on main is the ROLLBACK UNIT — every production commit addressable
+# without a release ceremony. It is minted only on main, where rollback is
+# actually worth having: merges are gated (rule 2) so they number in the dozens
+# per year, while on dev they would be one per push, forever, for a channel
+# whose entire contract is that it moves.
+#
+# There are NO :<version> image tags. This repo published :vYYYY.MM.DD.HHMM
+# until 2026-09-10 and it was the inverse of the rule on both counts — minting
+# a version tag nobody pinned while the rollback unit the rule names did not
+# exist here at all. Git and the build's own self-reported version answer
+# "which build is this"; a third name for the same thing is upkeep for a model
+# we do not run. Operator, 2026-09-10: "only things like the APK need that kind
+# of versioning for their update process."
+#
+# There is no :main either. :latest tracks main's tip with no gate between them
+# (rule 147), so a second name for the same image sends readers looking for a
+# distinction that does not exist.
+#
 # The dev channel exists so testing a build does not require shipping one.
 # Before it, the only way to get an APK onto a phone was to cut a release,
 # which made `main` the staging area by default. `:dev` carries its own
@@ -212,13 +232,12 @@ jobs:
             -PMINSTREL_VERSION_CODE=${{ steps.ver.outputs.code }}
 
       - name: Upload APK as workflow artifact
-        # Mirrored action, never actions/upload-artifact — @v4+ refuses on the
-        # hostname, @v3 uploads something Gitea will never serve back. This is
-        # the producing half of a pair: image-release downloads `minstrel-apk`
-        # below with the matching download-artifact mirror. Both must stay on
-        # the v4 protocol — mixing a v3 upload with a v4 download (or the
-        # reverse) yields an empty listing, not an error. See Scribe 2255 / 2270.
-        uses: https://git.fabledsword.com/bvandeusen/upload-artifact@cb8afe72b42edc798abfb8fcb556cf660d894245
+        # Stock action (snippet #2271) — never @v3, which uploads something Gitea
+        # will never serve back. This is the producing half of a pair:
+        # image-release downloads `minstrel-apk` below. Any upload v4+ pairs with
+        # any download v4+ on this forge (every combination tested 2026-09-10,
+        # Scribe spike #3843), so the two pins need not move together.
+        uses: actions/upload-artifact@v7
         with:
           name: minstrel-apk
           path: android/app/build/outputs/apk/release/app-release.apk
@@ -312,11 +331,16 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
         with:
-          # Shallow is fine here. This job used to need full history + tags to
-          # re-derive the bundled APK's version from the tagged commit; it now
-          # downloads the sidecar the release recorded, and touches git for
-          # nothing. MINSTREL_VERSION comes from GITHUB_REF, not from git.
-          fetch-depth: 1
+          # Full history, and rule 149 names this specifically: any job that
+          # DERIVES the version name needs it, because a shallow clone changes
+          # what git-derived values resolve to WITHOUT failing — a too-low
+          # value, silently, with every lane green.
+          #
+          # This job was depth-1 while it took the version from GITHUB_REF. It
+          # now runs ci/version.sh itself, because with :<version> image tags
+          # gone the server's self-reported version is the only thing that says
+          # which build an image is.
+          fetch-depth: 0
 
       - name: Detect buildable project
         id: guard
@@ -334,30 +358,68 @@ jobs:
         if: steps.guard.outputs.ready == 'true'
         shell: bash
         run: |
+          set -euo pipefail
+
+          # THE VERSION, and it is derived the same way on every ref — the
+          # branch decides the CHANNEL, never the version (family rule 149).
+          #
+          # This used to be three different things: the literal string "main"
+          # on main, "dev" on dev, and the tag name on a tag. None of them
+          # ordered, and the first two were the same string forever — two dev
+          # images eight weeks apart were indistinguishable in the UI. That
+          # mattered little while :vYYYY.MM.DD.HHMM existed to identify a
+          # build; with version image tags gone, this IS how an operator tells
+          # which build a container is running.
+          #
+          # `sed -n s///p` rather than `grep`: it exits 0 when nothing matches,
+          # so the empty check below is actually reachable. A grep here would
+          # kill the step at the assignment under the runner's pipefail — the
+          # exact bug that took down the first main build after the version
+          # rework.
+          VERSION="$(ci/version.sh HEAD | sed -n 's/^name=//p')"
+          if [ -z "${VERSION}" ]; then
+            echo "::error::could not derive a build version from ci/version.sh"
+            exit 1
+          fi
+
           if [[ "${GITHUB_REF}" == refs/tags/v* ]]; then
-            VERSION="${GITHUB_REF#refs/tags/}"
-            echo "args=-t ${IMAGE}:${VERSION} -t ${IMAGE}:latest" >> "$GITHUB_OUTPUT"
-            echo "version=${VERSION}" >> "$GITHUB_OUTPUT"
-            echo "::notice::Release build: ${VERSION} + latest"
+            # A release refreshes the CHANNEL and mints nothing else.
+            #
+            # The tag build exists to produce the signed APK and attach it to
+            # the release; the image it rebuilds is the SAME SOURCE as the main
+            # build minutes earlier, differing only in which APK is baked in.
+            # Rule 145 is explicit about that case: when the same source is
+            # rebuilt with different contents, publish the moving channel tag
+            # and never a commit-addressable one.
+            #
+            # :latest must move here rather than waiting for the next main
+            # push, or the channel would carry the PREVIOUS release's APK
+            # indefinitely — a channel that cannot refresh itself (rule 146).
+            CHANNEL=stable
+            echo "args=-t ${IMAGE}:latest" >> "$GITHUB_OUTPUT"
+            echo "::notice::Release build ${VERSION}: refreshing :latest around the new APK"
           elif [[ "${GITHUB_REF}" == "refs/heads/dev" ]]; then
             # The rolling test channel, and :dev ALONE — deliberately no
             # per-commit tag. A rolling channel is rolling by definition, so a
             # commit-addressable image here would be a rollback target nobody
             # has ever pulled, accumulating in the registry forever. Recovery
             # on dev is to fix forward.
+            CHANNEL=dev
             echo "args=-t ${IMAGE}:dev" >> "$GITHUB_OUTPUT"
-            echo "version=dev" >> "$GITHUB_OUTPUT"
-            echo "::notice::Dev-branch build: :dev"
+            echo "::notice::Dev-branch build ${VERSION}: :dev"
           else
-            # Main is the protected, post-PR-merge branch. Treat it as the
-            # rolling stable channel — every main push moves :latest.
-            # Pinned consumers can target :vYYYY.MM.DD.HHMM, which never
-            # moves; everyone else gets the newest main.
-            echo "args=-t ${IMAGE}:main -t ${IMAGE}:latest" >> "$GITHUB_OUTPUT"
-            echo "version=main" >> "$GITHUB_OUTPUT"
-            echo "::notice::Main-branch build: :main + :latest"
+            # The production line: :latest tracks main's tip (rule 147) and
+            # :<sha> is the rollback unit (rule 145). Full 40-char SHA, matching
+            # the family's other repos, so a rollback target is addressable
+            # straight from the commit anyone is reading.
+            CHANNEL=stable
+            echo "args=-t ${IMAGE}:latest -t ${IMAGE}:${GITHUB_SHA}" >> "$GITHUB_OUTPUT"
+            echo "::notice::Main-branch build ${VERSION}: :latest + :${GITHUB_SHA}"
           fi
 
+          echo "version=${VERSION}" >> "$GITHUB_OUTPUT"
+          echo "channel=${CHANNEL}" >> "$GITHUB_OUTPUT"
+
       - name: Registry login
         if: steps.guard.outputs.ready == 'true'
         shell: bash
@@ -372,20 +434,11 @@ jobs:
         if: >-
           steps.guard.outputs.ready == 'true' &&
           (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/dev')
-        # Consuming half of the pair — never actions/download-artifact. Same fork,
-        # same reason: upstream's client-side GHES check rejects this hostname
-        # before it connects. bvandeusen/download-artifact mirrors
-        # code.forgejo.org/forgejo/download-artifact.
-        #
-        # SHA below is that fork's `v6` tag. Match on @actions/artifact, NOT on
-        # the action's own version number — the two actions release on unrelated
-        # cadences, and download v5 would pair a ^2.3.2 client with this file's
-        # ^4.0.0 uploader. v6 is the tag whose bundled library major (^4.0.0) is
-        # the same one proven against this instance by the upload side.
-        # Deliberately NOT v7: it moves to node24 and upstream requires runner
-        # >= 2.327.1 for it, which act_runner does not claim to satisfy.
-        # Pinned, not tagged — the mirror auto-syncs every 8h.
-        uses: https://git.fabledsword.com/bvandeusen/download-artifact@8d4e9521a5f7e5f8b6351f341f719f9f45a92a3a
+        # Consuming half of the pair: stock download-artifact, which works here for
+        # the same reason as the upload (gitea/runner 3.x edits the GHES refusal
+        # out of the bundle; snippet #2271). v8 runs on node24, which every
+        # CI-runner image carries — the runner uses the image's own node.
+        uses: actions/download-artifact@v8
         with:
           name: minstrel-apk
           path: client/
@@ -478,6 +531,7 @@ jobs:
         run: |
           docker buildx build \
             --build-arg MINSTREL_VERSION="${{ steps.tags.outputs.version }}" \
+            --build-arg MINSTREL_CHANNEL="${{ steps.tags.outputs.channel }}" \
             --push ${{ steps.tags.outputs.args }} .
 
   # Verifies a tag release actually ended up complete, and names the specific
@@ -488,8 +542,8 @@ jobs:
   # `failure` with none executed and image-release showed `skipped`. The run was
   # red, but the *release page rendered fine*, and `main`'s own push build had
   # already moved `:latest`, so the code was deployable and nothing looked
-  # obviously wrong. The release was simply missing its APK and its immutable
-  # `:vYYYY.MM.DD` image, which is easy to skim past.
+  # obviously wrong. The release was simply missing its APK and its image,
+  # which is easy to skim past.
   #
   # This job cannot prevent that (the cause was a runner failing to launch, not
   # anything in this file). What it does is turn an incomplete release into an
@@ -540,18 +594,30 @@ jobs:
       # missing when v2026.08.07 had to be re-cut. `always()` on this job means
       # it runs even when image-release failed, so without this the guard would
       # cheerfully verify an incomplete release.
-      - name: Immutable image tag must exist
+      #
+      # This asserted `:${TAG}` — the :vYYYY.MM.DD.HHMM image — until
+      # 2026-09-10. Version image tags are no longer published (rule 145), so
+      # that assertion would now fail every release for a tag nothing mints.
+      # The rollback target it was really protecting is the :<sha> image, which
+      # main's own build published for this same commit before the tag was cut.
+      #
+      # Checking it here earns its keep twice over: it still catches an image
+      # push that silently did not happen, and it additionally proves the
+      # ORDERING — a tag cut on a commit whose main build never completed has
+      # no rollback target, and that is worth failing on rather than
+      # discovering during an incident.
+      - name: Rollback image must exist for the tagged commit
         shell: bash
         run: |
           set -euo pipefail
-          TAG="${GITHUB_REF#refs/tags/}"
           IMAGE="git.fabledsword.com/bvandeusen/minstrel"
 
           echo "${{ secrets.CI_TOKEN }}" \
             | docker login git.fabledsword.com -u "${{ github.actor }}" --password-stdin
 
