Merge PR #64: signed SHA256SUMS for releases (#63)

Publish SHA-256 checksums for every release artifact and sign them with a
domain-separated Ed25519 signature. Skips signing (loudly) if the key secret
is absent rather than failing the release. README documents verification and
states the limit plainly: this proves the file is the one we published; it
does not remove Gatekeeper/SmartScreen warnings.

.github/workflows/ci.yml

@@ -29,25 +29,42 @@ jobs:
         run: ruff format --check .
 
   test:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
-    name: Tests (py${{ matrix.python }})
+    name: Tests (py${{ matrix.python }} / ${{ matrix.os }})
     strategy:
       fail-fast: false
       matrix:
-        python: ["3.10", "3.12"]
+        os: [ubuntu-latest]
+        python: ["3.10", "3.12", "3.13"]
+        include:
+          # Windows tests on 3.12 only — the version the release binaries ship
+          # with. The self-hosted Windows runner blocks setup-python's install
+          # script (PowerShell execution policy), so it uses the host's `py`
+          # launcher + venv, same as release.yml.
+          - os: windows-latest
+            python: "3.12"
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Set up Python ${{ matrix.python }}
+      - name: Set up Python ${{ matrix.python }} (Linux)
+        if: runner.os == 'Linux'
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python }}
 
+      - name: Set up Python venv (Windows)
+        if: runner.os == 'Windows'
+        shell: pwsh
+        run: |
+          py -${{ matrix.python }} -m venv .venv
+          Add-Content -Path $env:GITHUB_PATH -Value "$env:GITHUB_WORKSPACE\.venv\Scripts"
+
       # bcc_core has no GUI imports, so the test suite needs no PySide6 —
       # keeps CI fast and avoids Qt system-library headaches on the runner.
+      # cryptography is for tests/test_checksums.py (release signing helper).
       - name: Install test dependencies
-        run: pip install pytest
+        run: pip install pytest cryptography
 
       - name: Run tests
         run: python -m pytest -v

.github/workflows/release.yml

@@ -107,11 +107,72 @@ jobs:
       contents: write
 
     steps:
+      # Needed for scripts/sign_checksums.py — the release job otherwise
+      # only downloads build artifacts, it doesn't check out the repo.
+      - name: Checkout
+        uses: actions/checkout@v4
+
       - name: Download all artifacts
         uses: actions/download-artifact@v3
         with:
           path: artifacts
 
+      - name: Set up Python 3.12
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      # download-artifact@v3 nests each artifact under a directory named
+      # after it (artifacts/<name>/<name>). Flatten into one directory so
+      # SHA256SUMS lists plain filenames, matching what `sha256sum -c`
+      # expects when run from inside an extracted release download.
+      - name: Collect release files
+        run: |
+          mkdir -p release-files
+          find artifacts -type f -exec cp {} release-files/ \;
+          ls -la release-files
+
+      - name: Generate SHA256SUMS
+        run: python3 scripts/sign_checksums.py generate release-files --out release-files/SHA256SUMS
+
+      # ── Sign the checksum manifest (best-effort) ──────────────────────
+      #
+      # BCC binaries are not code-signed (no budget for a paid cert). This
+      # is the free half: a checksum manifest, detached-signed with
+      # Ed25519, so a tampered download is detectable by anyone who
+      # checks. It does NOT remove Gatekeeper/SmartScreen warnings.
+      #
+      # The private key is a repo secret (RELEASE_SIGNING_KEY, base64 raw
+      # Ed25519 seed) generated via the Catalog Console (#62). If it's not
+      # set, we still publish the release — just without a .sig — rather
+      # than fail the release outright.
+      - name: Check for signing key
+        id: signing
+        run: |
+          if [ -n "${{ secrets.RELEASE_SIGNING_KEY }}" ]; then
+            echo "has_key=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "has_key=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Install signing dependencies
+        if: steps.signing.outputs.has_key == 'true'
+        run: pip install cryptography
+
+      - name: Sign SHA256SUMS
+        if: steps.signing.outputs.has_key == 'true'
+        env:
+          RELEASE_SIGNING_KEY: ${{ secrets.RELEASE_SIGNING_KEY }}
+        run: |
+          python3 scripts/sign_checksums.py sign \
+            --sums release-files/SHA256SUMS \
+            --out release-files/SHA256SUMS.sig
+
+      - name: Warn — release will be unsigned
+        if: steps.signing.outputs.has_key != 'true'
+        run: |
+          echo "::warning::RELEASE_SIGNING_KEY secret is not set — this release is being published WITHOUT a signed SHA256SUMS.sig. Add the secret (base64 raw Ed25519 seed, generated via the Catalog Console, #62) before the next tag."
+
       - name: Create GitHub Release
         uses: softprops/action-gh-release@v2
         with:
@@ -119,7 +180,9 @@ jobs:
           draft: false
           prerelease: false
           generate_release_notes: false
-          files: artifacts/**/*
+          files: |
+            artifacts/**/*
+            release-files/SHA256SUMS*
           body: |
             ## Better Claude Config ${{ github.ref_name }}
 
