usernames: operator reserved-username blocklist

A plain blocklist for names like @support - separate from the collectible
system, so a reservation has no owner, no price and no "bought on Fragment"
badge.

- reserved_usernames table + migration.
- Enforced in replacePeerUsernameTx (the single editable-username write point:
  account.updateUsername, channels.updateUsername, @BotFather /setusername) and
  in the collectible mint path; a reserved name returns USERNAME_OCCUPIED.
- admin.Service: ReserveUsername / UnreserveUsername (journalled commands) and
  the ReservedUsernames listing.
- adminapi: /v1/reserved-usernames{,/reserve,/unreserve}.
- telesrv-admin panel + a "Reserved Usernames" page in the web UI (dist rebuilt).
- Postgres and in-memory store implementations; the memory registry gains an
  optional reserved-name check so tests exercise the same rule.

cmd/telesrv-admin/server.go

@@ -12,6 +12,7 @@ import (
 	"io/fs"
 	"mime/multipart"
 	"net/http"
+	"net/url"
 	"path"
 	"strconv"
 	"strings"
@@ -74,6 +75,7 @@ func (s *server) routes() http.Handler {
 	mux.Handle("GET /api/messages/groups", s.requireAuthAPI(http.HandlerFunc(s.handleGroupMessagesAPI)))
 	mux.Handle("GET /api/messages/groups/detail", s.requireAuthAPI(http.HandlerFunc(s.handleGroupMessageDetailAPI)))
 	mux.Handle("GET /api/collectible-usernames", s.requireAuthAPI(http.HandlerFunc(s.handleCollectibleUsernamesAPI)))
+	mux.Handle("GET /api/reserved-usernames", s.requireAuthAPI(http.HandlerFunc(s.handleReservedUsernamesAPI)))
 	mux.Handle("GET /api/collectible-usernames/{id}", s.requireAuthAPI(http.HandlerFunc(s.handleCollectibleUsernameDetailAPI)))
 	mux.Handle("GET /api/storage/stats", s.requireAuthAPI(http.HandlerFunc(s.handleStorageStatsAPI)))
 	mux.Handle("GET /api/storage/accounts", s.requireAuthAPI(http.HandlerFunc(s.handleStorageAccountsAPI)))
@@ -128,6 +130,8 @@ func (s *server) routes() http.Handler {
 	mux.Handle("POST /api/actions/auto-categorize-gif-catalog", s.requireAuthAPI(http.HandlerFunc(s.handleAutoCategorizeGifCatalogAPI)))
 	mux.Handle("POST /api/actions/delete-uncategorized-gifs", s.requireAuthAPI(http.HandlerFunc(s.handleDeleteUncategorizedGifsAPI)))
 	mux.Handle("POST /api/actions/delete-gif-catalog-entry", s.requireAuthAPI(http.HandlerFunc(s.handleDeleteGifCatalogEntryAPI)))
+	mux.Handle("POST /api/actions/reserve-username", s.requireAuthAPI(http.HandlerFunc(s.handleReserveUsernameAPI)))
+	mux.Handle("POST /api/actions/unreserve-username", s.requireAuthAPI(http.HandlerFunc(s.handleUnreserveUsernameAPI)))
 	mux.Handle("POST /api/actions/mint-collectible-username", s.requireAuthAPI(http.HandlerFunc(s.handleMintCollectibleUsernameAPI)))
 	mux.Handle("POST /api/actions/transfer-collectible-username", s.requireAuthAPI(http.HandlerFunc(s.handleTransferCollectibleUsernameAPI)))
 	mux.Handle("POST /api/actions/revoke-collectible-username", s.requireAuthAPI(http.HandlerFunc(s.handleRevokeCollectibleUsernameAPI)))
@@ -2239,6 +2243,69 @@ type mintCollectibleUsernameAPIRequest struct {
 	PurchaseDate   flexUnix  `json:"purchase_date"`
 }
 
+type reserveUsernameAPIRequest struct {
+	CommandID string `json:"command_id"`
+	Reason    string `json:"reason"`
+	Confirm   bool   `json:"confirm"`
+	Username  string `json:"username"`
+}
+
+func (s *server) handleReserveUsernameAPI(w http.ResponseWriter, r *http.Request) {
+	var body reserveUsernameAPIRequest
+	if !decodeAction(w, r, &body) {
+		return
+	}
+	req := admin.ReserveUsernameRequest{
+		CommandMeta: s.commandMetaFromAPI(r, body.CommandID, body.Reason, body.Confirm, "reserve-username"),
+		Username:    body.Username,
+	}
+	result, err := s.callAdminAPI(r.Context(), "/v1/reserved-usernames/reserve", req)
+	writeCommandResultAPI(w, result, err)
+}
+
+func (s *server) handleUnreserveUsernameAPI(w http.ResponseWriter, r *http.Request) {
+	var body reserveUsernameAPIRequest
+	if !decodeAction(w, r, &body) {
+		return
+	}
+	req := admin.UnreserveUsernameRequest{
+		CommandMeta: s.commandMetaFromAPI(r, body.CommandID, body.Reason, body.Confirm, "unreserve-username"),
+		Username:    body.Username,
+	}
+	result, err := s.callAdminAPI(r.Context(), "/v1/reserved-usernames/unreserve", req)
+	writeCommandResultAPI(w, result, err)
+}
+
+func (s *server) handleReservedUsernamesAPI(w http.ResponseWriter, r *http.Request) {
+	q := r.URL.Query()
+	params := url.Values{}
+	for _, name := range []string{"q", "limit", "offset"} {
+		if v := strings.TrimSpace(q.Get(name)); v != "" {
+			params.Set(name, v)
+		}
+	}
+	apiPath := "/v1/reserved-usernames"
+	if enc := params.Encode(); enc != "" {
+		apiPath += "?" + enc
+	}
+	req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, s.cfg.AdminAPIURL+apiPath, nil)
+	if err != nil {
+		writeAPIError(w, http.StatusInternalServerError, "request build failed")
+		return
+	}
+	req.Header.Set("Authorization", "Bearer "+s.cfg.AdminAPIToken)
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		writeAPIError(w, http.StatusBadGateway, "admin api unreachable")
+		return
+	}
+	defer resp.Body.Close()
+	data, _ := io.ReadAll(io.LimitReader(resp.Body, 4<<20))
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(resp.StatusCode)
+	_, _ = w.Write(data)
+}
+
 func (s *server) handleMintCollectibleUsernameAPI(w http.ResponseWriter, r *http.Request) {
 	var body mintCollectibleUsernameAPIRequest
 	if !decodeAction(w, r, &body) {

