Merge branch 'main' into feat/10-browse-dialog

Finding 1: can_sign() returned True on an empty changeset, and _on_sign
compared the reviewed blob against a hardcoded "main" rather than the ref
actually reviewed — so the PR path could never sign, and the main-vs-main
path unlocked Sign with zero entries acknowledged. That is how commit b08cf21
signed 19 entries nobody reviewed. can_sign now refuses an empty diff, checks
has_blocking_risk itself instead of trusting a GUI checkbox, and resolves the
TOCTOU pin from the reviewed ref via a pure, testable sign_precondition().

Finding 5: the catalog key and the release key are now separate. The release
key lives in CI and signs checksums; the catalog key stays offline and signs
what users execute. A CI compromise gets the former, not the latter.

.github/workflows/ci.yml

@@ -95,12 +95,39 @@ jobs:
       - name: Install dependencies
         run: pip install cryptography
 
+      # 🔴 TRUST ANCHOR — issue #68 finding 4.
+      #
+      # This step used to do `import bcc_core as c` FROM THE CHECKED-OUT PR
+      # BRANCH and verify the catalog against c.CATALOG_PUBKEYS — i.e. it
+      # trusted the public key shipped in the very diff it was reviewing. A
+      # PR that changed data/catalog.json AND bcc_core.CATALOG_PUBKEYS (to
+      # an attacker key, with a matching signature produced by the attacker's
+      # matching private key) went green, because there was nothing outside
+      # the PR's own content to check the key against. The gate's whole
+      # point is catching a friendly-looking PR the maintainer merges
+      # without really reading it — and that hole made it a two-file diff.
+      #
+      # EXPECTED_CATALOG_PUBKEY_B64 below is hardcoded HERE, in the workflow
+      # file, independent of whatever bcc_core.py says on the PR branch. It
+      # is intentionally the only line in this step that matters for
+      # security review: changing it changes what this gate is willing to
+      # trust. THIS CONSTANT IS A TRUST ANCHOR. A PR that changes this line
+      # in the same diff as a catalog change is exactly the attack this gate
+      # exists to prevent — review a change to this line on its own,
+      # never bundled with a catalog update.
+      #
+      # NOTE for the next key rotation: update EXPECTED_CATALOG_PUBKEY_B64
+      # below to the new key's base64 form, as its own reviewed change.
       - name: Verify data/catalog.json.sig
+        env:
+          EXPECTED_CATALOG_PUBKEY_B64: "082NOwVB7uURkvfyS3+knJ+40Fk6C9unsF47+2uPKo4="
         run: |
           python - <<'PY'
-          import pathlib, sys
+          import base64, os, pathlib, sys
           import bcc_core as c
 
+          expected_pubkey_b64 = os.environ["EXPECTED_CATALOG_PUBKEY_B64"]
+
           raw = pathlib.Path("data/catalog.json").read_bytes()
           sig_path = pathlib.Path("data/catalog.json.sig")
 
@@ -111,6 +138,26 @@ jobs:
           if b"\x00" * 32 in c.CATALOG_PUBKEYS:
               sys.exit("FAIL: CATALOG_PUBKEYS still holds the placeholder key.")
 
+          # Trust anchor check FIRST, before verifying anything against
+          # bcc_core.CATALOG_PUBKEYS: a PR is not allowed to bring its own
+          # key. CATALOG_PUBKEYS on the checked-out branch must be EXACTLY
+          # the key(s) this workflow file itself expects -- no more, no
+          # fewer, no substitutions.
+          actual_pubkeys_b64 = [base64.b64encode(k).decode() for k in c.CATALOG_PUBKEYS]
+          if actual_pubkeys_b64 != [expected_pubkey_b64]:
+              sys.exit(
+                  "FAIL: bcc_core.CATALOG_PUBKEYS on this branch does not match the "
+                  "trust anchor hardcoded in .github/workflows/ci.yml.\n"
+                  f"  expected: {[expected_pubkey_b64]}\n"
+                  f"  actual:   {actual_pubkeys_b64}\n"
+                  "\n"
+                  "This PR is changing (or has changed) the catalog signing key. That "
+                  "change must be reviewed on its own, separately from any catalog "
+                  "content change, and the workflow's EXPECTED_CATALOG_PUBKEY_B64 "
+                  "updated deliberately -- not accepted because it happened to match "
+                  "whatever bcc_core.py says on this branch."
+              )
+
           if not c.verify_catalog_signature(raw, sig_path.read_bytes(), c.CATALOG_PUBKEYS):
               sys.exit(
                   "FAIL: data/catalog.json does NOT match its signature.\n"
@@ -124,5 +171,6 @@ jobs:
           if problems:
               sys.exit("FAIL: catalog failed validation:\n  " + "\n  ".join(problems))
 
-          print("OK: catalog signature verifies and the catalog validates clean.")
+          print("OK: catalog signature verifies, the pubkey matches the CI trust anchor, "
+                "and the catalog validates clean.")
           PY

bcc.py

@@ -10,6 +10,7 @@ Run:  python mcp_manager.py
 
 from __future__ import annotations
 
+import html
 import sys
 import time
 from pathlib import Path
@@ -26,10 +27,12 @@ from PySide6.QtGui import (
     QKeySequence,
     QPainter,
     QPixmap,
+    QTextCursor,
 )
 from PySide6.QtWidgets import (
     QAbstractItemView,
     QApplication,
+    QButtonGroup,
     QCheckBox,
     QComboBox,
     QDialog,
@@ -65,6 +68,26 @@ import bcc_core as core
 # thread during drag-and-drop import, so skip anything larger than this.
 MAX_DROP_IMPORT_BYTES = 5 * 1024 * 1024  # 5 MB
 
+
+def plain_label(text: object) -> QLabel:
+    """A QLabel guaranteed to render `text` as plain text, never HTML.
+
+    Qt's QLabel auto-interprets HTML by default (Qt.AutoText). Every catalog
+    entry field (description, notes, display name, urls -- and especially
+    args) is attacker-influenceable: catalog.json accepts community PRs, and
+    only a valid Ed25519 signature stands between a PR and what a user sees
+    here. A `<b>` or `<img onerror=...>` in a description must render as
+    visible text, not markup -- exactly the same reasoning catalog_console.py
+    documents for its own plain_label(). Every catalog-derived string shown
+    by the Browse dialog MUST go through this helper (or an inherently
+    plain-text widget like QPlainTextEdit) rather than a bare QLabel(...).
+    """
+    label = QLabel(html.escape(str(text)))
+    label.setTextFormat(Qt.TextFormat.PlainText)
+    label.setWordWrap(True)
+    return label
+
+
 # --- One-line rebrand: change this to recolor the whole app --------------- #
 ACCENT = "#f97316"  # warm orange
 ACCENT_DIM = "#c2570b"
@@ -676,6 +699,39 @@ class ServerEditor(QFrame):
     def current_name(self) -> str:
         return self.name.text().strip()
 
+    def focus_target(self, target: tuple[str, int | str] | None):
+        """
+        Focus the field a catalog Add left unfilled -- `target` is whatever
+        core.first_unfilled_focus_target() returned: ("args", line_index),
+        ("env", var_name), or None (nothing to fill, so do nothing).
+
+        Only meaningful on the stdio page, which is the only page a catalog
+        entry ever populates (link-only entries never reach dump_data()).
+        """
+        if not target or self.type.currentIndex() != 0:
+            return
+        kind, value = target
+        if kind == "args":
+            self.args.setFocus()
+            cursor = self.args.textCursor()
+            cursor.movePosition(QTextCursor.MoveOperation.Start)
+            cursor.movePosition(
+                QTextCursor.MoveOperation.Down, QTextCursor.MoveMode.MoveAnchor, int(value)
+            )
+            cursor.movePosition(
+                QTextCursor.MoveOperation.EndOfLine, QTextCursor.MoveMode.KeepAnchor
+            )
+            self.args.setTextCursor(cursor)
+        elif kind == "env":
+            for r in range(self.env.table.rowCount()):
+                key_item = self.env.table.item(r, 0)
+                if key_item and key_item.text() == value:
+                    self.env.table.setCurrentCell(r, 1)
+                    val_item = self.env.table.item(r, 1)
+                    if val_item:
+                        self.env.table.editItem(val_item)
+                    break
+
     def _type_switched(self):
         self.stack.setCurrentIndex(self.type.currentIndex())
         self._emit()
@@ -1204,6 +1260,262 @@ class PasteDialog(QDialog):
             self.err.setText(str(e))
 