@@ -139,5 +202,8 @@ jobs:
             xattr -cr /Applications/BetterClaudeConfig.app
             ```
 
+            ### Verifying your download
+            Every release includes `SHA256SUMS` (and, when the signing key is configured, a detached `SHA256SUMS.sig`). See [Verifying your download](https://git.avezzano.io/the_og/better-claude-config#verifying-your-download) in the README for commands. This proves you got the file we published — it does not remove Gatekeeper/SmartScreen warnings.
+
             ### Requirements
             No Python installation needed — the app is self-contained.

README.md

@@ -19,6 +19,65 @@ Pre-built self-contained binaries are attached to every [GitHub Release](../../r
 
 > **macOS Gatekeeper note:** the app is not notarized. On first launch, right-click → **Open**, or run `xattr -cr /Applications/BetterClaudeConfig.app` in a terminal.
 
+## Verifying your download
+
+BCC isn't code-signed — there's no budget for a paid certificate (macOS
+Developer ID, Windows Authenticode). Instead, every release publishes a
+`SHA256SUMS` file listing the checksum of each archive, detached-signed with
+Ed25519 as `SHA256SUMS.sig`. Both are attached to the release alongside the
+binaries.
+
+**What this proves:** the file you downloaded is byte-for-byte what we
+published, and the manifest itself was signed by our release key.
+
+**What this does NOT do:** it does not make the binary "safe," and it does
+**not** remove the macOS Gatekeeper or Windows SmartScreen warning — those
+are only suppressed by a paid OS-vendor certificate, which this project
+doesn't have. Verifying checksums is about detecting tampering in transit or
+on a mirror, not about vouching for the software.
+
+**Release signing public key** (Ed25519, base64, raw 32 bytes):
+
+```
+<PLACEHOLDER — AJ: paste the public key from the Catalog Console (#62) here>
+```
+
+### macOS / Linux
+
+```bash
+# From inside the folder you downloaded the release files into:
+sha256sum -c SHA256SUMS
+```
+
+If your `sha256sum` complains about missing files, download `SHA256SUMS`
+into the same directory as the archive you downloaded — it lists every
+platform's archive, and only the one(s) present will be checked.
+
+To also verify the manifest's signature (optional, requires Python +
+`pip install cryptography` and a checkout of this repo):
+
+```bash
+python3 scripts/sign_checksums.py verify \
+  --sums SHA256SUMS --sig SHA256SUMS.sig \
+  --pubkey-b64 "<the public key above>"
+```
+
+### Windows (PowerShell)
+
+```powershell
+Get-FileHash .\BetterClaudeConfig-Windows.zip -Algorithm SHA256
+```
+
+Compare the printed hash (case-insensitively) against the matching line in
+`SHA256SUMS`.
+
+### If a release has no `SHA256SUMS.sig`
+
+The signing key is a repo secret that has to be configured manually; if a
+release is missing the `.sig` file, the checksums themselves are still
+valid and safe to check against — the release workflow only skips signing,
+never checksum generation.
+
 ## Run from source
 
 ```bash
@@ -92,6 +151,7 @@ file is also listed, marked *legacy*, so you can copy them over.
 - `test_core.py` — unit suite for the core (`python test_core.py`).
 - `bcc.spec` — PyInstaller build spec (cross-platform).
 - `scripts/build_icons.py` — regenerates `icons/app.icns` and `icons/app.ico` from source PNGs.
+- `scripts/sign_checksums.py` — generates and Ed25519-signs the release `SHA256SUMS` manifest (see [Verifying your download](#verifying-your-download)).
 
 ## Building from source
 

bcc.spec

@@ -31,7 +31,7 @@ a = Analysis(
     ["bcc.py"],
     pathex=[],
     binaries=[],
-    datas=[],
+    datas=[("icons", "icons")],
     hiddenimports=[],
     hookspath=[],
     hooksconfig={},
@@ -78,8 +78,8 @@ if sys.platform == "darwin":
         info_plist={
             "CFBundleName": "Better Claude Config",
             "CFBundleDisplayName": "Better Claude Config",
-            "CFBundleShortVersionString": "1.0.0",
+            "CFBundleShortVersionString": "1.3.0",
-            "CFBundleVersion": "1.0.0",
+            "CFBundleVersion": "1.3.0",
             "NSHighResolutionCapable": True,
             "NSRequiresAquaSystemAppearance": False,  # supports dark mode
             "LSMinimumSystemVersion": "11.0",

bcc_core.py

@@ -29,6 +29,7 @@ import threading
 import time
