chore: the poster-picker comments name their task #4491

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

alembic/versions/0115_source_display_name.py

@@ -0,0 +1,27 @@
+"""source.display_name — what a source is called on its platform.
+
+#4481. A Discord source's URL is a server id and a channel id, so the
+Subscriptions page could only show two numbers. The Discord ingester already
+loads the server and channel names to walk them; it now keeps them here,
+refreshed on every walk. NULL until a walk has read it.
+
+Revision ID: 0115
+Revises: 0114
+Create Date: 2026-09-28
+
+"""
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0115"
+down_revision = "0114"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column("source", sa.Column("display_name", sa.Text(), nullable=True))
+
+
+def downgrade() -> None:
+    op.drop_column("source", "display_name")

alembic/versions/0116_single_color_threshold.py

@@ -0,0 +1,34 @@
+"""The single-color filter's default becomes near-total: 0.95 → 0.995.
+
+#4483. At 0.95 the filter rejected line art: a pencil doodle on white is
+mostly white, and five of Todding's Discord doodles were skipped on import as
+"single color", leaving their posts with text and no image. The predicate now
+samples real pixels instead of a blurred thumbnail, and the default only
+calls an image blank when it essentially is one.
+
+A stored 0.95 is the old default, so it moves with it. Any other value was
+chosen by hand and is left alone.
+
+Revision ID: 0116
+Revises: 0115
+Create Date: 2026-09-28
+
+"""
+from alembic import op
+
+revision = "0116"
+down_revision = "0115"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.alter_column("import_settings", "single_color_threshold", server_default="0.995")
+    op.execute(
+        "UPDATE import_settings SET single_color_threshold = 0.995 "
+        "WHERE single_color_threshold = 0.95"
+    )
+
+
+def downgrade() -> None:
+    op.alter_column("import_settings", "single_color_threshold", server_default="0.95")

backend/app/api/extension.py

@@ -19,8 +19,10 @@ from ..models import AppSetting
 from ..services.extension_service import (
     ExtensionService,
     InvalidUrlError,
+    PosterLookupError,
     UnknownArtistError,
     UnknownPlatformError,
+    UnknownSourceError,
 )
 from ..services.source_service import KNOWN_PLATFORMS
 from ._responses import error_response as _bad
@@ -121,6 +123,10 @@ async def quick_add_source():
     # Patreon is canon: adding a Patreon source to an existing artist can take
     # the creator's Patreon display name (name only; the slug never moves).
     use_platform_name = body.get("use_platform_name") is True
+    # #4491: a Discord add can carry the posters picked in the panel.
+    discord_authors = body.get("discord_authors")
+    if discord_authors is not None and not _valid_authors(discord_authors):
+        return _bad("invalid_body", detail="discord_authors must be a list of {id, name}")
 
     from .credentials import _get_crypto
 
@@ -133,6 +139,7 @@ async def quick_add_source():
             result = await ExtensionService(session, _get_crypto()).quick_add_source(
                 url, artist_id=artist_id, artist_name=artist_name,
                 use_platform_name=use_platform_name,
+                discord_authors=discord_authors,
             )
         except UnknownArtistError as exc:
             return _bad("not_found", detail=str(exc), status=404)
@@ -147,6 +154,59 @@ async def quick_add_source():
     return jsonify(result), (201 if result["created_source"] else 200)
 
 
+def _valid_authors(value) -> bool:
+    """[{id, name}]: the id is what the list keys on, the name only shows it."""
+    return isinstance(value, list) and all(
+        isinstance(a, dict) and isinstance(a.get("id"), str | int)
+        and not isinstance(a.get("id"), bool)
+        and (a.get("name") is None or isinstance(a.get("name"), str))
+        for a in value
+    )
+
+
+@extension_bp.route("/discord/posters", methods=["GET"])
+async def discord_posters():
+    """Who posts in the Discord channel `url` shows, lately, with the likely
+    creator marked (#4491). Reads the channel with the stored token; writes
+    nothing."""
+    url = (request.args.get("url") or "").strip()
+    if not url:
+        return _bad("invalid_body", detail="url query parameter is required")
+    from .credentials import _get_crypto
+
+    async with get_session() as session:
+        if not await _ext_key_required(session):
+            return _bad("unauthorized", status=401)
+        try:
+            result = await ExtensionService(session, _get_crypto()).discord_posters(url)
+        except (InvalidUrlError, UnknownPlatformError) as exc:
+            return _bad("invalid_url", detail=str(exc))
+        except PosterLookupError as exc:
+            return _bad("posters_unavailable", detail=str(exc), status=409)
+    return jsonify(result)
+
+
+@extension_bp.route("/discord/posters", methods=["POST"])
+async def set_discord_posters():
+    """Set the poster list of the source following `url`'s channel."""
+    body = await request.get_json(silent=True)
+    if not isinstance(body, dict) or not isinstance(body.get("url"), str):
+        return _bad("invalid_body", detail="url is required")
+    authors = body.get("authors")
+    if not _valid_authors(authors):
+        return _bad("invalid_body", detail="authors must be a list of {id, name}")
+    async with get_session() as session:
+        if not await _ext_key_required(session):
+            return _bad("unauthorized", status=401)
+        try:
+            result = await ExtensionService(session).set_discord_posters(body["url"], authors)
+        except (InvalidUrlError, UnknownPlatformError, PosterLookupError) as exc:
+            return _bad("invalid_url", detail=str(exc))
+        except UnknownSourceError as exc:
+            return _bad("not_found", detail=str(exc), status=404)
+    return jsonify(result)
+
+
 def _read_manifest_sync() -> dict | None:
     """All the filesystem-touching work for /api/extension/manifest,
     in a sync helper so the async route can dispatch it via

backend/app/api/sources.py

@@ -1,10 +1,13 @@
 """FC-3a: CRUD over Source rows. FC-3c adds POST /<id>/check."""
 
+from pathlib import Path
+
 from quart import Blueprint, jsonify, request
 from sqlalchemy import func, select
 
 from ..extensions import get_session
 from ..models import DownloadEvent, MembershipSync, PlatformMembership, Source
+from ..services import discord_poster_cleanup as poster_cleanup
 from ..services.artist_membership_service import ArtistMembershipService
 from ..services.artist_membership_service import rescan as membership_rescan
 from ..services.artist_service import ArtistService
@@ -463,3 +466,49 @@ async def adopt_membership():
             return jsonify({"already_tracked": exc.existing_id})
         artist_id = artist.id
     return jsonify({"source_id": record.id, "artist_id": artist_id}), 201
+
+
+# -- Discord: remove posts by people outside the poster list (#4486) --------------
+
+_IMAGES_ROOT = Path("/images")
+
+
+async def _poster_cleanup_preview(source_id: int):
+    async with get_session() as session:
+        return await session.run_sync(
+            lambda s: poster_cleanup.preview(s, source_id=source_id)
+        )
+
+
+@sources_bp.route("/<int:source_id>/discord/other-posters", methods=["GET"])
+async def other_posters_preview(source_id: int):
+    """What removing other posters' posts would delete. Nothing is touched."""
+    try:
+        projection = await _poster_cleanup_preview(source_id)
+    except LookupError:
+        return _bad("not_found", status=404)
+    except poster_cleanup.PosterCleanupError as exc:
+        return _bad("not_applicable", detail=str(exc), status=409)
+    projection["confirm_token"] = poster_cleanup.confirm_token(projection)
+    return jsonify(projection)
+
+
+@sources_bp.route("/<int:source_id>/discord/other-posters/remove", methods=["POST"])
+async def other_posters_remove(source_id: int):
+    """Delete them. `confirm` must be the token of the preview the operator saw:
+    a poster list edited since then changes the set, and the token with it."""
+    body = await request.get_json(silent=True) or {}
+    try:
+        projection = await _poster_cleanup_preview(source_id)
+    except LookupError:
+        return _bad("not_found", status=404)
+    except poster_cleanup.PosterCleanupError as exc:
+        return _bad("not_applicable", detail=str(exc), status=409)
+    expected = poster_cleanup.confirm_token(projection)
+    if body.get("confirm") != expected:
+        return _bad("confirm_mismatch", expected=expected)
+    async with get_session() as session:
+        result = await session.run_sync(
+            lambda s: poster_cleanup.apply(s, source_id=source_id, images_root=_IMAGES_ROOT)
+        )
+    return jsonify(result)

backend/app/models/import_settings.py

@@ -39,7 +39,7 @@ class ImportSettings(Base):
     transparency_threshold: Mapped[float] = mapped_column(Float, nullable=False, default=0.9, server_default="0.9")
 
     skip_single_color: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False, server_default="false")
-    single_color_threshold: Mapped[float] = mapped_column(Float, nullable=False, default=0.95, server_default="0.95")
+    single_color_threshold: Mapped[float] = mapped_column(Float, nullable=False, default=0.995, server_default="0.995")
     single_color_tolerance: Mapped[int] = mapped_column(Integer, nullable=False, default=30, server_default="30")
 
     # Hamming distance over a 256-bit pHash (utils.phash, hash_size=16). The

backend/app/models/source.py

@@ -46,6 +46,11 @@ class Source(Base):
     enabled: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True, server_default="true")
 
     config_overrides: Mapped[dict | None] = mapped_column(JSON, nullable=True)
+    # alembic 0115: what the source is called on its platform, where the URL
+    # alone doesn't say — a Discord link is two numbers. The ingester that
+    # walks it refreshes it every walk, so a rename reads as the new name.
+    # NULL until a walk has read it, and on platforms that don't write it.
+    display_name: Mapped[str | None] = mapped_column(Text, nullable=True)
 
     last_checked_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     last_error: Mapped[str | None] = mapped_column(Text, nullable=True)

backend/app/services/audits/single_color.py

@@ -4,11 +4,19 @@ predicate for BOTH surfaces: FC-Cleanup's retroactive audit and — since
 2026-07-02 — the import-side filter (Importer._single_color_hit /
 SkipReason.single_color), so what the audit flags and what the import
 skips can never disagree.
+
+It is meant to catch the blank: a placeholder, an error tile, a solid fill.
+Line art is the case it must not catch (#4483): a pencil doodle on white can be
+well over 95% white even at full size, and a smoothing downsample blends its strokes
+into the paper until it measures as blank. So the sample is taken by NEAREST
+(each sampled pixel is a real pixel, strokes keep their contrast), at 256px
+so thin strokes are still hit, and the default threshold is near-total
+(0.995) — a few percent of ink is a drawing, not an empty image.
 """
 
 from PIL import Image
 
-_THUMB_SIZE = (64, 64)
+_THUMB_SIZE = (256, 256)
 
 
 def evaluate(
@@ -20,7 +28,8 @@ def evaluate(
     """True iff the fraction of pixels within `tolerance` (Euclidean RGB
     distance) of the dominant color exceeds `threshold`.
 
-    Downsamples to 64x64 for speed (~4ms regardless of source size).
+    Samples 256x256 by NEAREST (see the module docstring for why not a
+    smoothing resample).
     Alpha channels are stripped; only RGB is considered. Animated images
     use frame 0 (PIL's default after Image.open without seek).
     """
@@ -30,7 +39,7 @@ def evaluate(
     elif im.mode not in ("RGB", "L"):
         im = im.convert("RGB")
     if im.size != _THUMB_SIZE:
-        im = im.resize(_THUMB_SIZE, Image.Resampling.BILINEAR)
+        im = im.resize(_THUMB_SIZE, Image.Resampling.NEAREST)
     pixels = list(im.getdata())
     if not pixels:
         return False

backend/app/services/discord_client.py

@@ -32,6 +32,13 @@ Two deliberate departures, both about the walk order, neither about content:
     the walk. gallery-dl skips only nested channels; one private thread the
     token cannot read would otherwise stop every channel after it.
 