 
+# --------------------------------------------------------------------------- #
+# Browse catalog dialog (issue #10 phase 2): search/filter the signed,
+# bundled server catalog and add a "basic" entry through the existing
+# paste/import path, or send a "link-only" entry to its setup docs.
+#
+# Every widget here that shows catalog-derived text uses plain_label() or an
+# inherently-plain widget (QPlainTextEdit) -- see plain_label()'s docstring.
+# The dialog itself does no signature/schema work: MainWindow hands it an
+# already-verified `entries` list (bcc_core.load_bundled_catalog_entries()),
+# and an empty list here means "show the empty state", never "fall back to
+# something less trusted".
+# --------------------------------------------------------------------------- #
+class BrowseCatalogDialog(QDialog):
+    def __init__(self, parent, entries: list[dict]):
+        super().__init__(parent)
+        self.setWindowTitle("Browse catalog")
+        self.resize(880, 560)
+        self.entries = entries or []
+        self.result_entry: dict | None = None
+        self._current_entry: dict | None = None
+        self._current_homepage: str | None = None
+        self._current_docs_url: str | None = None
+        self._current_group = "All"
+
+        outer = QVBoxLayout(self)
+
+        if not self.entries:
+            # Signature verification failed, or nothing was bundled -- never
+            # show a half-trusted list, and never explain WHY beyond this;
+            # a stale/tampered catalog isn't the user's problem to diagnose.
+            msg = plain_label("Catalog unavailable.")
+            msg.setObjectName("placeholder")
+            msg.setAlignment(Qt.AlignmentFlag.AlignCenter)
+            outer.addWidget(msg, 1)
+            btns = QDialogButtonBox(QDialogButtonBox.StandardButton.Close)
+            btns.rejected.connect(self.reject)
+            outer.addWidget(btns)
+            return
+
+        search_row = QHBoxLayout()
+        self.search_box = QLineEdit()
+        self.search_box.setPlaceholderText("Search by name, description, or category…")
+        self.search_box.setClearButtonEnabled(True)
+        self.search_box.textChanged.connect(self._refresh_list)
+        search_row.addWidget(self.search_box, 1)
+        outer.addLayout(search_row)
+
+        chip_row = QHBoxLayout()
+        self._chip_group = QButtonGroup(self)
+        self._chip_group.setExclusive(True)
+        for label in core.CATALOG_CATEGORY_CHIPS:
+            btn = QPushButton(label)
+            btn.setCheckable(True)
+            btn.setChecked(label == "All")
+            btn.clicked.connect(lambda _checked=False, g=label: self._set_group(g))
+            self._chip_group.addButton(btn)
+            chip_row.addWidget(btn)
+        chip_row.addStretch()
+        outer.addLayout(chip_row)
+
+        splitter = QSplitter(Qt.Orientation.Horizontal)
+
+        left = QWidget()
+        lv = QVBoxLayout(left)
+        lv.setContentsMargins(0, 0, 0, 0)
+        self.list = QListWidget()
+        self.list.currentItemChanged.connect(self._on_selected)
+        lv.addWidget(self.list, 1)
+        splitter.addWidget(left)
+
+        right = QFrame()
+        right.setObjectName("card")
+        rv = QVBoxLayout(right)
+        self.detail_title = plain_label("")
+        self.detail_title.setObjectName("h1")
+        rv.addWidget(self.detail_title)
+        self.detail_meta = plain_label("")
+        self.detail_meta.setObjectName("muted")
+        rv.addWidget(self.detail_meta)
+        self.detail_freshness = plain_label("")
+        self.detail_freshness.setObjectName("muted")
+        rv.addWidget(self.detail_freshness)
+        self.detail_desc = plain_label("")
+        rv.addWidget(self.detail_desc)
+        self.detail_notes = plain_label("")
+        self.detail_notes.setObjectName("muted")
+        rv.addWidget(self.detail_notes)
+        self.detail_homepage_btn = QPushButton("Open homepage")
+        self.detail_homepage_btn.clicked.connect(self._open_homepage)
+        rv.addWidget(self.detail_homepage_btn)
+        rv.addWidget(plain_label("Exact command this will add:"))
+        self.detail_command_preview = QPlainTextEdit()
+        self.detail_command_preview.setObjectName("diag")
+        self.detail_command_preview.setReadOnly(True)
+        # Read-only QPlainTextEdit never interprets HTML, regardless of what
+        # a compromised/careless catalog entry's command/args contain -- this
+        # is the field that renders "the exact bytes that will be written".
+        rv.addWidget(self.detail_command_preview, 1)
+        self.detail_action_btn = QPushButton("")
+        self.detail_action_btn.setObjectName("primary")
+        self.detail_action_btn.clicked.connect(self._on_action)
+        rv.addWidget(self.detail_action_btn)
+        splitter.addWidget(right)
+
+        splitter.setSizes([360, 480])
+        outer.addWidget(splitter, 1)
+
+        btns = QDialogButtonBox(QDialogButtonBox.StandardButton.Close)
+        btns.rejected.connect(self.reject)
+        outer.addWidget(btns)
+
+        self._refresh_list()
+
+    # --- list / filtering -------------------------------------------------- #
+    def _set_group(self, group: str):
+        self._current_group = group
+        self._refresh_list()
+
+    def _visible_entries(self) -> list[dict]:
+        filtered = core.filter_catalog_entries(self.entries, self.search_box.text())
+        return core.catalog_entries_in_group(filtered, self._current_group)
+
+    def _format_row(self, entry: dict) -> str:
+        display = str(entry.get("display") or entry.get("id") or "")
+        official = "✓ " if entry.get("official") else ""
+        stars = entry.get("stars")
+        star_txt = f"   ★ {stars:,}" if isinstance(stars, int) else ""
+        group = core.catalog_category_group(entry.get("category", ""))
+        desc = str(entry.get("description") or "")
+        if len(desc) > 88:
+            desc = desc[:87] + "…"
+        # QListWidgetItem text is always rendered literally by Qt (no HTML
+        # interpretation), so no escaping is needed here -- unlike QLabel.
+        return f"{official}{display}{star_txt}\n{desc}   ·   {group}"
+
+    def _refresh_list(self):
+        self.list.blockSignals(True)
+        self.list.clear()
+        for entry in self._visible_entries():
+            item = QListWidgetItem(self._format_row(entry))
+            item.setData(Qt.ItemDataRole.UserRole, entry)
+            # Tooltips DO auto-detect rich text in Qt, so escape defensively
+            # even though descriptions are already shown, unescaped-but-safe,
+            # in the QListWidgetItem text above.
+            item.setToolTip(html.escape(str(entry.get("description", ""))))
+            self.list.addItem(item)
+        self.list.blockSignals(False)
+        if self.list.count():
+            self.list.setCurrentRow(0)
+        else:
+            self._on_selected(None, None)
+
+    # --- detail pane -------------------------------------------------------- #
+    def _on_selected(self, current, _previous=None):
+        if current is None:
+            self._current_entry = None
+            self._current_homepage = None
+            self._current_docs_url = None
+            self.detail_title.setText("")
+            self.detail_meta.setText("")
+            self.detail_freshness.setText("")
+            self.detail_desc.setText("No matching servers." if self.entries else "")
+            self.detail_notes.setText("")
+            self.detail_homepage_btn.setVisible(False)
+            self.detail_command_preview.setPlainText("")
+            self.detail_action_btn.setEnabled(False)
+            self.detail_action_btn.setText("Add")
+            return
+
+        entry = current.data(Qt.ItemDataRole.UserRole)
+        self._current_entry = entry
+        self.detail_title.setText(str(entry.get("display") or entry.get("id") or ""))
+
+        official = "✓ Official" if entry.get("official") else ""
+        stars = entry.get("stars")
+        star_txt = f"★ {stars:,}" if isinstance(stars, int) else ""
+        group = core.catalog_category_group(entry.get("category", ""))
+        meta_bits = [b for b in (official, star_txt, group) if b]
+        self.detail_meta.setText("  ·  ".join(meta_bits))
+
+        freshness = core.format_freshness_hint(entry.get("last_release"))
+        self.detail_freshness.setText(freshness)
+        self.detail_freshness.setVisible(bool(freshness))
+
+        self.detail_desc.setText(str(entry.get("description") or ""))
+
+        notes = entry.get("notes") or ""
+        self.detail_notes.setText(notes)
+        self.detail_notes.setVisible(bool(notes))
+
+        homepage = entry.get("homepage")
+        self._current_homepage = homepage if isinstance(homepage, str) else None
+        self.detail_homepage_btn.setVisible(bool(self._current_homepage))
+
+        self._current_docs_url = (
+            entry.get("docs_url") if isinstance(entry.get("docs_url"), str) else None
+        )
+
+        self.detail_command_preview.setPlainText(self._render_command_preview(entry))
+
+        if entry.get("setup") == "basic":
+            self.detail_action_btn.setText("Add")
+            self.detail_action_btn.setEnabled(True)
+        else:
+            self.detail_action_btn.setText("Open setup docs")
+            self.detail_action_btn.setEnabled(bool(self._current_docs_url))
+
+    def _render_command_preview(self, entry: dict) -> str:
+        """
+        The exact command that will be written, rendered verbatim. Every
+        value here comes straight from the (signature-verified) catalog
+        entry with no interpretation beyond str() -- this must never be the
+        place a markup-laced description sneaks back in as "helpful"
+        formatting.
+        """
+        if entry.get("setup") != "basic":
+            docs = entry.get("docs_url") or "(none provided)"
+            return (
+                "This is a hosted/managed integration -- there is no local "
+                "command to add.\n\nSetup docs:\n  " + str(docs)
+            )
+
+        config = entry.get("config") or {}
+        lines = [f"command: {config.get('command', '')}"]
+        args = config.get("args") or []
+        if args:
+            lines.append("args:")
+            lines.extend(f"  {a}" for a in args)
+        env = config.get("env") or {}
+        env_required = entry.get("env_required") or {}
+        env_keys = list(env.keys()) + [k for k in env_required if k not in env]
+        if env_keys:
+            lines.append("env (names only -- you provide the values):")
+            lines.extend(f"  {k}" for k in env_keys)
+        return "\n".join(lines)
+
+    def _open_homepage(self):
+        url = self._current_homepage
+        if url and url.startswith("https://"):
+            QDesktopServices.openUrl(QUrl(url))
+
+    def _on_action(self):
+        entry = self._current_entry
+        if not entry:
+            return
+        if entry.get("setup") == "basic":
+            self.result_entry = entry
+            self.accept()
+        else:
+            url = self._current_docs_url
+            if url and url.startswith("https://"):
+                QDesktopServices.openUrl(QUrl(url))
+            # link-only never auto-adds and never closes the dialog -- the
+            # user can keep browsing after opening the docs in their browser.
+
+
 # --------------------------------------------------------------------------- #
 # Log viewer dialog (issue #6): a read-only, auto-tailing view of a single
 # server's MCP log file. Polls on a QTimer instead of watching the filesystem
@@ -1780,6 +2092,10 @@ class MainWindow(QMainWindow):
         self.del_btn = QPushButton("Delete")
         self.del_btn.setObjectName("danger")
         self.paste_btn = QPushButton("Paste JSON...")
+        self.browse_catalog_btn = QPushButton("Browse catalog…")
+        self.browse_catalog_btn.setToolTip(
+            "Add a popular MCP server from the curated, signed catalog"
+        )
         self.copy_btn = QPushButton("Copy to ▸")
         self.undo_btn = QPushButton("Undo")
         self.undo_btn.setEnabled(False)
@@ -1792,6 +2108,7 @@ class MainWindow(QMainWindow):
         self.dup_btn.clicked.connect(self.duplicate_server)
         self.del_btn.clicked.connect(self.delete_server)
         self.paste_btn.clicked.connect(self.paste_json)
+        self.browse_catalog_btn.clicked.connect(self.browse_catalog)
         self.copy_btn.clicked.connect(self.copy_to_menu)
         self.undo_btn.clicked.connect(self._undo)
         self.test_all_btn.clicked.connect(self._test_all_servers)
@@ -1800,6 +2117,7 @@ class MainWindow(QMainWindow):
             self.dup_btn,
             self.del_btn,
             self.paste_btn,
+            self.browse_catalog_btn,
             self.copy_btn,
             self.undo_btn,
             self.test_all_btn,
@@ -2378,6 +2696,41 @@ class MainWindow(QMainWindow):
         self._mark_dirty()
         self.status.setText(f"Imported {added} added, {replaced} replaced. Review and Save.")
 