cmd/telesrv-admin/web/dist/index.html

@@ -23,7 +23,7 @@
       })();
     </script>
 
-    <script type="module" crossorigin src="/assets/index-Bt9UBcEE.js"></script>
+    <script type="module" crossorigin src="/assets/index-BWYHyok0.js"></script>
     <link rel="stylesheet" crossorigin href="/assets/index-CQKJMNpu.css">
   </head>
   <body>

cmd/telesrv-admin/web/src/api.ts

@@ -22,6 +22,7 @@ import type {
   ChannelListResponse,
   CollectibleUsernameDetail,
   CollectibleUsernameListResponse,
+  ReservedUsernameListResponse,
   CommandResult,
   GroupMessageDetail,
   GroupMessageListResponse,
@@ -163,6 +164,8 @@ export const api = {
     request<CollectibleUsernameListResponse>(`/api/collectible-usernames?${params.toString()}`),
   collectibleUsername: (id: string) =>
     request<CollectibleUsernameDetail>(`/api/collectible-usernames/${encodeURIComponent(id)}`),
+  reservedUsernames: (params: URLSearchParams) =>
+    request<ReservedUsernameListResponse>(`/api/reserved-usernames?${params.toString()}`),
   dashboard: () => request<DashboardResponse>("/api/dashboard"),
   storageStats: () => request<StorageStatsResponse>("/api/storage/stats"),
   storageAccounts: (params: URLSearchParams) =>

cmd/telesrv-admin/web/src/components/Layout.tsx

@@ -1,6 +1,7 @@
 import {
   AtSign,
   BadgeCheck,
+  Ban,
   Bot,
   ChevronDown,
   Database,
@@ -99,6 +100,7 @@ export function Shell({
             <NavLink icon={<Stamp size={16} />} href="/bot-verification" route={route} navigate={navigate}>{"Third-party marks"}</NavLink>
           )}
           <NavLink icon={<AtSign size={16} />} href="/collectible-usernames" route={route} navigate={navigate}>{"NFT Usernames"}</NavLink>
+          <NavLink icon={<Ban size={16} />} href="/reserved-usernames" route={route} navigate={navigate}>{"Reserved Usernames"}</NavLink>
           <NavLink icon={<Database size={16} />} href="/storage" route={route} navigate={navigate}>{"Storage"}</NavLink>
 			<NavLink icon={<Sticker size={16} />} href="/stickers" route={route} navigate={navigate}>{"Stickers"}</NavLink>
 			<NavLink icon={<Smile size={16} />} href="/emoji" route={route} navigate={navigate}>{"Emoji"}</NavLink>

cmd/telesrv-admin/web/src/pages/ReservedUsernamesPage.tsx

@@ -0,0 +1,138 @@
+import { AtSign, Loader2, Plus, RefreshCw, Search, Trash2 } from "lucide-react";
+import { useEffect, useState } from "react";
+import { api, errorMessage } from "../api";
+import { ActionButton } from "../components/ActionButton";
+import { Alert, EmptyRow, Metric, PageFrame, QueryPanel } from "../components/ui";
+import { formatUnix } from "../lib/format";
+import type { ReservedUsernameRow } from "../types";
+
+// Reserved usernames are a plain operator blocklist: a name listed here cannot be
+// taken as an editable username by any peer and cannot be minted as a
+// collectible. No owner, no price, no Fragment badge - that is the collectible
+// tab's job.
+export function ReservedUsernamesPage() {
+  const [q, setQ] = useState("");
+  const [rows, setRows] = useState<ReservedUsernameRow[]>([]);
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState("");
+  const [newName, setNewName] = useState("");
+
+  async function load() {
+    setBusy(true);
+    setError("");
+    const params = new URLSearchParams({ limit: "200" });
+    if (q.trim()) params.set("q", q.trim().replace(/^@/, ""));
+    try {
+      const result = await api.reservedUsernames(params);
+      setRows(result.reserved ?? []);
+    } catch (err) {
+      setError(errorMessage(err));
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  useEffect(() => {
+    void load();
+  }, []);
+
+  const cleanNew = newName.trim().replace(/^@/, "");
+
+  return (
+    <PageFrame
+      title={"Reserved usernames"}
+      eyebrow={"Usernames / Blocklist"}
+      actions={
+        <button className="btn icon-text" type="button" onClick={() => load()} disabled={busy}>
+          <RefreshCw size={15} className={busy ? "spin" : ""} /> {"Refresh"}
+        </button>
+      }
+    >
+      {error && <Alert>{error}</Alert>}
+      <div className="metric-row">
+        <Metric label={"Reserved names"} value={String(rows.length)} />
+      </div>
+
+      <QueryPanel>
+        <div className="toolbar">
+          <label className="field-inline">
+            <span>{"Reserve"}</span>
+            <input
+              value={newName}
+              onChange={(event) => setNewName(event.target.value)}
+              placeholder={"support"}
+            />
+          </label>
+          <ActionButton
+            disabled={cleanNew.length < 5}
+            label={"Reserve username"}
+            icon={<Plus size={15} />}
+            tone="neutral"
+            path="/api/actions/reserve-username"
+            payload={() => ({ username: cleanNew })}
+            onDone={() => {
+              setNewName("");
+              void load();
+            }}
+          />
+        </div>
+        <form
+          className="toolbar"
+          onSubmit={(event) => {
+            event.preventDefault();
+            void load();
+          }}
+        >
+          <label className="searchbox">
+            <Search size={15} />
+            <input value={q} onChange={(event) => setQ(event.target.value)} placeholder={"Filter by prefix"} />
+          </label>
+          <button className="btn primary icon-text" type="submit" disabled={busy}>
+            {busy ? <Loader2 size={15} className="spin" /> : <Search size={15} />} {"Search"}
+          </button>
+        </form>
+      </QueryPanel>
+
+      <div className="table-wrap">
+        <table className="data-table">
+          <thead>
+            <tr>
+              <th>{"Username"}</th>
+              <th>{"Reason"}</th>
+              <th>{"Reserved by"}</th>
+              <th>{"Reserved (UTC)"}</th>
+              <th></th>
+            </tr>
+          </thead>
+          <tbody>
+            {rows.map((row) => (
+              <tr key={row.username}>
+                <td>
+                  <strong>
+                    <AtSign size={13} />
+                    {row.username}
+                  </strong>
+                </td>
+                <td>{row.reason || "-"}</td>
+                <td>{row.actor || "-"}</td>
+                <td>{formatUnix(row.created_at) || "-"}</td>
+                <td>
+                  <ActionButton
+                    compact
+                    label={"Unreserve"}
+                    icon={<Trash2 size={13} />}
+                    tone="danger"
+                    path="/api/actions/unreserve-username"
+                    payload={() => ({ username: row.username })}
+                    onDone={() => void load()}
+                  />
+                </td>
+              </tr>
+            ))}
+            {rows.length === 0 && <EmptyRow colSpan={5} />}
+          </tbody>
+        </table>
+      </div>
+    </PageFrame>
+  );
+}