-          if ! docker manifest inspect "${IMAGE}:${TAG}" > /dev/null 2>&1; then
-            echo "::error::image ${IMAGE}:${TAG} was never pushed — the release tag has no immutable image, so there is nothing to pin or roll back to. Re-run this workflow run."
+          if ! docker manifest inspect "${IMAGE}:${GITHUB_SHA}" > /dev/null 2>&1; then
+            echo "::error::image ${IMAGE}:${GITHUB_SHA} does not exist — this commit has no rollback target."
+            echo "::error::That image is published by the MAIN build of this commit, not by the tag build. If main's build never ran or failed, fix that first; a release whose commit cannot be rolled back to is the thing this check exists to refuse."
             exit 1
           fi
-          echo "::notice::image verified: ${IMAGE}:${TAG}"
+          echo "::notice::rollback target verified: ${IMAGE}:${GITHUB_SHA}"

.gitignore

@@ -12,6 +12,11 @@
 # Test binary, built with `go test -c`
 *.test
 
+# `make build` output. bin/minstrel was tracked until 2026-09-10 — an 18 MB
+# binary committed by accident, last refreshed by a commit about web test
+# mocks, and re-dirtied by every local build since.
+bin/
+
 # Bundled Android APK + version sidecar (#397). Populated by CI for
 # tag releases; never committed. README in client/ explains the flow.
 client/minstrel.apk

Dockerfile

@@ -15,12 +15,21 @@ COPY . .
 # Overwrite the committed placeholder with the freshly-built SPA assets.
 COPY --from=web /web/build ./web/build
 ENV CGO_ENABLED=0
-# Version stamping: release.yml passes the git tag via MINSTREL_VERSION
-# build-arg; local `docker build` falls back to "dev". Surfaced at
-# /healthz for operator-side image-version verification.
+# Version stamping. release.yml passes the DERIVED version name
+# (YYYY.MM.DD.HHMM) and the lane's channel; a local `docker build` falls back
+# to "dev"/"local". Both are surfaced at /healthz.
+#
+# These are two values on purpose (family rule 149): the same commit built on
+# dev and on main reports the same NAME and differs only in CHANNEL. Folding
+# the channel into the version string is what the rule forbids — the version
+# used to BE the channel word here ("main"/"dev"), which meant two dev images
+# eight weeks apart were indistinguishable.
 ARG MINSTREL_VERSION=dev
+ARG MINSTREL_CHANNEL=local
 RUN go build -trimpath \
-    -ldflags="-s -w -X 'git.fabledsword.com/bvandeusen/minstrel/internal/server.ServerVersion=${MINSTREL_VERSION}'" \
+    -ldflags="-s -w \
+      -X 'git.fabledsword.com/bvandeusen/minstrel/internal/server.ServerVersion=${MINSTREL_VERSION}' \
+      -X 'git.fabledsword.com/bvandeusen/minstrel/internal/server.ServerChannel=${MINSTREL_CHANNEL}'" \
     -o /out/minstrel ./cmd/minstrel
 
 FROM debian:bookworm-slim

README.md

@@ -112,18 +112,21 @@ Most operational keys have a `MINSTREL_<SECTION>_<FIELD>` env override. Recommen
 
 Image tags (`git.fabledsword.com/bvandeusen/minstrel:<tag>`):
 
-- `:latest` — the newest blessed image. Moves on every `main` push **and** every release. Recommended for most operators.
-- `:vYYYY.MM.DD.HHMM` — immutable release tags, never moved or deleted. Pin one for a deployment you don't want changing under you. The tag is the build's own version name with a `v` in front, derived from the tagged commit's UTC timestamp, so two releases can never collide and a re-cut is simply a new tag.
-- `:main` — the rolling post-merge tip. Same image as `:latest` at push time; choose it if you want to track `main` explicitly rather than the release line.
-- `:dev` — the rolling test channel, rebuilt on every push to `dev` and carrying its own freshly-built Android APK. Run this when you want to try something before it ships. It moves constantly, has no per-commit tag to pin, and its only recovery path is forward — if a `:dev` image is broken, the fix is the next push, not a rollback.
+- `:latest` — production. Tracks `main`'s tip and moves on every `main` push and every release. What most operators should run.
+- `:<commit-sha>` — the rollback unit. Every `main` push publishes one, so any production commit is addressable without a release ceremony. Immutable: a given SHA tag is never re-pushed. Pin one if you need a deployment that cannot change under you, and use it to roll back.
+- `:dev` — the rolling test channel, rebuilt on every push to `dev` and carrying its own freshly-built Android APK. Run this to try something before it ships. It moves constantly, has no per-commit tag, and its only recovery path is forward — if a `:dev` image is broken, the fix is the next push, not a rollback.
 
-Every `:latest`, `:vYYYY.MM.DD.HHMM` and `:dev` bundles a signed Android APK, so the in-app update channel is always live. All of them are signed with the same key, so a phone can move between the stable and dev channels without uninstalling — point it at a `:dev` server and the in-app updater offers that channel's build.
+That is the whole tag map. **There are no version-numbered image tags**, and no `:main`. Git and the build's own self-reported version answer "which build is this" — the Settings page shows it, and so does `/healthz`. Release *tags* in git are still `vYYYY.MM.DD.HHMM`; they name a changelog entry and the APK attached to it, not an image.
+
+Rolling back to `:<commit-sha>` pins the **server code** at that commit — not the server-and-app pair. The Android APK is baked in at image build time, so a SHA image carries whichever app was current when that commit was built, which may be older than what `:latest` bundles now. If both halves matter, check what the image bundles rather than trusting the tag's name.
+
+Every `:latest`, `:<commit-sha>` and `:dev` bundles a signed Android APK, so the in-app update channel is always live. All are signed with the same key, so a phone can move between the stable and dev channels without uninstalling — point it at a `:dev` server and the in-app updater offers that channel's build.
 
 The app reports which channel it is on alongside its version, and decides whether an update is available using the build's ordering key rather than its displayed name — the same value Android installs by, so an offer it makes is one the platform will accept.
 
 Database migrations run automatically at startup; rollbacks require restoring a Postgres dump.
 
-Releases before 2026-09-10 use the older per-day `:vYYYY.MM.DD` shape. Those tags still exist and still work — they are simply not extended.
+Releases up to 2026-09-10 also published a `:vYYYY.MM.DD[.HHMM]` image tag. Those images still exist and still work — they are simply not extended.
 
 ## Specs
 
@@ -157,7 +160,7 @@ Two concurrent dev processes:
 
 - Day-to-day work happens on `dev` (or feature branches merged into `dev`).
 - `main` is **protected** — changes land via PR from `dev`.
-- Releases are cut by tagging `v*` off `main`; the release workflow builds and pushes the container image to the Gitea registry.
+- Releases are cut by tagging `v*` off `main`; the release workflow builds the signed APK, attaches it to the release, and refreshes `:latest` around it.
 
 Task and milestone tracking: Fable (`Minstrel` project, id 12).
 

ci-requirements.md

@@ -62,57 +62,30 @@ None.
 - **Go toolchain pin.** `go.mod` is on `go 1.25.0` because `golang.org/x/crypto v0.51.0` declares 1.25 as its minimum. `ci-go:1.26` satisfies this with headroom. Future `x/crypto` bumps that move the Go floor should be paired with an image-tag bump in this file + the workflows.
 - **In-app update channel — `needs:`, not polling.** `release.yml`'s `image-release` job declares `needs: [android-release]`, so on tag pushes the signed APK is guaranteed present before the image build starts — no polling window, no race. (The old cross-workflow polling against `flutter.yml` is gone with that workflow.) On non-tag `main` pushes `android-release` is skipped and `image-release` instead pulls the most recent release's APK and reconstructs its exact `versionName`, so `:latest` never ships without an update channel. It degrades to an empty `client/` — never a wrong version — if no release, asset, or tag commit-count can be resolved.
 - **Cache server reachability.** `test-web.yml` does NOT use `cache: 'npm'` on `actions/setup-node` — the Gitea Actions cache server isn't reachable from this runner's container network and `setup-node` was burning ~4m41s on ETIMEDOUT before failing open. With the migration to `ci-go:1.26`, `setup-node` is removed entirely (Node is in the image). The cache concern reappears if a future change re-introduces a network-dependent action.
-- **Artifacts — use the mirrored actions, never `actions/{upload,download}-artifact`.**
+- **Artifacts — stock `actions/upload-artifact@v7` and `actions/download-artifact@v8`; never `@v3`.**
   ```yaml
-  uses: https://git.fabledsword.com/bvandeusen/upload-artifact@cb8afe72b42edc798abfb8fcb556cf660d894245
-  uses: https://git.fabledsword.com/bvandeusen/download-artifact@8d4e9521a5f7e5f8b6351f341f719f9f45a92a3a
+  uses: actions/upload-artifact@v7
+  uses: actions/download-artifact@v8
   ```
-  Upstream's `@v4+` cannot work against this instance and no server-side change
-  will help: `isGhes()` rejects any hostname that isn't `github.com` /
-  `*.ghe.com` / `*.localhost` and throws before it opens a connection, so the
-  server is never asked what it supports. `@v3` is worse — it reports success,
-  and Gitea then serves artifacts back only through the v4 API
-  (`content_encoding = application/zip`), so a v3 upload is stored but invisible
-  to every retrieval path. A green job producing nothing retrievable; that is how
-  72 unreachable artifacts accumulated on this repo. Scribe issues 2255 / 2270.
+  Stock works on this forge since the runner moved to gitea/runner 3.x, which
+  edits the actions' client-side `isGhes()` refusal out of their bundles. Proven
+  on 2026-09-10 for upload v4–v7 and download v4–v8 (Scribe spike #3843). Until
+  then this repo pinned SHA mirrors of the Forgejo project's forks, because
+  upstream threw on the hostname before it opened a connection (Scribe 2255).
 
-  Both are pull mirrors of the Forgejo project's forks
-  (`code.forgejo.org/forgejo/{upload,download}-artifact`, one commit on upstream
-  disabling that check), mirrored so CI depends on commits we hold and pinned by
-  SHA because the mirrors auto-sync every 8h — a moved upstream tag would
-  otherwise silently change what runs.
+  `@v3` is still broken: it reports success, and Gitea serves artifacts back only
+  through the v4 API (`content_encoding = application/zip`), so a v3 upload is
+  stored but invisible to every retrieval path. That is how 72 unreachable
+  artifacts accumulated on this repo (Scribe 2270).
 
-  **Match the pins on `@actions/artifact`, not on the actions' own version
-  numbers.** The two actions release on unrelated cadences, so equal version
-  numbers do NOT mean a compatible pair — upload `v5` bundles `@actions/artifact`
-  ^4.0.0 while download `v5` bundles ^2.3.2. The pins above are upload **v5** and
-  download **v6**, which is the pairing that puts ^4.0.0 on both sides. This
-  matters because `release.yml` is a producer/consumer pair — `android-release`
-  uploads `minstrel-apk`, `image-release` downloads it — and a protocol mismatch
-  across it yields an empty listing rather than an error, exactly the silent
-  failure this entry exists to prevent.
-
-  | tag | `@actions/artifact` | runtime |
-  |---|---|---|
-  | upload v4 | ^2.1.1 | node20 |
-  | **upload v5** ← pinned | **^4.0.0** | node20 |
-  | download v4 | ^2.1.1 | node20 |
-  | download v5 | ^2.3.2 | node20 |
-  | **download v6** ← pinned | **^4.0.0** | node20 |
-  | download v7 | ^5.0.0 | **node24** |
-
-  The only true protocol break in this history was **v3 → v4** (upstream:
-  "Downloading artifacts that were created from `actions/upload-artifact@v3` and
-  below are not supported"); v4-and-up are one family. Later majors are mostly
-  ergonomics and runtime — upload v4 forbids re-uploading a name and caps a job
-  at 500 artifacts; download v5 made by-ID extraction match by-name.
-
-  **Do not jump the download pin to v7.** That major is a runner requirement, not
-  a feature change: it moves to `runs.using: node24` and upstream states it
-  "requires a minimum Actions Runner version of 2.327.1 … if you are using
-  self-hosted runners, ensure they are updated before upgrading." act_runner is
-  not GitHub's runner and makes no such version claim, so node24 is unverified
-  here. Everything currently pinned is node20.
+  **Pairing no longer needs managing.** This entry used to pin upload v5 against
+  download v6 so both bundled `@actions/artifact` ^4.0.0, warning that a mismatch
+  across `release.yml`'s producer/consumer pair would list empty. Tested, and not
+  true on this instance: every download major v4–v8 read the artifacts of every
+  upload major v4–v7, by name and by pattern (CI-runner run 6312). The only real
+  protocol break is v3 → v4. node24 is no longer a concern either — every
+  CI-runner image carries Node 24 and the runner runs actions with the image's
+  `node`.
 