+    def browse_catalog(self):
+        """
+        Open the Browse-catalog dialog (issue #10 phase 2). The catalog is
+        loaded and signature-verified fresh every time the dialog opens --
+        never cached across app runs at this phase (remote fetch/cache is
+        #61, not yet built) -- so a bundled-catalog swap only takes effect
+        on next dialog open, never mid-session in a stale way.
+        """
+        entries = core.load_bundled_catalog_entries(
+            _asset_dir() / "data" / "catalog.json", _asset_dir() / "data" / "catalog.json.sig"
+        )
+        dlg = BrowseCatalogDialog(self, entries)
+        if dlg.exec() != QDialog.DialogCode.Accepted or not dlg.result_entry:
+            return
+        entry = dlg.result_entry
+        paste = core.catalog_entry_to_paste_json(entry)
+        name, data = next(iter(paste.items()))
+
+        existing_before = {s.name: i for i, s in enumerate(self.servers)}
+        self._push_undo()
+        _added, replaced = self._import_server(name, data)
+        idx = (
+            existing_before.get(name, len(self.servers) - 1) if replaced else len(self.servers) - 1
+        )
+        self._refresh_tables(select_index=idx)
+        self._mark_dirty()
+
+        target = core.first_unfilled_focus_target(data)
+        self.editor.focus_target(target)
+
+        verb = "Replaced" if replaced else "Added"
+        self.status.setText(
+            f"{verb} “{name}” from the catalog. Fill in the highlighted field and Save."
+        )
+
     def copy_to_menu(self):
         idx = self._current_index()
         if not (0 <= idx < len(self.servers)):
@@ -2456,6 +2809,29 @@ class MainWindow(QMainWindow):
             QMessageBox.warning(self, "Can't save yet", "Fix the highlighted problem first.")
             return
 
+        # Placeholder guard (issue #10): a catalog Add can leave a
+        # <PLACEHOLDER>-style token in args/env until the user fills it in.
+        # This warns, it does not block -- the user may be deliberately
+        # saving a stub to finish later -- but it must never save silently,
+        # since a server launched with a literal "<PLACEHOLDER>" argument
+        # just fails in a confusing way at spawn time.
+        placeholder_names = [
+            s.name for s in self.servers if core.config_has_unfilled_placeholders(s.data)
+        ]
+        if placeholder_names:
+            names = ", ".join(f"“{n}”" for n in placeholder_names)
+            ans = QMessageBox.warning(
+                self,
+                "Unfilled placeholder",
+                f"{names} still has a <PLACEHOLDER> value that hasn't been "
+                "replaced with a real value. Claude won't be able to use "
+                "it as-is.\n\nSave anyway?",
+                QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No,
+                QMessageBox.StandardButton.No,
+            )
+            if ans != QMessageBox.StandardButton.Yes:
+                return
+
         # Stale-file check: if the file changed on disk since we loaded it, prompt.
         # Compare mtime AND size (not mtime alone) so a concurrent external write
         # that lands within the mtime resolution window, or that restores the

bcc.spec

@@ -31,7 +31,11 @@ a = Analysis(
     ["bcc.py"],
     pathex=[],
     binaries=[],
-    datas=[("icons", "icons"), ("data/catalog.json", "data")],
+    datas=[
+        ("icons", "icons"),
+        ("data/catalog.json", "data"),
+        ("data/catalog.json.sig", "data"),
+    ],
     hiddenimports=[],
     hookspath=[],
     hooksconfig={},

bcc_core.py

@@ -29,6 +29,7 @@ import tempfile
 import threading
 import time
 from dataclasses import dataclass
+from datetime import date
 from pathlib import Path
 from typing import NamedTuple
 from urllib.parse import urlparse
@@ -2164,6 +2165,30 @@ def restart_claude_desktop() -> RestartResult:
 # is rejected by validate_catalog() regardless of how plausible it looks.
 CATALOG_ALLOWED_COMMANDS = frozenset({"npx", "uvx", "docker", "node", "python", "python3"})
 
+# Env var keys a catalog entry's config.env must never set. Every one of
+# these is a loader/interpreter override that lets a value walk straight
+# past CATALOG_ALLOWED_COMMANDS and the -e/--eval/-c deny-rule below: e.g.
+# NODE_OPTIONS="--require /tmp/x.js" turns an allowlisted `npx` entry into
+# arbitrary code execution without ever touching config.args, which is the
+# only field the allowlist/deny-rules/ASCII/secret checks used to cover.
+# Matched case-insensitively -- env keys are case-sensitive on POSIX, but a
+# `node_options` lookalike is exactly the kind of thing this must catch.
+CATALOG_DENIED_ENV_KEYS = frozenset(
+    {
+        "NODE_OPTIONS",
+        "PYTHONSTARTUP",
+        "PYTHONPATH",
+        "PYTHONHOME",
+        "LD_PRELOAD",
+        "LD_LIBRARY_PATH",
+        "DYLD_INSERT_LIBRARIES",
+        "DYLD_LIBRARY_PATH",
+        "BROWSER",
+        "PATH",
+        "NODE_REPL_EXTERNAL_MODULE",
+    }
+)
+
 # Ed25519 public keys allowed to sign a catalog, raw 32-byte form. A LIST
 # (not a single key) so keys can be rotated without bricking installs that
 # still trust an older key: verify_catalog_signature() accepts a match
@@ -2189,6 +2214,36 @@ _CATALOG_SECRET_ARG_RE = re.compile(r"(?i)--api[-_]?key=|--token=|--password=")
 # <PLACEHOLDER>-style tokens the GUI must have the user fill in before Save.
 _PLACEHOLDER_RE = re.compile(r"<[^<>\s]+>")
 
+# A catalog entry's id becomes an mcpServers JSON key AND is interpolated
+# into Qt.AutoText widgets (status bar, QMessageBox) -- an id like
+# "<b>Verified</b>" renders as markup there. Not RCE, but UI spoofing, so
+# ids are constrained to a plain lowercase slug.
+_CATALOG_ID_RE = re.compile(r"^[a-z0-9][a-z0-9._-]{0,63}$")
+
+# Docker flags that consume the next arg as a value (so that value must not
+# be mistaken for the image reference when locating it in config.args).
+_DOCKER_VALUE_FLAGS = frozenset(
+    {
+        "-e",
+        "--env",
+        "-v",
+        "--volume",
+        "-p",
+        "--publish",
+        "--name",
+        "-w",
+        "--workdir",
+        "-u",
+        "--user",
+        "--entrypoint",
+        "--network",
+        "--platform",
+        "--add-host",
+        "-l",
+        "--label",
+    }
+)
+
 # How many versions a single accepted catalog jump may leap in one go. Bounds
 # a "freeze" attack: a compromised/leaked signing key claiming an absurd
 # future version would otherwise permanently outrank every legitimate
@@ -2263,6 +2318,121 @@ def _docker_arg_violations(tag: str, args: list[str]) -> list[str]:
     return problems
 
 
+def _catalog_package_spec_version(spec: str) -> str | None:
+    """
+    Extract the version pin from an npm-style package spec, or None if the
+    spec carries no pin.
+
+    Handles unscoped "name@version" and scoped "@scope/name@version" --
+    scoped names have a leading "@" that is NOT the version separator, so a
+    naive split on the first/only "@" misparses "@scope/pkg" (no version)
+    as pinned to "scope/pkg". Splitting from the right side instead is safe
+    for both forms because a package name may contain "@" only as the
+    scope's leading character.
+    """
+    if spec.startswith("@"):
+        rest = spec[1:]
+        if "@" not in rest:
+            return None
+        _, _, version = rest.rpartition("@")
+        return version or None
+    if "@" not in spec:
+        return None
+    _, _, version = spec.rpartition("@")
+    return version or None
+
+
+def _catalog_package_spec_pinned(spec: str) -> bool:
+    """
+    True if `spec` carries an exact version pin. Covers npm's "name@version"
+    / "@scope/name@version" and uv's documented PyPI pin forms
+    "name@version" and "name==version".
+    """
+    if "==" in spec:
+        _, _, version = spec.partition("==")
+        return bool(version)
+    return bool(_catalog_package_spec_version(spec))
+
+
+def _first_catalog_package_spec(args: list[str]) -> str | None:
+    """
+    The first arg that could plausibly BE a package spec: skip flags
+    (leading "-") and <PLACEHOLDER> tokens (which can't be validated and
+    are filled in by the user later, never shipped by the catalog as the
+    package name itself). Everything after the first hit is ignored --
+    trailing flags, paths, and placeholders are not package specs.
+    """
+    for a in args:
+        if a.startswith("-"):
+            continue
+        if _PLACEHOLDER_RE.fullmatch(a):
+            continue
+        return a
+    return None
+
+
+def _catalog_pin_violations(tag: str, command: str, args: list[str]) -> list[str]:
+    """
+    Version-pinning enforcement (finding #3): a catalog PR can otherwise
+    ship `npx -y @scope/pkg` or `docker run img:latest` and the *next*
+    resolve of that package/image is whatever the registry serves that day
+    -- outside review, outside the signature's meaning. This is the only
+    place that enforces pinning at runtime; catalog_review.py's
+    risk_unpinned_package() is a maintainer-facing hint, not a gate.
+    """
+    if command in ("npx", "uvx"):
+        spec = _first_catalog_package_spec(args)
+        if spec is None:
+            return [f"{tag}: config.args must include a package spec to pin (e.g. name@1.2.3)."]
+        if not _catalog_package_spec_pinned(spec):
+            return [
+                f"{tag}: config.args package {spec!r} is not version-pinned; use "
+                "name@version, @scope/name@version, or name==version."
+            ]
+        return []
+
+    if command == "docker":
+        image = _docker_image_ref(args)
+        if image is None:
+            return [f"{tag}: config.args docker command has no image reference to pin."]
+        _, sep, image_tag = image.rpartition(":")
+        if not sep or "/" in image_tag:
+            return [
+                f"{tag}: config.args docker image {image!r} has no explicit tag; "
+                "pin an exact version (not 'latest', not untagged)."
+            ]
+        if image_tag == "latest":
+            return [
+                f"{tag}: config.args docker image {image!r} uses the 'latest' tag, "
+                "which is not allowed; pin an exact version."
+            ]
+        return []
+
+    return []
+
+
+def _docker_image_ref(args: list[str]) -> str | None:
+    """
+    Locate the image reference in a `docker run ...` args list: skip the
+    "run" subcommand and any flags, including ones that consume the next
+    token as a value (-e, -v, --name, ...) so that value isn't mistaken for
+    the image. The first remaining positional token is the image.
+    """
+    i = 0
+    if i < len(args) and args[i] == "run":
+        i += 1
+    while i < len(args):
+        a = args[i]
+        if a.startswith("-"):
+            if a in _DOCKER_VALUE_FLAGS and "=" not in a:
+                i += 2
+            else:
+                i += 1
+            continue
+        return a
+    return None
+
+
 def _validate_catalog_config(tag: str, config) -> list[str]:
     """Validate the `config` block of a basic-tier catalog entry."""
     if not isinstance(config, dict):
@@ -2283,10 +2453,11 @@ def _validate_catalog_config(tag: str, config) -> list[str]:
             f"({', '.join(sorted(CATALOG_ALLOWED_COMMANDS))})."
         )
 