cmd/telesrv-admin/web/src/pages/Routes.tsx

@@ -4,6 +4,7 @@ import { AccountsPage } from "./AccountsPage";
 import { SharedDevicesPage } from "./SharedDevicesPage";
 import { CollectibleUsernameDetailPage } from "./CollectibleUsernameDetailPage";
 import { CollectibleUsernamesPage } from "./CollectibleUsernamesPage";
+import { ReservedUsernamesPage } from "./ReservedUsernamesPage";
 import { ChannelDetailPage } from "./ChannelDetailPage";
 import { ChannelsPage } from "./ChannelsPage";
 import { BotDetailPage } from "./BotDetailPage";
@@ -82,6 +83,9 @@ export function Routes({ route, navigate }: { route: RouteState; navigate: Navig
   if (route.path === "/collectible-usernames") {
     return <CollectibleUsernamesPage navigate={navigate} />;
   }
+  if (route.path === "/reserved-usernames") {
+    return <ReservedUsernamesPage />;
+  }
   if (route.path === "/storage") {
     return <StoragePage navigate={navigate} />;
   }

cmd/telesrv-admin/web/src/routing.ts

@@ -20,6 +20,7 @@ export function routeTitle(pathname: string): string {
   if (pathname.startsWith("/bot-verification")) return "Third-party verification";
   if (pathname.startsWith("/verification")) return "Official Verification";
   if (pathname.startsWith("/collectible-usernames")) return "Collectible Usernames";
+  if (pathname.startsWith("/reserved-usernames")) return "Reserved Usernames";
   if (pathname.startsWith("/storage")) return "Storage";
   if (pathname.startsWith("/accounts/shared-devices")) return "Shared Devices";
   if (pathname.startsWith("/accounts")) return "Accounts";

cmd/telesrv-admin/web/src/types.ts

@@ -347,6 +347,17 @@ export type CollectibleUsernameDetail = {
   transfers: CollectibleUsernameTransferRow[] | null;
 };
 
+export type ReservedUsernameRow = {
+  username: string;
+  reason: string;
+  actor: string;
+  created_at: number;
+};
+
+export type ReservedUsernameListResponse = {
+  reserved: ReservedUsernameRow[] | null;
+};
+
 // Official platform verification. Every int64 the backend tags `,string` stays a
 // decimal string here: application ids, peer ids and the optimistic-locking
 // version all outgrow the exact range of a JSON number, and a rounded version

cmd/telesrv/main.go

@@ -1203,6 +1203,7 @@ func run(logger *zap.Logger) error {
 	// Collectible (NFT) usernames are an optional read model projected at the
 	// protocol edge.
 	collectibleUsernameStore := postgres.NewCollectibleUsernameStore(pool)
+	reservedUsernameStore := postgres.NewReservedUsernameStore(pool)
 	usernamesService := usernamesapp.NewService(
 		usernamesapp.WithRegistryStore(collectibleUsernameStore),
 		usernamesapp.WithCollectibleStore(collectibleUsernameStore),
@@ -1390,6 +1391,7 @@ func run(logger *zap.Logger) error {
 		Emoji:                  filesService,
 		Moderation:             moderationService,
 		Usernames:              usernamesService,
+		ReservedUsernames:      reservedUsernameStore,
 		Verification:           verificationService,
 		BotVerification:        botVerificationService,
 		Account:                accountService,

deploy/migrations/20260909190000_reserved_usernames.down.sql

@@ -0,0 +1 @@
+DROP TABLE IF EXISTS public.reserved_usernames;

deploy/migrations/20260909190000_reserved_usernames.up.sql

@@ -0,0 +1,17 @@
+-- Operator-maintained username blocklist. A name listed here cannot be taken as
+-- an editable username by any peer (account.updateUsername, channels.updateUsername,
+-- @BotFather /setusername, or the admin set-username actions). It is a plain
+-- blocklist: no owner, no price, no Fragment collectible badge.
+
+CREATE TABLE public.reserved_usernames (
+    username_lower text PRIMARY KEY CHECK (
+        username_lower <> '' AND username_lower = lower(username_lower)
+    ),
+    username   text NOT NULL,
+    reason     text NOT NULL DEFAULT '' CHECK (octet_length(reason) <= 512),
+    actor      text NOT NULL DEFAULT '' CHECK (octet_length(actor) <= 256),
+    created_at timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE INDEX reserved_usernames_created_at_idx
+    ON public.reserved_usernames (created_at DESC, username_lower);

internal/admin/service.go

@@ -66,6 +66,9 @@ const (
 	ActionTransferCollectibleUsername = "usernames.collectible.transfer"
 	ActionRevokeCollectibleUsername   = "usernames.collectible.revoke"
 	ActionDeleteCollectibleUsername   = "usernames.collectible.delete"
+	// Operator username blocklist.
+	ActionReserveUsername   = "usernames.reserve"
+	ActionUnreserveUsername = "usernames.unreserve"
 	// Official platform verification review. Claim/approve/reject act on one
 	// application; revoke acts on a target, because clearing a badge is not a
 	// decision on the application that granted it.
@@ -363,6 +366,16 @@ type CollectibleUsernamesService interface {
 	Transfers(ctx context.Context, collectibleID int64, limit int) ([]domain.CollectibleUsernameTransfer, error)
 }
 