+And one about content: a message is taken only if it has an image or video
+ATTACHMENT (`has_visual_attachment`). Discord is where creators chat as well
+as post, and the operator wants the art, not the conversation (2026-09-28): a
+text line, a lone archive or PSD, a pasted link's preview or a Tenor GIF is
+chat. A message that passes keeps every file gallery-dl would take, numbered
+as gallery-dl numbers them, so the on-disk names still match.
+
 FC runs on a plain-HTTP homelab; nothing here uses a secure-context Web API.
 """
 
@@ -68,6 +75,9 @@ _THREADS_BATCH = 25
 # it is honoured when present; 60s is the fallback and the cap.
 _MAX_429_RETRIES = 4
 _429_WAIT_SECONDS = 60.0
+# How far back the poster picker looks: two pages. Enough to see who posts in
+# a channel, few enough to answer while the operator waits (#4491).
+_POSTER_SCAN = 200
 
 # https://discord.com/developers/docs/resources/message#message-object-message-types
 # DEFAULT, REPLY, CHAT_INPUT_COMMAND — the ones that carry user content.
@@ -79,6 +89,13 @@ _FORUM = frozenset({15, 16})            # forum, media: threads only
 _CATEGORY = 4
 _SERVER_WALK = _TEXT | _FORUM
 _EMBED_TYPES = frozenset({"image", "gifv", "video"})
+# What makes a message art rather than chat: an attached file FC imports as an
+# image or video. Mirrors importer.ALL_EXTS (not imported: that module is the
+# import pipeline, and this one is a network client).
+_VISUAL_EXTS = frozenset({
+    "png", "jpg", "jpeg", "gif", "webp", "bmp", "tif", "tiff",
+    "mp4", "mov", "avi", "mkv", "webm", "m4v", "wmv", "flv",
+})
 
 _URL_RE = re.compile(
     r"^(?:https?://)?(?:www\.|ptb\.|canary\.)?discord(?:app)?\.com/channels/"
@@ -163,6 +180,82 @@ def message_text(message: dict) -> str:
     return "\n".join(p for p in parts if p)
 
 
+def _message_and_snapshots(message: dict) -> list[dict]:
+    """The message itself, then each forwarded message it carries."""
+    return [message] + [
+        (s or {}).get("message") or {}
+        for s in message.get("message_snapshots") or []
+        if ((s or {}).get("message") or {}).get("type", 0) in MESSAGE_TYPES
+    ]
+
+
+def _is_visual(attachment: dict) -> bool:
+    ctype = (attachment.get("content_type") or "").lower()
+    if ctype.startswith(("image/", "video/")):
+        return True
+    name = attachment.get("filename") or attachment.get("url") or ""
+    return nameext_from_url(name)[1] in _VISUAL_EXTS
+
+
+def has_visual_attachment(message: dict) -> bool:
+    """Does this message, or a message it forwards, have an image or video
+    attached? The one test for "art, not chat" — see the module docstring."""
+    return any(
+        att.get("url") and _is_visual(att)
+        for snap in _message_and_snapshots(message)
+        for att in snap.get("attachments") or []
+    )
+
+
+_SQUASH = re.compile(r"[\W_]+", re.UNICODE)
+# Words a server name wraps around its creator's: "Todding's Server",
+# "The Official Todding Discord".
+_SERVER_WORDS = frozenset({"server", "discord", "the", "official", "community", "s"})
+
+
+def _squash(text: str | None) -> str:
+    return _SQUASH.sub("", (text or "").lower())
+
+
+def _server_tokens(server_name: str | None) -> list[str]:
+    name = (server_name or "").lower().replace("'s", " ").replace("\u2019s", " ")
+    words = [w for w in _SQUASH.split(name) if w and w not in _SERVER_WORDS]
+    tokens = [w for w in words if len(w) >= 3]
+    joined = "".join(words)
+    if len(joined) >= 3 and joined not in tokens:
+        tokens.append(joined)
+    return tokens
+
+
+def rank_posters(server_name: str | None, owner_id, posters: list[dict]) -> list[dict]:
+    """Mark who is probably the creator a server is named for, and order the
+    list for picking: suggested first, then by images posted, then messages.
+
+    Two signals, each a reason the picker shows beside the name:
+      - they own the server;
+      - their username or display name matches the server's name, once
+        "'s Server", "Official", "Discord" and punctuation are taken off
+        ("Todding's Server" and "todding").
+    Neither signal alone is proof, which is why this suggests and never
+    decides: the operator ticks the list. Bots are never suggested."""
+    tokens = _server_tokens(server_name)
+    owner = str(owner_id) if owner_id else None
+    ranked = []
+    for p in posters:
+        reasons = []
+        if owner and p.get("id") == owner:
+            reasons.append("owns the server")
+        names = [n for n in (_squash(p.get("username")), _squash(p.get("global_name"))) if len(n) >= 3]
+        if any(t in n or n in t for t in tokens for n in names):
+            reasons.append("name matches the server")
+        ranked.append({**p, "reasons": reasons, "suggested": False})
+    best = max((len(r["reasons"]) for r in ranked if not r.get("bot")), default=0)
+    for r in ranked:
+        r["suggested"] = best > 0 and not r.get("bot") and len(r["reasons"]) == best
+    ranked.sort(key=lambda r: (not r["suggested"], -r.get("images", 0), -r.get("messages", 0)))
+    return ranked
+
+
 @dataclass
 class MediaItem:
     """One file of a Discord message. `filename`/`extension` are gallery-dl's
@@ -212,6 +305,8 @@ class DiscordClient:
         self._server: dict = {}
         self._channels: dict[str, dict] = {}
         self._skip_feed = False
+        # Whose messages the walk takes (`only_from`); empty takes everyone's.
+        self._authors: frozenset[str] = frozenset()
 
     # -- request -----------------------------------------------------------
 
@@ -373,6 +468,43 @@ class DiscordClient:
             if meta["channel_type"] in _SERVER_WALK:
                 yield from self._feeds(meta["channel_id"], safe=True)
 
+    def only_from(self, authors) -> None:
+        """Take only messages posted by these people: user ids, usernames or
+        display names, any case. A creator's server is full of other members
+        posting their own pictures; the source is subscribed to the creator.
+        Empty or None takes everyone's, as before."""
+        self._authors = frozenset(
+            str(a).strip().lower() for a in authors or () if str(a).strip()
+        )
+
+    def _author_wanted(self, message: dict) -> bool:
+        if not self._authors:
+            return True
+        author = message.get("author") or {}
+        names = (author.get("id"), author.get("username"), author.get("global_name"))
+        return any(str(n).lower() in self._authors for n in names if n)
+
+    def source_label(self, url: str) -> str | None:
+        """What the source is called in Discord — `Server · #channel`, a
+        thread as `#parent › thread`, a whole server by its name — from the
+        metadata the walk loaded. None when the walk never got that far."""
+        try:
+            _, channel_id = parse_source_url(url)
+        except DiscordAPIError:
+            return None
+        server = self._server.get("server") or None
+        if channel_id is None:
+            return server
+        meta = self._channels.get(channel_id) or {}
+        name = meta.get("channel")
+        if not name:
+            return None
+        if name != "DMs":
+            name = f"#{name}"
+            if meta.get("is_thread") and meta.get("parent"):
+                name = f"#{meta['parent']} › {meta['channel']}"
+        return f"{server} · {name}" if server else name
+
     def skip_feed(self) -> None:
         """Optional core seam (#4413): end the current channel and go on to the
         next one. A tick's early-out means THIS channel has nothing new, not
@@ -440,6 +572,8 @@ class DiscordClient:
             for message in messages:
                 if message.get("type") not in MESSAGE_TYPES:
                     continue
+                if not self._author_wanted(message):
+                    continue
                 message["_meta"] = meta
                 yield message, meta, page_cursor
                 if self._skip_feed:
@@ -454,13 +588,14 @@ class DiscordClient:
     def extract_media(post: dict, included: dict | None = None) -> list[MediaItem]:
         """gallery-dl's file list for one message: attachments, then the first
         of video/image/thumbnail `proxy_url` of each file-bearing embed, then
-        the same for every forwarded snapshot; numbered from 1 across them."""
+        the same for every forwarded snapshot; numbered from 1 across them.
+
+        Empty for a message with no image or video attached: that is chat,
+        whatever else it carries (`has_visual_attachment`)."""
+        if not has_visual_attachment(post):
+            return []
         mid = str(post.get("id") or "")
-        snapshots = [post] + [
-            (s or {}).get("message") or {}
-            for s in post.get("message_snapshots") or []
-            if ((s or {}).get("message") or {}).get("type", 0) in MESSAGE_TYPES
-        ]
+        snapshots = _message_and_snapshots(post)
         found: list[tuple[str, str, str | None]] = []
         for snap in snapshots:
             for att in snap.get("attachments") or []:
@@ -498,10 +633,10 @@ class DiscordClient:
         """`(message:<id>, <id>)` — gates the message record through the seen
         ledger, like `post:<id>` on the other platforms.
 
-        None for a message with no files. gallery-dl wrote a sidecar only
-        beside a file, so a text-only chat line never became a post, and the
-        drop grouping (discord_grouping) is built on that: a channel's chatter
-        recorded as posts would bury the drops it exists to surface."""
+        None for a message `extract_media` takes nothing from, i.e. one with
+        no image or video attached. The drop grouping (discord_grouping) is
+        built on that: a channel's chatter recorded as posts would bury the
+        drops it exists to surface."""
         mid = post.get("id")
         mid = str(mid) if mid is not None else ""
         if not mid or not cls.extract_media(post):
@@ -528,6 +663,61 @@ class DiscordClient:
                 pass
         return out
 
+    def recent_posters(
+        self, server_id: str | None, channel_id: str, *, max_messages: int = _POSTER_SCAN,
+    ) -> dict:
+        """Who has posted lately in a channel, for picking a source's poster
+        list (#4491): the newest `max_messages` messages, tallied per author.
+        Deliberately shallow — it answers "who posts here", not "who ever did".
+        Every poster comes back with their stable id, which is what the list
+        stores: a username can change on a whim, an id can't."""
+        server: dict = {}
+        if server_id:
+            try:
+                server = self._get(f"/guilds/{server_id}") or {}
+            except DiscordAPIError:
+                server = {}
+        tally: dict[str, dict] = {}
+        before = None
+        seen = 0
+        while seen < max_messages:
+            page = self._get(
+                f"/channels/{channel_id}/messages",
+                {"limit": min(_MESSAGES_BATCH, max_messages - seen), "before": before},
+            )
+            if not isinstance(page, list) or not page:
+                break
+            for message in page:
+                seen += 1
+                if message.get("type") not in MESSAGE_TYPES:
+                    continue
+                author = message.get("author") or {}
+                aid = str(author.get("id") or "")
+                if not aid:
+                    continue
+                row = tally.setdefault(aid, {
+                    "id": aid,
+                    "username": author.get("username"),
+                    "global_name": author.get("global_name"),
+                    "bot": bool(author.get("bot")),
+                    "messages": 0,
+                    "images": 0,
+                })
+                row["messages"] += 1
+                if has_visual_attachment(message):
+                    row["images"] += 1
+            if len(page) < _MESSAGES_BATCH:
+                break
+            before = str(page[-1]["id"])
+        return {
+            "server": server.get("name") or None,
+            "owner_id": str(server["owner_id"]) if server.get("owner_id") else None,
+            "scanned": seen,
+            "posters": rank_posters(
+                server.get("name"), server.get("owner_id"), list(tally.values()),
+            ),
+        }
+
     def verify_auth(self, url: str) -> tuple[bool | None, str]:
         """Is the token valid, and can it see what the source names?"""
         try:

backend/app/services/discord_downloader.py

@@ -195,6 +195,7 @@ class DiscordDownloader(BaseNativeDownloader):
             "parent": meta.get("parent"),
             "is_thread": meta.get("is_thread"),
             "author": author.get("username"),
+            "author_name": author.get("global_name"),
             "author_id": author.get("id"),
             "message": body,
             "date": post.get("timestamp"),

backend/app/services/discord_ingester.py

@@ -13,6 +13,11 @@ Two things differ from the cookie platforms:
     something; a Discord drop is routinely files and nothing else, so on
     Discord that is an ordinary backfill, not a broken parser.
 