   Upload steps set `if-no-files-found: error` rather than the default `warn`, so
   an upload that matches nothing fails its own job instead of failing the

ci/version.sh

@@ -2,7 +2,8 @@
 #
 # Derives the three values a build is stamped with, and the tag that names it.
 #
-#   name=YYYY.MM.DD.HHMM   label for people, from the COMMIT's timestamp
+#   name=YYYY.MM.DD.HHMM   label for people, from the timestamp of the newest
+#                          commit that CHANGED SOMETHING SHIPPED (see SHIPPED)
 #   code=<int>             ordering key, minutes since 2020-01-01 at BUILD time
 #   tag=v<name>            what a release of this commit must be called
 #
@@ -33,9 +34,83 @@ readonly REF="${1:-HEAD}"
 
 # Both clocks are overridable so a test can pin them. Nothing but tests should
 # set these — the defaults are the real derivation.
+# The paths that do NOT ship, in either artifact. Everything else counts.
+#
+# A DENYLIST, and the direction is the whole point. As an allowlist, the list
+# has to be updated by whoever adds a directory and nothing fails if they
+# don't — so the failure mode is a changed artifact keeping its old version,
+# silently, on a green run. That is a build lying about what it is. Inverted,
+# new content counts by default and the only way to wrongly EXCLUDE something
+# is to name it here deliberately.
+#
+# The two error directions are not symmetric, which is why this is not taste:
+#   wrongly excluded → changed artifact, unchanged version. A silent lie.
+#   wrongly included → version moves when nothing shipped. Cosmetic noise in
+#                      a string nobody sorts.
+#
+# THIS REPO SHIPS TWO ARTIFACTS FROM ONE DERIVATION, and that is why the list
+# is shorter than it looks like it should be. The server image ships cmd/,
+# internal/, shared/, web/, config.example.yaml and client/; the APK ships
+# android/. Neither ships the other's sources — but excluding android/ here
+# would stop an Android-only commit from moving the APK's OWN version, which
+# is the dangerous direction. So this is the union: exclude only what ships in
+# NEITHER, and accept that an Android commit also nudges the server's reported
+# version. Over-inclusion across the two, which is the harmless direction.
+#
+# The family's other repos (roundtable / roundtable-android) each keep a
+# tighter list because they are separate repos with one artifact apiece. Do
+# not copy theirs onto this one.
+readonly SHIPPED=(
+  .
+  ':!.gitea'          # CI workflows — including this script's own caller
+  ':!ci'              # CI scripts — including this script
+  ':!docs'
+  ':!tools'           # asset/font generators; their OUTPUT ships, they do not
+  ':!deploy'          # test-database bootstrap SQL
+  ':!bin'             # local `make build` output
+  ':!*.md'
+  ':!Makefile'
+  ':!docker-compose.yml'
+  ':!.env.example'
+  ':!.gitignore'
+  ':!.dockerignore'
+  ':!renovate.json'
+  ':!.golangci.yml'
+
+  # TESTS DO NOT SHIP, so they must not re-version an artifact.
+  #
+  # Named as globs rather than a directory because this repo has no tests/
+  # tree to exclude: Go tests sit inline beside the code they cover, and the
+  # web suite sits beside its modules. `go build` drops *_test.go outright and
+  # the Vite build never imports a .test.ts, so neither reaches an artifact.
+  #
+  # A commit touching a test AND its source still moves the version — the
+  # source path matches on its own. Only a test-ONLY commit is inert, which is
+  # the whole intent.
+  #
+  # Patterns match what exists today and nothing speculative: there are no
+  # .spec.* files, no __tests__/ directories and no androidTest/ tree. If any
+  # appear they will re-version until named here, which is the harmless
+  # direction and the reason this list is a denylist.
+  ':!*_test.go'                   # 158 files, inline beside the code
+  ':!*.test.ts'                   # 114 files
+  ':!*.test.js'
+  ':!android/app/src/test'        # JVM unit tests; no androidTest tree exists
+  ':!web/vitest.config.ts'        # test-harness config, not build config
+  ':!web/vitest.setup.ts'
+)
+
 commit_epoch="${MINSTREL_COMMIT_EPOCH:-}"
 if [ -z "${commit_epoch}" ]; then
-  commit_epoch="$(git log --format=%ct -1 "${REF}")"
+  commit_epoch="$(git log --format=%ct -1 "${REF}" -- "${SHIPPED[@]}")"
+  # Loudly, on purpose. A silent fallback here is the landmine this whole
+  # script exists to avoid: a plausible-looking version that is quietly wrong,
+  # on a green run. Realistically this means a shallow clone (no commit in
+  # range touches the shipped set) rather than a repo of pure CI config.
+  if [ -z "${commit_epoch}" ]; then
+    echo "version.sh: no commit under '${REF}' touches the shipped file set — shallow clone? (needs fetch-depth: 0)" >&2
+    exit 1
+  fi
 fi
 now_epoch="${MINSTREL_NOW_EPOCH:-$(date -u +%s)}"
 

internal/api/admin_recommendation_tuning.go

@@ -99,12 +99,14 @@ func (h *handlers) tuningSnapshot() tuningSnapshot {
 	out.Profiles = map[string]weightsResp{
 		recsettings.ScopeRadio:     weightsRespFrom(h.recSettings.Weights(recsettings.ScopeRadio)),
 		recsettings.ScopeDailyMix:  weightsRespFrom(h.recSettings.Weights(recsettings.ScopeDailyMix)),
+		recsettings.ScopeSongsLike: weightsRespFrom(h.recSettings.Weights(recsettings.ScopeSongsLike)),
 	}
 	out.Taste = tasteRespFrom(h.recSettings.Taste())
 	out.Discover = discoverRespFrom(h.recSettings.Discover())
 	out.Shipped.Profiles = map[string]weightsResp{
 		recsettings.ScopeRadio:     weightsRespFrom(recsettings.ShippedRadioWeights()),
 		recsettings.ScopeDailyMix:  weightsRespFrom(recsettings.ShippedDailyMixWeights()),
+		recsettings.ScopeSongsLike: weightsRespFrom(recsettings.ShippedSongsLikeWeights()),
 	}
 	out.Shipped.Taste = tasteRespFrom(recsettings.ShippedTasteTuning())
 	out.Shipped.Discover = discoverRespFrom(recsettings.ShippedDiscoverTuning())

internal/db/migrations/0057_songs_like_tuning.down.sql

@@ -0,0 +1,16 @@
+-- Drop the rows the narrower constraints are about to forbid, or re-adding
+-- them fails against existing data (the 0051 down-migration pattern).
+DELETE FROM recommendation_weight_profiles WHERE profile = 'songs_like';
+DELETE FROM recommendation_tuning_audit WHERE scope = 'songs_like';
+
+ALTER TABLE recommendation_tuning_audit
+    DROP CONSTRAINT recommendation_tuning_audit_scope_check;
+ALTER TABLE recommendation_tuning_audit
+    ADD CONSTRAINT recommendation_tuning_audit_scope_check
+    CHECK (scope IN ('radio', 'daily_mix', 'taste', 'discover'));
+
+ALTER TABLE recommendation_weight_profiles
+    DROP CONSTRAINT recommendation_weight_profiles_profile_check;
+ALTER TABLE recommendation_weight_profiles
+    ADD CONSTRAINT recommendation_weight_profiles_profile_check
+    CHECK (profile IN ('radio', 'daily_mix'));

internal/db/migrations/0057_songs_like_tuning.up.sql

@@ -0,0 +1,37 @@
+-- 0057_songs_like_tuning.up.sql — a THIRD weight profile, for Songs-like
+-- (Scribe #3881, milestone #398).
+--
+-- Songs-like shared the `daily_mix` profile with For-You, and that is the bug.
+-- The two surfaces want opposite things: For-You is a broad "what will they
+-- enjoy today", Songs-like answers "what sounds like THIS", and under one set
+-- of weights the broad answer wins. Operator, 2026-09-10: "I'm expecting to
+-- get a consistent sound and style from the experience... I was getting a
+-- seeming wide variety of music from each one when I was hoping to stay in a
+-- certain neighborhood."
+--
+-- Under the shared daily_mix weights, an UNRELATED track the user had liked
+-- and not played recently scored 1.0 + 2.0 + 1.0 = 4.0 before taste, while a
+-- PERFECT similarity match they had not liked scored 1.0 + 1.5 = 2.5. Liking
+-- something outranked sounding like the seed. Splitting the profile is what
+-- lets similarity dominate here without making For-You narrow.
+--
+-- Rows are seeded by the recsettings boot reconcile, not here, so shipped
+-- defaults live in exactly one place (Go) — same as 0040.
+
+-- Rule #36: a new value for a CHECK-gated column needs the constraint
+-- rewritten in the SAME change, or the first row written under the new
+-- profile fails at runtime rather than at migrate time.
+ALTER TABLE recommendation_weight_profiles
+    DROP CONSTRAINT recommendation_weight_profiles_profile_check;
+ALTER TABLE recommendation_weight_profiles
+    ADD CONSTRAINT recommendation_weight_profiles_profile_check
+    CHECK (profile IN ('radio', 'daily_mix', 'songs_like'));
+
+-- The audit table gates the same name on a separate constraint. Missing this
+-- one would let the profile be seeded and then fail on the first knob turn —
+-- green at boot, 500 on first use.
+ALTER TABLE recommendation_tuning_audit
+    DROP CONSTRAINT recommendation_tuning_audit_scope_check;
+ALTER TABLE recommendation_tuning_audit
+    ADD CONSTRAINT recommendation_tuning_audit_scope_check
+    CHECK (scope IN ('radio', 'daily_mix', 'taste', 'discover', 'songs_like'));

internal/playlists/system.go

@@ -219,6 +219,24 @@ var (
 		// uniform with radio pending trend data.
 		ContextTimeWeight: 1.0,
 	}
+	// Songs-like's own profile (#3881). Pre-push literal only; shipped
+	// defaults live in recsettings.ShippedSongsLikeWeights and must stay in
+	// sync with it, exactly as systemMixWeights does above.
+	//
+	// SimilarityWeight dominates here and every seed-INDEPENDENT term is
+	// demoted, which is the whole difference between this surface and For-You.
+	// See ShippedSongsLikeWeights for the property the numbers encode.
+	songsLikeWeights = recommendation.ScoringWeights{
+		BaseWeight:        1.0,
+		LikeBoost:         0.5,
+		RecencyWeight:     0.25,
+		SkipPenalty:       2.0,
+		JitterMagnitude:   0.05,
+		ContextWeight:     0.5,
+		SimilarityWeight:  4.0,
+		TasteWeight:       0.25,
+		ContextTimeWeight: 0.5,
+	}
 	systemTasteConfig = taste.DefaultConfig()
 )
 