+// ReservedUsernamesService is the operator username blocklist: a plain list of
+// names no peer may take. Separate from the collectible lifecycle - a reservation
+// has no owner, no price and no Fragment badge.
+type ReservedUsernamesService interface {
+	IsReserved(ctx context.Context, usernameLower string) (bool, error)
+	ReserveUsername(ctx context.Context, username, reason, actor string) (created bool, err error)
+	UnreserveUsername(ctx context.Context, username string) (removed bool, err error)
+	ReservedUsernames(ctx context.Context, filter domain.ReservedUsernameFilter) ([]domain.ReservedUsername, error)
+}
+
 // collectibleUsernameByIDLookup is the optional by-identity read. Stores that
 // expose it answer a detail request in one round trip; the keyset fallback in
 // CollectibleUsernameByID keeps a service without it correct.
@@ -389,6 +402,7 @@ type Dependencies struct {
 	Emoji                  EmojiService
 	Moderation             ModerationService
 	Usernames              CollectibleUsernamesService
+	ReservedUsernames      ReservedUsernamesService
 	Verification           VerificationService
 	// BotVerification is the third-party mechanism, wired separately from
 	// Verification: the two never read each other's state.
@@ -420,6 +434,7 @@ type Service struct {
 	emoji                  EmojiService
 	moderation             ModerationService
 	usernames              CollectibleUsernamesService
+	reservedUsernames      ReservedUsernamesService
 	verification           VerificationService
 	botVerification        BotVerificationService
 	account                AccountService
@@ -487,6 +502,9 @@ func (s *Service) Configure(deps Dependencies) *Service {
 	if deps.Usernames != nil {
 		s.usernames = deps.Usernames
 	}
+	if deps.ReservedUsernames != nil {
+		s.reservedUsernames = deps.ReservedUsernames
+	}
 	if deps.Verification != nil {
 		s.verification = deps.Verification
 	}
@@ -2059,6 +2077,91 @@ func (s *Service) DeleteCollectibleUsername(ctx context.Context, req DeleteColle
 	})
 }
 
+// ReserveUsernameRequest / UnreserveUsernameRequest add or remove a blocklist
+// entry. reservedUsernameFromRequest normalises the name; the reason is a free
+// operator note.
+type ReserveUsernameRequest struct {
+	CommandMeta
+	Username string
+}
+
+type UnreserveUsernameRequest struct {
+	CommandMeta
+	Username string
+}
+
+// ReserveUsername adds a name to the operator blocklist. Journalled and
+// replay-safe like every other command.
+func (s *Service) ReserveUsername(ctx context.Context, req ReserveUsernameRequest) (CommandResult, error) {
+	if s == nil || s.reservedUsernames == nil {
+		return CommandResult{}, fmt.Errorf("admin reserved username dependency is not configured")
+	}
+	req.Username = domain.NormalizeUsername(req.Username)
+	if !domain.ValidCollectibleUsername(req.Username) {
+		return CommandResult{}, codedError(CodeUsernameInvalid, domain.ErrUsernameInvalid)
+	}
+	if len(req.Reason) > domain.MaxReservedUsernameReasonLength {
+		return CommandResult{}, fmt.Errorf("reason must be <= %d bytes", domain.MaxReservedUsernameReasonLength)
+	}
+	return s.runCommand(ctx, req.CommandMeta, ActionReserveUsername, 0, domain.Peer{}, req, func() (CommandResult, error) {
+		details := map[string]any{"username": req.Username}
+		if s.usernames != nil {
+			if asset, err := s.usernames.Collectible(ctx, req.Username); err == nil {
+				details["existing_collectible_id"] = strconv.FormatInt(asset.ID, 10)
+				return CommandResult{Details: details}, codedError(CodeUsernameOccupied, domain.ErrUsernameOccupied)
+			}
+		}
+		if req.DryRun {
+			return CommandResult{Message: "username reservation validated", Details: details}, nil
+		}
+		created, err := s.reservedUsernames.ReserveUsername(ctx, req.Username, req.Reason, req.Actor)
+		if err != nil {
+			return CommandResult{Details: details}, err
+		}
+		details["created"] = created
+		message := "username reserved"
+		if !created {
+			message = "username was already reserved"
+		}
+		return CommandResult{Message: message, Details: details}, nil
+	})
+}
+
+// UnreserveUsername removes a name from the operator blocklist.
+func (s *Service) UnreserveUsername(ctx context.Context, req UnreserveUsernameRequest) (CommandResult, error) {
+	if s == nil || s.reservedUsernames == nil {
+		return CommandResult{}, fmt.Errorf("admin reserved username dependency is not configured")
+	}
+	req.Username = domain.NormalizeUsername(req.Username)
+	if strings.TrimSpace(req.Username) == "" {
+		return CommandResult{}, codedError(CodeUsernameInvalid, domain.ErrUsernameInvalid)
+	}
+	return s.runCommand(ctx, req.CommandMeta, ActionUnreserveUsername, 0, domain.Peer{}, req, func() (CommandResult, error) {
+		details := map[string]any{"username": req.Username}
+		if req.DryRun {
+			return CommandResult{Message: "username unreservation validated", Details: details}, nil
+		}
+		removed, err := s.reservedUsernames.UnreserveUsername(ctx, req.Username)
+		if err != nil {
+			return CommandResult{Details: details}, err
+		}
+		details["removed"] = removed
+		message := "username unreserved"
+		if !removed {
+			message = "username was not reserved"
+		}
+		return CommandResult{Message: message, Details: details}, nil
+	})
+}
+
+// ReservedUsernames is the admin listing read for the blocklist.
+func (s *Service) ReservedUsernames(ctx context.Context, filter domain.ReservedUsernameFilter) ([]domain.ReservedUsername, error) {
+	if s == nil || s.reservedUsernames == nil {
+		return nil, fmt.Errorf("reserved username dependency is not configured")
+	}
+	return s.reservedUsernames.ReservedUsernames(ctx, filter)
+}
+
 func collectibleOwnerPeer(userID, channelID int64) (domain.Peer, error) {
 	if userID < 0 || channelID < 0 {
 		return domain.Peer{}, fmt.Errorf("owner id must be positive")

internal/admin/service_test.go

@@ -12,6 +12,7 @@ import (
 
 	usernamesapp "telesrv/internal/app/usernames"
 	"telesrv/internal/domain"
+	"telesrv/internal/store/memory"
 )
 