+And two things only a Discord source has: `discord_authors` in its
+config_overrides limits it to the creator's own messages (a server's other
+members post pictures too), and it learns its own name — the server and
+channel it walks — into `source.display_name`.
+
 `campaign_id` is the source URL (a server, channel, thread or category link).
 FC runs on a plain-HTTP homelab; nothing here uses a secure-context Web API.
 """
@@ -20,15 +25,23 @@ FC runs on a plain-HTTP homelab; nothing here uses a secure-context Web API.
 from __future__ import annotations
 
 import asyncio
+import logging
 from collections.abc import Callable
 from pathlib import Path
 
-from ..models import DiscordFailedMedia, DiscordSeenMedia
+from sqlalchemy import select, update
+
+from ..models import DiscordFailedMedia, DiscordSeenMedia, Source
 from .discord_client import DiscordAPIError, DiscordClient, MediaItem
 from .discord_downloader import DiscordDownloader
 from .ingest_core import Ingester
 
+log = logging.getLogger(__name__)
+
 _LEDGER_KEY_MAX = 128
+# `config_overrides` key: the people whose messages this source takes (user
+# ids, usernames or display names). Absent or empty takes everyone's.
+AUTHORS_KEY = "discord_authors"
 
 
 def _ledger_key(media: MediaItem) -> str:
@@ -74,6 +87,46 @@ class DiscordIngester(Ingester):
             body_canary=False,
         )
 
+    def run(self, **kwargs):
+        """The core walk, bracketed by the two things only a Discord source
+        has: whose messages it takes, read before the walk, and the name of
+        what it walks, written after it (the walk is what loads that name)."""
+        source_id = kwargs["source_id"]
+        self.client.only_from(self._source_authors(source_id))
+        try:
+            return super().run(**kwargs)
+        finally:
+            self._record_display_name(source_id, kwargs["campaign_id"])
+
+    def _source_authors(self, source_id: int) -> list:
+        if self.session_factory is None:
+            return []
+        with self.session_factory() as session:
+            overrides = session.execute(
+                select(Source.config_overrides).where(Source.id == source_id)
+            ).scalar_one_or_none() or {}
+        authors = overrides.get(AUTHORS_KEY) or []
+        return authors if isinstance(authors, list) else []
+
+    def _record_display_name(self, source_id: int, url: str) -> None:
+        """Refreshed on every walk, never written once: a renamed channel
+        should read as its new name. A name the walk couldn't read leaves the
+        stored one alone, and a failure here never fails the walk."""
+        label = self.client.source_label(url)
+        if not label or self.session_factory is None:
+            return
+        try:
+            with self.session_factory() as session:
+                session.execute(
+                    update(Source)
+                    .where(Source.id == source_id)
+                    .where(Source.display_name.is_distinct_from(label))
+                    .values(display_name=label)
+                )
+                session.commit()
+        except Exception as exc:  # a name is decoration — never fail the walk
+            log.warning("Discord: couldn't record source %s's name: %s", source_id, exc)
+
 
 async def verify_discord_credential(url: str, auth_token: str | None) -> tuple[bool | None, str]:
     """The uniform `(ok, message)` probe: is the token valid, and can its

backend/app/services/discord_poster_cleanup.py

@@ -0,0 +1,243 @@
+"""Remove a Discord source's posts by people outside its poster list (#4486).
+
+A creator's server is full of other members posting their own pictures. The
+poster list (`discord_authors`, #4481) stops a walk taking them; this removes
+the ones taken before the list existed. The operator sets the list first, then
+previews what would go, then applies.
+
+## What goes
+
+A post of this source whose record names its poster (`author_id` / `author`,
+written by `DiscordDownloader.write_post_record`) and names someone NOT on the
+list. Two kinds of post are never touched:
+
+* a post whose record names no poster — a message recorded before the native
+  ingester, whose poster FC cannot tell. Counted as `unknown`, never guessed;
+* a synthetic drop post (`synthesized_by`) — FC authored it, and it is handled
+  below as a consequence, not matched as a poster's post.
+
+An image goes when every REAL post it belongs to is going. A link to a
+synthetic drop does not keep an image: the drop only references its members'
+images. An image also on a kept post — the creator re-posting a piece someone
+else shared — stays.
+
+A drop that absorbed a removed message is deleted outright. Deleting a drop is
+its undo (discord_grouping's honesty rule): its remaining members return to
+the feed and the grouping sweep regroups them on its next run, so no half-
+rebuilt drop keeps text or thumbnails from someone it no longer contains.
+
+Preview and apply spread the same predicates (rule 93, snippet #3087).
+"""
+
+from __future__ import annotations
+
+import logging
+from pathlib import Path
+
+from sqlalchemy import and_, delete, exists, func, or_, select
+from sqlalchemy.orm import Session, aliased
+
+from ..models import ImageProvenance, ImageRecord, Post, PostAttachment, Source
+from .cleanup_service import delete_images
+from .discord_ingester import AUTHORS_KEY
+
+log = logging.getLogger(__name__)
+
+PLATFORM = "discord"
+# The record keys that name a message's poster. `author_name` (the display
+# name) is only on records written after 2026-09-28.
+_POSTER_KEYS = ("author_id", "author", "author_name")
+
+
+class PosterCleanupError(ValueError):
+    """The source can't be cleaned this way (not Discord, or no list)."""
+
+
+def source_authors(source: Source) -> list[str]:
+    """The source's poster list, lowercased; empty means everyone's wanted."""
+    authors = (source.config_overrides or {}).get(AUTHORS_KEY) or []
+    if not isinstance(authors, list):
+        return []
+    return sorted({str(a).strip().lower() for a in authors if str(a).strip()})
+
+
+def _poster(key: str):
+    return func.lower(Post.raw_metadata[key].as_string())
+
+
+def _has_poster():
+    return or_(*(Post.raw_metadata[k].as_string().isnot(None) for k in ("author_id", "author")))
+
+
+def _real_post_conditions(source_id: int) -> list:
+    return [Post.source_id == source_id, Post.synthesized_by.is_(None)]
+
+
+def _named_poster_conditions(source_id: int) -> list:
+    """A real post of this source whose record says who posted it."""
+    return [*_real_post_conditions(source_id), _has_poster()]
+
+
+def _other_poster_post_conditions(source_id: int, authors: list[str]) -> list:
+    """The posts that go: a named poster none of whose names is on the list."""
+    return [
+        *_named_poster_conditions(source_id),
+        *(func.coalesce(_poster(k), "").notin_(authors) for k in _POSTER_KEYS),
+    ]
+
+
+def _doomed_post_ids(source_id: int, authors: list[str]):
+    # correlate(None): used inside queries that are themselves over `post` (the
+    # drops, the delete), where auto-correlation would bind this to the outer
+    # row instead of scanning the table.
+    return (
+        select(Post.id)
+        .where(*_other_poster_post_conditions(source_id, authors))
+        .correlate(None)
+    )
+
+
+def _image_conditions(source_id: int, authors: list[str]) -> list:
+    """Images that belong to a removed post and to no kept real post."""
+    doomed = _doomed_post_ids(source_id, authors)
+    keeper = aliased(Post)
+    on_doomed = or_(
+        ImageRecord.primary_post_id.in_(doomed),
+        exists().where(
+            ImageProvenance.image_record_id == ImageRecord.id,
+            ImageProvenance.post_id.in_(doomed),
+        ),
+    )
+    on_kept = or_(
+        and_(
+            ImageRecord.primary_post_id.isnot(None),
+            ImageRecord.primary_post_id.notin_(doomed),
+        ),
+        exists().where(
+            ImageProvenance.image_record_id == ImageRecord.id,
+            ImageProvenance.post_id == keeper.id,
+            keeper.synthesized_by.is_(None),
+            keeper.id.notin_(doomed),
+        ),
+    )
+    return [on_doomed, ~on_kept]
+
+
+def _drop_conditions(source_id: int, authors: list[str]) -> list:
+    """The synthetic drops that absorbed a removed message."""
+    member = aliased(Post)
+    return [
+        Post.source_id == source_id,
+        Post.synthesized_by.isnot(None),
+        exists().where(
+            member.absorbed_by_post_id == Post.id,
+            member.id.in_(_doomed_post_ids(source_id, authors)),
+        ),
+    ]
+
+
+def _attachment_conditions(source_id: int, authors: list[str]) -> list:
+    return [PostAttachment.post_id.in_(_doomed_post_ids(source_id, authors))]
+
+
+def _load(session: Session, source_id: int) -> tuple[Source, list[str]]:
+    source = session.get(Source, source_id)
+    if source is None:
+        raise LookupError(source_id)
+    if source.platform != PLATFORM:
+        raise PosterCleanupError("Only a Discord source has posters to filter by.")
+    authors = source_authors(source)
+    if not authors:
+        raise PosterCleanupError(
+            "Set this source's 'Only posts by' list first — with no list, "
+            "every poster is wanted and nothing would be removed."
+        )
+    return source, authors
+
+
+def _count(session: Session, stmt) -> int:
+    return session.execute(stmt).scalar_one()
+
+
+def preview(session: Session, *, source_id: int) -> dict:
+    """What `apply` would remove, per poster, without touching anything."""
+    _, authors = _load(session, source_id)
+    who = func.coalesce(
+        Post.raw_metadata["author_name"].as_string(),
+        Post.raw_metadata["author"].as_string(),
+        Post.raw_metadata["author_id"].as_string(),
+    )
+    rows = session.execute(
+        select(who, func.count(Post.id))
+        .where(*_other_poster_post_conditions(source_id, authors))
+        .group_by(who)
+        .order_by(func.count(Post.id).desc())
+    ).all()
+    posters = [{"poster": name, "posts": n} for name, n in rows]
+    unknown = _count(session, select(func.count(Post.id)).where(
+        *_real_post_conditions(source_id), ~_has_poster(),
+    ))
+    return {
+        "authors": authors,
+        "posters": posters,
+        "posts": sum(p["posts"] for p in posters),
+        "images": _count(session, select(func.count(ImageRecord.id)).where(
+            *_image_conditions(source_id, authors))),
+        "attachments": _count(session, select(func.count(PostAttachment.id)).where(
+            *_attachment_conditions(source_id, authors))),
+        "drops": _count(session, select(func.count(Post.id)).where(
+            *_drop_conditions(source_id, authors))),
+        "unknown_posts": unknown,
+    }
+
+
+def confirm_token(projection: dict) -> str:
+    """What the operator's apply must echo: the preview it was shown, so a
+    list edited between preview and apply can't delete an unseen set."""
+    return f"remove-{projection['posts']}-posts-{projection['images']}-images"
+
+
+def apply(session: Session, *, source_id: int, images_root: Path) -> dict:
+    """Remove them. Counts are taken before the deletes they describe — once
+    the rows are gone there is nothing left to count (snippet #3087 note 2)."""
+    projection = preview(session, source_id=source_id)
+    _, authors = _load(session, source_id)
+
+    image_ids = session.execute(
+        select(ImageRecord.id).where(*_image_conditions(source_id, authors))
+    ).scalars().all()
+    # Drops first-class: found BEFORE their members go, since the link that
+    # finds them is the member's absorbed_by_post_id.
+    drop_ids = session.execute(
+        select(Post.id).where(*_drop_conditions(source_id, authors))
+    ).scalars().all()
+
+    deleted = delete_images(session, image_ids=list(image_ids), images_root=images_root)
+    # Attachments before posts: post_attachment.post_id is SET NULL, and a
+    # NULL-post attachment collides on its partial unique index (see
+    # cleanup_service.delete_artist_cascade).
+    attachments = session.execute(
+        delete(PostAttachment).where(*_attachment_conditions(source_id, authors))
+    ).rowcount or 0
+    posts = session.execute(
+        Post.__table__.delete().where(Post.id.in_(_doomed_post_ids(source_id, authors)))
+    ).rowcount or 0
+    drops = 0
+    if drop_ids:
+        drops = session.execute(
+            Post.__table__.delete().where(Post.id.in_(drop_ids))
+        ).rowcount or 0
+    session.commit()
+    log.info(
+        "discord poster cleanup (source %s, keeping %s): %d post(s), %d image(s), "
+        "%d attachment(s), %d drop(s) removed",
+        source_id, authors, posts, deleted["images_deleted"], attachments, drops,
+    )
+    return {
+        **projection,
+        "posts_deleted": posts,
+        "images_deleted": deleted["images_deleted"],
+        "files_deleted": deleted["files_deleted"],
+        "attachments_deleted": attachments,
+        "drops_deleted": drops,
+    }

backend/app/services/extension_service.py

@@ -23,6 +23,12 @@ log = logging.getLogger(__name__)
 
 # The probe runs while the chip is drawing; names that take longer are skipped.
 _NAME_LOOKUP_SECONDS = 6.0
+# The poster picker waits on two pages of a channel's messages (#4491).
+_POSTER_LOOKUP_SECONDS = 20.0
+
+# A source's poster list (discord_ingester.AUTHORS_KEY) holds user ids; this
+# keeps the name each id was picked under, for showing the list to a person.
+AUTHOR_LABELS_KEY = "discord_author_labels"
 
 
 class UnknownPlatformError(Exception):
@@ -37,6 +43,15 @@ class UnknownArtistError(Exception):
     """quick-add named an `artist_id` that does not exist."""
 