 from dataclasses import dataclass
 from pathlib import Path
+from typing import NamedTuple
 from urllib.parse import urlparse
 
 CONFIG_FILENAME = "claude_desktop_config.json"
@@ -38,6 +39,12 @@ CONFIG_FILENAME = "claude_desktop_config.json"
 # we can toggle it back on without losing the definition.
 DISABLED_KEY = "_disabledMcpServers"
 
+# Named server sets: {set_name: [enabled server names]}. Same pattern as
+# DISABLED_KEY — a bcc-owned key Claude ignores, stored in the config file so
+# sets travel with it. Applying a set enables exactly the listed servers and
+# parks the rest under DISABLED_KEY.
+SETS_KEY = "_bccServerSets"
+
 BACKUP_DIRNAME = ".bcc_backups"
 MAX_BACKUPS = 15
 
@@ -46,6 +53,112 @@ MAX_BACKUPS = 15
 KNOWN_FIELDS = {"command", "args", "env", "url", "type", "headers"}
 
 
+# --------------------------------------------------------------------------- #
+# Version / update checking
+#
+# __version__ is the single source of truth for the app version (must match
+# pyproject.toml's [project] version). The About dialog and the update
+# checker both read this constant instead of hard-coding a version string.
+#
+# The update checker is notify-only: it reads release metadata from the
+# repo's Gitea releases API and NEVER downloads or replaces the running
+# binary. All network I/O here is fail-quiet (returns None on any problem)
+# so it's safe to run unattended, off the UI thread, at startup.
+# --------------------------------------------------------------------------- #
+__version__ = "1.3.0"
+
+REPO_URL = "https://git.avezzano.io/the_og/better-claude-config"
+ISSUES_URL = f"{REPO_URL}/issues"
+RELEASES_URL = f"{REPO_URL}/releases"
+LICENSE_URL = f"{REPO_URL}/raw/branch/main/LICENSE"
+
+# Public repo -> anonymously reachable, no auth/token needed or embedded.
+_RELEASES_API_URL = (
+    "https://git.avezzano.io/api/v1/repos/the_og/better-claude-config/releases/latest"
+)
+
+
+def parse_version(v: str) -> tuple[int, ...]:
+    """
+    Parse a version string into a tuple of ints for numeric comparison.
+
+    Strips a leading 'v' ("v1.2.3" -> "1.2.3") and any pre-release/build
+    metadata after a '-' or '+' ("1.2.3-beta.1" -> "1.2.3"). Stops at the
+    first non-numeric dotted component. Empty or entirely non-numeric input
+    returns an empty tuple rather than raising, so a malformed tag from a
+    flaky API response degrades gracefully instead of crashing the caller.
+    """
+    s = (v or "").strip()
+    if s[:1].lower() == "v":
+        s = s[1:]
+    s = re.split(r"[-+]", s, maxsplit=1)[0]
+    parts: list[int] = []
+    for chunk in s.split("."):
+        m = re.match(r"\d+", chunk)
+        if not m:
+            break
+        parts.append(int(m.group()))
+    return tuple(parts)
+
+
+def is_newer_version(current: str, candidate: str) -> bool:
+    """
+    True if `candidate` is a strictly newer version than `current`.
+
+    Comparison is purely numeric (major.minor.patch, ...) — NEVER a lexical
+    string compare, so "v2.0.0" vs "v10.0.0" resolves correctly instead of
+    sorting "2" after "10". Tuples of differing length are zero-padded before
+    comparing, so "1.2" and "1.2.0" are correctly treated as equal.
+
+    An unparseable `candidate` always yields False (nothing to report). An
+    unparseable `current` is treated as "0" for comparison purposes — a
+    malformed local version shouldn't silently suppress a real update.
+    """
+    cur = parse_version(current)
+    new = parse_version(candidate)
+    if not new:
+        return False
+    width = max(len(cur), len(new), 1)
+    cur = cur + (0,) * (width - len(cur))
+    new = new + (0,) * (width - len(new))
+    return new > cur
+
+
+def fetch_latest_release(timeout: float = 4.0) -> dict | None:
+    """
+    Query the repo's (public, anonymous) Gitea releases API for the latest
+    release. Returns {"version": "<tag>", "url": "<releases page>"} on
+    success, or None on ANY failure: network error, timeout, bad status,
+    malformed JSON, or a response missing tag_name.
+
+    Fail-quiet by design — this is meant to be called off the UI thread
+    (see UpdateCheckWorker in bcc.py) for both the About dialog's "Check for
+    updates" button and an optional silent startup check. Never downloads or
+    touches any binary; this only ever reads release metadata.