 // Compile-time proof that the shipped use-case services satisfy the admin ports.
@@ -1427,3 +1428,76 @@ func TestDeleteCollectibleUsernameCommand(t *testing.T) {
 		t.Fatalf("delete of invalid name = nil error, want rejection")
 	}
 }
+
+func TestReserveAndUnreserveUsername(t *testing.T) {
+	ctx := context.Background()
+	reserved := memory.NewReservedUsernameStore()
+	svc := NewService(Dependencies{
+		Commands:          newMemoryCommandRepo(),
+		ReservedUsernames: reserved,
+		Now:               fixedNow,
+	})
+
+	dry, err := svc.ReserveUsername(ctx, ReserveUsernameRequest{
+		CommandMeta: CommandMeta{CommandID: "rv-dry", Actor: "ops", Reason: "official handle", DryRun: true},
+		Username:    "@Support",
+	})
+	if err != nil {
+		t.Fatalf("dry-run reserve: %v", err)
+	}
+	if got, _ := reserved.IsReserved(ctx, "support"); got {
+		t.Fatal("dry-run reserved the name")
+	}
+	if dry.Details["username"] != "Support" {
+		t.Fatalf("dry-run details = %+v", dry.Details)
+	}
+
+	if _, err := svc.ReserveUsername(ctx, ReserveUsernameRequest{
+		CommandMeta: CommandMeta{CommandID: "rv-exec", Actor: "ops", Reason: "official handle"},
+		Username:    "support",
+	}); err != nil {
+		t.Fatalf("reserve: %v", err)
+	}
+	if got, _ := reserved.IsReserved(ctx, "support"); !got {
+		t.Fatal("name not reserved after exec")
+	}
+
+	if _, err := svc.UnreserveUsername(ctx, UnreserveUsernameRequest{
+		CommandMeta: CommandMeta{CommandID: "urv-exec", Actor: "ops", Reason: "no longer needed"},
+		Username:    "SUPPORT",
+	}); err != nil {
+		t.Fatalf("unreserve: %v", err)
+	}
+	if got, _ := reserved.IsReserved(ctx, "support"); got {
+		t.Fatal("name still reserved after unreserve")
+	}
+
+	if _, err := svc.ReserveUsername(ctx, ReserveUsernameRequest{
+		CommandMeta: CommandMeta{CommandID: "bad", Actor: "ops", Reason: "x"},
+		Username:    "ab",
+	}); err == nil {
+		t.Fatal("reserve of a too-short name = nil error, want rejection")
+	}
+}
+
+func TestMemoryRegistryRefusesReservedName(t *testing.T) {
+	ctx := context.Background()
+	reserved := memory.NewReservedUsernameStore()
+	if _, err := reserved.ReserveUsername(ctx, "support", "", "ops"); err != nil {
+		t.Fatalf("seed reserve: %v", err)
+	}
+	registry := memory.NewCollectibleUsernameStore().WithReservedUsernames(reserved)
+
+	if _, err := registry.SetEditableUsername(ctx, domain.Peer{Type: domain.PeerTypeUser, ID: 1}, "support"); !errors.Is(err, domain.ErrUsernameOccupied) {
+		t.Fatalf("SetEditableUsername(reserved) err = %v, want ErrUsernameOccupied", err)
+	}
+	if _, _, err := registry.MintCollectibleUsername(ctx, domain.MintCollectibleUsernameRequest{
+		Username: "support", Currency: domain.CollectibleCurrencyUSD, Amount: 0, CommandKey: "k1",
+	}); !errors.Is(err, domain.ErrUsernameOccupied) {
+		t.Fatalf("Mint(reserved) err = %v, want ErrUsernameOccupied", err)
+	}
+	// A different name is unaffected.
+	if _, err := registry.SetEditableUsername(ctx, domain.Peer{Type: domain.PeerTypeUser, ID: 1}, "freename"); err != nil {
+		t.Fatalf("SetEditableUsername(free) err = %v", err)
+	}
+}

internal/adminapi/server.go

@@ -98,6 +98,9 @@ type Service interface {
 	CollectibleUsernames(ctx context.Context, filter domain.CollectibleUsernameFilter) ([]domain.CollectibleUsername, error)
 	CollectibleUsernameByID(ctx context.Context, id int64) (domain.CollectibleUsername, error)
 	CollectibleUsernameTransfers(ctx context.Context, collectibleID int64, limit int) ([]domain.CollectibleUsernameTransfer, error)
+	ReserveUsername(ctx context.Context, req admin.ReserveUsernameRequest) (admin.CommandResult, error)
+	UnreserveUsername(ctx context.Context, req admin.UnreserveUsernameRequest) (admin.CommandResult, error)
+	ReservedUsernames(ctx context.Context, filter domain.ReservedUsernameFilter) ([]domain.ReservedUsername, error)
 	ClaimVerification(ctx context.Context, req admin.ClaimVerificationRequest) (admin.CommandResult, error)
 	ApproveVerification(ctx context.Context, req admin.ApproveVerificationRequest) (admin.CommandResult, error)
 	RejectVerification(ctx context.Context, req admin.RejectVerificationRequest) (admin.CommandResult, error)
@@ -234,6 +237,9 @@ func (s *Server) routes() http.Handler {
 	mux.HandleFunc("POST /v1/collectible-usernames/delete", s.authenticated(s.handleDeleteCollectibleUsername))
 	mux.HandleFunc("GET /v1/collectible-usernames", s.authenticated(s.handleCollectibleUsernames))
 	mux.HandleFunc("GET /v1/collectible-usernames/{id}", s.authenticated(s.handleCollectibleUsername))
+	mux.HandleFunc("POST /v1/reserved-usernames/reserve", s.authenticated(s.handleReserveUsername))
+	mux.HandleFunc("POST /v1/reserved-usernames/unreserve", s.authenticated(s.handleUnreserveUsername))
+	mux.HandleFunc("GET /v1/reserved-usernames", s.authenticated(s.handleReservedUsernames))
 	// Official platform verification. Unlike every route above, these carry a
 	// named permission, so a scoped token can be given the review surface and
 	// nothing else. Revocation additionally requires verification.revoke.
@@ -1186,6 +1192,54 @@ func (s *Server) handleDeleteCollectibleUsername(w http.ResponseWriter, r *http.
 	writeCommandResult(w, result, err)
 }
 