 
+class PosterLookupError(Exception):
+    """The Discord poster picker couldn't read the channel (no token, no
+    access, not a channel page, or Discord was slow)."""
+
+
+class UnknownSourceError(Exception):
+    """No source follows this Discord channel or its server."""
+
+
 # Mirrored byte-for-byte from extension/lib/platforms.js
 # PLATFORM_ARTIST_PATTERNS. Keep these two copies in sync by hand —
 # reviewers catch drift.
@@ -110,6 +125,7 @@ class ExtensionService:
         artist_id: int | None = None,
         artist_name: str | None = None,
         use_platform_name: bool = False,
+        discord_authors: list[dict] | None = None,
     ) -> dict:
         """Add `url` as a source. `artist_id` connects it to an existing
         artist, `artist_name` to that artist (created if new); with neither,
@@ -119,7 +135,10 @@ class ExtensionService:
         name is canon: a Patreon source added to an existing artist renames
         that artist to the creator's Patreon display name. Name only — the
         slug, and every path keyed off it, never moves (#130). Ignored on every
-        other platform, and when the name can't be read."""
+        other platform, and when the name can't be read.
+
+        `discord_authors` ([{id, name}], #4491) sets a Discord source's poster
+        list in the same step, on a new source or one already there."""
         platform, raw_slug = self._derive(url)
         url = canonical_source_url(platform, url, raw_slug)
         renamed_from = None
@@ -133,6 +152,8 @@ class ExtensionService:
             artist = (await self.session.execute(
                 select(Artist).where(Artist.id == existing.artist_id)
             )).scalar_one()
+            if platform == DISCORD and discord_authors is not None:
+                await self._apply_posters(existing, discord_authors)
             return self._shape(existing, artist, created_source=False, created_artist=False)
 
         if artist_id is not None:
@@ -154,11 +175,98 @@ class ExtensionService:
         source, created_source = await self._find_or_create_source(
             artist_id=artist.id, platform=platform, url=url,
         )
+        if platform == DISCORD and discord_authors is not None:
+            await self._apply_posters(source, discord_authors)
         shaped = self._shape(source, artist, created_source, created_artist)
         if renamed_from is not None:
             shaped["renamed_from"] = renamed_from
         return shaped
 
+    # -- Discord poster picker (#4491) ------------------------------------------
+
+    def _discord_page(self, url: str) -> tuple[str, str]:
+        platform, raw_slug = self._derive(url)
+        if platform != DISCORD:
+            raise InvalidUrlError("not a Discord page")
+        server_id, _, channel_id = raw_slug.partition("/")
+        if not channel_id:
+            raise PosterLookupError("Open a channel to see who posts in it.")
+        return server_id, channel_id
+
+    async def _source_for_page(self, server_id: str, channel_id: str) -> Source | None:
+        """The source this channel's posts land on: the channel's own, else a
+        whole-server source that walks it."""
+        base = f"https://discord.com/channels/{server_id}"
+        return (
+            await self._existing_source(DISCORD, f"{base}/{channel_id}")
+            or await self._existing_source(DISCORD, base)
+        )
+
+    async def discord_posters(self, url: str) -> dict:
+        """Who posts in the channel `url` shows, newest `_POSTER_SCAN`
+        messages deep, with the likely creator marked — and, when a source
+        already follows it, the poster list that source has now."""
+        server_id, channel_id = self._discord_page(url)
+        import asyncio
+
+        from .credential_service import CredentialService
+        from .discord_client import DiscordAPIError, DiscordClient
+        token = None
+        if self._crypto is not None:
+            token = await CredentialService(self.session, self._crypto).get_token(DISCORD)
+        if not token:
+            raise PosterLookupError("No Discord token is saved in FabledCurator.")
+        client = DiscordClient(token, max_retries=0)
+        loop = asyncio.get_running_loop()
+        try:
+            found = await asyncio.wait_for(
+                loop.run_in_executor(None, client.recent_posters, server_id, channel_id),
+                timeout=_POSTER_LOOKUP_SECONDS,
+            )
+        except TimeoutError as exc:
+            raise PosterLookupError("Discord took too long to answer; try again.") from exc
+        except DiscordAPIError as exc:
+            raise PosterLookupError(f"Couldn't read this channel: {exc}") from exc
+        source = await self._source_for_page(server_id, channel_id)
+        co = (source.config_overrides or {}) if source is not None else {}
+        from .discord_ingester import AUTHORS_KEY
+        return {
+            **found,
+            "source_id": source.id if source is not None else None,
+            "selected": list(co.get(AUTHORS_KEY) or []),
+            # So someone on the list who hasn't posted lately still shows by
+            # name, and can be unticked.
+            "selected_labels": dict(co.get(AUTHOR_LABELS_KEY) or {}),
+        }
+
+    async def set_discord_posters(self, url: str, authors: list[dict]) -> dict:
+        """Store the picked posters on the source that follows `url`'s channel."""
+        server_id, channel_id = self._discord_page(url)
+        source = await self._source_for_page(server_id, channel_id)
+        if source is None:
+            raise UnknownSourceError("No source follows this channel yet.")
+        return await self._apply_posters(source, authors)
+
+    async def _apply_posters(self, source: Source, authors: list[dict]) -> dict:
+        """Ids are what the list keys on — a username can change on a whim,
+        an id can't — and the name each was picked under rides beside it for
+        showing the list to a person. An empty pick clears the list, which
+        takes everyone's posts again."""
+        from .discord_ingester import AUTHORS_KEY
+        picked = [a for a in authors if str(a.get("id") or "").strip()]
+        co = dict(source.config_overrides or {})
+        if picked:
+            co[AUTHORS_KEY] = [str(a["id"]).strip() for a in picked]
+            co[AUTHOR_LABELS_KEY] = {
+                str(a["id"]).strip(): str(a.get("name") or a["id"]) for a in picked
+            }
+        else:
+            co.pop(AUTHORS_KEY, None)
+            co.pop(AUTHOR_LABELS_KEY, None)
+        source.config_overrides = co or None
+        await self.session.commit()
+        return {"source_id": source.id, "discord_authors": co.get(AUTHORS_KEY, [])}
+
     async def _adopt_patreon_name(self, artist, raw_slug: str, url: str) -> str | None:
         """Rename `artist` to the Patreon display name; the old name when it
         changed, else None. Unreadable name → no rename, never the handle."""

backend/app/services/post_feed_service.py

@@ -479,6 +479,10 @@ class PostFeedService:
             # the UI uses this to explain why a post it linked to is not in the
             # stream.
             "absorbed_by_post_id": post.absorbed_by_post_id,
+            # #4481. The Discord channel a message was posted in: both the native
+            # post record and gallery-dl's sidecars carry it as `channel`. None
+            # on every other platform, and on a Discord post that never said.
+            "channel": _discord_channel(post, source),
             "artist": {"id": artist.id, "name": artist.name, "slug": artist.slug},
             "source": (
                 {"id": source.id, "platform": source.platform}
@@ -488,3 +492,13 @@ class PostFeedService:
             "thumbnails_more": thumbs_entry["more"],
             "attachments": atts_map.get(post.id, []),
         }
+
+
+def _discord_channel(post: Post, source: Source | None) -> str | None:
+    if source is None or source.platform != "discord":
+        return None
+    raw = post.raw_metadata if isinstance(post.raw_metadata, dict) else {}
+    channel = raw.get("channel")
+    if not isinstance(channel, str):
+        return None
+    return channel.strip() or None

backend/app/services/source_service.py

@@ -68,6 +68,9 @@ class SourceRecord:
     artist_slug: str
     platform: str
     url: str
+    # alembic 0115: the name the platform gives it, where the URL is opaque
+    # (a Discord link is two ids). None until a walk has read it.
+    display_name: str | None
     enabled: bool
     config_overrides: dict | None
     last_checked_at: str | None
@@ -110,6 +113,7 @@ class SourceRecord:
             "artist_slug": self.artist_slug,
             "platform": self.platform,
             "url": self.url,
+            "display_name": self.display_name,
             "enabled": self.enabled,
             "config_overrides": self.config_overrides,
             "last_checked_at": self.last_checked_at,
@@ -301,6 +305,7 @@ class SourceService:
             artist_slug=artist.slug,
             platform=source.platform,
             url=source.url,
+            display_name=source.display_name,
             enabled=source.enabled,
             config_overrides=source.config_overrides,
             last_checked_at=source.last_checked_at.isoformat() if source.last_checked_at else None,

extension/background/background.js

@@ -276,11 +276,26 @@ browser.runtime.onMessage.addListener(async (msg) => {
           artistId: msg.artistId ?? null,
           artistName: msg.artistName ?? null,
           usePlatformName: msg.usePlatformName === true,
+          discordAuthors: Array.isArray(msg.discordAuthors) ? msg.discordAuthors : null,
         });
       } catch (e) {
         return { error: e.message };
       }
 
+    case 'DISCORD_POSTERS':
+      try {
+        return await api.getDiscordPosters(msg.url);
+      } catch (e) {
+        return { error: e.message };
+      }
+
+    case 'SET_DISCORD_POSTERS':
+      try {
+        return await api.setDiscordPosters(msg.url, msg.authors || []);
+      } catch (e) {
+        return { error: e.message };
+      }
+
     case 'SEARCH_ARTISTS':
       try {
         return { artists: await api.searchArtists(msg.q || '') };

extension/content/content-script.css

@@ -100,3 +100,7 @@
 /* The panel's own [hidden] — its rows are display:flex, which beats the UA's. */
 .fc-panel [hidden] { display: none !important; }
 .fc-panel__rename { margin-top: 8px; font-size: 13px; }
+/* Poster picker (#4491): who posts in the channel, the likely creator ticked. */
+.fc-panel__posters { max-height: 220px; overflow-y: auto; }
+.fc-panel__poster { flex-wrap: wrap; }
+.fc-panel__poster-meta { flex-basis: 100%; padding-left: 21px; font-size: 11px; color: rgb(170, 166, 156); }

extension/content/content-script.js

@@ -81,6 +81,13 @@
     const probe = currentProbe;
 
     if (probe?.state === 'source_match') {
+      // A followed Discord channel opens its poster list (#4491); the artist
+      // page is one click further, in that panel.
+      if (probe.platform === 'discord' && probe.discord?.channel_id) {
+        if (document.getElementById('fc-add-panel')) closePanel();
+        else openPostersPanel(btn, probe);
+        return;
+      }
       await openArtist(btn, probe.artist?.slug);
       return;
     }
@@ -158,6 +165,120 @@
     document.getElementById('fc-add-panel')?.remove();
   }
 