-    args = config.get("args")
-    if not isinstance(args, list) or not all(isinstance(a, str) for a in args):
+    raw_args = config.get("args")
+    args_ok = isinstance(raw_args, list) and all(isinstance(a, str) for a in raw_args)
+    args = raw_args if args_ok else []
+    if not args_ok:
         problems.append(f"{tag}: config.args must be a list of strings.")
-        args = []
 
     for a in args:
         if not a.isascii():
@@ -2305,11 +2476,55 @@ def _validate_catalog_config(tag: str, config) -> list[str]:
     if command == "docker":
         problems.extend(_docker_arg_violations(tag, args))
 
+    # Version pinning (finding #3) -- only meaningful once command/args are
+    # actually well-formed; a malformed args list already got its own
+    # problem above and has nothing left to pin-check.
+    if args_ok and command in ("npx", "uvx", "docker"):
+        problems.extend(_catalog_pin_violations(tag, command, args))
+
     env = config.get("env")
-    if env is not None and (
-        not isinstance(env, dict) or any(not isinstance(v, str) for v in env.values())
-    ):
+    if env is not None:
+        env_ok = isinstance(env, dict) and all(
+            isinstance(k, str) and isinstance(v, str) for k, v in env.items()
+        )
+        if not env_ok:
             problems.append(f"{tag}: config.env must be an object of string values.")
+        else:
+            # config.env (finding #2): unlike args, env was previously
+            # type-checked ONLY -- no allowlist, no deny-rule, no ASCII
+            # check, no secret check. That made it the single easiest way
+            # to smuggle a payload past every other guard in this
+            # function: an allowlisted `command: npx` plus
+            # NODE_OPTIONS=--require /tmp/x.js in env walks straight past
+            # the command allowlist AND the -e/--eval/-c deny-rule above,
+            # because neither of those ever looks at env.
+            for key, value in env.items():
+                if not key.isascii():
+                    problems.append(
+                        f"{tag}: config.env key {key!r} must be ASCII "
+                        "(non-ASCII code points rejected)."
+                    )
+                if key.upper() in CATALOG_DENIED_ENV_KEYS:
+                    problems.append(
+                        f"{tag}: config.env key {key!r} is on the catalog deny-list "
+                        "(interpreter/loader override) and is not allowed."
+                    )
+                if not value.isascii():
+                    problems.append(
+                        f"{tag}: config.env value for {key!r} must be ASCII "
+                        "(non-ASCII code points rejected)."
+                    )
+                if _is_secret_value(value):
+                    problems.append(
+                        f"{tag}: config.env[{key!r}] looks like a real secret value; "
+                        "catalog entries must never ship secret values."
+                    )
+                if value != "" and not _PLACEHOLDER_RE.fullmatch(value):
+                    problems.append(
+                        f"{tag}: config.env[{key!r}] must be an empty string or a "
+                        "single <PLACEHOLDER> token -- the catalog declares which env "
+                        "vars a server needs, it never supplies their values."
+                    )
 
     return problems
 
@@ -2329,6 +2544,12 @@ def _validate_catalog_entry(idx: int, entry, seen_ids: set[str]) -> list[str]:
         tag = f"servers[{idx}] ({entry_id!r})"
         if not entry_id.isascii():
             problems.append(f"{tag}: 'id' must be ASCII (non-ASCII code points rejected).")
+        elif not _CATALOG_ID_RE.match(entry_id):
+            problems.append(
+                f"{tag}: 'id' must match ^[a-z0-9][a-z0-9._-]{{0,63}}$ "
+                "(it becomes an mcpServers JSON key and is interpolated into "
+                "Qt.AutoText widgets)."
+            )
         if entry_id in seen_ids:
             problems.append(f"{tag}: duplicate id.")
         seen_ids.add(entry_id)
@@ -2442,15 +2663,32 @@ def verify_catalog_signature(raw: bytes, sig: bytes, pubkeys: list[bytes]) -> bo
     return False
 
 
+def _verify_catalog_candidate(candidate: tuple[bytes, bytes] | None) -> tuple[dict | None, int]:
+    """Verify+load+validate one (raw, sig) candidate. Returns (None, -1) on any failure."""
+    if not candidate:
+        return None, -1
+    raw, sig = candidate
+    if not verify_catalog_signature(raw, sig, CATALOG_PUBKEYS):
+        return None, -1
+    try:
+        data = load_catalog(raw)
+    except (ValueError, TypeError):
+        return None, -1
+    if validate_catalog(data):
+        return None, -1
+    return data, catalog_version(data)
+
+
 def resolve_catalog(
     bundled: tuple[bytes, bytes] | None,
     cached: tuple[bytes, bytes] | None,
     remote: tuple[bytes, bytes] | None,
+    floor: int = 0,
 ) -> dict:
     """
-    Pick the highest-version catalog among bundled/cached/remote. Each
-    argument is either None (unavailable) or an (raw_bytes, signature_bytes)
-    pair.
+    Pick the highest-version catalog among bundled/cached/remote. Each of
+    bundled/cached/remote is either None (unavailable) or an (raw_bytes,
+    signature_bytes) pair.
 
     🔴 SECURITY: every candidate — including `bundled`, the copy frozen into
     this binary — is verified against CATALOG_PUBKEYS and re-validated from
@@ -2461,46 +2699,68 @@ def resolve_catalog(
     by virtue of being local. Signing (and checking the signature at
     runtime, every time) closes that.
 
-    Anti-rollback: a candidate's version is never accepted if it's lower
-    than the best verified candidate already found in this same resolution
-    pass — an attacker replaying an old, since-superseded signed catalog
-    can't downgrade you.
+    `floor` is a pure, caller-supplied lower bound (e.g. a persisted
+    "last accepted version" the GUI can load from disk and pass in) — this
+    function does no storage of its own.
 
-    Anti-freeze: a candidate whose version leaps more than
-    _CATALOG_MAX_VERSION_JUMP past the current best is also rejected. A
-    compromised/leaked signing key claiming an absurd future version would
-    otherwise permanently outrank every legitimate release from then on,
-    since the resolver always prefers the highest verified version — this
-    caps how far a single accepted jump can go.
+    Anti-rollback / anti-freeze, and WHY they apply to every candidate
+    including the first one evaluated: the previous version of this
+    function only ran these checks `if best_version >= 0`, i.e. once a
+    candidate had already been accepted in this pass. That let the FIRST
+    verified candidate through unconditionally — a signed catalog claiming
+    version=999999999 sailed straight past both guards if it happened to be
+    evaluated first, and rollback protection reset on every call anyway
+    (nothing persisted across restarts). Now both guards are anchored to
+    something that doesn't depend on iteration order:
+
+    - The anti-freeze cap is measured against the BUNDLED catalog's version
+      (verified independently, once), not against "whatever was accepted
+      so far in this loop." Bundled ships inside the binary, so it's the
+      one candidate that isn't attacker-supplied at resolve time — the
+      natural trust anchor. If bundled itself doesn't verify, `floor` is
+      the anchor instead.
+    - The anti-rollback floor is max(floor, bundled's version), so a
+      caller that persists `floor` across restarts gets real rollback
+      protection; a caller that doesn't still gets "never below bundled."
+
+    On a version TIE, the bundled candidate wins over cached/remote (it
+    previously lost ties to whichever candidate happened to be evaluated
+    last, silently preferring remote over bundled at equal version).
 