+func (s *Server) handleReserveUsername(w http.ResponseWriter, r *http.Request) {
+	var req admin.ReserveUsernameRequest
+	if !decodeJSON(w, r, &req) {
+		return
+	}
+	result, err := s.svc.ReserveUsername(r.Context(), req)
+	writeCommandResult(w, result, err)
+}
+
+func (s *Server) handleUnreserveUsername(w http.ResponseWriter, r *http.Request) {
+	var req admin.UnreserveUsernameRequest
+	if !decodeJSON(w, r, &req) {
+		return
+	}
+	result, err := s.svc.UnreserveUsername(r.Context(), req)
+	writeCommandResult(w, result, err)
+}
+
+func (s *Server) handleReservedUsernames(w http.ResponseWriter, r *http.Request) {
+	query := r.URL.Query()
+	filter := domain.ReservedUsernameFilter{Query: query.Get("q")}
+	limit, ok := optionalQueryInt(w, query, "limit")
+	if !ok {
+		return
+	}
+	filter.Limit = limit
+	offset, ok := optionalQueryInt(w, query, "offset")
+	if !ok {
+		return
+	}
+	filter.Offset = offset
+	items, err := s.svc.ReservedUsernames(r.Context(), filter)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "list failed")
+		return
+	}
+	out := make([]map[string]any, 0, len(items))
+	for _, item := range items {
+		out = append(out, map[string]any{
+			"username":   item.Username,
+			"reason":     item.Reason,
+			"actor":      item.Actor,
+			"created_at": item.CreatedAt.Unix(),
+		})
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"reserved": out})
+}
+
 func (s *Server) handleCollectibleUsernames(w http.ResponseWriter, r *http.Request) {
 	query := r.URL.Query()
 	filter := domain.CollectibleUsernameFilter{

internal/adminapi/server_test.go

@@ -510,12 +510,30 @@ func (fakeService) ReviewModerationAppeal(context.Context, domain.ModerationDeci
 
 type captureCollectibleUsernameService struct {
 	fakeService
-	mint     admin.MintCollectibleUsernameRequest
-	transfer admin.TransferCollectibleUsernameRequest
-	revoke   admin.RevokeCollectibleUsernameRequest
-	del      admin.DeleteCollectibleUsernameRequest
-	filter   domain.CollectibleUsernameFilter
-	assetID  int64
+	mint      admin.MintCollectibleUsernameRequest
+	transfer  admin.TransferCollectibleUsernameRequest
+	revoke    admin.RevokeCollectibleUsernameRequest
+	del       admin.DeleteCollectibleUsernameRequest
+	reserve   admin.ReserveUsernameRequest
+	unreserve admin.UnreserveUsernameRequest
+	resFilter domain.ReservedUsernameFilter
+	filter    domain.CollectibleUsernameFilter
+	assetID   int64
+}
+
+func (s *captureCollectibleUsernameService) ReserveUsername(_ context.Context, req admin.ReserveUsernameRequest) (admin.CommandResult, error) {
+	s.reserve = req
+	return admin.CommandResult{CommandID: req.CommandID, Status: "completed", DryRun: req.DryRun}, nil
+}
+
+func (s *captureCollectibleUsernameService) UnreserveUsername(_ context.Context, req admin.UnreserveUsernameRequest) (admin.CommandResult, error) {
+	s.unreserve = req
+	return admin.CommandResult{CommandID: req.CommandID, Status: "completed", DryRun: req.DryRun}, nil
+}
+
+func (s *captureCollectibleUsernameService) ReservedUsernames(_ context.Context, filter domain.ReservedUsernameFilter) ([]domain.ReservedUsername, error) {
+	s.resFilter = filter
+	return []domain.ReservedUsername{{Username: "support", Reason: "official", Actor: "ops"}}, nil
 }
 
 func (s *captureCollectibleUsernameService) MintCollectibleUsername(_ context.Context, req admin.MintCollectibleUsernameRequest) (admin.CommandResult, error) {
@@ -731,3 +749,49 @@ func (fakeService) CollectibleUsernameByID(context.Context, int64) (domain.Colle
 func (fakeService) CollectibleUsernameTransfers(context.Context, int64, int) ([]domain.CollectibleUsernameTransfer, error) {
 	return nil, nil
 }
+
+func (fakeService) ReserveUsername(_ context.Context, req admin.ReserveUsernameRequest) (admin.CommandResult, error) {
+	return admin.CommandResult{CommandID: req.CommandID, Status: "completed", DryRun: req.DryRun}, nil
+}
+
+func (fakeService) UnreserveUsername(_ context.Context, req admin.UnreserveUsernameRequest) (admin.CommandResult, error) {
+	return admin.CommandResult{CommandID: req.CommandID, Status: "completed", DryRun: req.DryRun}, nil
+}
+
+func (fakeService) ReservedUsernames(context.Context, domain.ReservedUsernameFilter) ([]domain.ReservedUsername, error) {
+	return nil, nil
+}
+
+func TestAdminAPIReservedUsernames(t *testing.T) {
+	svc := &captureCollectibleUsernameService{}
+	srv := &Server{token: "secret", svc: svc}
+
+	reserve := httptest.NewRequest(http.MethodPost, "/v1/reserved-usernames/reserve", strings.NewReader(
+		`{"command_id":"r-1","actor":"ops","reason":"official","username":"support"}`))
+	reserve.Header.Set("Authorization", "Bearer secret")
+	rec := httptest.NewRecorder()
+	srv.routes().ServeHTTP(rec, reserve)
+	if rec.Code != http.StatusOK || svc.reserve.Username != "support" || svc.reserve.CommandID != "r-1" {
+		t.Fatalf("reserve status=%d req=%+v", rec.Code, svc.reserve)
+	}
+
+	unreserve := httptest.NewRequest(http.MethodPost, "/v1/reserved-usernames/unreserve", strings.NewReader(
+		`{"command_id":"u-1","actor":"ops","reason":"done","username":"support"}`))
+	unreserve.Header.Set("Authorization", "Bearer secret")
+	rec = httptest.NewRecorder()
+	srv.routes().ServeHTTP(rec, unreserve)
+	if rec.Code != http.StatusOK || svc.unreserve.Username != "support" {
+		t.Fatalf("unreserve status=%d req=%+v", rec.Code, svc.unreserve)
+	}
+
+	list := httptest.NewRequest(http.MethodGet, "/v1/reserved-usernames?q=sup&limit=10", nil)
+	list.Header.Set("Authorization", "Bearer secret")
+	rec = httptest.NewRecorder()
+	srv.routes().ServeHTTP(rec, list)
+	if rec.Code != http.StatusOK || !strings.Contains(rec.Body.String(), `"username":"support"`) {
+		t.Fatalf("list status=%d body=%s", rec.Code, rec.Body.String())
+	}
+	if svc.resFilter.Query != "sup" || svc.resFilter.Limit != 10 {
+		t.Fatalf("list filter = %+v", svc.resFilter)
+	}
+}