+    """
+    import urllib.error
+    import urllib.request
+
+    req = urllib.request.Request(
+        _RELEASES_API_URL,
+        headers={
+            "Accept": "application/json",
+            "User-Agent": f"BetterClaudeConfig/{__version__}",
+        },
+    )
+    try:
+        with urllib.request.urlopen(req, timeout=timeout) as r:
+            payload = json.loads(r.read().decode("utf-8"))
+    except (urllib.error.URLError, TimeoutError, ValueError, OSError):
+        return None
+    if not isinstance(payload, dict):
+        return None
+    tag = payload.get("tag_name")
+    if not tag or not isinstance(tag, str):
+        return None
+    return {"version": tag, "url": payload.get("html_url") or RELEASES_URL}
+
+
 # --------------------------------------------------------------------------- #
 # Data model
 # --------------------------------------------------------------------------- #
@@ -84,17 +197,150 @@ def app_support_base() -> Path:
     return Path(os.environ.get("XDG_CONFIG_HOME", Path.home() / ".config"))
 
 
+def msix_config_paths(localappdata: str | os.PathLike | None = None) -> list[Path]:
+    """
+    Find MSIX/Store-packaged Claude Desktop configs.
+
+    When Claude Desktop is installed from the Microsoft Store (MSIX), Windows
+    virtualizes its filesystem writes to a per-package folder under
+    `%LOCALAPPDATA%\\Packages\\<PackageFamilyName>\\LocalCache\\Roaming\\Claude\\`
+    instead of the normal `%APPDATA%\\Claude\\`. A user (or BCC) editing the
+    plain %APPDATA% path can end up changing a file the running app never
+    reads -- see anthropics/claude-code issues #26073, #29100, #38830.
+
+    Globs `<localappdata>/Packages/*Claude*/LocalCache/Roaming/Claude/
+    claude_desktop_config.json` and returns every match that actually exists,
+    sorted for determinism. `localappdata` defaults to the %LOCALAPPDATA% env
+    var (falling back to the usual Windows path) but is accepted as a
+    parameter so this is unit-testable with tmp_path on any platform.
+
+    This function itself is platform-independent (it just globs whatever
+    directory it's given); callers that care about the *current* machine
+    should gate on sys.platform -- see `detect_msix_claude`.
+    """
+    base = (
+        Path(localappdata)
+        if localappdata is not None
+        else Path(os.environ.get("LOCALAPPDATA", str(Path.home() / "AppData" / "Local")))
+    )
+    packages = base / "Packages"
+    if not packages.is_dir():
+        return []
+    out: list[Path] = []
+    for pkg_dir in sorted(packages.glob("*Claude*")):
+        cfg = pkg_dir / "LocalCache" / "Roaming" / "Claude" / CONFIG_FILENAME
+        if cfg.is_file():
+            out.append(cfg)
+    return out
+
+
+def detect_msix_claude(
+    appdata: str | os.PathLike | None = None,
+    localappdata: str | os.PathLike | None = None,
+) -> Path | None:
+    """
+    Best-effort detection of an MSIX-virtualized Claude Desktop install.
+
+    Returns the first virtualized `claude_desktop_config.json` found (see
+    `msix_config_paths`), or None when not running on Windows, no matching
+    package folder exists, or a package folder exists but has no config file
+    written yet. The sys.platform gate makes this a safe no-op to call
+    unconditionally from discovery/diagnostics code on macOS/Linux.
+
+    `appdata`/`localappdata` are threaded through (rather than read straight
+    from os.environ) purely so the whole detection path is unit-testable via
+    tmp_path + monkeypatch without mutating real env vars.
+    """
+    if not sys.platform.startswith("win"):
+        return None
+    hits = msix_config_paths(localappdata)
+    return hits[0] if hits else None
+
+
+def msix_warning_text(
+    appdata: str | os.PathLike | None = None,
+    localappdata: str | os.PathLike | None = None,
+) -> str | None:
+    """
+    A one-line, paste-safe warning for the diagnostics/status surface when
+    Claude Desktop looks like an MSIX/Store install whose real config lives
+    somewhere other than the plain %APPDATA%\\Claude\\ path. Returns None
+    when nothing was detected (including on non-Windows platforms) or when
+    the virtualized path and the plain path happen to coincide -- i.e. there
+    is nothing surprising to warn about. Contains only filesystem paths, no