@@ -230,6 +248,20 @@ func SetSystemMixWeights(w recommendation.ScoringWeights) {
 	systemMixWeights = w
 }
 
+// SetSongsLikeWeights installs the songs_like scoring profile (#3881).
+// Same push model as SetSystemMixWeights — recsettings calls it on boot and
+// after every knob turn, so a tuning change takes effect on the next daily
+// build with no restart.
+//
+// Separate from systemMixWeights because Songs-like and For-You want opposite
+// things: For-You roams, Songs-like must not. Sharing one profile is what made
+// "Songs like X" wander.
+func SetSongsLikeWeights(w recommendation.ScoringWeights) {
+	systemTuningMu.Lock()
+	defer systemTuningMu.Unlock()
+	songsLikeWeights = w
+}
+
 // SetTasteConfig installs the taste-profile build configuration
 // (half-life + engagement curve, #1250). Same push model as
 // SetSystemMixWeights.
@@ -239,6 +271,12 @@ func SetTasteConfig(c taste.Config) {
 	systemTasteConfig = c
 }
 
+func currentSongsLikeWeights() recommendation.ScoringWeights {
+	systemTuningMu.RLock()
+	defer systemTuningMu.RUnlock()
+	return songsLikeWeights
+}
+
 func currentSystemMixWeights() recommendation.ScoringWeights {
 	systemTuningMu.RLock()
 	defer systemTuningMu.RUnlock()
@@ -392,7 +430,13 @@ func pickWeightedTail(tailPool []recommendation.Candidate, dateStr string, tailN
 // tieBreakHash). The scoring RNG is seeded by userIDHash so jitter is
 // deterministic per (user, day) but rotates across days. Pure — no
 // truncation, no cap.
-func scoreAndSortCandidates(cands []recommendation.Candidate, userID pgtype.UUID, dateStr string, now time.Time) []recommendation.Candidate {
+// weights is a parameter rather than a read of currentSystemMixWeights()
+// because this sort IS the selection: the caller caps and truncates in the
+// order this returns, so whatever profile ranks here decides which tracks
+// reach the playlist. Scoring with daily_mix here and re-scoring with
+// songs_like afterwards would have let the new profile relabel tracks it had
+// no part in choosing — inert where it matters (#3881).
+func scoreAndSortCandidates(cands []recommendation.Candidate, userID pgtype.UUID, dateStr string, now time.Time, weights recommendation.ScoringWeights) []recommendation.Candidate {
 	rng := rand.New(rand.NewSource(int64(userIDHash(userID, dateStr))))
 	type scored struct {
 		c     recommendation.Candidate
@@ -411,7 +455,6 @@ func scoreAndSortCandidates(cands []recommendation.Candidate, userID pgtype.UUID
 	sort.SliceStable(ordered, func(i, j int) bool {
 		return uuidLessPL(ordered[i].Track.ID, ordered[j].Track.ID)
 	})
-	weights := currentSystemMixWeights()
 	pairs := make([]scored, len(ordered))
 	for i, c := range ordered {
 		pairs[i] = scored{c: c, score: recommendation.Score(c.Inputs, weights, now, rng.Float64)}
@@ -647,9 +690,13 @@ func produceSeedMixes(
 			continue
 		}
 		zeroVec := recommendation.SessionVector{Seed: true}
+		// Songs-like's own pool shape, not the default (#3881). Same total
+		// size; the composition shifts toward arms that actually measure
+		// distance from the seed. The default gave ~29% of candidates a
+		// sim_score of literally 0.
 		cands, cerr := recommendation.LoadCandidatesFromSimilarity(
 			ctx, q, userID, seedTrack, 1, zeroVec, []pgtype.UUID{seedTrack},
-			recommendation.DefaultCandidateSourceLimits(),
+			recommendation.SongsLikeCandidateSourceLimits(),
 		)
 		if cerr != nil {
 			logger.Warn("system playlist: seed candidates load failed; skipping",
@@ -838,13 +885,20 @@ func BuildSystemPlaylists(ctx context.Context, pool *pgxpool.Pool, logger *slog.
 // truncates to n. Used by Songs-like-X (and as the fallback inside
 // pickHeadAndTail for small pools).
 func pickTopN(cands []recommendation.Candidate, userID pgtype.UUID, dateStr string, now time.Time, n int) []rankedCandidate {
-	sorted := scoreAndSortCandidates(cands, userID, dateStr, now)
+	// songs_like, not daily_mix (#3881). produceSeedMixes is this function's
+	// only caller, so the switch moves exactly one surface — For-You ranks
+	// through pickHeadAndTail and keeps the broader daily_mix profile.
+	//
+	// The SAME profile does the selection sort and the final score. Passing
+	// one and using the other is the subtle version of this bug: the playlist
+	// would still be chosen by daily_mix and merely wear songs_like numbers.
+	weights := currentSongsLikeWeights()
+	sorted := scoreAndSortCandidates(cands, userID, dateStr, now, weights)
 	capped := capCandidatesByAlbumAndArtist(sorted)
 	if len(capped) > n {
 		capped = capped[:n]
 	}
 	rng := rand.New(rand.NewSource(int64(userIDHash(userID, dateStr))))
-	weights := currentSystemMixWeights()
 	out := make([]rankedCandidate, len(capped))
 	for i, c := range capped {
 		out[i] = rankedCandidate{
@@ -873,10 +927,11 @@ func pickHeadAndTail(
 	cands []recommendation.Candidate, seedOf map[pgtype.UUID]int, numSeeds int,
 	userID pgtype.UUID, dateStr string, now time.Time, headN, tailN int,
 ) []rankedCandidate {
-	sorted := scoreAndSortCandidates(cands, userID, dateStr, now)
+	// daily_mix — For-You is the broad surface and keeps the roaming profile.
+	weights := currentSystemMixWeights()
+	sorted := scoreAndSortCandidates(cands, userID, dateStr, now, weights)
 	capped := capCandidatesByAlbumAndArtist(sorted)
 	rng := rand.New(rand.NewSource(int64(userIDHash(userID, dateStr))))
-	weights := currentSystemMixWeights()
 
 	total := headN + tailN
 	if len(capped) <= total {

internal/recommendation/candidates.go

@@ -105,6 +105,59 @@ func DefaultCandidateSourceLimits() CandidateSourceLimits {
 	}
 }
 
+// SongsLikeCandidateSourceLimits is the pool shape for "Songs like {X}"
+// (#3881). Same total size as the default (~170) — the composition is what
+// changes, shifted hard toward arms that actually measure distance from the
+// seed.
+//
+// The surface answers "what sounds like THIS", and it shared the default
+// pool with For-You, which answers the much broader "what will they enjoy
+// today". Under the default, 50 of ~170 candidates carried sim_score = 0 by
+// construction — `taste_overlap` (tracks by the user's top taste artists) and
+// `random_fill` (literally any track not already in the pool), both of which
+// are seed-INDEPENDENT. Nearly a third of the pool had no relationship to the
+// seed at all, and the operator saw it: "I was getting a seeming wide variety
+// of music from each one when I was hoping to stay in a certain neighborhood."
+//
+// TIERED, per rule 131 — a system mix degrades, it never vanishes:
+//
+//	tier 1  lb_similar      real track-level similarity. The exact promise.
+//	tier 2  similar_artist, tag_overlap, coplay, likes_overlap
+//	                        seed-RELATED but weaker signal.
+//	tier 3  taste_overlap, random_fill
+//	                        seed-independent. The floor, and nothing more.
+//
+// The tiering is enforced by SCORE rather than by a fallback ladder: tier-3
+// arms carry sim_score 0, so under SongsLike weights (SimilarityWeight 4.0,
+// everything seed-independent demoted) they rank below any real match and
+// surface only when tiers 1–2 cannot fill the mix. That is the rule's
+// "fill from tier 1 first, reach down only when a tier cannot fill".
+//
+// Which is exactly why tier 3 is REDUCED rather than removed. Zeroing those
+// two arms was the first instinct and it is the vanish-or-nothing shape rule
+// 131 exists to forbid: a seed whose artist has thin ListenBrainz coverage
+// would produce a short mix or none at all, and "no playlist" is a worse
+// answer than "a few tracks further from the seed than we would like".
+//
+// likes_overlap is cut hardest of the tier-2 arms for a specific reason: its
+// SQL assigns a FLAT 0.6 sim_score (recommendation.sql:108) rather than
+// measuring anything. It is a collaborative signal wearing similarity's
+// clothes, and raising SimilarityWeight amplifies it — if real ListenBrainz
+// scores commonly land below 0.6 it would outrank genuine matches. Halved
+// here pending the fill-rate measurement in #3879; the honest fix is to stop
+// it claiming a similarity score it did not compute.
+func SongsLikeCandidateSourceLimits() CandidateSourceLimits {
+	return CandidateSourceLimits{
+		LBSimilar:     60, // tier 1 — doubled; the only arm that measures the seed
+		SimilarArtist: 40, // tier 2
+		TagOverlap:    20, // tier 2
+		UserCoplay:    20, // tier 2
+		LikesOverlap:  10, // tier 2, halved — flat 0.6, see above
+		TasteOverlap:  10, // tier 3 floor — halved, not removed
+		RandomFill:    10, // tier 3 floor — cut hard, never to zero
+	}
+}
+
 // LoadCandidatesFromSimilarity is M4c's primary candidate-pool loader.
 // 5-way SQL UNION (LB-similar / similar-artist tracks / MB-tag overlap /
 // likes-overlap / random fill) + dedup-by-max sim_score. Returns

internal/recommendation/songs_like_limits_test.go

@@ -0,0 +1,61 @@
+package recommendation
+
+import "testing"
+
+// Songs-like's pool must lean on arms that MEASURE distance from the seed.
+// The default gave ~29% of candidates a sim_score of literally 0
+// (taste_overlap and random_fill are both `0.0::float8` in
+// recommendation.sql), which is what let "Songs like X" wander.
+func TestSongsLikeLimits_FavourTheArmsThatMeasureTheSeed(t *testing.T) {
+	d := DefaultCandidateSourceLimits()
+	s := SongsLikeCandidateSourceLimits()
+
+	if s.LBSimilar <= d.LBSimilar {
+		t.Errorf("LBSimilar %d is not above the default %d — the only arm that "+
+			"measures track-level distance from the seed should be favoured here",
+			s.LBSimilar, d.LBSimilar)
+	}
+	// The two seed-INDEPENDENT arms, which is the whole complaint.
+	zeroSimDefault := d.TasteOverlap + d.RandomFill
+	zeroSimSongsLike := s.TasteOverlap + s.RandomFill
+	if zeroSimSongsLike >= zeroSimDefault {
+		t.Errorf("seed-independent arms total %d, not reduced from the default %d; "+
+			"these carry sim_score 0 by construction", zeroSimSongsLike, zeroSimDefault)
+	}
+}
+
+// RULE 131: a system playlist degrades, it never vanishes.
+//
+// Zeroing the seed-independent arms was the first instinct and is exactly the
+// vanish-or-nothing shape that rule forbids: a seed whose artist has thin
+// ListenBrainz coverage would yield a short mix or none at all. They are the
+// tier-3 FLOOR — reduced hard, never removed — and the songs_like weights are
+// what keep them at the bottom of the ranking rather than out of the pool.
+//
+// "A few tracks further from the seed than we would like" beats "no playlist".
+func TestSongsLikeLimits_KeepATierThreeFloor(t *testing.T) {
+	s := SongsLikeCandidateSourceLimits()
+	if s.RandomFill <= 0 {
+		t.Error("RandomFill is zero: a seed with thin similarity coverage now produces " +
+			"a short or empty mix instead of degrading (rule 131)")
+	}
+	if s.TasteOverlap <= 0 {
+		t.Error("TasteOverlap is zero: the graded floor is gone, leaving only random " +
+			"fill between a sparse seed and an empty playlist (rule 131)")
+	}
+}
+
+// The pool should stay roughly the size it was — this change is about
+// COMPOSITION, not about starving the surface. A much smaller pool would also
+// shrink what the per-artist cap has to work with.
+func TestSongsLikeLimits_KeepThePoolRoughlyTheSameSize(t *testing.T) {
+	total := func(l CandidateSourceLimits) int {
+		return l.LBSimilar + l.SimilarArtist + l.TagOverlap + l.LikesOverlap +
+			l.RandomFill + l.TasteOverlap + l.UserCoplay
+	}
+	d, s := total(DefaultCandidateSourceLimits()), total(SongsLikeCandidateSourceLimits())
+	if s < d/2 {
+		t.Errorf("songs_like pool is %d against the default %d — less than half; "+
+			"this was meant to re-weight the pool, not starve it", s, d)
+	}
+}

internal/recsettings/service.go

@@ -40,6 +40,13 @@ const (
 	// never be read as taste signal (#2374) — filing it under taste would put
 	// it one careless join from the leak that design forbids.
 	ScopeDiscover = "discover"
+	// ScopeSongsLike is the "Songs like {X}" surface (#3881). It shared
+	// daily_mix with For-You until 2026-09-10, and that sharing WAS the bug:
+	// the two surfaces want opposite things. For-You answers "what will they
+	// enjoy today" and is supposed to roam; Songs-like answers "what sounds
+	// like THIS" and is the tightest surface in the product. One set of
+	// weights cannot serve both, and the broad answer was winning.
+	ScopeSongsLike = "songs_like"
 )
 