     Returns the winning catalog dict, or {} if nothing verified and
     validated.
     """
+    bundled_data, bundled_version = _verify_catalog_candidate(bundled)
+
+    anchor = bundled_version if bundled_version >= 0 else floor
+    min_accepted = max(floor, bundled_version if bundled_version >= 0 else 0)
+
+    candidates = (
+        ("bundled", bundled_data, bundled_version),
+        ("cached", *_verify_catalog_candidate(cached)),
+        ("remote", *_verify_catalog_candidate(remote)),
+    )
+
     best: dict = {}
     best_version = -1
+    best_is_bundled = False
 
-    for candidate in (bundled, cached, remote):
-        if not candidate:
-            continue
-        raw, sig = candidate
-        if not verify_catalog_signature(raw, sig, CATALOG_PUBKEYS):
-            continue
-        try:
-            data = load_catalog(raw)
-        except (ValueError, TypeError):
-            continue
-        if validate_catalog(data):
+    for source, data, version in candidates:
+        if data is None:
             continue
+        if version < min_accepted:
+            continue  # anti-rollback / below the persisted floor
+        if version > anchor + _CATALOG_MAX_VERSION_JUMP:
+            continue  # anti-freeze, capped against the bundled trust anchor
 
-        version = catalog_version(data)
-        if best_version >= 0:
-            if version < best_version:
-                continue  # anti-rollback
-            if version > best_version + _CATALOG_MAX_VERSION_JUMP:
-                continue  # anti-freeze
-
+        is_bundled = source == "bundled"
+        better = version > best_version or (
+            version == best_version and is_bundled and not best_is_bundled
+        )
+        if better:
             best = data
             best_version = version
+            best_is_bundled = is_bundled
 
     return best
 
@@ -2509,8 +2769,17 @@ def catalog_entry_to_paste_json(entry: dict) -> dict:
     """
     Convert a basic-tier catalog entry into the {name: {command, args, env}}
     shape parse_pasted_json()/_import_server() already understand, so the
-    (future) catalog picker dialog can feed a selection straight into the
-    existing paste-import path instead of growing a parallel one.
+    Browse-catalog dialog can feed a selection straight into the existing
+    paste-import path instead of growing a parallel one.
+
+    `env` is seeded from two sources: config.env (rare -- e.g. grafana's
+    non-secret GRAFANA_URL) and, for every key in `env_required` not already
+    present, an empty-string placeholder. env_required is where the seed
+    data actually keeps its secret VAR NAMES (validate_catalog requires its
+    values to be "" -- never a real secret); config.env alone, without this,
+    would silently drop those names on Add for the 9 of 19 seed entries that
+    need a secret and only declare it via env_required -- the user would
+    see a server added with no field prompting them for the key it needs.
     """
     config = entry.get("config") or {}
     name = entry.get("id") or entry.get("display") or "server"
@@ -2518,9 +2787,11 @@ def catalog_entry_to_paste_json(entry: dict) -> dict:
         "command": config.get("command", ""),
         "args": list(config.get("args") or []),
     }
-    env = config.get("env")
+    env = dict(config.get("env") or {})
+    for key in entry.get("env_required") or {}:
+        env.setdefault(key, "")
     if env:
-        data["env"] = dict(env)
+        data["env"] = env
     return {str(name): data}
 
 
@@ -2540,3 +2811,190 @@ def config_has_unfilled_placeholders(cfg: dict) -> bool:
     if isinstance(env, dict):
         values.extend(v for v in env.values() if isinstance(v, str))
     return any(_PLACEHOLDER_RE.search(v) for v in values)
+
+
+# --------------------------------------------------------------------------- #
+# Catalog: Browse-dialog helpers (issue #10 phase 2)
+#
+# Everything below is pure and GUI-free on purpose (per the design comment on
+# #10): the dialog itself should be a thin shell that calls into this module,
+# the same relationship bcc.py already has with the rest of bcc_core.py.
+# --------------------------------------------------------------------------- #
+
+# Collapses the 20-value category taxonomy from the catalog research pass
+# down to the 7 chips shown in the Browse dialog. Any category not listed
+# here (including one a future catalog entry introduces that we don't yet
+# know about) falls back to "Other" rather than raising -- an unrecognized
+# category must never make an entry disappear from the dialog.
+CATALOG_CATEGORY_GROUPS: dict[str, str] = {
+    "files": "Files & Dev",
+    "dev": "Files & Dev",
+    "code-hosting": "Files & Dev",
+    "browser": "Files & Dev",
+    "database": "Data",
+    "data": "Data",
+    "search": "Search & AI",
+    "ai": "Search & AI",
+    "cloud": "Cloud & Infra",
+    "infra": "Cloud & Infra",
+    "observability": "Cloud & Infra",
+    "productivity": "Work",
+    "communication": "Work",
+    "crm": "Work",
+    "finance": "Work",
+    "design": "Work",
+    "media": "Home & Personal",
+    "smart-home": "Home & Personal",
+    "personal": "Home & Personal",
+}
+
+# Ordered for chip display: "All" first, the 6 named groups next in the order
+# given in the #10 design comment, "Other" last as the catch-all.
+CATALOG_CATEGORY_CHIPS: tuple[str, ...] = (
+    "All",
+    "Files & Dev",
+    "Data",
+    "Search & AI",
+    "Cloud & Infra",
+    "Work",
+    "Home & Personal",
+    "Other",
+)
+
+
+def catalog_category_group(category: str) -> str:
+    """Collapse a raw catalog `category` value to one of the 7 UI chips.
+
+    Unknown/missing categories map to "Other" -- never raises, never drops
+    an entry from the list just because its category tag doesn't match one
+    of the ones known at the time this mapping was written.
+    """
+    return CATALOG_CATEGORY_GROUPS.get(str(category or "").strip().lower(), "Other")
+
+
+def catalog_entry_matches_query(entry: dict, query: str) -> bool:
+    """
+    Case-insensitive substring match against a catalog entry's id, display
+    name, description, and category. An empty/whitespace-only query matches
+    everything, so the search box doubles as "no filter" when cleared --
+    the same convention server_matches_filter() uses for the main table.
+    """
+    q = (query or "").strip().lower()
+    if not q:
+        return True
+    haystacks = (
+        str(entry.get("id", "")),
+        str(entry.get("display", "")),
+        str(entry.get("description", "")),
+        str(entry.get("category", "")),
+    )
+    return any(q in h.lower() for h in haystacks)
+
+
+def filter_catalog_entries(entries: list[dict], query: str) -> list[dict]:
+    """Return only the catalog entries that match `query` (see
+    catalog_entry_matches_query)."""
+    return [e for e in entries if catalog_entry_matches_query(e, query)]
+
+
+def catalog_entries_in_group(entries: list[dict], group: str) -> list[dict]:
+    """
+    Return only the entries whose category collapses into `group` (one of
+    CATALOG_CATEGORY_CHIPS). "All" (or a falsy/unrecognized group) returns
+    every entry unfiltered -- that's the default chip state.
+    """
+    if not group or group == "All":
+        return list(entries)
+    return [e for e in entries if catalog_category_group(e.get("category", "")) == group]
+
+
+def format_freshness_hint(last_release: str | None, today: date | None = None) -> str:
+    """
+    Turn a catalog entry's `last_release` (an ISO "YYYY-MM-DD" date, or None
+    when the registry didn't expose one) into a short freshness hint for the
+    detail pane, e.g. "Last updated 14 months ago".
+
+    Returns "" (nothing to show) when `last_release` is missing or
+    unparseable, or when it's somehow in the future relative to `today` --
+    a bogus "-3 months ago" would undermine the one signal this hint exists
+    to give the user, so we'd rather show nothing than something wrong.
+
+    `today` is an injectable override so this is exactly reproducible in
+    tests without depending on the wall clock.
+    """
+    if not last_release or not isinstance(last_release, str):
+        return ""
+    try:
+        released = date.fromisoformat(last_release)
+    except ValueError:
+        return ""
+    now = today or date.today()
+    if released > now:
+        return ""
+
+    months = (now.year - released.year) * 12 + (now.month - released.month)
+    if now.day < released.day:
+        months -= 1
+    months = max(months, 0)
+
+    if months == 0:
+        return "Last updated this month"
+    if months == 1:
+        return "Last updated 1 month ago"
+    if months < 24:
+        return f"Last updated {months} months ago"
+    years = months // 12
+    return f"Last updated {years} year{'s' if years != 1 else ''} ago"
+
+
+def first_unfilled_focus_target(data: dict) -> tuple[str, int | str] | None:
+    """
+    Given a server config dict shaped like catalog_entry_to_paste_json()'s
+    output (command/args/env), find the first thing a user must fill in
+    after a catalog Add: a <PLACEHOLDER>-style arg (checked first, since a
+    missing path/target usually blocks the server from starting at all) or
+    else the first env var the catalog left blank.
+
+    Returns ("args", index) or ("env", key), or None when there's nothing
+    left to fill (e.g. a server with no placeholders and no required env).
+    The GUI uses this to focus+select the right field right after Add,
+    instead of leaving the user to hunt for what still needs a value.
+    """
+    args = data.get("args") or []
+    for i, a in enumerate(args):
+        if isinstance(a, str) and _PLACEHOLDER_RE.search(a):
+            return ("args", i)
+
+    env = data.get("env") or {}
+    if isinstance(env, dict):
+        for k, v in env.items():
+            if not isinstance(v, str) or not v.strip() or _PLACEHOLDER_RE.search(v):
+                return ("env", k)
+
+    return None
+
+
+def load_bundled_catalog_entries(catalog_path: Path, sig_path: Path) -> list[dict]:
+    """
+    Read+verify+validate the bundled catalog.json/.sig pair from disk and
+    return its `servers` list -- or an EMPTY list if anything at all is
+    wrong: files missing/unreadable, signature doesn't verify, JSON doesn't
+    parse, or validate_catalog() finds a problem.
+
+    🔴 SECURITY: this is the load-bearing guarantee for the Browse dialog.
+    There is deliberately no partial-success path here -- a signature
+    failure must never surface a half-trusted list, only an empty one, so
+    the GUI's only job is to render "Catalog unavailable" when this comes
+    back empty. All the real trust decisions (signature, schema, command
+    allowlist) already live in resolve_catalog()/validate_catalog(); this
+    is a thin disk-reading wrapper around them so the GUI never touches
+    catalog bytes directly.
+    """
+    try:
+        raw = catalog_path.read_bytes()
+        sig = sig_path.read_bytes()
+    except OSError:
+        return []
+    data = resolve_catalog(bundled=(raw, sig), cached=None, remote=None)
+    servers = data.get("servers") if isinstance(data, dict) else None
+    return servers if isinstance(servers, list) else []

tests/test_core.py

@@ -1690,8 +1690,12 @@ def _minimal_catalog(version: int = 1) -> dict:
                 "official": True,
                 "setup": "basic",
                 "config": {
+                    # Pinned on purpose (issue #68 finding 3): an earlier
+                    # version of this fixture used an unpinned package and
+                    # asserted it validated clean, which enshrined the bug
+                    # instead of catching it.
                     "command": "npx",
-                    "args": ["-y", "widget-mcp"],
+                    "args": ["-y", "widget-mcp@1.0.0"],
                 },
                 "placeholders": {},
                 "env_required": {},
@@ -1952,6 +1956,213 @@ def test_validate_catalog_rejects_duplicate_ids():
     assert any("duplicate id" in p for p in problems)
 