+    env values or secrets.
+    """
+    real = detect_msix_claude(appdata, localappdata)
+    if real is None:
+        return None
+    plain_base = (
+        Path(appdata)
+        if appdata is not None
+        else Path(os.environ.get("APPDATA", str(Path.home() / "AppData" / "Roaming")))
+    )
+    plain_cfg = plain_base / "Claude" / CONFIG_FILENAME
+    if plain_cfg == real:
+        return None
+    return (
+        "Claude Desktop looks like it's installed from the Microsoft Store (MSIX). "
+        f"Windows virtualizes its config, so edits to {plain_cfg} may be silently "
+        f"ignored by the running app. The real config is at: {real}"
+    )
+
+
+def discover_project_configs(claude_json_path: str | os.PathLike) -> list[Profile]:
+    """
+    Find project-scope `.mcp.json` configs known to Claude Code.
+
+    `~/.claude.json` keeps a `projects` map keyed by absolute project
+    directory path (that's what the CLI writes as it's used in each repo).
+    Any project whose directory has a `.mcp.json` file next to it -- a
+    standalone file with a top-level `mcpServers` object, same shape BCC
+    already edits -- is surfaced here as its own profile so it can be opened
+    via 'Add config...' without hunting for the path by hand.
+
+    Fails quiet: a missing/unreadable/malformed `claude_json_path`, or a
+    `projects` value that isn't a dict, just yields an empty list rather than
+    raising -- this is best-effort discovery, not a required config load.
+    """
+    try:
+        cfg = load_config(claude_json_path)
+    except Exception:
+        return []
+    projects = cfg.get("projects")
+    if not isinstance(projects, dict):
+        return []
+    out: list[Profile] = []
+    for key in sorted(k for k in projects if isinstance(k, str)):
+        mcp_path = Path(key) / ".mcp.json"
+        if mcp_path.is_file():
+            out.append(
+                Profile(label=f"Project: {Path(key).name}", path=mcp_path, config_exists=True)
+            )
+    return out
+
+
 def discover_profiles() -> list[Profile]:
     """
     Find every `Claude*` data directory in the platform's app-support base
-    (Claude Desktop installs), then also check for a Claude Code global config.
+    (Claude Desktop installs), then also check for a Claude Code global config
+    and any project-scope `.mcp.json` configs it knows about.
 
     Claude Desktop: scans the platform app-support folder for any `Claude*`
     directory (catches `Claude`, `Claude-Work`, etc.).
+    Windows/MSIX: if Claude Desktop was installed from the Microsoft Store,
+    its real config lives in a virtualized per-package folder rather than the
+    plain %APPDATA%\\Claude\\ path above (see `detect_msix_claude`); when
+    that's detected, it's surfaced here as its own profile so the user can
+    edit the file the app actually reads.
     Claude Code: user-scope MCP servers live in ~/.claude.json (that's what
     `claude mcp add` writes; project scope is a per-repo .mcp.json, which can
     be opened via 'Add config…'). NOT ~/.claude/settings.json — that file is
     for permissions/hooks and rejects an mcpServers key with a schema error.
+    Project scope: ~/.claude.json also tracks a `projects` map, one entry per
+    directory Claude Code has been run in; any of those with a `.mcp.json`
+    file are surfaced as their own profiles too (see
+    `discover_project_configs`).
     """
     base = app_support_base()
     out: list[Profile] = []
@@ -106,10 +352,22 @@ def discover_profiles() -> list[Profile]:
                 cfg = d / CONFIG_FILENAME
                 out.append(Profile(label=d.name, path=cfg, config_exists=cfg.is_file()))
 
+    msix_cfg = detect_msix_claude()
+    if msix_cfg is not None and str(msix_cfg) not in {str(p.path) for p in out}:
+        out.append(
+            Profile(label="Claude (Microsoft Store / MSIX)", path=msix_cfg, config_exists=True)
+        )
+
     home = Path.home()
     cc_cfg = home / ".claude.json"
     out.append(Profile(label="Claude Code", path=cc_cfg, config_exists=cc_cfg.is_file()))
 
+    existing_paths = {str(p.path) for p in out}
+    for proj in discover_project_configs(cc_cfg):
+        if str(proj.path) not in existing_paths:
+            existing_paths.add(str(proj.path))