 // TasteTuning is the tunable subset of taste.Config: the engagement
@@ -92,6 +99,76 @@ func ShippedDailyMixWeights() recommendation.ScoringWeights {
 	}
 }
 
+// ShippedSongsLikeWeights are the shipped songs_like-profile defaults
+// (#3881). The whole point is that SIMILARITY DOMINATES; every other
+// profile balances it against taste and engagement, and this one must not.
+//
+// The failure being corrected, arithmetic from the daily_mix profile that
+// this surface used to share:
+//
+//	unrelated track, liked, not played recently → 1.0 + 2.0 + 1.0 = 4.0
+//	PERFECT similarity match, not liked         → 1.0 + 1.5       = 2.5
+//
+// Liking something outranked sounding like the seed, because LikeBoost (2.0)
+// exceeded SimilarityWeight's entire range (1.5) and TasteWeight (1.5, and
+// seed-independent) matched it outright.
+//
+// THE PROPERTY THESE NUMBERS ENCODE, which is what to preserve if they are
+// retuned: the similarity term's range must exceed the combined range of
+// every seed-INDEPENDENT differentiator, so that a closer match cannot be
+// beaten on the strength of likes, freshness and taste alone.
+//
+//	seed-independent spread = LikeBoost 0.5 + Recency 0.25
+//	                        + Taste 0.25 + ContextTime 0.5
+//	                        + jitter 0.05                  = 1.55
+//	similarity spread       = 0 → 4.0
+//
+// So a similarity advantage of ~0.39 (1.55/4.0) wins outright regardless of
+// everything else, while tracks within that band still get ordered by what
+// the user likes and has not heard lately. Tight, not deaf.
+//
+// BaseWeight stays 1.0: it is identical for every candidate and so
+// differentiates nothing — it sets the floor, not the shape. SkipPenalty
+// stays 2.0 because a track the user skips is still unwanted no matter how
+// similar it is.
+//
+// These are DEFAULTS, not settings (rule 25) — the operator turns them in the
+// admin tuning card and good values get baked back here. They are a
+// defensible starting point rather than a measured optimum: the per-arm fill
+// rates and the real sim_score distribution are still unknown (#3879), and
+// `likes_overlap` contributes a flat 0.6 that a high SimilarityWeight
+// amplifies. Expect to move these once that lands.
+func ShippedSongsLikeWeights() recommendation.ScoringWeights {
+	return recommendation.ScoringWeights{
+		BaseWeight:        1.0,  // same for all candidates; differentiates nothing
+		LikeBoost:         0.5,  // was 2.0 — a tie-break among similar tracks, not an override
+		RecencyWeight:     0.25, // was 1.0 — freshness must not outrank sounding right
+		SkipPenalty:       2.0,  // unchanged — a skipped track stays unwanted
+		JitterMagnitude:   0.05, // was 0.1 — less shuffle on a coherence surface
+		ContextWeight:     0.5,
+		SimilarityWeight:  4.0,  // was 1.5 — dominant, by design
+		TasteWeight:       0.25, // was 1.5 — seed-INDEPENDENT, so demoted hard
+		ContextTimeWeight: 0.5,  // was 1.0
+	}
+}
+
+// shippedWeightsFor returns the shipped defaults for a weight-profile scope,
+// or ok=false if the scope is not a weight profile. Single source for the
+// three call sites (seed, update-validation, reset) so adding a fourth
+// profile cannot be half-wired — which is how a scope ends up seedable but
+// not resettable.
+func shippedWeightsFor(scope string) (recommendation.ScoringWeights, bool) {
+	switch scope {
+	case ScopeRadio:
+		return ShippedRadioWeights(), true
+	case ScopeDailyMix:
+		return ShippedDailyMixWeights(), true
+	case ScopeSongsLike:
+		return ShippedSongsLikeWeights(), true
+	}
+	return recommendation.ScoringWeights{}, false
+}
+
 // DiscoverTuning is the tunable set for the Discover request surface (#2377).
 type DiscoverTuning struct {
 	// TagOverlapWeight scales the taste-tag term: score × (1 + w × overlap).
@@ -167,6 +244,7 @@ func (s *Service) reconcile(ctx context.Context) error {
 	for profile, w := range map[string]recommendation.ScoringWeights{
 		ScopeRadio:     ShippedRadioWeights(),
 		ScopeDailyMix:  ShippedDailyMixWeights(),
+		ScopeSongsLike: ShippedSongsLikeWeights(),
 	} {
 		if err := q.UpsertWeightProfileDefaults(ctx, upsertParams(profile, w)); err != nil {
 			return fmt.Errorf("seed profile %q: %w", profile, err)
@@ -234,6 +312,7 @@ func (s *Service) reconcile(ctx context.Context) error {
 // reads Weights(ScopeRadio) per request.
 func (s *Service) push() {
 	playlists.SetSystemMixWeights(s.Weights(ScopeDailyMix))
+	playlists.SetSongsLikeWeights(s.Weights(ScopeSongsLike))
 	playlists.SetTasteConfig(s.TasteConfig())
 }
 
@@ -297,7 +376,7 @@ type fieldChange struct {
 // Unknown fields and out-of-range values reject the whole patch. A
 // no-op patch (all values equal to current) writes no audit row.
 func (s *Service) UpdateProfile(ctx context.Context, profile string, patch map[string]float64) error {
-	if profile != ScopeRadio && profile != ScopeDailyMix {
+	if _, ok := shippedWeightsFor(profile); !ok {
 		return fmt.Errorf("%w: %q", ErrUnknownScope, profile)
 	}
 	current := s.Weights(profile)
@@ -340,17 +419,18 @@ func (s *Service) UpdateDiscover(ctx context.Context, patch map[string]float64)
 // Reset restores a scope to its shipped defaults, with one audit row
 // carrying the full diff. A scope already at defaults is a no-op.
 func (s *Service) Reset(ctx context.Context, scope string) error {
-	switch scope {
-	case ScopeRadio, ScopeDailyMix:
-		shipped := ShippedRadioWeights()
-		if scope == ScopeDailyMix {
-			shipped = ShippedDailyMixWeights()
-		}
+	if shipped, ok := shippedWeightsFor(scope); ok {
+		// Every weight profile resets the same way; the per-scope defaults
+		// come from one place so a new profile cannot be seedable but not
+		// resettable. This was an if/else over two hard-coded scopes until
+		// songs_like made it three.
 		changes := diffWeights(s.Weights(scope), shipped)
 		if len(changes) == 0 {
 			return nil
 		}
 		return s.persistProfile(ctx, scope, shipped, "reset", changes)
+	}
+	switch scope {
 	case ScopeTaste:
 		shipped := ShippedTasteTuning()
 		changes := diffTaste(s.Taste(), shipped)

internal/recsettings/songs_like_weights_test.go

@@ -0,0 +1,130 @@
+package recsettings
+
+import (
+	"testing"
+	"time"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/recommendation"
+)
+
+// The bug, reproduced as a ranking: a track that sounds nothing like the seed
+// but which the user liked and has not played lately used to OUTRANK a perfect
+// similarity match. Operator, 2026-09-10: "I was getting a seeming wide variety
+// of music from each one when I was hoping to stay in a certain neighborhood."
+//
+// This is the whole point of the songs_like profile, so it is asserted as
+// BEHAVIOUR — two candidates, which one wins — rather than by checking the
+// weight numbers. Numbers get retuned; this property must survive that.
+//
+// It also pins the contrast: daily_mix is EXPECTED to fail this. If both
+// profiles started ranking the same way, the split would have quietly become
+// pointless and nothing else would notice.
+func TestSongsLikeWeights_SimilarityBeatsAnUnrelatedLikedTrack(t *testing.T) {
+	now := time.Now().UTC()
+	stale := now.Add(-365 * 24 * time.Hour)
+
+	// A perfect similarity match the user has never liked and played recently.
+	// Everything except similarity is working against it.
+	perfectMatch := recommendation.ScoringInputs{
+		SimilarityScore: 1.0,
+		IsGeneralLiked:  false,
+		LastPlayedAt:    &now,
+	}
+	// Nothing to do with the seed, but liked and long unplayed — every
+	// seed-independent term in its favour.
+	unrelatedFavourite := recommendation.ScoringInputs{
+		SimilarityScore: 0.0,
+		IsGeneralLiked:  true,
+		LastPlayedAt:    &stale,
+		TasteMatchScore: 1.0,
+	}
+
+	// Jitter fixed at its midpoint so the comparison is about the weights.
+	noJitter := func() float64 { return 0.5 }
+
+	songsLike := ShippedSongsLikeWeights()
+	matchScore := recommendation.Score(perfectMatch, songsLike, now, noJitter)
+	favScore := recommendation.Score(unrelatedFavourite, songsLike, now, noJitter)
+	if matchScore <= favScore {
+		t.Errorf("songs_like ranks an unrelated liked track (%.3f) at or above a "+
+			"perfect similarity match (%.3f) — the mix will wander", favScore, matchScore)
+	}
+
+	// The contrast that makes the split worth having. If this ever passes,
+	// daily_mix has been tightened into songs_like and one of them is redundant.
+	daily := ShippedDailyMixWeights()
+	dMatch := recommendation.Score(perfectMatch, daily, now, noJitter)
+	dFav := recommendation.Score(unrelatedFavourite, daily, now, noJitter)
+	if dMatch > dFav {
+		t.Errorf("daily_mix now also puts similarity first (%.3f vs %.3f); the two "+
+			"profiles no longer differ, so songs_like is buying nothing", dMatch, dFav)
+	}
+}
+
+// The property the songs_like numbers encode, stated independently of them:
+// the similarity term's range must exceed the combined range of every
+// seed-INDEPENDENT differentiator, so a closer match cannot be beaten on
+// likes, freshness and taste alone.
+//
+// BaseWeight is excluded deliberately — it is identical for every candidate
+// and so differentiates nothing. SkipPenalty is excluded because it only ever
+// pushes a candidate DOWN, and a skipped track should lose however similar.
+func TestSongsLikeWeights_SimilarityOutrangesEverySeedIndependentTerm(t *testing.T) {
+	w := ShippedSongsLikeWeights()
+
+	// TasteMatchScore and ContextAffinityScore are in [-1,+1]; recencyDecay is
+	// in [0,1]; LikeBoost is all-or-nothing.
+	seedIndependent := w.LikeBoost + w.RecencyWeight + w.TasteWeight +
+		w.ContextTimeWeight + w.JitterMagnitude
+
+	if w.SimilarityWeight <= seedIndependent {
+		t.Errorf("SimilarityWeight %.2f does not outrange the seed-independent "+
+			"terms (%.2f) — likes/recency/taste can outvote sounding like the seed",
+			w.SimilarityWeight, seedIndependent)
+	}
+}
+
+// A scope that is seedable but not resettable is the half-wired shape this
+// guards: the profile appears in the admin card, the operator turns a knob,
+// and Reset then 404s on a scope the rest of the service knows about.
+func TestShippedWeightsFor_CoversEveryWeightProfile(t *testing.T) {
+	for _, scope := range []string{ScopeRadio, ScopeDailyMix, ScopeSongsLike} {
+		if _, ok := shippedWeightsFor(scope); !ok {
+			t.Errorf("scope %q has no shipped defaults; it cannot be seeded or reset", scope)
+		}
+	}
+	// Non-weight scopes must NOT resolve here, or Reset would treat the taste
+	// singleton as a weight profile and write nonsense.
+	for _, scope := range []string{ScopeTaste, ScopeDiscover, "nonsense"} {
+		if _, ok := shippedWeightsFor(scope); ok {
+			t.Errorf("scope %q resolved as a weight profile and is not one", scope)
+		}
+	}
+}
+
+// Guards the sync the comment in playlists/system.go asks for: the pre-push
+// literal there must match the shipped defaults here, or a build that has not
+// yet been reconciled ranks differently from one that has.
+func TestShippedSongsLikeWeights_AreDominatedBySimilarity(t *testing.T) {
+	w := ShippedSongsLikeWeights()
+	daily := ShippedDailyMixWeights()
+
+	if w.SimilarityWeight <= daily.SimilarityWeight {
+		t.Errorf("songs_like SimilarityWeight %.2f is not above daily_mix's %.2f",
+			w.SimilarityWeight, daily.SimilarityWeight)
+	}
+	for _, tc := range []struct {
+		name       string
+		songs, day float64
+	}{
+		{"LikeBoost", w.LikeBoost, daily.LikeBoost},
+		{"TasteWeight", w.TasteWeight, daily.TasteWeight},
+		{"RecencyWeight", w.RecencyWeight, daily.RecencyWeight},
+	} {
+		if tc.songs >= tc.day {
+			t.Errorf("songs_like %s (%.2f) is not demoted below daily_mix (%.2f); "+
+				"these are the seed-independent terms that made the mix wander",
+				tc.name, tc.songs, tc.day)
+		}
+	}
+}