 
+# --- validate_catalog: config.env (issue #68 finding 2) -------------------- #
+def test_validate_catalog_rejects_each_denied_env_key():
+    for key in sorted(c.CATALOG_DENIED_ENV_KEYS):
+        data = _catalog_with(
+            {"config": {"command": "npx", "args": ["-y", "widget-mcp@1.0.0"], "env": {key: ""}}}
+        )
+        problems = c.validate_catalog(data)
+        assert any("deny-list" in p for p in problems), (key, problems)
+
+
+def test_validate_catalog_rejects_denied_env_key_case_insensitively():
+    data = _catalog_with(
+        {
+            "config": {
+                "command": "npx",
+                "args": ["-y", "widget-mcp@1.0.0"],
+                "env": {"node_options": ""},
+            }
+        }
+    )
+    problems = c.validate_catalog(data)
+    assert any("deny-list" in p for p in problems)
+
+
+def test_validate_catalog_rejects_nonempty_nonplaceholder_env_value():
+    data = _catalog_with(
+        {
+            "config": {
+                "command": "npx",
+                "args": ["-y", "widget-mcp@1.0.0"],
+                "env": {"FOO_URL": "https://example.com"},
+            }
+        }
+    )
+    problems = c.validate_catalog(data)
+    assert any("empty string or a single <PLACEHOLDER>" in p for p in problems)
+
+
+def test_validate_catalog_accepts_empty_and_placeholder_env_values():
+    data = _catalog_with(
+        {
+            "config": {
+                "command": "npx",
+                "args": ["-y", "widget-mcp@1.0.0"],
+                "env": {"FOO": "", "BAR_URL": "<BAR_URL>"},
+            }
+        }
+    )
+    assert c.validate_catalog(data) == []
+
+
+def test_validate_catalog_rejects_non_ascii_env_key():
+    data = _catalog_with(
+        {
+            "config": {
+                "command": "npx",
+                "args": ["-y", "widget-mcp@1.0.0"],
+                "env": {"FÖO": ""},
+            }
+        }
+    )
+    problems = c.validate_catalog(data)
+    assert any("config.env key" in p and "ASCII" in p for p in problems)
+
+
+def test_validate_catalog_rejects_non_ascii_env_value():
+    data = _catalog_with(
+        {
+            "config": {
+                "command": "npx",
+                "args": ["-y", "widget-mcp@1.0.0"],
+                "env": {"FOO": "<Bäd>"},
+            }
+        }
+    )
+    problems = c.validate_catalog(data)
+    assert any("config.env value" in p and "ASCII" in p for p in problems)
+
+
+def test_validate_catalog_rejects_secret_looking_env_value():
+    data = _catalog_with(
+        {
+            "config": {
+                "command": "npx",
+                "args": ["-y", "widget-mcp@1.0.0"],
+                "env": {"SOME_TOKEN": "ghp_abcdef1234567890"},
+            }
+        }
+    )
+    problems = c.validate_catalog(data)
+    assert any("real secret value" in p for p in problems)
+
+
+def test_validate_catalog_rejects_node_options_env_walking_past_allowlist():
+    # The exact reproduction from issue #68 finding 2: an allowlisted
+    # `npx` command carrying NODE_OPTIONS in env, which previously passed
+    # validation and would have flowed straight into the executed
+    # subprocess via catalog_entry_to_paste_json().
+    data = _catalog_with(
+        {
+            "config": {
+                "command": "npx",
+                "args": ["-y", "widget-mcp@1.0.0"],
+                "env": {"NODE_OPTIONS": "--require /tmp/payload.js"},
+            }
+        }
+    )
+    problems = c.validate_catalog(data)
+    assert problems != []
+
+
+# --- validate_catalog: version pinning (issue #68 finding 3) --------------- #
+def test_validate_catalog_rejects_unpinned_npx_package():
+    data = _catalog_with({"config": {"command": "npx", "args": ["-y", "widget-mcp"]}})
+    problems = c.validate_catalog(data)
+    assert any("not version-pinned" in p for p in problems)
+
+
+def test_validate_catalog_rejects_unpinned_scoped_npx_package():
+    data = _catalog_with({"config": {"command": "npx", "args": ["-y", "@scope/pkg"]}})
+    problems = c.validate_catalog(data)
+    assert any("not version-pinned" in p for p in problems)
+
+
+def test_validate_catalog_accepts_pinned_scoped_npx_package():
+    data = _catalog_with({"config": {"command": "npx", "args": ["-y", "@scope/pkg@1.2.3"]}})
+    assert c.validate_catalog(data) == []
+
+
+def test_validate_catalog_rejects_unpinned_uvx_package():
+    data = _catalog_with({"config": {"command": "uvx", "args": ["some-tool"]}})
+    problems = c.validate_catalog(data)
+    assert any("not version-pinned" in p for p in problems)
+
+
+def test_validate_catalog_accepts_uvx_at_version_pin():
+    data = _catalog_with({"config": {"command": "uvx", "args": ["some-tool@1.0.0"]}})
+    assert c.validate_catalog(data) == []
+
+
+def test_validate_catalog_accepts_uvx_double_equals_pin():
+    data = _catalog_with({"config": {"command": "uvx", "args": ["some-tool==1.0.0"]}})
+    assert c.validate_catalog(data) == []
+
+
+def test_validate_catalog_rejects_docker_latest_tag():
+    data = _catalog_with({"config": {"command": "docker", "args": ["run", "some/image:latest"]}})
+    problems = c.validate_catalog(data)
+    assert any("'latest'" in p for p in problems)
+
+
+def test_validate_catalog_rejects_docker_untagged_image():
+    data = _catalog_with({"config": {"command": "docker", "args": ["run", "some/image"]}})
+    problems = c.validate_catalog(data)
+    assert any("no explicit tag" in p for p in problems)
+
+
+def test_validate_catalog_accepts_pinned_docker_image_with_flags():
+    data = _catalog_with(
+        {
+            "config": {
+                "command": "docker",
+                "args": ["run", "-i", "--rm", "-e", "SOME_TOKEN", "some/image:1.2.3"],
+            }
+        }
+    )
+    assert c.validate_catalog(data) == []
+
+
+def test_validate_catalog_does_not_pin_check_placeholders_flags_or_subcommand():
+    # A pinned uvx spec followed by flags and a <PLACEHOLDER> positional
+    # must not itself get mistaken for an unpinned package.
+    data = _catalog_with(
+        {
+            "config": {
+                "command": "uvx",
+                "args": ["mcp-server-git@2026.7.10", "--repository", "<REPO_PATH>"],
+            }
+        }
+    )
+    assert c.validate_catalog(data) == []
+
+
+# --- validate_catalog: id constraint (issue #68 finding 7) ----------------- #
+def test_validate_catalog_rejects_id_with_markup():
+    data = _catalog_with({"id": "<b>Verified</b>"})
+    problems = c.validate_catalog(data)
+    assert any("must match" in p for p in problems)
+
+
+def test_validate_catalog_rejects_id_with_uppercase():
+    data = _catalog_with({"id": "Widget"})
+    problems = c.validate_catalog(data)
+    assert any("must match" in p for p in problems)
+
+
+def test_validate_catalog_rejects_id_starting_with_dash():
+    data = _catalog_with({"id": "-widget"})
+    problems = c.validate_catalog(data)
+    assert any("must match" in p for p in problems)
+
+
+def test_validate_catalog_accepts_valid_slug_id():
+    data = _catalog_with({"id": "widget-2.thing-ok"})
+    assert c.validate_catalog(data) == []
+
+
 # --- resolve_catalog -------------------------------------------------------- #
 def test_resolve_catalog_nothing_available_returns_empty_dict():
     assert c.resolve_catalog(None, None, None) == {}
@@ -2003,13 +2214,93 @@ def test_resolve_catalog_rejects_absurd_version_jump(monkeypatch):
     pub = priv.public_key().public_bytes_raw()
     monkeypatch.setattr(c, "CATALOG_PUBKEYS", [pub])
 
-    cached = _signed(_minimal_catalog(version=5), priv)
+    # The freeze attempt goes FIRST (as `cached`), the legitimate catalog
+    # SECOND (as `remote`) -- on purpose. Putting the good catalog first
+    # (as an earlier version of this test did) never exercises the
+    # vulnerable path: the old implementation only guarded a candidate
+    # against "the best accepted so far," so whichever candidate was
+    # evaluated FIRST got in unconditionally, uncapped. Ordering the freeze
+    # attempt first is what actually proves the cap holds regardless of
+    # evaluation order.
     freeze_attempt = _signed(_minimal_catalog(version=999999), priv)
+    good = _signed(_minimal_catalog(version=5), priv)
 
-    result = c.resolve_catalog(None, cached, freeze_attempt)
+    result = c.resolve_catalog(None, freeze_attempt, good)
     assert c.catalog_version(result) == 5
 