+            out.append(proj)
+
     # Legacy: earlier BCC versions (and hand-edits) may have parked servers in
     # ~/.claude/settings.json, where Claude Code ignores them. Surface that
     # file only when it actually contains an mcpServers block, so the user can
@@ -135,6 +393,17 @@ def profile_from_path(path: str | os.PathLike) -> Profile:
     return Profile(label=label, path=p, config_exists=p.is_file())
 
 
+def profile_targets_claude_desktop(profile: Profile) -> bool:
+    """
+    True when `profile` points at a Claude Desktop config
+    (claude_desktop_config.json), as opposed to Claude Code (~/.claude.json
+    or the legacy ~/.claude/settings.json). Used to gate Desktop-only actions
+    like "Restart Claude Desktop" so they never show up for a Claude Code
+    profile -- restarting the CLI makes no sense.
+    """
+    return Path(profile.path).name == CONFIG_FILENAME
+
+
 # --------------------------------------------------------------------------- #
 # Load / extract / apply
 # --------------------------------------------------------------------------- #
@@ -189,6 +458,89 @@ def extract_servers(cfg: dict) -> list[ServerEntry]:
     return out
 
 
+# --------------------------------------------------------------------------- #
+# Named server sets (issue #52)
+# --------------------------------------------------------------------------- #
+def list_server_sets(cfg: dict) -> dict[str, list[str]]:
+    """
+    Return {set_name: [enabled server names]} from cfg's SETS_KEY.
+
+    Fail-soft: entries whose value isn't a list of strings (hand-edited or
+    corrupted) are skipped rather than raising, so one bad set never hides
+    the rest.
+    """
+    raw = cfg.get(SETS_KEY)
+    if not isinstance(raw, dict):
+        return {}
+    out: dict[str, list[str]] = {}
+    for name, members in raw.items():
+        if isinstance(members, list) and all(isinstance(m, str) for m in members):
+            out[str(name)] = list(members)
+    return out
+
+
+def save_server_set(cfg: dict, name: str, servers: list[ServerEntry]) -> list[str]:
+    """
+    Snapshot the current enabled-server names into cfg under SETS_KEY as
+    `name` (overwriting an existing set of that name). Returns the saved
+    member list. The caller decides when cfg reaches disk (normal Save flow).
+    """
+    members = [s.name for s in servers if s.enabled]
+    sets = cfg.get(SETS_KEY)
+    if not isinstance(sets, dict):
+        sets = {}
+        cfg[SETS_KEY] = sets
+    sets[name] = members
+    return members
+
+
+def delete_server_set(cfg: dict, name: str) -> bool:
+    """Remove set `name` from cfg. Drops SETS_KEY entirely when the last set
+    goes, so untouched configs don't grow an empty bcc key. Returns True if
+    something was deleted."""
+    sets = cfg.get(SETS_KEY)
+    if not isinstance(sets, dict) or name not in sets:
+        return False
+    del sets[name]
+    if not sets:
+        cfg.pop(SETS_KEY, None)
+    return True
+
+
+def apply_server_set(servers: list[ServerEntry], enabled_names: list[str]) -> list[str]:
+    """
+    Enable exactly the servers named in `enabled_names`; disable every other
+    entry (in place). Returns the set members that no longer exist in
+    `servers` — the caller surfaces those as a warning, and the rest of the
+    set still applies.
+    """
+    wanted = set(enabled_names)
+    present: set[str] = set()
+    for s in servers:
+        s.enabled = s.name in wanted
+        present.add(s.name)
+    return sorted(wanted - present)
+
+
+def resolve_name_collision(name: str, existing: set[str]) -> str:
+    """
+    Return a name guaranteed not to collide with `existing`.
+
+    If `name` isn't already taken it's returned unchanged. Otherwise a
+    `-2`, `-3`, ... suffix is appended until the result is unique — this is
+    the "keep both (renamed)" branch used by paste/import when the user
+    doesn't want to overwrite an existing server of the same name.
+    """
+    if name not in existing:
+        return name
+    n = 2
+    candidate = f"{name}-{n}"
+    while candidate in existing:
+        n += 1
+        candidate = f"{name}-{n}"
+    return candidate
+
+
 def apply_servers(cfg: dict, servers: list[ServerEntry]) -> dict:
     """
     Write the server list back into `cfg` in place, preserving every other key