+  // ---- Poster picker (#4491) ----
+  // Who posted in this channel lately, read by FabledCurator with its Discord
+  // token, the creator the server is named for (or owned by) ticked. The
+  // source keeps their ids: a username can change on a whim, an id can't, so
+  // the list never quietly stops matching. Names are other people's text —
+  // createElement only.
+
+  function posterSection() {
+    const list = el('div', { class: 'fc-panel__posters' }, [
+      el('div', { class: 'fc-panel__hint', text: 'Reading who posts here…' }),
+    ]);
+    const node = el('div', {}, [
+      el('div', { class: 'fc-panel__label', text: 'Only posts by' }),
+      list,
+    ]);
+    const state = { data: null, picked: new Set() };
+
+    function render() {
+      const posters = withSelected(state.data);
+      if (!posters.length) {
+        list.replaceChildren(el('div', { class: 'fc-panel__hint', text: 'No one has posted here lately.' }));
+        return;
+      }
+      const rows = posters.map((p) => {
+        const id = String(p.id);
+        const box = el('input', { type: 'checkbox', checked: state.picked.has(id) });
+        box.addEventListener('change', () => {
+          if (box.checked) state.picked.add(id);
+          else state.picked.delete(id);
+          hint.textContent = pickHint();
+        });
+        const bits = [`${p.images} image${p.images === 1 ? '' : 's'}`, `${p.messages} message${p.messages === 1 ? '' : 's'}`];
+        if (p.reasons?.length) bits.unshift(p.reasons.join(', '));
+        return el('label', { class: 'fc-panel__radio fc-panel__poster' }, [
+          box,
+          el('span', { text: posterLabel(p) }),
+          el('span', { class: 'fc-panel__poster-meta', text: bits.join(' · ') }),
+        ]);
+      });
+      const hint = el('div', { class: 'fc-panel__hint', text: pickHint() });
+      list.replaceChildren(...rows, hint);
+    }
+
+    function pickHint() {
+      return state.picked.size
+        ? 'Only the ticked people’s posts are taken.'
+        : 'Nothing ticked: everyone’s posts are taken.';
+    }
+
+    async function load() {
+      let r;
+      try {
+        r = await browser.runtime.sendMessage({ type: 'DISCORD_POSTERS', url: window.location.href });
+      } catch (e) {
+        r = { error: e.message };
+      }
+      if (r?.error) {
+        list.replaceChildren(el('div', { class: 'fc-panel__hint', text: `Couldn’t list posters — ${r.error}` }));
+        return;
+      }
+      state.data = r;
+      state.picked = initialPosterPick(r);
+      render();
+    }
+
+    // null until the list has loaded: an add made before then leaves the
+    // source's list as it is instead of clearing it.
+    const request = () => (state.data ? postersRequest(state.data.posters, state.picked) : null);
+    return { node, load, request };
+  }
+
+  function openPostersPanel(btn, probe) {
+    closePanel();
+    const d = probe.discord || {};
+    const posters = posterSection();
+    const saveBtn = el('button', { class: 'fc-panel__btn fc-panel__btn--primary', text: 'Save' });
+    const artistBtn = el('button', { class: 'fc-panel__btn', text: `Open ${probe.artist?.name || 'artist'}` });
+    const cancelBtn = el('button', { class: 'fc-panel__btn', text: 'Close' });
+    const panel = el('div', { id: 'fc-add-panel', class: 'fc-panel' }, [
+      el('div', { class: 'fc-panel__title', text: 'Discord source' }),
+      el('div', { class: 'fc-panel__sub', text: d.channel_id ? channelLabel(d) : serverLabel(d) }),
+      posters.node,
+      el('div', { class: 'fc-panel__actions' }, [artistBtn, cancelBtn, saveBtn]),
+    ]);
+    panel.addEventListener('keydown', (e) => {
+      e.stopPropagation();
+      if (e.key === 'Escape') closePanel();
+    });
+    cancelBtn.addEventListener('click', closePanel);
+    artistBtn.addEventListener('click', () => { closePanel(); openArtist(btn, probe.artist?.slug); });
+    saveBtn.addEventListener('click', async () => {
+      const authors = posters.request();
+      if (!authors) return;
+      saveBtn.disabled = true;
+      try {
+        const r = await browser.runtime.sendMessage({
+          type: 'SET_DISCORD_POSTERS', url: window.location.href, authors,
+        });
+        if (r?.error) {
+          showToast(`Error: ${r.error}`, 'error');
+          return;
+        }
+        showToast(authors.length ? `Only posts by ${authors.map((a) => a.name || a.id).join(', ')}` : 'Taking everyone’s posts', 'success');
+        closePanel();
+      } catch (e) {
+        showToast(`Error: ${e.message}`, 'error');
+      } finally {
+        saveBtn.disabled = false;
+      }
+    });
+    document.body.appendChild(panel);
+    posters.load();
+  }
+
   async function openAddPanel(btn, probe) {
     closePanel();
     const platformName = PLATFORMS[probe.platform]?.name || probe.platform;
@@ -184,6 +305,8 @@
     const d = probe.discord || {};
     const discord = probe.platform === 'discord';
     const choice = panelDefaults(probe, window.location.href);
+    // #4491: on a channel page, pick whose posts the new source takes.
+    const posters = discord && d.channel_id ? posterSection() : null;
 
     const scopeRow = (value, label, disabled) => {
       const input = el('input', {
@@ -234,6 +357,7 @@
       el('div', { class: 'fc-panel__label', text: 'Artist' }),
       el('div', { class: 'fc-panel__combo' }, [nameInput, results]),
       renameRow,
+      ...(posters ? [posters.node] : []),
       hint,
       el('div', { class: 'fc-panel__actions' }, [cancelBtn, addBtn]),
     ]);
@@ -392,6 +516,8 @@
     addBtn.addEventListener('click', async () => {
       const req = addRequest(choice);
       if (!req) return;
+      const authors = posters?.request();
+      if (authors) req.discordAuthors = authors;
       const btn = document.getElementById('fc-add-source-btn');
       addBtn.disabled = true;
       const ok = await add(btn || addBtn, req);
@@ -402,6 +528,7 @@
     document.body.appendChild(panel);
     refresh();
     nameInput.focus();
+    posters?.load();
     nameInput.select();
     // Search what the field opens with — the server's name, usually — so an
     // artist it already matches is picked before the operator types anything.

extension/lib/api.js

@@ -106,8 +106,11 @@ class FabledCuratorAPI {
   // artist from the URL. A Discord channel always sends one.
   // usePlatformName: a Patreon source joining an existing artist renames it
   // to the Patreon display name (Patreon is canon; name only, never the slug).
-  quickAddSource(url, { artistId = null, artistName = null, usePlatformName = false } = {}) {
+  // discordAuthors ([{id, name}], #4491): a Discord source's poster list, set
+  // in the same step.
+  quickAddSource(url, { artistId = null, artistName = null, usePlatformName = false, discordAuthors = null } = {}) {
     const body = { url };
+    if (discordAuthors) body.discord_authors = discordAuthors;
     if (artistId != null) body.artist_id = artistId;
     else if (artistName) body.artist_name = artistName;
     if (usePlatformName) body.use_platform_name = true;
@@ -123,6 +126,15 @@ class FabledCuratorAPI {
     const qs = new URLSearchParams(params).toString();
     return this.request('GET', `/extension/probe?${qs}`);
   }
+  // #4491: who posts in the Discord channel `url` shows, lately, with the
+  // likely creator marked; and setting the list on the source that follows it.
+  getDiscordPosters(url) {
+    const qs = new URLSearchParams({ url }).toString();
+    return this.request('GET', `/extension/discord/posters?${qs}`);
+  }
+  setDiscordPosters(url, authors) {
+    return this.request('POST', '/extension/discord/posters', { url, authors });
+  }
   // Latest published extension version on this instance — drives the in-app
   // update prompt. Public endpoint (no key needed, but request() sends it
   // harmlessly). Returns {version, xpi_url, latest_url, sha256}.

extension/lib/chip.js

@@ -144,3 +144,49 @@ function inlineCompletion(typed, results) {
   if (!t) return null;
   return (results || []).find((a) => a.name.length > t.length && a.name.toLowerCase().startsWith(t)) || null;
 }
+
+// ---- Discord poster picker (#4491) ----
+// /api/extension/discord/posters lists who posted in the channel lately, with
+// the creator the server is named for (or owned by) marked `suggested`. The
+// picker ticks posters; the source keeps their ids, since a username can
+// change on a whim and an id can't.
+
+/** "Todding (@todding)" — the display name, then the handle when it differs. */
+function posterLabel(p) {
+  const shown = p?.global_name || p?.username || p?.id || '';
+  const handle = p?.username && p.username !== shown ? ` (@${p.username})` : '';
+  return `${shown}${handle}`;
+}
+
+/** What the picker starts with: the source's current list when it has one,
+ *  else the suggested creator(s). A set of ids. */
+function initialPosterPick(data) {
+  const current = (data?.selected || []).map(String);
+  if (current.length) return new Set(current);
+  return new Set((data?.posters || []).filter((p) => p.suggested).map((p) => String(p.id)));
+}
+
+/** The checklist's rows: who posted lately, then anyone already on the
+ *  source's list who hasn't — by the name they were picked under — so they
+ *  can still be unticked. */
+function withSelected(data) {
+  const posters = [...(data?.posters || [])];
+  const shown = new Set(posters.map((p) => String(p.id)));
+  const labels = data?.selected_labels || {};
+  for (const id of (data?.selected || []).map(String)) {
+    if (shown.has(id)) continue;
+    posters.push({ id, global_name: labels[id] || null, username: null,
+      messages: 0, images: 0, reasons: ['on the list, not posting lately'] });
+  }
+  return posters;
+}
+
+/** The picked posters as the API takes them: [{id, name}], in list order.
+ *  An id already on the source but no longer posting lately is kept. */
+function postersRequest(posters, picked) {
+  const byId = new Map((posters || []).map((p) => [String(p.id), p]));
+  return [...picked].map((id) => ({
+    id,
+    name: byId.has(id) ? (byId.get(id).global_name || byId.get(id).username || id) : null,
+  }));
+}

extension/test/chip.spec.js

@@ -198,3 +198,46 @@ describe('Add panel on Patreon and SubscribeStar', () => {
     expect(c.artistName).toBe('Tamada')
   })
 })
+
+const { posterLabel, initialPosterPick, postersRequest, withSelected } = loadLib('chip.js', [
+  'posterLabel', 'initialPosterPick', 'postersRequest', 'withSelected',
+])
+
+describe('the poster checklist rows', () => {
+  it('adds someone on the list who has not posted lately, by their saved name', () => {
+    const rows = withSelected({
+      posters: [{ id: '7', username: 'todding', global_name: 'Todding' }],
+      selected: ['7', '42'],
+      selected_labels: { 42: 'Old Name' },
+    })
+    expect(rows.map((r) => r.id)).toEqual(['7', '42'])
+    expect(posterLabel(rows[1])).toBe('Old Name')
+    expect(rows[1].reasons).toEqual(['on the list, not posting lately'])
+  })
+})
+
+describe('the Discord poster picker (#4491)', () => {
+  const posters = [
+    { id: '7', username: 'todding', global_name: 'Todding', suggested: true },
+    { id: '8', username: 'jakeboii', global_name: 'Jake Boii', suggested: false },
+    { id: '9', username: 'plain', global_name: null, suggested: false },
+  ]
+
+  it('labels a poster by display name, then handle', () => {
+    expect(posterLabel(posters[0])).toBe('Todding (@todding)')
+    expect(posterLabel(posters[2])).toBe('plain')
+  })
+
+  it('starts from the source list when it has one, else the suggestion', () => {
+    expect([...initialPosterPick({ posters, selected: [] })]).toEqual(['7'])
+    expect([...initialPosterPick({ posters, selected: ['8'] })]).toEqual(['8'])
+    expect([...initialPosterPick({ posters: [] })]).toEqual([])
+  })
+
+  it('sends ids with the names they were picked under, keeping unknown ids', () => {
+    expect(postersRequest(posters, new Set(['7', '42']))).toEqual([
+      { id: '7', name: 'Todding' },
+      { id: '42', name: null },
+    ])
+  })
+})

frontend/src/components/cleanup/SingleColorAuditCard.vue

@@ -101,7 +101,7 @@ import MaintenanceTile from '../common/MaintenanceTile.vue'
 import { useCleanupStore } from '../../stores/cleanup.js'
 
 const store = useCleanupStore()
-const threshold = ref(0.95)
+const threshold = ref(0.995)
 const tolerance = ref(30)
 const audit = ref(null)
 const busy = ref(false)

frontend/src/components/posts/PostCard.vue

@@ -26,6 +26,7 @@
         :to="{ name: 'artist', params: { slug: post.artist.slug } }"
         class="fc-post-card__artist"
       >{{ post.artist.name }}</RouterLink>
+      <span v-if="post.channel" class="fc-post-card__meta">#{{ post.channel }}</span>
       <span class="fc-post-card__date" :title="absoluteDate">{{ relativeDate }}</span>
       <span v-if="totalImages" class="fc-post-card__meta">
         · {{ totalImages }} image{{ totalImages === 1 ? '' : 's' }}