internal/domain/reserved_username.go

@@ -0,0 +1,24 @@
+package domain
+
+import "time"
+
+// MaxReservedUsernameReasonLength bounds the operator note on a reservation.
+const MaxReservedUsernameReasonLength = 512
+
+// ReservedUsername is one entry in the operator username blocklist. A reserved
+// name cannot be taken as an editable username by any peer and cannot be minted
+// as a collectible.
+type ReservedUsername struct {
+	Username  string // display form (original case at reservation time)
+	Reason    string
+	Actor     string
+	CreatedAt time.Time
+}
+
+// ReservedUsernameFilter pages the blocklist. Query matches a username prefix
+// (case-insensitive); an empty query lists everything.
+type ReservedUsernameFilter struct {
+	Query  string
+	Limit  int
+	Offset int
+}

internal/store/memory/collectible_username.go

@@ -55,6 +55,24 @@ type CollectibleUsernameStore struct {
 	transfers map[int64][]domain.CollectibleUsernameTransfer
 	// commands maps a provenance command key onto the asset it touched.
 	commands map[string]int64
+	// reserved, when set, is the operator blocklist consulted before a name is
+	// assigned to an editable slot or minted, mirroring the PostgreSQL checks.
+	reserved *ReservedUsernameStore
+}
+
+// WithReservedUsernames wires the operator blocklist into the registry so a
+// reserved name is refused, matching PostgreSQL.
+func (s *CollectibleUsernameStore) WithReservedUsernames(reserved *ReservedUsernameStore) *CollectibleUsernameStore {
+	s.reserved = reserved
+	return s
+}
+
+func (s *CollectibleUsernameStore) nameReservedLocked(usernameLower string) bool {
+	if s.reserved == nil {
+		return false
+	}
+	r, _ := s.reserved.IsReserved(context.Background(), usernameLower)
+	return r
 }
 
 // collectibleRegistryRow is one peer_usernames row: the owning peer plus the
@@ -101,6 +119,9 @@ func (s *CollectibleUsernameStore) SetEditableUsername(_ context.Context, peer d
 		return false, domain.ErrUsernameInvalid
 	}
 	key := strings.ToLower(username)
+	if s.nameReservedLocked(key) {
+		return false, domain.ErrUsernameOccupied
+	}
 	if existing, ok := s.registry[key]; ok {
 		if existing.peer == peer && existing.row.Editable {
 			if existing.row.Username == username {
@@ -313,6 +334,9 @@ func (s *CollectibleUsernameStore) MintCollectibleUsername(_ context.Context, re
 	if _, ok := s.registry[key]; ok {
 		return domain.CollectibleUsername{}, false, domain.ErrUsernameOccupied
 	}
+	if s.nameReservedLocked(key) {
+		return domain.CollectibleUsername{}, false, domain.ErrUsernameOccupied
+	}
 	now := time.Now().UTC()
 	purchaseDate := req.PurchaseDate
 	if purchaseDate.IsZero() {

internal/store/memory/reserved_username.go

@@ -0,0 +1,100 @@
+package memory
+
+import (
+	"context"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"telesrv/internal/domain"
+)
+
+// ReservedUsernameStore is the in-memory operator username blocklist.
+type ReservedUsernameStore struct {
+	mu      sync.Mutex
+	entries map[string]domain.ReservedUsername // keyed by username_lower
+}
+
+// NewReservedUsernameStore creates an empty blocklist.
+func NewReservedUsernameStore() *ReservedUsernameStore {
+	return &ReservedUsernameStore{entries: make(map[string]domain.ReservedUsername)}
+}
+
+func (s *ReservedUsernameStore) IsReserved(_ context.Context, usernameLower string) (bool, error) {
+	if s == nil {
+		return false, nil
+	}
+	usernameLower = strings.ToLower(strings.TrimSpace(usernameLower))
+	if usernameLower == "" {
+		return false, nil
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	_, ok := s.entries[usernameLower]
+	return ok, nil
+}
+
+func (s *ReservedUsernameStore) ReserveUsername(_ context.Context, username, reason, actor string) (bool, error) {
+	username = strings.TrimSpace(username)
+	lower := strings.ToLower(username)
+	if lower == "" {
+		return false, domain.ErrUsernameInvalid
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if _, ok := s.entries[lower]; ok {
+		return false, nil
+	}
+	s.entries[lower] = domain.ReservedUsername{Username: username, Reason: reason, Actor: actor, CreatedAt: time.Now().UTC()}
+	return true, nil
+}
+
+func (s *ReservedUsernameStore) UnreserveUsername(_ context.Context, username string) (bool, error) {
+	lower := strings.ToLower(strings.TrimSpace(username))
+	if lower == "" {
+		return false, domain.ErrUsernameInvalid
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if _, ok := s.entries[lower]; !ok {
+		return false, nil
+	}
+	delete(s.entries, lower)
+	return true, nil
+}
+
+func (s *ReservedUsernameStore) ReservedUsernames(_ context.Context, filter domain.ReservedUsernameFilter) ([]domain.ReservedUsername, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	q := strings.ToLower(strings.TrimSpace(filter.Query))
+	out := make([]domain.ReservedUsername, 0, len(s.entries))
+	for key, entry := range s.entries {
+		if q != "" && !strings.HasPrefix(key, q) {
+			continue
+		}
+		out = append(out, entry)
+	}
+	sort.Slice(out, func(i, j int) bool {
+		if !out[i].CreatedAt.Equal(out[j].CreatedAt) {
+			return out[i].CreatedAt.After(out[j].CreatedAt)
+		}
+		return strings.ToLower(out[i].Username) < strings.ToLower(out[j].Username)
+	})
+	limit := filter.Limit
+	if limit <= 0 || limit > 500 {
+		limit = 100
+	}
+	offset := filter.Offset
+	if offset < 0 {
+		offset = 0
+	}
+	if offset >= len(out) {
+		return []domain.ReservedUsername{}, nil
+	}
+	end := offset + limit
+	if end > len(out) {
+		end = len(out)
+	}
+	return out[offset:end], nil
+}

internal/store/postgres/collectible_username.go

@@ -206,6 +206,11 @@ func (s *CollectibleUsernameStore) MintCollectibleUsername(ctx context.Context,
 		} else if found {
 			return domain.ErrUsernameOccupied
 		}
+		if reserved, err := usernameReservedTx(ctx, tx, usernameLower); err != nil {
+			return err
+		} else if reserved {
+			return domain.ErrUsernameOccupied
+		}
 		var existing int64
 		switch err := tx.QueryRow(ctx, `
 SELECT id FROM collectible_usernames

internal/store/postgres/peer_username.go

@@ -61,6 +61,21 @@ func getPeerUsernameOwner(ctx context.Context, db sqlcgen.DBTX, usernameLower st
 	return owner, true, nil
 }
 