@@ -380,6 +732,30 @@ def config_mtime(path: Path | str) -> float | None:
         return None
 
 
+class ConfigStat(NamedTuple):
+    """A snapshot of a config file's mtime + size.
+
+    Pairing size with mtime hardens stale-file detection beyond bare mtime
+    equality: a concurrent external write can land within the filesystem's
+    mtime resolution (e.g. same-second writes on ext4/HFS+) or have its mtime
+    restored by the writing process, in which case mtime alone would miss the
+    change. Comparing both fields catches those cases without the cost of a
+    full content hash.
+    """
+
+    mtime: float
+    size: int
+
+
+def config_fingerprint(path: Path | str) -> ConfigStat | None:
+    """Return the file's (mtime, size) snapshot, or None if it does not exist."""
+    try:
+        st = Path(path).stat()
+    except OSError:
+        return None
+    return ConfigStat(st.st_mtime, st.st_size)
+
+
 def external_change_summary(original_cfg: dict, path: Path | str) -> tuple[list[str], str]:
     """
     Compare original_cfg (what BCC loaded) with the current on-disk state.
@@ -474,7 +850,7 @@ def _normalize_unicode(text: str, notes: list[str]) -> str:
     out = text
     for junk in _JUNK_CHARS:
         out = out.replace(junk, "")
-    out = out.replace(" ", " ")  # non-breaking space
+    out = out.replace(chr(0xA0), " ")  # non-breaking space (defensive: avoid a literal char here)
     for smart, ascii_q in _QUOTE_MAP.items():
         out = out.replace(smart, ascii_q)
     if out != text:
@@ -950,6 +1326,89 @@ def validate_servers(servers: list[ServerEntry]) -> list[str]:
     return problems
 
 
+def lint_server(name: str, data: dict) -> list[str]:
+    """Return non-blocking structural warnings for a single server definition.
+
+    Unlike validate_servers, nothing here blocks Save -- these are advisory
+    notes about shapes that will round-trip through JSON fine but are
+    probably not what the user intended (args given as a plain string
+    instead of a list, an env value that isn't a string, an unrecognized
+    `type`, unknown top-level fields, etc.).
+    """
+    nm = name.strip() or "(unnamed)"
+    warnings: list[str] = []
+
+    if "command" in data and not isinstance(data["command"], str):
+        warnings.append(f"'{nm}': 'command' should be a string")
+
+    if "args" in data:
+        args = data["args"]
+        if not isinstance(args, list):
+            warnings.append(f"'{nm}': 'args' should be a list (one argument per item)")
+        elif any(not isinstance(a, str) for a in args):
+            warnings.append(
+                f"'{nm}': 'args' contains non-string values "
+                "(they will be saved as-is; Claude expects strings)"
+            )
+
+    for field in ("env", "headers"):
+        if field not in data:
+            continue
+        val = data[field]
+        if not isinstance(val, dict):
+            warnings.append(f"'{nm}': '{field}' should be an object of string key/value pairs")
+        elif any(not isinstance(v, str) for v in val.values()):
+            warnings.append(
+                f"'{nm}': '{field}' contains non-string values "
+                "(they will be saved as-is; Claude expects strings)"
+            )
+
+    if "type" in data:
+        t = data["type"]
+        if t not in ("http", "sse", "stdio"):
+            warnings.append(f"'{nm}': 'type' should be one of http, sse, stdio (found {t!r})")
+
+    extra = sorted(k for k in data if k not in KNOWN_FIELDS)
+    if extra:
+        warnings.append(f"'{nm}': extra fields preserved as-is: {', '.join(extra)}")
+
+    return warnings
+
+
+def lint_servers(servers: list[ServerEntry]) -> list[str]:
+    """Concatenate lint_server warnings across every entry, in order."""
+    out: list[str] = []
+    for s in servers:
+        out.extend(lint_server(s.name, s.data))
+    return out
+
+
+# --------------------------------------------------------------------------- #
+# Search / filter
+# --------------------------------------------------------------------------- #
+def server_matches_filter(entry: ServerEntry, query: str) -> bool:
+    """
+    Case-insensitive substring match against a server's name, and its
+    command (stdio) or url (remote). An empty/whitespace-only query matches