frontend/src/components/settings/ImportFiltersForm.vue

@@ -77,7 +77,7 @@
         <v-col cols="12" sm="6">
           <v-slider
             v-model="local.single_color_threshold" label="Single-color threshold"
-            min="0.5" max="1" step="0.05" thumb-label hide-details color="accent"
+            min="0.9" max="1" step="0.005" thumb-label hide-details color="accent"
             :disabled="!local.skip_single_color" @end="save"
           />
         </v-col>
@@ -142,7 +142,7 @@ const PHASH_TICKS = { 0: 'Exact', 12: 'Strict', 24: 'Default', 48: 'Loose' }
 const local = reactive({
   min_width: 0, min_height: 0,
   skip_transparent: false, transparency_threshold: 0.9,
-  skip_single_color: false, single_color_threshold: 0.95,
+  skip_single_color: false, single_color_threshold: 0.995,
   phash_threshold: 24,
   wip_title_tagging_enabled: true,
 })

frontend/src/components/subscriptions/PosterCleanupDialog.vue

@@ -0,0 +1,135 @@
+<template>
+  <!-- #4486. A Discord source's posts by people outside its "Only posts by"
+       list, taken before the list existed. Preview first, always: nothing is
+       deleted until the operator has seen the per-poster breakdown and typed
+       the token that preview returned. -->
+  <v-dialog :model-value="modelValue" max-width="560"
+            @update:model-value="$emit('update:modelValue', $event)">
+    <v-card>
+      <v-card-title>Remove posts from other posters</v-card-title>
+      <v-card-text>
+        <div class="text-caption mb-2">{{ source.display_name || source.url }}</div>
+        <v-progress-linear v-if="loading" indeterminate color="accent" class="mb-3" />
+        <v-alert v-else-if="error" type="warning" variant="tonal" density="compact">
+          {{ error }}
+        </v-alert>
+        <template v-else-if="result">
+          <v-alert type="success" variant="tonal" density="compact">
+            Removed {{ result.posts_deleted }} post(s), {{ result.images_deleted }} image(s),
+            {{ result.attachments_deleted }} attachment(s) and {{ result.drops_deleted }}
+            grouped post(s). Grouping rebuilds what remains on its next sweep.
+          </v-alert>
+        </template>
+        <template v-else-if="preview">
+          <p class="mb-2">
+            Keeping posts by <strong>{{ preview.authors.join(', ') }}</strong>.
+          </p>
+          <p v-if="!preview.posts" class="fc-dim">
+            Nothing to remove: every post with a known poster is by someone on the list.
+          </p>
+          <template v-else>
+            <v-table density="compact" class="mb-3">
+              <thead><tr><th>Poster</th><th class="text-right">Posts</th></tr></thead>
+              <tbody>
+                <tr v-for="p in preview.posters" :key="p.poster">
+                  <td>{{ p.poster }}</td>
+                  <td class="text-right">{{ p.posts }}</td>
+                </tr>
+              </tbody>
+            </v-table>
+            <p class="mb-1">
+              {{ preview.posts }} post(s), {{ preview.images }} image(s) found only on them,
+              {{ preview.attachments }} attachment(s).
+            </p>
+            <p v-if="preview.drops" class="mb-1">
+              {{ preview.drops }} grouped post(s) that include them are ungrouped; the
+              rest regroup on the next sweep.
+            </p>
+            <p class="fc-dim">
+              Images that also belong to a kept post stay. If a name you want to keep
+              appears above, add it to the source's "Only posts by" list first.
+            </p>
+          </template>
+          <p v-if="preview.unknown_posts" class="fc-dim mt-2">
+            {{ preview.unknown_posts }} older post(s) don't record who posted them and
+            are left alone.
+          </p>
+        </template>
+      </v-card-text>
+      <v-card-actions>
+        <v-spacer />
+        <v-btn variant="text" @click="$emit('update:modelValue', false)">
+          {{ result ? 'Close' : 'Cancel' }}
+        </v-btn>
+        <v-btn
+          v-if="preview && preview.posts && !result"
+          color="error" variant="flat" :loading="busy"
+          @click="confirmOpen = true"
+        >Remove {{ preview.posts }} post(s)</v-btn>
+      </v-card-actions>
+    </v-card>
+    <DestructiveConfirmModal
+      v-if="preview"
+      v-model="confirmOpen"
+      action="delete" kind="other posters' posts" tier="C"
+      :expected-token-override="preview.confirm_token"
+      :projected-counts="{ posts: preview.posts, images: preview.images,
+                           attachments: preview.attachments, grouped: preview.drops }"
+      @confirm="onConfirm"
+    />
+  </v-dialog>
+</template>
+
+<script setup>
+import { ref, watch } from 'vue'
+import { useSourcesStore } from '../../stores/sources.js'
+import DestructiveConfirmModal from '../modal/DestructiveConfirmModal.vue'
+
+const props = defineProps({
+  modelValue: { type: Boolean, default: false },
+  source: { type: Object, required: true },
+})
+defineEmits(['update:modelValue'])
+const store = useSourcesStore()
+
+const loading = ref(false)
+const busy = ref(false)
+const error = ref('')
+const preview = ref(null)
+const result = ref(null)
+const confirmOpen = ref(false)
+
+function message(e) {
+  return e?.body?.detail || e?.body?.error || e?.message || String(e)
+}
+
+watch(() => props.modelValue, async (open) => {
+  if (!open) return
+  preview.value = null
+  result.value = null
+  error.value = ''
+  loading.value = true
+  try {
+    preview.value = await store.previewOtherPosters(props.source.id)
+  } catch (e) {
+    error.value = message(e)
+  } finally {
+    loading.value = false
+  }
+})
+
+async function onConfirm(token) {
+  busy.value = true
+  try {
+    result.value = await store.removeOtherPosters(props.source.id, token)
+  } catch (e) {
+    error.value = message(e)
+  } finally {
+    busy.value = false
+  }
+}
+</script>
+
+<style scoped>
+.fc-dim { color: rgb(var(--v-theme-on-surface-variant)); }
+</style>

frontend/src/components/subscriptions/SourceActions.vue

@@ -50,6 +50,17 @@
           library — without re-downloading media
         </v-list-item-subtitle>
       </v-list-item>
+      <v-list-item
+        v-if="hasPosterList && !running"
+        prepend-icon="mdi-account-remove-outline"
+        @click="cleanupOpen = true"
+      >
+        <v-list-item-title>Remove posts from other posters</v-list-item-title>
+        <v-list-item-subtitle>
+          Preview, then delete the posts taken from people outside this
+          source's "Only posts by" list
+        </v-list-item-subtitle>
+      </v-list-item>
       <v-divider v-if="isNative && !running" />
       <v-list-item
         base-color="error"
@@ -59,12 +70,14 @@
         <v-list-item-title>Remove source</v-list-item-title>
       </v-list-item>
     </KebabMenu>
+    <PosterCleanupDialog v-if="hasPosterList" v-model="cleanupOpen" :source="source" />
   </div>
 </template>
 
 <script setup>
-import { computed } from 'vue'
+import { computed, ref } from 'vue'
 import KebabMenu from '../common/KebabMenu.vue'
+import PosterCleanupDialog from './PosterCleanupDialog.vue'
 
 const props = defineProps({
   source: { type: Object, required: true },
@@ -80,6 +93,10 @@ const recapturing = computed(() => !!props.source.backfill_recapture)
 // which those are (`native_ingester`); a copied list here went stale when
 // Discord moved over.
 const isNative = computed(() => !!props.source.native_ingester)
+// #4486: only a Discord source with an "Only posts by" list has other posters.
+const hasPosterList = computed(() => props.source.platform === 'discord'
+  && (props.source.config_overrides?.discord_authors || []).length > 0)
+const cleanupOpen = ref(false)
 </script>
 
 <style scoped>

frontend/src/components/subscriptions/SourceCard.vue

@@ -16,7 +16,7 @@
       <a
         :href="source.url" target="_blank" rel="noopener"
         class="fc-source-card__url" @click.stop
-      >{{ source.url }}</a>
+      >{{ source.display_name || source.url }}</a>
       <v-btn
         icon="mdi-pencil" size="x-small" variant="text"
         @click.stop="$emit('edit', source)"
@@ -39,18 +39,18 @@
       </v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'running'"
-        size="x-small" color="info" variant="tonal" label
+        size="x-small" color="info" variant="flat" label
       >{{ source.backfill_bypass_seen ? 'Recovering' : (source.backfill_recapture ? 'Recapturing' : 'Backfilling')
         }}{{ source.backfill_posts
               ? ` · ${source.backfill_posts} posts`
               : (source.backfill_chunks ? ` (${source.backfill_chunks})` : '') }}</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'complete'"
-        size="x-small" color="success" variant="tonal" label
+        size="x-small" color="success" variant="flat" label
       >Backfilled</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'stalled'"
-        size="x-small" color="warning" variant="tonal" label
+        size="x-small" color="warning" variant="flat" label
       >Stalled</v-chip>
     </div>
 

frontend/src/components/subscriptions/SourceFormDialog.vue

@@ -44,6 +44,17 @@
               v-model="structuredSince" label="Skip posts older than (YYYY-MM-DD)"
               placeholder="2024-01-01" hide-details class="mt-2"
             />
+            <!-- A creator's server is full of other members posting their own
+                 pictures; the source is subscribed to the creator (#4481). -->
+            <v-text-field
+              v-if="platform === 'discord'"
+              v-model="structuredAuthors" label="Only posts by (Discord names or ids)"
+              placeholder="Todding" hint="Comma-separated. Empty takes everyone's."
+              persistent-hint class="mt-2"
+            />
+            <div v-if="platform === 'discord' && authorNames.length" class="text-caption mt-2">
+              {{ authorNames.join(', ') }}
+            </div>
             <p class="text-caption mt-2" style="opacity: 0.75">
               More per-platform fields land here over time. Use Advanced JSON for everything else.
             </p>
@@ -98,6 +109,33 @@ const urlError = ref('')
 const configTab = ref('structured')
 const structuredVideos = ref(true)
 const structuredSince = ref('')
+const structuredAuthors = ref('')
+// Keys the structured view has no field for, carried through its saves so
+// switching tabs never drops what the JSON view set.
+const otherConfig = ref({})
+const STRUCTURED_KEYS = ['videos', 'since', 'discord_authors']
+
+// The extension's poster picker stores ids (#4491) and the name each was
+// picked under, so a list of numbers still says who it means.
+const authorNames = computed(() => {
+  const labels = otherConfig.value.discord_author_labels || {}
+  return splitAuthors(structuredAuthors.value)
+    .map(a => (labels[a] ? `${labels[a]} (${a})` : null))
+    .filter(Boolean)
+})
+
+function splitAuthors(txt) {
+  return (txt || '').split(',').map(s => s.trim()).filter(Boolean)
+}
+
+function takeConfig(co) {
+  structuredVideos.value = co.videos !== false
+  structuredSince.value = co.since ?? ''
+  structuredAuthors.value = Array.isArray(co.discord_authors) ? co.discord_authors.join(', ') : ''
+  otherConfig.value = Object.fromEntries(
+    Object.entries(co).filter(([k]) => !STRUCTURED_KEYS.includes(k)),
+  )
+}
 const jsonText = ref('{}')
 const jsonError = ref('')
 
@@ -105,13 +143,15 @@ const busy = ref(false)
 
 // Sync config_overrides between the two views.
 const config = computed(() => {
-  const out = {}
+  const out = { ...otherConfig.value }
   if (!structuredVideos.value) out.videos = false
   if (structuredSince.value) out.since = structuredSince.value
+  const authors = splitAuthors(structuredAuthors.value)
+  if (authors.length) out.discord_authors = authors
   return out
 })
 