 
+def test_resolve_catalog_caps_first_and_only_candidate(monkeypatch):
+    # issue #68 finding 6: with no bundled catalog to anchor against, a
+    # signed catalog claiming an absurd version must still be capped even
+    # when it is the ONLY candidate resolve_catalog() ever sees -- there is
+    # no "best so far" for it to be compared against, so the cap has to
+    # apply unconditionally, not "once something else has already landed."
+    priv = Ed25519PrivateKey.generate()
+    pub = priv.public_key().public_bytes_raw()
+    monkeypatch.setattr(c, "CATALOG_PUBKEYS", [pub])
+
+    freeze_attempt = _signed(_minimal_catalog(version=999999999), priv)
+
+    result = c.resolve_catalog(None, None, freeze_attempt)
+    assert result == {}
+
+
+def test_resolve_catalog_anchors_cap_to_bundled_not_a_chained_best(monkeypatch):
+    # Anti-freeze must be measured against the BUNDLED version specifically,
+    # not against "whatever the best-so-far happens to be after each
+    # candidate is accepted" -- a chained anchor lets each accepted
+    # candidate ratchet the allowed ceiling upward, so a legitimate
+    # moderate bump (cached) plus a second, much larger jump (remote) can
+    # each individually look "within _CATALOG_MAX_VERSION_JUMP of the
+    # previous one" while remote is nowhere near bundled's version.
+    priv = Ed25519PrivateKey.generate()
+    pub = priv.public_key().public_bytes_raw()
+    monkeypatch.setattr(c, "CATALOG_PUBKEYS", [pub])
+
+    bundled = _signed(_minimal_catalog(version=2), priv)
+    cached = _signed(_minimal_catalog(version=1000), priv)  # within 1000 of bundled
+    remote = _signed(_minimal_catalog(version=1900), priv)  # within 1000 of cached,
+    #                                                          NOT of bundled
+
+    result = c.resolve_catalog(bundled, cached, remote)
+    assert c.catalog_version(result) == 1000
+
+
+def test_resolve_catalog_prefers_bundled_on_version_tie(monkeypatch):
+    # issue #68 finding 6: on a tie the LAST candidate evaluated used to
+    # win, so remote silently beat bundled at equal version. Bundled --
+    # the copy frozen into the binary -- must win ties.
+    priv = Ed25519PrivateKey.generate()
+    pub = priv.public_key().public_bytes_raw()
+    monkeypatch.setattr(c, "CATALOG_PUBKEYS", [pub])
+
+    bundled_data = _minimal_catalog(version=5)
+    bundled = _signed(bundled_data, priv)
+
+    remote_data = _minimal_catalog(version=5)
+    remote_data["servers"][0]["display"] = "Remote Impostor"
+    remote = _signed(remote_data, priv)
+
+    result = c.resolve_catalog(bundled, None, remote)
+    assert c.catalog_version(result) == 5
+    assert result["servers"][0]["display"] == "Widget"
+
+
+def test_resolve_catalog_floor_rejects_below_persisted_version(monkeypatch):
+    # `floor` is a pure parameter: the caller (eventually the GUI, from
+    # persisted storage) can pass a previously-accepted version, and
+    # nothing below it may be accepted even with no bundled catalog to
+    # anchor against.
+    priv = Ed25519PrivateKey.generate()
+    pub = priv.public_key().public_bytes_raw()
+    monkeypatch.setattr(c, "CATALOG_PUBKEYS", [pub])
+
+    stale = _signed(_minimal_catalog(version=3), priv)
+
+    result = c.resolve_catalog(None, None, stale, floor=10)
+    assert result == {}
+
+
 def test_resolve_catalog_malformed_candidate_does_not_raise(monkeypatch):
     priv = Ed25519PrivateKey.generate()
     pub = priv.public_key().public_bytes_raw()
@@ -2039,15 +2330,69 @@ def test_resolve_catalog_invalid_but_signed_candidate_is_skipped(monkeypatch):
 def test_catalog_entry_to_paste_json_basic_shape():
     entry = _minimal_catalog()["servers"][0]
     result = c.catalog_entry_to_paste_json(entry)
-    assert result == {"widget": {"command": "npx", "args": ["-y", "widget-mcp"]}}
+    assert result == {"widget": {"command": "npx", "args": ["-y", "widget-mcp@1.0.0"]}}
 
 
 def test_catalog_entry_to_paste_json_includes_env_when_present():
+    # NOTE: catalog_entry_to_paste_json() is a pure shape-converter for an
+    # entry that has ALREADY passed validate_catalog() -- it is correct for
+    # it to carry env through verbatim. The bug (issue #68 finding 2) was
+    # never in this function; it was that validate_catalog() let entries
+    # with dangerous/non-placeholder env values reach this function in the
+    # first place. This test now proves that boundary explicitly: a
+    # validation-legal env value (a <PLACEHOLDER> token) survives the
+    # conversion, and a value validate_catalog() would have rejected is
+    # confirmed rejected before it ever gets here.
     entry = _minimal_catalog()["servers"][0]
     entry["config"]["env"] = {"GRAFANA_URL": "<GRAFANA_URL>"}
     result = c.catalog_entry_to_paste_json(entry)
     assert result["widget"]["env"] == {"GRAFANA_URL": "<GRAFANA_URL>"}
 
+    catalog = _minimal_catalog()
+    catalog["servers"][0]["config"]["env"] = {"GRAFANA_URL": "<GRAFANA_URL>"}
+    assert c.validate_catalog(catalog) == []
+
+    malicious = _minimal_catalog()
+    malicious["servers"][0]["config"]["env"] = {"NODE_OPTIONS": "--require /tmp/payload.js"}
+    assert c.validate_catalog(malicious) != []
+
+
+def test_catalog_entry_to_paste_json_seeds_env_required_keys():
+    # Regression: env_required is where the seed data actually keeps its
+    # secret VAR NAMES (postgres/github/notion/etc. all declare their secret
+    # here with config.env left empty) -- catalog_entry_to_paste_json must
+    # surface those names as blank env rows, not silently drop them.
+    entry = _minimal_catalog()["servers"][0]
+    entry["env_required"] = {"DATABASE_URI": ""}
+    result = c.catalog_entry_to_paste_json(entry)
+    assert result["widget"]["env"] == {"DATABASE_URI": ""}
+
+
+def test_catalog_entry_to_paste_json_config_env_wins_over_env_required_default():
+    entry = _minimal_catalog()["servers"][0]
+    entry["config"]["env"] = {"GRAFANA_URL": "<GRAFANA_URL>"}
+    entry["env_required"] = {"GRAFANA_URL": "", "GRAFANA_SERVICE_ACCOUNT_TOKEN": ""}
+    result = c.catalog_entry_to_paste_json(entry)
+    assert result["widget"]["env"] == {
+        "GRAFANA_URL": "<GRAFANA_URL>",
+        "GRAFANA_SERVICE_ACCOUNT_TOKEN": "",
+    }
+
+
+def test_catalog_entry_to_paste_json_real_postgres_entry_seeds_database_uri():
+    """End-to-end regression against the actual shipped postgres entry,
+    which needs DATABASE_URI via env_required and has no config.env at
+    all -- this is exactly the shape that was silently dropping the env
+    field before catalog_entry_to_paste_json accounted for env_required."""
+    root = Path(__file__).resolve().parent.parent
+    raw = (root / "data" / "catalog.json").read_bytes()
+    data = c.load_catalog(raw)
+    entry = next(s for s in data["servers"] if s["id"] == "postgres")
+    result = c.catalog_entry_to_paste_json(entry)
+    assert result["postgres"]["env"] == {"DATABASE_URI": ""}
+    # And the focus-target helper now has something to point the user at.
+    assert c.first_unfilled_focus_target(result["postgres"]) == ("env", "DATABASE_URI")
+
 