internal/server/release_version_test.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 	"testing"
@@ -178,19 +179,86 @@ func TestReleaseWorkflow_UsesTheSharedDerivation(t *testing.T) {
 	}
 }
 
-// devArm returns the branch of "Compute image tags" that handles refs/heads/dev.
-func devArm(t *testing.T, yaml string) string {
+// jobBoundary matches a blank line followed by job-level (two-space)
+// indentation — the end of the last step in a job.
+var jobBoundary = regexp.MustCompile(`\n\n  [^ \n]`)
+
+// stepBody returns one workflow step's text, from its `- name:` line to the
+// start of the next step or the next job.
+//
+// The naive cut — "up to the next `- name:`" — silently returns an EMPTY body
+// for the last step in a job, and every assertion over it then passes
+// vacuously. That is the failure rule 167 names: a check that reads as
+// coverage while asserting on nothing. Cutting at a blank line followed by
+// job-level indentation handles the last-step case, which is exactly where
+// `Build and push` sits.
+func stepBody(t *testing.T, yaml, name string) string {
 	t.Helper()
-	const marker = `elif [[ "${GITHUB_REF}" == "refs/heads/dev" ]]; then`
-	i := strings.Index(yaml, marker)
+	i := strings.Index(yaml, "- name: "+name)
 	if i < 0 {
-		t.Fatal("no refs/heads/dev arm in Compute image tags — the dev channel is not wired")
+		t.Fatalf("no %q step in release.yml", name)
 	}
-	rest := yaml[i+len(marker):]
-	if j := strings.Index(rest, "\n          else"); j >= 0 {
-		return rest[:j]
+	body := yaml[i:]
+	end := len(body)
+	if j := strings.Index(body, "\n      - name:"); j >= 0 {
+		end = j
 	}
-	return rest
+	// A blank line followed by EXACTLY two spaces and then content starts a
+	// new job or job-level comment. The "exactly" matters: a blank line inside
+	// a `run:` block is followed by ten-space indentation and would otherwise
+	// match, truncating the step mid-body — which is how this helper first
+	// sliced the verify step down to its first two lines.
+	if loc := jobBoundary.FindStringIndex(body); loc != nil && loc[0] < end {
+		end = loc[0]
+	}
+	body = body[:end]
+	if strings.TrimSpace(strings.TrimPrefix(body, "- name: "+name)) == "" {
+		t.Fatalf("step %q sliced to an empty body — the assertions below would pass vacuously", name)
+	}
+	return body
+}
+
+// releaseYAML reads the workflow once per test.
+func releaseYAML(t *testing.T) string {
+	t.Helper()
+	body, err := os.ReadFile(filepath.Join(repoRoot(t), ".gitea", "workflows", "release.yml"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	return string(body)
+}
+
+// imageTagArms splits "Compute image tags" into its three ref branches. The
+// whole tag policy lives in that if/elif/else, so the arms are the unit worth
+// asserting on — a tag published from the wrong arm reaches the wrong
+// audience, and every such mistake still builds and still pushes a valid
+// image.
+func imageTagArms(t *testing.T, yaml string) (tagArm, devArm, mainArm string) {
+	t.Helper()
+	const (
+		tagMarker  = `if [[ "${GITHUB_REF}" == refs/tags/v* ]]; then`
+		devMarker  = `elif [[ "${GITHUB_REF}" == "refs/heads/dev" ]]; then`
+		mainMarker = "\n          else"
+		endMarker  = "\n          fi"
+	)
+	iTag := strings.Index(yaml, tagMarker)
+	iDev := strings.Index(yaml, devMarker)
+	iMain := -1
+	if iDev >= 0 {
+		if k := strings.Index(yaml[iDev:], mainMarker); k >= 0 {
+			iMain = iDev + k
+		}
+	}
+	if iTag < 0 || iDev < 0 || iMain < 0 {
+		t.Fatal("Compute image tags no longer has a tag/dev/main arm — the tag policy has been restructured, so these guards are pinning nothing")
+	}
+	iEnd := iMain
+	if k := strings.Index(yaml[iMain:], endMarker); k >= 0 {
+		iEnd = iMain + k
+	} else {
+		t.Fatal("no closing fi after the main arm")
+	}
+	return yaml[iTag:iDev], yaml[iDev:iMain], yaml[iMain:iEnd]
 }
 
 // The worst regression this wiring can produce: a dev push that also moves
@@ -198,11 +266,7 @@ func devArm(t *testing.T, yaml string) string {
 // next pull. Nothing else in the suite would notice — the build stays green
 // and the image is valid, it is simply the wrong audience.
 func TestDevChannel_PublishesDevAloneAndNeverLatest(t *testing.T) {
-	body, err := os.ReadFile(filepath.Join(repoRoot(t), ".gitea", "workflows", "release.yml"))
-	if err != nil {
-		t.Fatal(err)
-	}
-	arm := devArm(t, string(body))
+	_, arm, _ := imageTagArms(t, releaseYAML(t))
 