-watch([structuredVideos, structuredSince], () => {
+watch([structuredVideos, structuredSince, structuredAuthors], () => {
   if (configTab.value === 'structured') {
     jsonText.value = JSON.stringify(config.value, null, 2)
     jsonError.value = ''
@@ -128,8 +168,7 @@ watch(jsonText, (txt) => {
     }
     jsonError.value = ''
     // Reflect recognized keys into the structured view.
-    structuredVideos.value = parsed.videos !== false
-    structuredSince.value = parsed.since ?? ''
+    takeConfig(parsed)
   } catch {
     jsonError.value = 'Invalid JSON'
   }
@@ -146,14 +185,13 @@ watch(() => props.modelValue, async (open) => {
     url.value = props.source.url
     enabled.value = props.source.enabled
     const co = props.source.config_overrides || {}
-    structuredVideos.value = co.videos !== false
-    structuredSince.value = co.since ?? ''
+    takeConfig(co)
     jsonText.value = JSON.stringify(co, null, 2)
     artistChoice.value = { id: props.source.artist_id, name: props.source.artist_name }
   } else {
     platform.value = platformsStore.list[0]?.key || 'patreon'
     url.value = ''; enabled.value = true
-    structuredVideos.value = true; structuredSince.value = ''
+    takeConfig({})
     jsonText.value = '{}'
     artistChoice.value = props.initialArtist
       ? { id: props.initialArtist.id, name: props.initialArtist.name }

frontend/src/components/subscriptions/SourceRow.vue

@@ -10,7 +10,7 @@
       <div class="fc-source-row__url-wrap">
         <a :href="source.url" target="_blank" rel="noopener" class="fc-source-row__url"
            @click.stop>
-          {{ source.url }}
+          {{ source.display_name || source.url }}
         </a>
         <!-- Edit sits next to the source identity (operator-requested), not in
              the action cluster where it was easy to fat-finger Remove. -->
@@ -72,7 +72,7 @@
            worked, the content just isn't ours. -->
       <v-chip
         v-else-if="source.error_type === 'tier_limited'"
-        size="x-small" color="info" variant="tonal" label
+        size="x-small" color="info" variant="flat" label
         prepend-icon="mdi-lock-outline"
       >{{ source.tier_gated_count ? `${source.tier_gated_count} gated` : 'No access' }}
         <v-tooltip activator="parent" location="top" max-width="480">
@@ -81,18 +81,18 @@
       </v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'running'"
-        size="x-small" color="info" variant="tonal" label
+        size="x-small" color="info" variant="flat" label
       >{{ source.backfill_bypass_seen ? 'Recovering' : (source.backfill_recapture ? 'Recapturing' : 'Backfilling')
         }}{{ source.backfill_posts
               ? ` · ${source.backfill_posts} posts`
               : (source.backfill_chunks ? ` (${source.backfill_chunks})` : '') }}</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'complete'"
-        size="x-small" color="success" variant="tonal" label
+        size="x-small" color="success" variant="flat" label
       >Backfilled</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'stalled'"
-        size="x-small" color="warning" variant="tonal" label
+        size="x-small" color="warning" variant="flat" label
       >Stalled</v-chip>
       <span v-else class="fc-source-row__zero">0</span>
     </td>

frontend/src/components/subscriptions/SubscriptionsTab.vue

@@ -108,7 +108,7 @@
             v-if="item.singleSource"
             :href="item.singleSource.url" target="_blank" rel="noopener"
             class="fc-subs__sub-url" @click.stop
-          >{{ item.singleSource.url }}</a>
+          >{{ item.singleSource.display_name || item.singleSource.url }}</a>
         </template>
 
         <template #item.platforms="{ item }">
@@ -517,6 +517,7 @@ const filteredGroups = computed(() => {
         g.sources.some(
           (s) =>
             (s.url || '').toLowerCase().includes(q) ||
+            (s.display_name || '').toLowerCase().includes(q) ||
             (s.platform || '').toLowerCase().includes(q),
         ),
     )

frontend/src/stores/cleanup.js

@@ -12,7 +12,7 @@ export const useCleanupStore = defineStore('cleanup', () => {
     min_width: 0,
     min_height: 0,
     transparency_threshold: 0.9,
-    single_color_threshold: 0.95,
+    single_color_threshold: 0.995,
     single_color_tolerance: 30,
   })
 
@@ -24,7 +24,7 @@ export const useCleanupStore = defineStore('cleanup', () => {
       min_width: s.min_width ?? 0,
       min_height: s.min_height ?? 0,
       transparency_threshold: s.transparency_threshold ?? 0.9,
-      single_color_threshold: s.single_color_threshold ?? 0.95,
+      single_color_threshold: s.single_color_threshold ?? 0.995,
       single_color_tolerance: s.single_color_tolerance ?? 30,
     }
   }

frontend/src/stores/sources.js

@@ -149,6 +149,15 @@ export const useSourcesStore = defineStore('sources', () => {
     return body
   }
 
+  // #4486: a Discord source's posts by people outside its poster list.
+  // The preview touches nothing and hands back the token the remove must echo.
+  async function previewOtherPosters(id) {
+    return api.get(`/api/sources/${id}/discord/other-posters`)
+  }
+  async function removeOtherPosters(id, confirm) {
+    return api.post(`/api/sources/${id}/discord/other-posters/remove`, { body: { confirm } })
+  }
+
   function sourcesByArtistGrouped() {
     // returns [{artist: {id,name,slug}, sources: [...]}, ...]
     const arr = byArtist.value.get(null) ?? []
@@ -179,6 +188,7 @@ export const useSourcesStore = defineStore('sources', () => {
     stopBackfill,
     recoverSource,
     recaptureSource,
+    previewOtherPosters, removeOtherPosters,
     findOrCreateArtist, autocompleteArtist, reassign,
     loadScheduleStatus,
     sourcesByArtistGrouped,

tests/test_audits_single_color.py

@@ -40,3 +40,48 @@ def test_single_color_evaluate_handles_rgba_input():
     # Alpha channel should be ignored — only RGB matters for the rule.
     im = Image.new("RGBA", (50, 50), (100, 100, 100, 128))
     assert single_color.evaluate(im, threshold=0.9, tolerance=10) is True
+
+
+# -- line art is a drawing, not a blank (#4483) ---------------------------------
+
+_T = 0.995  # the default since alembic 0116
+_TOL = 30
+
+
+def _doodle(size=(1500, 2000), lines=12):
+    """Pencil line art on white: a few thin dark strokes plus faint
+    construction lines — a couple of percent ink, the rest paper."""
+    from PIL import ImageDraw
+
+    im = Image.new("RGB", size, (255, 255, 255))
+    draw = ImageDraw.Draw(im)
+    w, h = size
+    for i in range(lines):
+        x = (i + 1) * w // (lines + 1)
+        draw.line([(x, 0), (w - x, h)], fill=(70, 60, 60), width=3)
+        draw.line([(0, (i + 1) * h // (lines + 1)), (w, h - x)], fill=(235, 235, 235), width=2)
+    return im
+
+
+def test_line_art_on_white_is_not_single_color():
+    """Five of Todding's Discord doodles were skipped as blank: a smoothing
+    64px thumbnail blended the strokes into the paper."""
+    assert single_color.evaluate(_doodle(), threshold=_T, tolerance=_TOL) is False
+
+
+def test_a_blank_page_with_a_small_mark_is_still_single_color():
+    from PIL import ImageDraw
+
+    im = Image.new("RGB", (1000, 1000), (250, 250, 250))
+    ImageDraw.Draw(im).rectangle([480, 480, 520, 520], fill=(40, 40, 40))
+    assert single_color.evaluate(im, threshold=_T, tolerance=_TOL) is True
+
+
+def test_a_noisy_solid_fill_is_still_single_color():
+    """JPEG noise on a placeholder stays inside the tolerance."""
+    im = Image.new("RGB", (600, 600), (30, 90, 160))
+    for i in range(0, 600 * 600, 7):
+        x, y = i % 600, i // 600
+        d = (i % 21) - 10
+        im.putpixel((x, y), (30 + d, 90 + d, 160 + d))
+    assert single_color.evaluate(im, threshold=_T, tolerance=_TOL) is True

tests/test_discord_client.py

@@ -153,9 +153,11 @@ def test_an_embeds_identity_ignores_its_signature():
     def embed(sig):
         return {"type": "image", "image": {"proxy_url": f"https://media/p/x.png?ex={sig}"}}
 
-    one = DiscordClient.extract_media(_msg(9, embeds=[embed("a")]))[0].media_id
-    two = DiscordClient.extract_media(_msg(9, embeds=[embed("b")]))[0].media_id
-    assert one == two and len(one) <= 33
+    art = [{"url": "https://cdn/a/1.png"}]
+    one = DiscordClient.extract_media(_msg(9, attachments=art, embeds=[embed("a")]))[1]
+    two = DiscordClient.extract_media(_msg(9, attachments=art, embeds=[embed("b")]))[1]
+    assert one.kind == two.kind == "embed"
+    assert one.media_id == two.media_id and len(one.media_id) <= 33
 
 
 def test_post_seams():
@@ -165,11 +167,52 @@ def test_post_seams():
 
 
 def test_a_text_only_message_is_not_a_post():
-    """gallery-dl never made one: chat lines would bury the drops."""
+    """Chat lines would bury the drops."""
     assert DiscordClient.post_record_key(_msg(6, content="brb")) is None
     assert DiscordClient.post_meta(_msg(1))["date"].startswith("2026-09-20")
 
 
+def test_a_message_without_an_attached_image_is_chat():
+    """Operator 2026-09-28: only content with an image attached. A lone
+    archive, a link preview or a Tenor GIF takes nothing and records nothing."""
+    chat = [
+        _msg(1, content="the stash", attachments=[
+            {"url": "https://cdn/a/Links_Stash.rar", "content_type": "application/x-rar"},
+        ]),
+        _msg(2, content="look", embeds=[
+            {"type": "image", "image": {"proxy_url": "https://media/p/x.png"}},
+        ]),
+        _msg(3, content="lol", embeds=[
+            {"type": "gifv", "video": {"proxy_url": "https://media/p/t.mp4"}},
+        ]),
+        _msg(4, content="wip", attachments=[{"url": "https://cdn/a/wip.psd"}]),
+    ]
+    for m in chat:
+        assert DiscordClient.extract_media(m) == []
+        assert DiscordClient.post_record_key(m) is None
+
+
+def test_an_attached_image_takes_every_file_numbered_as_gallery_dl_does():
+    """The gate decides WHETHER a message is taken, never which of its files:
+    the rar beside the image keeps its number, so on-disk names still match."""
+    m = _msg(7, attachments=[
+        {"url": "https://cdn/a/pack.rar"},
+        {"url": "https://cdn/a/noext", "content_type": "image/png"},
+    ])
+    items = DiscordClient.extract_media(m)
+    assert [(i.num, i.filename) for i in items] == [(1, "pack"), (2, "noext")]
+    assert DiscordClient.post_record_key(m) == ("message:7", "7")
+    video = _msg(8, attachments=[{"url": "https://cdn/a/clip.MP4?ex=1"}])
+    assert len(DiscordClient.extract_media(video)) == 1
+
+
+def test_a_forwarded_image_counts_as_attached():
+    m = _msg(9, message_snapshots=[
+        {"message": {"type": 0, "attachments": [{"url": "https://cdn/a/fwd.png"}]}},
+    ])
+    assert DiscordClient.post_record_key(m) == ("message:9", "9")
+
+
 # -- the walk --------------------------------------------------------------------
 
 def test_a_channel_pages_newest_first_and_skips_system_messages():
@@ -206,6 +249,50 @@ def test_messages_carry_server_and_channel_metadata():
     assert meta["parent"] == "Art"
 