+// usernameReservedTx reports whether a name is on the operator blocklist. It is
+// consulted before every editable-username write and before a collectible mint.
+func usernameReservedTx(ctx context.Context, db sqlcgen.DBTX, usernameLower string) (bool, error) {
+	if usernameLower == "" {
+		return false, nil
+	}
+	var exists bool
+	if err := db.QueryRow(ctx,
+		`SELECT EXISTS (SELECT 1 FROM reserved_usernames WHERE username_lower = $1)`,
+		usernameLower).Scan(&exists); err != nil {
+		return false, fmt.Errorf("check reserved username: %w", err)
+	}
+	return exists, nil
+}
+
 func peerUsernameAvailable(ctx context.Context, db sqlcgen.DBTX, usernameLower, peerType string, peerID int64) (bool, error) {
 	owner, found, err := getPeerUsernameOwner(ctx, db, usernameLower, false)
 	if err != nil || !found {
@@ -111,6 +126,11 @@ WHERE peer_type = $1
 // otherwise account.updateUsername would silently release a minted asset.
 func replacePeerUsernameTx(ctx context.Context, tx pgx.Tx, peerType string, peerID int64, username, usernameLower string) error {
 	if usernameLower != "" {
+		if reserved, err := usernameReservedTx(ctx, tx, usernameLower); err != nil {
+			return err
+		} else if reserved {
+			return domain.ErrUsernameOccupied
+		}
 		owner, found, err := getPeerUsernameOwner(ctx, tx, usernameLower, true)
 		if err != nil {
 			return err

internal/store/postgres/reserved_username.go

@@ -0,0 +1,99 @@
+package postgres
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"telesrv/internal/domain"
+	"telesrv/internal/store/postgres/sqlcgen"
+)
+
+// ReservedUsernameStore is the operator username blocklist backed by the
+// reserved_usernames table.
+type ReservedUsernameStore struct {
+	db sqlcgen.DBTX
+}
+
+// NewReservedUsernameStore builds the store on a pgx pool or transaction.
+func NewReservedUsernameStore(db sqlcgen.DBTX) *ReservedUsernameStore {
+	return &ReservedUsernameStore{db: db}
+}
+
+func (s *ReservedUsernameStore) IsReserved(ctx context.Context, usernameLower string) (bool, error) {
+	usernameLower = strings.ToLower(strings.TrimSpace(usernameLower))
+	if usernameLower == "" {
+		return false, nil
+	}
+	var exists bool
+	if err := s.db.QueryRow(ctx,
+		`SELECT EXISTS (SELECT 1 FROM reserved_usernames WHERE username_lower = $1)`,
+		usernameLower).Scan(&exists); err != nil {
+		return false, fmt.Errorf("check reserved username: %w", err)
+	}
+	return exists, nil
+}
+
+func (s *ReservedUsernameStore) ReserveUsername(ctx context.Context, username, reason, actor string) (bool, error) {
+	username = strings.TrimSpace(username)
+	lower := strings.ToLower(username)
+	if lower == "" {
+		return false, domain.ErrUsernameInvalid
+	}
+	tag, err := s.db.Exec(ctx, `
+INSERT INTO reserved_usernames (username_lower, username, reason, actor)
+VALUES ($1, $2, $3, $4)
+ON CONFLICT (username_lower) DO NOTHING`, lower, username, reason, actor)
+	if err != nil {
+		return false, fmt.Errorf("reserve username: %w", err)
+	}
+	return tag.RowsAffected() > 0, nil
+}
+
+func (s *ReservedUsernameStore) UnreserveUsername(ctx context.Context, username string) (bool, error) {
+	lower := strings.ToLower(strings.TrimSpace(username))
+	if lower == "" {
+		return false, domain.ErrUsernameInvalid
+	}
+	tag, err := s.db.Exec(ctx, `DELETE FROM reserved_usernames WHERE username_lower = $1`, lower)
+	if err != nil {
+		return false, fmt.Errorf("unreserve username: %w", err)
+	}
+	return tag.RowsAffected() > 0, nil
+}
+
+func (s *ReservedUsernameStore) ReservedUsernames(ctx context.Context, filter domain.ReservedUsernameFilter) ([]domain.ReservedUsername, error) {
+	limit := filter.Limit
+	if limit <= 0 || limit > 500 {
+		limit = 100
+	}
+	offset := filter.Offset
+	if offset < 0 {
+		offset = 0
+	}
+	args := []any{limit, offset}
+	where := ""
+	if q := strings.ToLower(strings.TrimSpace(filter.Query)); q != "" {
+		args = append(args, q+"%")
+		where = "WHERE username_lower LIKE $3"
+	}
+	rows, err := s.db.Query(ctx, `
+SELECT username, reason, actor, created_at
+FROM reserved_usernames
+`+where+`
+ORDER BY created_at DESC, username_lower
+LIMIT $1 OFFSET $2`, args...)
+	if err != nil {
+		return nil, fmt.Errorf("list reserved usernames: %w", err)
+	}
+	defer rows.Close()
+	out := make([]domain.ReservedUsername, 0, limit)
+	for rows.Next() {
+		var item domain.ReservedUsername
+		if err := rows.Scan(&item.Username, &item.Reason, &item.Actor, &item.CreatedAt); err != nil {
+			return nil, fmt.Errorf("scan reserved username: %w", err)
+		}
+		out = append(out, item)
+	}
+	return out, rows.Err()
+}

internal/store/reserved_username.go

@@ -0,0 +1,22 @@
+package store
+
+import (
+	"context"
+
+	"telesrv/internal/domain"
+)
+
+// ReservedUsernameStore owns the operator username blocklist. IsReserved is the
+// hot path consulted on every editable-username write; the rest are the admin
+// lifecycle.
+type ReservedUsernameStore interface {
+	// IsReserved reports whether usernameLower (already lowercased) is blocked.
+	IsReserved(ctx context.Context, usernameLower string) (bool, error)
+	// ReserveUsername adds an entry. Returns created=false if it already existed
+	// (the existing reason/actor are kept).
+	ReserveUsername(ctx context.Context, username, reason, actor string) (created bool, err error)
+	// UnreserveUsername removes an entry. Returns removed=false if absent.
+	UnreserveUsername(ctx context.Context, username string) (removed bool, err error)
+	// ReservedUsernames pages the blocklist, newest first.
+	ReservedUsernames(ctx context.Context, filter domain.ReservedUsernameFilter) ([]domain.ReservedUsername, error)
+}