 	if !strings.Contains(arm, "${IMAGE}:dev") {
 		t.Errorf("dev arm does not publish :dev\n%s", arm)
@@ -286,3 +350,369 @@ func TestBundleStep_GrepsCannotKillTheStep(t *testing.T) {
 		}
 	}
 }
+
+// The rollback unit, and the reason it is worth a guard: it is invisible until
+// the moment it is needed. Nothing pulls :<sha> during normal operation, so if
+// this arm stopped minting one, every build would stay green and every image
+// would be valid — and the absence would surface only during an incident, as
+// "there is nothing to roll back to."
+//
+// Rules 145 and 147: main push → :latest + :<sha>.
+func TestMainChannel_PublishesLatestAndTheRollbackUnit(t *testing.T) {
+	_, _, arm := imageTagArms(t, releaseYAML(t))
+
+	if !strings.Contains(arm, "${IMAGE}:latest") {
+		t.Errorf("main arm does not move :latest — production would stop tracking main's tip\n%s", arm)
+	}
+	if !strings.Contains(arm, "${IMAGE}:${GITHUB_SHA}") {
+		t.Errorf("main arm publishes no commit-addressable image; there is no rollback target for production commits\n%s", arm)
+	}
+	// Rule 147: :latest tracks main's tip, and a second name for the same
+	// image sends readers looking for a distinction that does not exist.
+	if strings.Contains(arm, "${IMAGE}:main") {
+		t.Errorf("main arm publishes :main — rule 147 says that tag should not exist\n%s", arm)
+	}
+}
+
+// A release refreshes the CHANNEL and mints nothing else (rules 145 + 146).
+//
+// The specific regression: re-adding :<sha> here. The tag build rebuilds the
+// SAME SOURCE as main's build minutes earlier, differing only in which APK is
+// baked in — so a :<sha> minted here would overwrite main's immutable rollback
+// target with different contents, under the same name. That is the exact thing
+// rule 145's immutability clause exists to prevent, and it is the half with
+// the incidents behind it.
+func TestReleaseBuild_RefreshesTheChannelAndMintsNothingElse(t *testing.T) {
+	arm, _, _ := imageTagArms(t, releaseYAML(t))
+
+	if !strings.Contains(arm, "${IMAGE}:latest") {
+		t.Errorf("tag arm does not refresh :latest — the channel would keep serving the PREVIOUS release's APK until someone pushed to main\n%s", arm)
+	}
+	if strings.Contains(arm, "GITHUB_SHA") {
+		t.Errorf("tag arm mints a :<sha> image; that would re-push main's immutable rollback target with different bundled contents\n%s", arm)
+	}
+}
+
+// No version-numbered image tags anywhere, on any arm (rule 145, and the
+// operator's 2026-09-10 decision to drop them across every project).
+//
+// Asserted across the whole step rather than per-arm because the mistake this
+// catches is re-adding one ANYWHERE, and the tag arm is only the likeliest
+// spot. `${VERSION}` still legitimately appears in the step as the build's
+// self-reported version, so the assertion has to name the image-tag form
+// specifically rather than the variable — otherwise it would fire on correct
+// code and get "fixed" by deleting the guard.
+func TestNoVersionNumberedImageTags(t *testing.T) {
+	yaml := releaseYAML(t)
+	tagArm, devArm, mainArm := imageTagArms(t, yaml)
+
+	for _, tc := range []struct{ name, arm string }{
+		{"tag", tagArm}, {"dev", devArm}, {"main", mainArm},
+	} {
+		for _, forbidden := range []string{
+			"${IMAGE}:${VERSION}",
+			"${IMAGE}:v",
+			"${IMAGE}:${GITHUB_REF#refs/tags/}",
+		} {
+			if strings.Contains(tc.arm, forbidden) {
+				t.Errorf("%s arm publishes a version-numbered image tag (%q); git and the build's self-reported version answer \"which build is this\"\n%s",
+					tc.name, forbidden, tc.arm)
+			}
+		}
+	}
+}
+
+// The verify job asserted the :<version> image existed. With version tags
+// gone that assertion would fail every release for a tag nothing mints — so
+// this pins that it was re-pointed rather than deleted, since deleting it is
+// the tempting way to make a failing guard go green.
+func TestVerifyJob_ChecksTheRollbackImageNotAVersionTag(t *testing.T) {
+	yaml := releaseYAML(t)
+
+	if !strings.Contains(yaml, "- name: Rollback image must exist for the tagged commit") {
+		t.Fatal("the release-verification step that checks an image exists is gone; an image push that silently did not happen would now pass verification")
+	}
+	step := stepBody(t, yaml, "Rollback image must exist for the tagged commit")
+	if !strings.Contains(step, "${IMAGE}:${GITHUB_SHA}") {
+		t.Errorf("the verify step does not inspect the commit's rollback image\n%s", step)
+	}
+	if strings.Contains(step, "${IMAGE}:${TAG}") {
+		t.Errorf("the verify step still inspects a version-numbered image, which is no longer published — this would fail every release\n%s", step)
+	}
+}
+
+// The server's self-reported version is now the ONLY thing that identifies a
+// build, so a lane that stamps a channel word instead of a version silently
+// removes that ability. It used to stamp the literal "main"/"dev".
+func TestImageBuild_StampsADerivedVersionAndAChannel(t *testing.T) {
+	yaml := releaseYAML(t)
+
+	step := stepBody(t, yaml, "Build and push")
+	for _, want := range []string{
+		"MINSTREL_VERSION=",
+		"MINSTREL_CHANNEL=",
+	} {
+		if !strings.Contains(step, want) {
+			t.Errorf("Build and push does not pass %s — the image cannot report which build it is\n%s", want, step)
+		}
+	}
+
+	// The version must come from the shared derivation, not from the ref.
+	// Reading it off GITHUB_REF is what produced "main" and "dev" as version
+	// strings, which is the regression this pins.
+	_, _, mainArm := imageTagArms(t, yaml)
+	if strings.Contains(mainArm, `version=main`) {
+		t.Errorf("the main arm stamps the literal string \"main\" as a version; two images months apart would be indistinguishable\n%s", mainArm)
+	}
+	if !strings.Contains(yaml, "ci/version.sh HEAD | sed") {
+		t.Error("the image job no longer derives its version from ci/version.sh — the version and the APK's version can now drift apart")
+	}
+}
+
+// gitRepo builds a throwaway repo and returns its path. Commit timestamps are
+// pinned so the derivation is deterministic.
+func gitRepo(t *testing.T) string {
+	t.Helper()
+	dir := t.TempDir()
+	run := func(args ...string) {
+		t.Helper()
+		cmd := exec.Command("git", args...)
+		cmd.Dir = dir
+		cmd.Env = append(os.Environ(), "GIT_CONFIG_GLOBAL=/dev/null", "GIT_CONFIG_SYSTEM=/dev/null")
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Fatalf("git %v: %v\n%s", args, err, out)
+		}
+	}
+	run("-c", "init.defaultBranch=main", "init", "-q")
+	run("config", "user.email", "t@example.invalid")
+	run("config", "user.name", "t")
+	return dir
+}
+
+// commitFile writes path and commits it with a pinned committer timestamp.
+func commitFile(t *testing.T, dir, path, epoch string) {
+	t.Helper()
+	full := filepath.Join(dir, path)
+	if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	// Content must DIFFER from any earlier write to the same path, or git
+	// records nothing and the commit silently covers fewer files than the
+	// test believes. That is not hypothetical: it made the
+	// source-alongside-test case pass vacuously.
+	if err := os.WriteFile(full, []byte("content @"+epoch+"\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	for _, args := range [][]string{{"add", "-A"}, {"commit", "-q", "-m", path}} {
+		cmd := exec.Command("git", args...)
+		cmd.Dir = dir
+		cmd.Env = append(os.Environ(),
+			"GIT_CONFIG_GLOBAL=/dev/null", "GIT_CONFIG_SYSTEM=/dev/null",
+			"GIT_AUTHOR_DATE=@"+epoch+" +0000",
+			"GIT_COMMITTER_DATE=@"+epoch+" +0000",
+		)
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Fatalf("git %v: %v\n%s", args, err, out)
+		}
+	}
+}
+
+// versionIn runs ci/version.sh inside dir, reading real git rather than the
+// pinned-clock override, so the PATHSPEC is what is under test.
+func versionIn(t *testing.T, dir string) (string, error) {
+	t.Helper()
+	cmd := exec.Command(filepath.Join(repoRoot(t), "ci", "version.sh"), "HEAD")
+	cmd.Dir = dir
+	cmd.Env = append(os.Environ(),
+		"GIT_CONFIG_GLOBAL=/dev/null", "GIT_CONFIG_SYSTEM=/dev/null",
+		"MINSTREL_NOW_EPOCH=1789000920",
+	)
+	out, err := cmd.CombinedOutput()
+	return string(out), err
+}
+
+// The version names what SHIPPED, so a commit that changes nothing shippable
+// must not move it.
+//
+// The failure this prevents is not the cosmetic one. The derivation is a
+// denylist precisely so that new content counts by default: the direction that
+// matters is a changed artifact keeping its OLD version, silently, on a green
+// run. This test pins the cheap half of that (CI-only commits are inert) and,
+// in the same breath, that a source commit still moves it — because a pathspec
+// typo that excluded everything would satisfy the first assertion alone.
+func TestVersionName_IgnoresCommitsThatShipNothing(t *testing.T) {
+	const (
+		shipped = "1757443736" // 2025-09-09T18:48:56Z
+		ciOnly  = "1789000920" // 2026-09-10T00:42:00Z, later
+	)
+	dir := gitRepo(t)
+	commitFile(t, dir, "internal/server/thing.go", shipped)
+	commitFile(t, dir, ".gitea/workflows/release.yml", ciOnly)
+
+	out, err := versionIn(t, dir)
+	if err != nil {
+		t.Fatalf("version.sh failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(out, "name=2025.09.09.1848") {
+		t.Errorf("a CI-only commit moved the version — the pathspec is not excluding it\n%s", out)
+	}
+
+	// ...and the pathspec must not be so broad it excludes everything.
+	commitFile(t, dir, "internal/server/other.go", ciOnly)
+	out, err = versionIn(t, dir)
+	if err != nil {
+		t.Fatalf("version.sh failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(out, "name=2026.09.10.0042") {
+		t.Errorf("a source commit did NOT move the version — the pathspec excludes too much, which is the silent-lie direction\n%s", out)
+	}
+}
+
+// android/ is deliberately NOT excluded, and that is the subtle half of the
+// list. It ships in no server image — but it is the APK's entire source, and
+// ONE script derives the version for both artifacts. Excluding it would stop
+// an Android-only commit from moving the APK's own version, which is exactly
+// the silent downgrade the versioning rework exists to prevent.
+func TestVersionName_AndroidSourcesCount(t *testing.T) {
+	dir := gitRepo(t)
+	commitFile(t, dir, "internal/server/thing.go", "1757443736")
+	commitFile(t, dir, "android/app/src/main/Thing.kt", "1789000920")
+
+	out, err := versionIn(t, dir)
+	if err != nil {
+		t.Fatalf("version.sh failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(out, "name=2026.09.10.0042") {
+		t.Errorf("an Android commit did not move the version; the APK would ship new code under its old version name\n%s", out)
+	}
+}
+
+// No shipped commit in range means a shallow clone, and the script must refuse
+// rather than emit something plausible. A wrong version builds, signs and
+// publishes perfectly happily; it surfaces later as an update channel that has
+// quietly stopped offering anything.
+func TestVersionScript_RefusesWhenNothingShippedIsInRange(t *testing.T) {
+	dir := gitRepo(t)
+	commitFile(t, dir, "ci/version.sh", "1789000920")
+
+	out, err := versionIn(t, dir)
+	if err == nil {
+		t.Fatalf("script succeeded with no shipped commit in range; it should refuse\n%s", out)
+	}
+	if strings.Contains(out, "name=") {
+		t.Errorf("script emitted a version name while refusing — that value could still be consumed\n%s", out)
+	}
+}
+
+// commitFiles is commitFile for more than one path in a single commit.
+func commitFiles(t *testing.T, dir, epoch string, paths ...string) {
+	t.Helper()
+	for _, rel := range paths {
+		full := filepath.Join(dir, rel)
+		if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(full, []byte("content @"+epoch+"\n"), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	for _, args := range [][]string{{"add", "-A"}, {"commit", "-q", "-m", strings.Join(paths, " ")}} {
+		cmd := exec.Command("git", args...)
+		cmd.Dir = dir
+		cmd.Env = append(os.Environ(),
+			"GIT_CONFIG_GLOBAL=/dev/null", "GIT_CONFIG_SYSTEM=/dev/null",
+			"GIT_AUTHOR_DATE=@"+epoch+" +0000",
+			"GIT_COMMITTER_DATE=@"+epoch+" +0000",
+		)
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Fatalf("git %v: %v\n%s", args, err, out)
+		}
+	}
+}
+
+// gitOutput runs a git command in dir and returns its combined output.
+func gitOutput(t *testing.T, dir string, args ...string) string {
+	t.Helper()
+	cmd := exec.Command("git", args...)
+	cmd.Dir = dir
+	cmd.Env = append(os.Environ(), "GIT_CONFIG_GLOBAL=/dev/null", "GIT_CONFIG_SYSTEM=/dev/null")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("git %v: %v\n%s", args, err, out)
+	}
+	return string(out)
+}
+
+// Tests do not ship, so a test-only commit must not re-version an artifact.
+//
+// `go build` drops *_test.go outright and the Vite build never imports a
+// .test.ts, so neither reaches an image or an APK. This repo has no tests/
+// tree — Go tests sit inline beside the code — so the exclusions are globs,
+// and a glob is easy to get subtly wrong in a way that still looks right.
+func TestVersionName_TestsDoNotReVersionTheArtifact(t *testing.T) {
+	const (
+		shipped = "1757443736" // 2025.09.09.1848
+		later   = "1789000920" // 2026.09.10.0042
+	)
+	for _, tc := range []struct{ name, path string }{
+		{"go test beside its source", "internal/server/thing_test.go"},
+		{"web unit test", "web/src/lib/api/admin.test.ts"},
+		{"web script test", "web/scripts/tokens-to-css.test.js"},
+		{"android JVM unit test", "android/app/src/test/java/A.kt"},
+		{"vitest harness config", "web/vitest.config.ts"},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			dir := gitRepo(t)
+			commitFile(t, dir, "internal/server/thing.go", shipped)
+			commitFile(t, dir, tc.path, later)
+
+			out, err := versionIn(t, dir)
+			if err != nil {
+				t.Fatalf("version.sh failed: %v\n%s", err, out)
+			}
+			if !strings.Contains(out, "name=2025.09.09.1848") {
+				t.Errorf("a commit touching only %s moved the version; tests do not ship\n%s", tc.path, out)
+			}
+		})
+	}
+}
+
+// The direction that actually costs something, and the reason the exclusions
+// above are globs over FILES rather than over their directories.
+//
+// `':!internal'` would satisfy every assertion in the test above while
+// silently excluding the entire server. This pins the opposite: a commit that
+// changes a test AND the source under it must still move the version, because
+// the source path matches on its own. Without this, a too-broad exclusion
+// reads as a passing test suite and ships an artifact under a stale version.
+func TestVersionName_ATestAlongsideItsSourceStillCounts(t *testing.T) {
+	const (
+		shipped = "1757443736"
+		later   = "1789000920"
+	)
+	dir := gitRepo(t)
+	commitFile(t, dir, "internal/server/thing.go", shipped)
+	commitFiles(t, dir, later,
+		"internal/server/thing.go",
+		"internal/server/thing_test.go",
+	)
+
+	// The commit must actually contain BOTH paths. Rewriting a file with
+	// identical bytes records nothing, and this assertion would then be
+	// checking a test-only commit while appearing to check a mixed one.
+	touched := gitOutput(t, dir, "show", "--name-only", "--format=", "HEAD")
+	for _, want := range []string{"internal/server/thing.go", "internal/server/thing_test.go"} {
+		if !strings.Contains(touched, want) {
+			t.Fatalf("fixture is wrong: HEAD does not contain %s\n%s", want, touched)
+		}
+	}
+
+	out, err := versionIn(t, dir)
+	if err != nil {
+		t.Fatalf("version.sh failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(out, "name=2026.09.10.0042") {
+		t.Errorf("a source change accompanied by a test change did NOT move the version — "+
+			"the exclusions are matching directories rather than test files\n%s", out)
+	}
+}

internal/server/server.go

@@ -218,6 +218,7 @@ func (s *Server) handleHealthz(w http.ResponseWriter, _ *http.Request) {
 	_ = json.NewEncoder(w).Encode(map[string]string{
 		"status":             "ok",
 		"version":            ServerVersion,
+		"channel":            ServerChannel,
 		"min_client_version": MinClientVersion,
 	})
 }

internal/server/version.go

@@ -5,12 +5,27 @@ package server
 // older clients see version_too_old at /healthz and refuse to operate.
 const MinClientVersion = "0.1.0"
 