 def test_config_has_unfilled_placeholders_true_for_token():
     cfg = {"command": "npx", "args": ["-y", "server", "<ALLOWED_DIR>"]}
@@ -2062,3 +2407,310 @@ def test_config_has_unfilled_placeholders_false_after_fill():
 def test_config_has_unfilled_placeholders_checks_env_too():
     cfg = {"command": "uvx", "args": ["mcp-grafana"], "env": {"GRAFANA_URL": "<GRAFANA_URL>"}}
     assert c.config_has_unfilled_placeholders(cfg) is True
+
+
+# --------------------------------------------------------------------------- #
+# Browse-catalog dialog helpers (issue #10 phase 2)
+# --------------------------------------------------------------------------- #
+
+
+# --- catalog_category_group / CATALOG_CATEGORY_GROUPS --------------------- #
+@pytest.mark.parametrize(
+    "category,expected_group",
+    [
+        ("files", "Files & Dev"),
+        ("dev", "Files & Dev"),
+        ("code-hosting", "Files & Dev"),
+        ("browser", "Files & Dev"),
+        ("database", "Data"),
+        ("data", "Data"),
+        ("search", "Search & AI"),
+        ("ai", "Search & AI"),
+        ("cloud", "Cloud & Infra"),
+        ("infra", "Cloud & Infra"),
+        ("observability", "Cloud & Infra"),
+        ("productivity", "Work"),
+        ("communication", "Work"),
+        ("crm", "Work"),
+        ("finance", "Work"),
+        ("design", "Work"),
+        ("media", "Home & Personal"),
+        ("smart-home", "Home & Personal"),
+        ("personal", "Home & Personal"),
+    ],
+)
+def test_catalog_category_group_maps_every_taxonomy_value(category, expected_group):
+    assert c.catalog_category_group(category) == expected_group
+
+
+def test_catalog_category_group_unknown_falls_back_to_other():
+    assert c.catalog_category_group("some-future-category-nobody-has-seen-yet") == "Other"
+    assert c.catalog_category_group("") == "Other"
+    assert c.catalog_category_group(None) == "Other"
+
+
+def test_catalog_category_group_is_case_insensitive():
+    assert c.catalog_category_group("Files") == "Files & Dev"
+    assert c.catalog_category_group("DATABASE") == "Data"
+
+
+def test_shipped_catalog_categories_all_have_a_known_group():
+    """Regression: every category actually used in data/catalog.json must
+    collapse to one of the 7 chips, never silently drop an entry."""
+    root = Path(__file__).resolve().parent.parent
+    raw = (root / "data" / "catalog.json").read_bytes()
+    data = c.load_catalog(raw)
+    for entry in data["servers"]:
+        group = c.catalog_category_group(entry["category"])
+        assert group in c.CATALOG_CATEGORY_CHIPS
+
+
+# --- catalog_entry_matches_query / filter_catalog_entries ------------------ #
+def _catalog_entries():
+    return [
+        {
+            "id": "filesystem",
+            "display": "Filesystem",
+            "description": "Read/write access to local directories you choose.",
+            "category": "files",
+        },
+        {
+            "id": "postgres",
+            "display": "Postgres MCP Pro",
+            "description": "Query and inspect a PostgreSQL database.",
+            "category": "database",
+        },
+        {
+            "id": "slack",
+            "display": "Slack",
+            "description": "Search messages and send messages from your assistant.",
+            "category": "communication",
+        },
+    ]
+
+
+def test_catalog_entry_matches_query_empty_matches_everything():
+    entries = _catalog_entries()
+    assert c.filter_catalog_entries(entries, "") == entries
+    assert c.filter_catalog_entries(entries, "   ") == entries
+
+
+def test_catalog_entry_matches_query_matches_id():
+    result = c.filter_catalog_entries(_catalog_entries(), "postgres")
+    assert [e["id"] for e in result] == ["postgres"]
+
+
+def test_catalog_entry_matches_query_matches_display_case_insensitive():
+    result = c.filter_catalog_entries(_catalog_entries(), "SLACK")
+    assert [e["id"] for e in result] == ["slack"]
+
+
+def test_catalog_entry_matches_query_matches_description():
+    result = c.filter_catalog_entries(_catalog_entries(), "PostgreSQL database")
+    assert [e["id"] for e in result] == ["postgres"]
+
+
+def test_catalog_entry_matches_query_matches_category():
+    result = c.filter_catalog_entries(_catalog_entries(), "database")
+    assert [e["id"] for e in result] == ["postgres"]
+
+
+def test_catalog_entry_matches_query_no_match_returns_empty():
+    assert c.filter_catalog_entries(_catalog_entries(), "kubernetes") == []
+
+
+def test_catalog_entries_in_group_all_returns_everything():
+    entries = _catalog_entries()
+    assert c.catalog_entries_in_group(entries, "All") == entries
+    assert c.catalog_entries_in_group(entries, "") == entries
+    assert c.catalog_entries_in_group(entries, None) == entries
+
+
+def test_catalog_entries_in_group_filters_by_collapsed_category():
+    result = c.catalog_entries_in_group(_catalog_entries(), "Data")
+    assert [e["id"] for e in result] == ["postgres"]
+
+    result = c.catalog_entries_in_group(_catalog_entries(), "Work")
+    assert [e["id"] for e in result] == ["slack"]
+
+
+# --- format_freshness_hint -------------------------------------------------- #
+def test_format_freshness_hint_none_returns_empty_string():
+    assert c.format_freshness_hint(None) == ""
+    assert c.format_freshness_hint("") == ""
+
+
+def test_format_freshness_hint_unparseable_returns_empty_string():
+    assert c.format_freshness_hint("not-a-date") == ""
+
+
+def test_format_freshness_hint_this_month():
+    assert (
+        c.format_freshness_hint("2026-07-01", today=c.date(2026, 7, 12))
+        == "Last updated this month"
+    )
+
+
+def test_format_freshness_hint_one_month_singular():
+    assert (
+        c.format_freshness_hint("2026-06-01", today=c.date(2026, 7, 12))
+        == "Last updated 1 month ago"
+    )
+
+
+def test_format_freshness_hint_months_ago():
+    # Exactly 14 full months elapsed, no day-of-month remainder to round off.
+    assert (
+        c.format_freshness_hint("2025-01-15", today=c.date(2026, 3, 15))
+        == "Last updated 14 months ago"
+    )
+
+
+def test_format_freshness_hint_rounds_down_partial_month():
+    # 2025-05-16 -> 2026-07-12 is 13 full months, not 14: the 14th month
+    # would only complete on 2026-07-16.
+    assert (
+        c.format_freshness_hint("2025-05-16", today=c.date(2026, 7, 12))
+        == "Last updated 13 months ago"
+    )
+
+
+def test_format_freshness_hint_years_ago():
+    assert (
+        c.format_freshness_hint("2024-01-01", today=c.date(2026, 7, 12))
+        == "Last updated 2 years ago"
+    )
+
+
+def test_format_freshness_hint_23_months_stays_in_months_not_years():
+    # The switch to "N years ago" happens at 24 full months, not 12 -- the
+    # whole point of this hint is the granular "14 months ago" phrasing the
+    # design comment on #10 asked for, so 13-23 months must stay in months.
+    assert (
+        c.format_freshness_hint("2024-08-12", today=c.date(2026, 7, 12))
+        == "Last updated 23 months ago"
+    )
+
+
+def test_format_freshness_hint_future_date_returns_empty_string():
+    # A last_release "in the future" relative to `today` is nonsensical --
+    # show nothing rather than a misleading negative offset.
+    assert c.format_freshness_hint("2027-01-01", today=c.date(2026, 7, 12)) == ""
+
+
+# --- first_unfilled_focus_target -------------------------------------------- #
+def test_first_unfilled_focus_target_prefers_placeholder_arg():
+    data = {
+        "command": "npx",
+        "args": ["-y", "server", "<ALLOWED_DIR>"],
+        "env": {"API_KEY": ""},
+    }
+    assert c.first_unfilled_focus_target(data) == ("args", 2)
+
+
+def test_first_unfilled_focus_target_falls_back_to_first_blank_env():
+    data = {"command": "uvx", "args": ["mcp-grafana"], "env": {"GRAFANA_URL": ""}}
+    assert c.first_unfilled_focus_target(data) == ("env", "GRAFANA_URL")
+
+
+def test_first_unfilled_focus_target_none_when_fully_filled():
+    data = {"command": "npx", "args": ["-y", "server"], "env": {"API_KEY": "sk-real-value"}}
+    assert c.first_unfilled_focus_target(data) is None
+
+
+def test_first_unfilled_focus_target_none_for_config_with_no_env_or_args():
+    assert c.first_unfilled_focus_target({"command": "npx", "args": []}) is None
+
+
+# --- load_bundled_catalog_entries ------------------------------------------- #
+def test_load_bundled_catalog_entries_valid_signature(tmp_path, monkeypatch):
+    priv = Ed25519PrivateKey.generate()
+    pub = priv.public_key().public_bytes_raw()
+    monkeypatch.setattr(c, "CATALOG_PUBKEYS", [pub])
+
+    raw, sig = _signed(_minimal_catalog(version=1), priv)
+    catalog_path = tmp_path / "catalog.json"
+    sig_path = tmp_path / "catalog.json.sig"
+    catalog_path.write_bytes(raw)
+    sig_path.write_bytes(sig)
+
+    entries = c.load_bundled_catalog_entries(catalog_path, sig_path)
+    assert len(entries) == 1
+    assert entries[0]["id"] == "widget"
+
+
+def test_load_bundled_catalog_entries_tampered_payload_returns_empty_list(tmp_path, monkeypatch):
+    priv = Ed25519PrivateKey.generate()
+    pub = priv.public_key().public_bytes_raw()
+    monkeypatch.setattr(c, "CATALOG_PUBKEYS", [pub])
+
+    raw, sig = _signed(_minimal_catalog(version=1), priv)
+    tampered = bytearray(raw)
+    tampered[-2] ^= 0xFF  # flip a byte inside the trailing bytes, still valid-ish JSON shape
+    catalog_path = tmp_path / "catalog.json"
+    sig_path = tmp_path / "catalog.json.sig"
+    catalog_path.write_bytes(bytes(tampered))
+    sig_path.write_bytes(sig)
+
+    assert c.load_bundled_catalog_entries(catalog_path, sig_path) == []
+
+
+def test_load_bundled_catalog_entries_wrong_key_returns_empty_list(tmp_path, monkeypatch):
+    priv = Ed25519PrivateKey.generate()
+    other_priv = Ed25519PrivateKey.generate()
+    other_pub = other_priv.public_key().public_bytes_raw()
+    monkeypatch.setattr(c, "CATALOG_PUBKEYS", [other_pub])
+
+    raw, sig = _signed(_minimal_catalog(version=1), priv)  # signed by the WRONG key
+    catalog_path = tmp_path / "catalog.json"
+    sig_path = tmp_path / "catalog.json.sig"
+    catalog_path.write_bytes(raw)
+    sig_path.write_bytes(sig)
+
+    assert c.load_bundled_catalog_entries(catalog_path, sig_path) == []
+
+
+def test_load_bundled_catalog_entries_missing_files_returns_empty_list(tmp_path):
+    assert c.load_bundled_catalog_entries(tmp_path / "nope.json", tmp_path / "nope.json.sig") == []
+
+
+def test_load_bundled_catalog_entries_missing_sig_returns_empty_list(tmp_path, monkeypatch):
+    priv = Ed25519PrivateKey.generate()
+    pub = priv.public_key().public_bytes_raw()
+    monkeypatch.setattr(c, "CATALOG_PUBKEYS", [pub])
+
+    raw, _sig = _signed(_minimal_catalog(version=1), priv)
+    catalog_path = tmp_path / "catalog.json"
+    catalog_path.write_bytes(raw)
+    missing_sig_path = tmp_path / "catalog.json.sig"  # never written
+
+    assert c.load_bundled_catalog_entries(catalog_path, missing_sig_path) == []
+
+
+def test_load_bundled_catalog_entries_invalid_but_signed_returns_empty_list(tmp_path, monkeypatch):
+    """A payload that verifies but fails validate_catalog() (disallowed
+    command) must still come back empty -- signing is necessary, not
+    sufficient."""
+    priv = Ed25519PrivateKey.generate()
+    pub = priv.public_key().public_bytes_raw()
+    monkeypatch.setattr(c, "CATALOG_PUBKEYS", [pub])
+
+    raw, sig = _signed(_catalog_with({"config": {"command": "bash", "args": []}}), priv)
+    catalog_path = tmp_path / "catalog.json"
+    sig_path = tmp_path / "catalog.json.sig"
+    catalog_path.write_bytes(raw)
+    sig_path.write_bytes(sig)
+
+    assert c.load_bundled_catalog_entries(catalog_path, sig_path) == []
+
+
+def test_load_bundled_catalog_entries_real_shipped_catalog():
+    """End-to-end regression against the actual bundled data/catalog.json +
+    .sig, using the real CATALOG_PUBKEYS (no monkeypatch) -- this is what
+    the Browse dialog actually calls on startup."""
+    root = Path(__file__).resolve().parent.parent
+    entries = c.load_bundled_catalog_entries(
+        root / "data" / "catalog.json", root / "data" / "catalog.json.sig"
+    )
+    assert len(entries) == 19
+    assert {e["id"] for e in entries} >= {"filesystem", "github", "slack", "postgres"}