 
+def _one_channel(messages):
+    return {
+        "/guilds/1": _ok({"id": "1", "name": "Todding's Server"}),
+        "/guilds/1/channels": _ok([
+            {"id": "4", "type": 4, "name": "Todding"},
+            {"id": "2", "type": 0, "name": "banana-land", "parent_id": "4"},
+        ]),
+        ("/channels/2/messages", None): _ok(messages),
+        ("/channels/2/threads/search", 0): _ok({"threads": []}),
+    }
+
+
+def test_only_from_takes_the_creators_messages_and_no_one_elses():
+    """Operator 2026-09-28: in the creator's server, another member posting a
+    meme is not the creator's art. Matched by id, username or display name."""
+    creator = {"id": "7", "username": "todding", "global_name": "Todding"}
+    other = {"id": "8", "username": "jakeboii", "global_name": "Jake Boii"}
+    msgs = [_msg(3, author=creator), _msg(2, author=other), _msg(1, author=creator)]
+    url = "https://discord.com/channels/1/2"
+
+    everyone = _client(_one_channel([dict(m) for m in msgs]))
+    assert [mid for mid, _ in _ids(everyone, url)] == ["3", "2", "1"]
+    for who in (["Todding"], ["TODDING "], ["7"]):
+        client = _client(_one_channel([dict(m) for m in msgs]))
+        client.only_from(who)
+        assert [mid for mid, _ in _ids(client, url)] == ["3", "1"]
+    client = _client(_one_channel([dict(m) for m in msgs]))
+    client.only_from([])
+    assert len(_ids(client, url)) == 3
+
+
+def test_the_source_label_names_the_server_and_channel_the_walk_read():
+    client = _client(_one_channel([]))
+    url = "https://discord.com/channels/1/2"
+    assert client.source_label(url) is None  # nothing walked yet
+    list(client.iter_posts(url))
+    assert client.source_label(url) == "Todding's Server · #banana-land"
+    assert client.source_label("https://discord.com/channels/1") == "Todding's Server"
+    client._channels["9"] = {"channel": "wip", "is_thread": True, "parent": "banana-land"}
+    assert client.source_label("https://discord.com/channels/1/9") == (
+        "Todding's Server · #banana-land › wip"
+    )
+
+
 def test_a_server_walks_text_then_threads_newest_created_first_and_skips_private():
     routes = {
         "/guilds/1": _ok({"id": "1", "name": "S"}),
@@ -337,3 +424,60 @@ def test_the_adapter_authenticates_with_the_token_and_keys_by_identity(tmp_path)
         _msg(9, attachments=[{"id": "300", "url": "https://cdn/a/1.png"}])
     )
     assert _ledger_key(media) == "9:300"
+
+
+# -- the poster picker (#4491) -------------------------------------------------
+
+def _person(pid, username, global_name=None, **extra):
+    return {"id": pid, "username": username, "global_name": global_name,
+            "messages": 1, "images": 0, **extra}
+
+
+def test_the_creator_a_server_is_named_for_is_suggested():
+    ranked = dc.rank_posters("Todding's Server", "99", [
+        _person("8", "jakeboii", "Jake Boii", images=3),
+        _person("7", "todding", "Todding", images=1),
+    ])
+    assert ranked[0]["id"] == "7" and ranked[0]["suggested"] is True
+    assert ranked[0]["reasons"] == ["name matches the server"]
+    assert ranked[1]["suggested"] is False
+
+
+def test_owning_the_server_and_matching_its_name_outranks_either_alone():
+    ranked = dc.rank_posters("The Official Todding Discord", "7", [
+        _person("5", "toddingfan"),
+        _person("7", "t0dd", "Todding"),
+    ])
+    assert [r["id"] for r in ranked if r["suggested"]] == ["7"]
+    assert ranked[0]["reasons"] == ["owns the server", "name matches the server"]
+
+
+def test_no_signal_suggests_no_one_and_bots_never():
+    assert not any(r["suggested"] for r in dc.rank_posters("Art Club", None, [
+        _person("1", "alice"), _person("2", "bob"),
+    ]))
+    ranked = dc.rank_posters("Todding's Server", None, [_person("3", "toddingbot", bot=True)])
+    assert ranked[0]["suggested"] is False
+
+
+def test_recent_posters_tallies_a_shallow_window_by_id():
+    creator = {"id": "7", "username": "todding", "global_name": "Todding"}
+    other = {"id": "8", "username": "jakeboii", "global_name": "Jake Boii"}
+    art = [{"url": "https://cdn/a/1.png"}]
+    page = [_msg(i, author=creator, attachments=art) for i in range(300, 240, -1)]
+    page += [_msg(i, author=other) for i in range(240, 200, -1)]
+    routes = {
+        "/guilds/1": _ok({"id": "1", "name": "Todding's Server", "owner_id": "7"}),
+        ("/channels/2/messages", None): _ok(page),
+        ("/channels/2/messages", "201"): _ok([_msg(150, author=other)]),
+    }
+    client = _client(routes)
+    got = client.recent_posters("1", "2", max_messages=150)
+    assert got["server"] == "Todding's Server" and got["owner_id"] == "7"
+    assert got["scanned"] == 101
+    first = got["posters"][0]
+    assert (first["id"], first["messages"], first["images"], first["suggested"]) == ("7", 60, 60, True)
+    assert got["posters"][1]["messages"] == 41
+    # It asked for no more than the window: 100, then the 50 left of 150.
+    limits = [p.get("limit") for e, p in client._session.calls if e.endswith("/messages")]
+    assert limits == [100, 50]

tests/test_discord_poster_cleanup.py

@@ -0,0 +1,131 @@
+"""Removing a Discord source's posts by people outside its poster list (#4486).
+
+Real Postgres (db_sync): the predicates read `raw_metadata->>'author'`, which
+only the database can evaluate. The test that matters runs preview and apply
+on one fixture and asserts they agree AND that the rows went (snippet #3087).
+"""
+
+import pytest
+from sqlalchemy import func, select
+
+from backend.app.models import (
+    Artist,
+    ImageProvenance,
+    ImageRecord,
+    Post,
+    PostAttachment,
+    Source,
+)
+from backend.app.services import discord_poster_cleanup as cleanup
+
+pytestmark = pytest.mark.integration
+
+
+def _image(db, artist, tmp_path, name, post):
+    f = tmp_path / f"{name}.png"
+    f.write_bytes(b"x")
+    img = ImageRecord(
+        artist_id=artist.id, path=str(f), sha256=name.ljust(64, "0"),
+        size_bytes=1, mime="image/png", origin="downloaded", primary_post_id=post.id,
+    )
+    db.add(img)
+    db.flush()
+    return img
+
+
+def _post(db, source, mid, raw, **extra):
+    p = Post(
+        source_id=source.id, artist_id=source.artist_id, external_post_id=mid,
+        raw_metadata=raw, **extra,
+    )
+    db.add(p)
+    db.flush()
+    return p
+
+
+def _fixture(db, tmp_path, authors=("Todding",)):
+    """Todding's post, two of Jake's (one sharing an image with Todding's), an
+    old post with no poster, and a drop that absorbed Todding's and Jake's."""
+    artist = Artist(name="Todding", slug="todding-cleanup")
+    db.add(artist)
+    db.flush()
+    src = Source(
+        artist_id=artist.id, platform="discord",
+        url="https://discord.com/channels/1/2",
+        config_overrides={"discord_authors": list(authors)} if authors else None,
+    )
+    db.add(src)
+    db.flush()
+    todd = _post(db, src, "10", {"author": "todding", "author_name": "Todding", "author_id": "1"})
+    jake1 = _post(db, src, "11", {"author": "jakeboii", "author_id": "8"})
+    jake2 = _post(db, src, "12", {"author": "jakeboii", "author_id": "8"})
+    old = _post(db, src, "13", {"category": "discord"})
+    drop = _post(db, src, "fc-drop:10", None, synthesized_by="discord_drop")
+    todd.absorbed_by_post_id = drop.id
+    jake1.absorbed_by_post_id = drop.id
+
+    art = _image(db, artist, tmp_path, "art", todd)
+    meme = _image(db, artist, tmp_path, "meme", jake1)
+    shared = _image(db, artist, tmp_path, "shared", jake2)
+    legacy = _image(db, artist, tmp_path, "legacy", old)
+    db.add_all([
+        ImageProvenance(image_record_id=shared.id, post_id=todd.id, source_id=src.id),
+        ImageProvenance(image_record_id=art.id, post_id=drop.id, source_id=src.id),
+        ImageProvenance(image_record_id=meme.id, post_id=drop.id, source_id=src.id),
+        PostAttachment(
+            post_id=jake2.id, artist_id=artist.id, sha256="z" * 64,
+            path="/store/z/f.zip", original_filename="f.zip", ext=".zip", size_bytes=1,
+        ),
+    ])
+    db.commit()
+    return src, {
+        "todd": todd.id, "jake1": jake1.id, "jake2": jake2.id, "old": old.id,
+        "drop": drop.id, "art": art.id, "meme": meme.id, "shared": shared.id,
+        "legacy": legacy.id,
+    }
+
+
+def test_preview_matches_apply_and_the_rows_go(db_sync, tmp_path):
+    src, ids = _fixture(db_sync, tmp_path)
+
+    projected = cleanup.preview(db_sync, source_id=src.id)
+    assert projected["authors"] == ["todding"]
+    assert projected["posters"] == [{"poster": "jakeboii", "posts": 2}]
+    assert projected["unknown_posts"] == 1
+
+    done = cleanup.apply(db_sync, source_id=src.id, images_root=tmp_path)
+    assert projected["posts"] == done["posts_deleted"] == 2
+    assert projected["images"] == done["images_deleted"] == 1  # the meme only
+    assert projected["attachments"] == done["attachments_deleted"] == 1
+    assert projected["drops"] == done["drops_deleted"] == 1
+
+    post_ids = set(db_sync.execute(select(Post.id).where(Post.source_id == src.id)).scalars())
+    assert post_ids == {ids["todd"], ids["old"]}
+    image_ids = set(db_sync.execute(
+        select(ImageRecord.id).where(ImageRecord.id.in_(
+            [ids["art"], ids["meme"], ids["shared"], ids["legacy"]]))
+    ).scalars())
+    # The meme was only Jake's. The shared piece is also on Todding's post, and
+    # the drop's link to the art was never what kept it.
+    assert image_ids == {ids["art"], ids["shared"], ids["legacy"]}
+    assert not (tmp_path / "meme.png").exists()
+    # Todding's message is back in the feed, for the sweep to regroup.
+    assert db_sync.get(Post, ids["todd"]).absorbed_by_post_id is None
+    assert db_sync.execute(select(func.count(PostAttachment.id)).where(
+        PostAttachment.sha256 == "z" * 64)).scalar_one() == 0
+
+
+def test_a_poster_matches_by_display_name_or_id_too(db_sync, tmp_path):
+    src, _ = _fixture(db_sync, tmp_path, authors=("8",))
+    projected = cleanup.preview(db_sync, source_id=src.id)
+    assert projected["posters"] == [{"poster": "Todding", "posts": 1}]
+
+
+def test_no_list_means_nothing_to_remove(db_sync, tmp_path):
+    src, _ = _fixture(db_sync, tmp_path, authors=())
+    with pytest.raises(cleanup.PosterCleanupError):
+        cleanup.preview(db_sync, source_id=src.id)
+
+
+def test_the_token_names_what_the_preview_showed():
+    assert cleanup.confirm_token({"posts": 2, "images": 1}) == "remove-2-posts-1-images"

tests/test_post_feed_service.py

@@ -283,6 +283,27 @@ async def test_scroll_item_shape_minimal(db):
     assert "description_full" not in item
 
 
+@pytest.mark.asyncio
+async def test_a_discord_post_names_its_channel(db):
+    """#4481: the card says which channel a message came from. Read from the
+    record's `channel`; never on another platform, even with the same key."""
+    artist = await _seed_artist(db, "todding-ch")
+    dsrc = await _seed_source(db, artist.id, "discord", "https://discord.com/channels/1/2")
+    psrc = await _seed_source(db, artist.id, "patreon", "https://p/todding-ch")
+    now = datetime.now(UTC)
+    d = await _seed_post(db, dsrc.id, external_id="D1", post_date=now)
+    d.raw_metadata = {"category": "discord", "channel": "banana-land"}
+    blank = await _seed_post(db, dsrc.id, external_id="D2", post_date=now)
+    blank.raw_metadata = {"category": "discord", "channel": "  "}
+    p = await _seed_post(db, psrc.id, external_id="P1", post_date=now)
+    p.raw_metadata = {"channel": "not-discord"}
+    await db.commit()
+
+    page = await PostFeedService(db).scroll(cursor=None, limit=10, artist_id=artist.id)
+    by_id = {it["external_post_id"]: it["channel"] for it in page["items"]}
+    assert by_id == {"D1": "banana-land", "D2": None, "P1": None}
+
+
 @pytest.mark.asyncio
 async def test_scroll_surfaces_translation_fields(db):
     # #143: a translated post exposes the translated title/description + source