-// ServerVersion is the deployed server image's version tag. Defaults to
-// "dev" for local builds; overridden at link time via:
+// ServerVersion is the build's own version name — YYYY.MM.DD.HHMM, derived
+// from the commit it was built from by ci/version.sh. Defaults to "dev" for
+// local builds; overridden at link time via:
 //
-//	-ldflags="-X 'git.fabledsword.com/bvandeusen/minstrel/internal/server.ServerVersion=v2026.05.10.2'"
+//	-ldflags="-X 'git.fabledsword.com/bvandeusen/minstrel/internal/server.ServerVersion=2026.09.10.1449'"
 //
-// release.yml passes the git tag through MINSTREL_VERSION build-arg →
-// Dockerfile ldflag. Surfaced at /healthz so operators can verify which
-// image their container is running without exec'ing into it.
+// release.yml passes it through the MINSTREL_VERSION build-arg → Dockerfile
+// ldflag. Surfaced at /healthz so operators can verify which image their
+// container is running without exec'ing into it.
+//
+// This carried the literal strings "main" and "dev" until 2026-09-10, which
+// made every image on a channel report the same thing forever. It stopped
+// being cosmetic when :vYYYY.MM.DD.HHMM image tags were retired (family rule
+// 145): this is now the ONLY thing that says which build is running.
 var ServerVersion = "dev"
+
+// ServerChannel is which line this build came off — "stable" or "dev", or
+// "local" for a plain `docker build`.
+//
+// A SIBLING FIELD, never a suffix inside ServerVersion (family rule 149). The
+// same commit built on both lanes reports the same version and differs only
+// here; folding the two together is what makes a version string stop being
+// comparable.
+var ServerChannel = "local"

web/src/lib/api/tuning.ts

@@ -34,14 +34,17 @@ export type DiscoverTuning = {
   snooze_days: number;
 };
 
-export type TuningScope = 'radio' | 'daily_mix' | 'taste' | 'discover';
+export type TuningScope = 'radio' | 'daily_mix' | 'songs_like' | 'taste' | 'discover';
+
+/** The weight-profile scopes, as distinct from the singleton-settings scopes. */
+export type WeightProfileScope = 'radio' | 'daily_mix' | 'songs_like';
 
 export type TuningSnapshot = {
-  profiles: Record<'radio' | 'daily_mix', WeightProfile>;
+  profiles: Record<WeightProfileScope, WeightProfile>;
   taste: TasteTuning;
   discover: DiscoverTuning;
   shipped: {
-    profiles: Record<'radio' | 'daily_mix', WeightProfile>;
+    profiles: Record<WeightProfileScope, WeightProfile>;
     taste: TasteTuning;
     discover: DiscoverTuning;
   };

web/src/lib/components/ServerVersion.svelte

@@ -6,26 +6,36 @@
   // is actually running (came up debugging the in-app update flow when
   // it wasn't obvious whether v2026.05.10.0 or .1 was deployed).
   //
+  // This is now the ONLY place an operator can see which build they are on.
+  // Image tags stopped carrying the version on 2026-09-10 — :latest and :dev
+  // are rolling names and :<sha> answers "which commit", not "which build" —
+  // so the server's self-report is the answer.
+  //
+  // The channel is shown BESIDE the version, never spliced into it: the same
+  // commit built on both lanes reports an identical version and differs only
+  // in channel, so "2026.09.10.1449 · dev" and "2026.09.10.1449 · stable" are
+  // the same code on two lines. Suppressed for stable, which is the
+  // unremarkable case and would just be noise on every install.
+  //
   // /healthz is unauthenticated, so the bare fetch works without
   // credentials. Renders nothing on parse failure or pre-version
   // images that don't include the field — graceful degradation.
 
-  type Health = { status: string; version?: string };
+  type Health = { status: string; version?: string; channel?: string };
 
   let version = $state<string | null>(null);
+  let channel = $state<string | null>(null);
 
   onMount(async () => {
     try {
       const res = await fetch('/healthz');
       if (!res.ok) return;
       const body = (await res.json()) as Partial<Health>;
-      if (body.version && body.version !== 'dev') {
+      if (!body.version) return;
       version = body.version;
-      } else if (body.version === 'dev') {
-        // Local dev images report "dev" — show it so the operator
-        // can tell they're not on a release tag.
-        version = 'dev';
-      }
+      // Reported verbatim rather than validated against an enum — a build
+      // claiming something unexpected is better shown than dropped.
+      channel = body.channel && body.channel !== 'stable' ? body.channel : null;
     } catch {
       // network / parse error — silent.
     }
@@ -33,5 +43,7 @@
 </script>
 
 {#if version}
-  <p class="text-xs text-text-secondary">Server {version}</p>
+  <p class="text-xs text-text-secondary">
+    Server {version}{#if channel}&nbsp;·&nbsp;{channel}{/if}
+  </p>
 {/if}

web/src/routes/admin/tuning/+page.svelte

@@ -6,6 +6,7 @@
     resetTuning,
     getTrends,
     type TuningScope,
+    type WeightProfileScope,
     type TuningSnapshot,
     type WeightProfile,
     type TasteTuning,
@@ -49,9 +50,15 @@
     { key: 'snooze_days',        label: 'Snooze length (days)', hint: 'How long "not right now" parks a suggestion before it returns on its own. Records no opinion about the artist and never feeds the taste profile.' }
   ];
 
-  const profileScopes: { scope: 'radio' | 'daily_mix'; label: string; blurb: string }[] = [
+  const profileScopes: { scope: WeightProfileScope; label: string; blurb: string }[] = [
     { scope: 'radio', label: 'Radio', blurb: 'Seed-directed listening — the user picked a direction.' },
-    { scope: 'daily_mix', label: 'Daily mixes', blurb: 'For You, Songs like…, and the discovery mixes.' }
+    { scope: 'daily_mix', label: 'Daily mixes', blurb: 'For You, the discovery mixes, and "You might like".' },
+    {
+      scope: 'songs_like',
+      label: 'Songs like…',
+      blurb:
+        'The tightest surface: everything here should sound like the seed track. Similarity dominates on purpose — raising like/taste/recency here is what makes these mixes wander.'
+    }
   ];
 
   let snapshot = $state<TuningSnapshot | null>(null);
@@ -64,10 +71,11 @@
     const f: Record<string, Record<string, string>> = {
       radio: {},
       daily_mix: {},
+      songs_like: {},
       taste: {},
       discover: {}
     };
-    for (const p of ['radio', 'daily_mix'] as const) {
+    for (const p of profileScopes.map((s) => s.scope)) {
       for (const { key } of weightFields) f[p][key] = String(snap.profiles[p][key]);
     }
     for (const { key } of tasteFields) f.taste[key] = String(snap.taste[key]);

web/src/routes/admin/tuning/tuning.test.ts

@@ -55,11 +55,19 @@ const discover = (over: Partial<Record<string, number>> = {}) => ({
 // new scopes to BOTH this fixture and `shipped`.
 function snapshot(over: Partial<TuningSnapshot> = {}): TuningSnapshot {
   return {
-    profiles: { radio: weights({ taste_weight: 1 }), daily_mix: weights() },
+    profiles: {
+      radio: weights({ taste_weight: 1 }),
+      daily_mix: weights(),
+      songs_like: weights({ similarity_weight: 4, like_boost: 0.5, taste_weight: 0.25 })
+    },
     taste: taste(),
     discover: discover(),
     shipped: {
-      profiles: { radio: weights({ taste_weight: 1 }), daily_mix: weights() },
+      profiles: {
+        radio: weights({ taste_weight: 1 }),
+        daily_mix: weights(),
+        songs_like: weights({ similarity_weight: 4, like_boost: 0.5, taste_weight: 0.25 })
+      },
       taste: taste(),
       discover: discover()
     },
@@ -75,11 +83,12 @@ beforeEach(() => {
 });
 
 describe('Admin tuning page', () => {
-  test('renders both profiles and the taste card with current values', async () => {
+  test('renders every weight profile and the taste card with current values', async () => {
     (getTuning as ReturnType<typeof vi.fn>).mockResolvedValue(snapshot());
     render(TuningPage);
     await waitFor(() => expect(screen.getByText('Radio')).toBeInTheDocument());
     expect(screen.getByText('Daily mixes')).toBeInTheDocument();
+    expect(screen.getByText('Songs like…')).toBeInTheDocument();
     expect(screen.getByText('Taste profile build')).toBeInTheDocument();
     const radioTaste = screen.getByLabelText(/taste weight/i, {
       selector: '#radio-taste_weight'
@@ -89,6 +98,27 @@ describe('Admin tuning page', () => {
     expect(halfLife.value).toBe('75');
   });
 
+  // Songs-like is a separate weight profile precisely so it can be tuned
+  // apart from For-You (#3881). If its card stopped rendering its OWN values
+  // — or quietly fell back to daily_mix's — the split would exist in the
+  // backend and be unreachable in the UI, which is the same as not shipping
+  // it (rule 27).
+  test('the songs-like card carries its own weights, not daily_mix\'s', async () => {
+    (getTuning as ReturnType<typeof vi.fn>).mockResolvedValue(snapshot());
+    render(TuningPage);
+    await waitFor(() => expect(screen.getByText('Songs like…')).toBeInTheDocument());
+
+    const sim = document.getElementById('songs_like-similarity_weight') as HTMLInputElement;
+    const like = document.getElementById('songs_like-like_boost') as HTMLInputElement;
+    expect(sim.value).toBe('4');
+    expect(like.value).toBe('0.5');
+
+    // The contrast that makes the card worth having: daily_mix must still show
+    // its own, different numbers on the same page.
+    const dailySim = document.getElementById('daily_mix-similarity_weight') as HTMLInputElement;
+    expect(dailySim.value).not.toBe(sim.value);
+  });
+
   test('save sends only the changed fields for the scope', async () => {
     (getTuning as ReturnType<typeof vi.fn>).mockResolvedValue(snapshot());
     (patchTuning as ReturnType<typeof vi.fn>).mockResolvedValue(snapshot());