+    everything -- that's what lets the search box double as "no filter".
+    """
+    q = (query or "").strip().lower()
+    if not q:
+        return True
+    if q in entry.name.lower():
+        return True
+    if entry.kind == "remote":
+        haystack = str(entry.data.get("url", ""))
+    else:
+        haystack = str(entry.data.get("command", ""))
+    return q in haystack.lower()
+
+
+def filter_servers(entries: list[ServerEntry], query: str) -> list[ServerEntry]:
+    """Return only the entries that match `query` (see server_matches_filter)."""
+    return [e for e in entries if server_matches_filter(e, query)]
+
+
 # --------------------------------------------------------------------------- #
 # Dependency / PATH checking
 # --------------------------------------------------------------------------- #
@@ -1270,9 +1729,45 @@ def diagnostics_text(name: str, data: dict) -> str:
     return "\n".join(L)
 
 
+def server_log_path(name: str) -> Path | None:
+    """
+    The platform-specific Claude Desktop MCP server log file for `name`, or
+    None if it doesn't exist yet (nothing has been logged for this server).
+
+    macOS  : ~/Library/Logs/Claude/mcp-server-<name>.log   (one file per server)
+    Windows: %APPDATA%\\Claude\\logs\\mcp.log               (one shared file)
+    Other platforms: Claude Desktop doesn't ship a log in a known location -> None.
+    """
+    if sys.platform == "darwin":
+        p = Path.home() / "Library" / "Logs" / "Claude" / f"mcp-server-{name}.log"
+    elif sys.platform.startswith("win"):
+        appdata = Path(os.environ.get("APPDATA", Path.home() / "AppData" / "Roaming"))
+        p = appdata / "Claude" / "logs" / "mcp.log"
+    else:
+        return None
+    return p if p.is_file() else None
+
+
 _STDERR_CAP = 4096  # bytes
 
 
+def _kill_process_tree_windows(pid: int) -> None:
+    """
+    Kill `pid` and its whole descendant tree via `taskkill /T /F` (issue #13).
+
+    Popen.kill() only terminates the direct child; runner-style commands
+    (npx → node → server, cmd → real process) leave the actual server alive,
+    leaking a process on every Windows spawn test. taskkill walks the tree.
+    """
+    flags = getattr(subprocess, "CREATE_NO_WINDOW", 0)  # no console flash from the GUI exe
+    with contextlib.suppress(OSError):
+        subprocess.run(
+            ["taskkill", "/PID", str(pid), "/T", "/F"],
+            capture_output=True,
+            creationflags=flags,
+        )
+
+
 def spawn_test(data: dict, timeout: float = 3.0) -> dict:
     """
     Attempt to start a stdio server and observe it for `timeout` seconds.
@@ -1283,12 +1778,29 @@ def spawn_test(data: dict, timeout: float = 3.0) -> dict:
                 "crashed"        — exited with a non-zero code before timeout
                 "not_found"      — command could not be resolved to an executable
                 "not_applicable" — remote server or no command; nothing to spawn
+                "error"          — unexpected internal failure while spawning/observing
       returncode: int | None
       stderr:    str  (first ~4 KB)
       detail:    str
 
+    Never raises: the GUI threads (Test launch / Test all) re-enable their
+    buttons only when a result arrives, so an escaping exception would leave
+    the UI stuck. Anything unexpected comes back as outcome "error".
+
     Run this off the UI thread — it blocks for up to `timeout` seconds.
     """
+    try:
+        return _spawn_test_impl(data, timeout)
+    except Exception as e:
+        return {
+            "outcome": "error",
+            "returncode": None,
+            "stderr": "",
+            "detail": f"unexpected error: {e!r}",
+        }
+
+
+def _spawn_test_impl(data: dict, timeout: float) -> dict:
     if "url" in data and "command" not in data:
         return {
             "outcome": "not_applicable",
@@ -1297,7 +1809,9 @@ def spawn_test(data: dict, timeout: float = 3.0) -> dict:
             "detail": "remote server",
         }
 
-    cmd = (data.get("command") or "").strip()
+    # str() first: pasted JSON can legally carry a non-string here and the
+    # value never round-trips through the editor before a Test all run.
+    cmd = str(data.get("command") or "").strip()
     if not cmd:
         return {
             "outcome": "not_applicable",
@@ -1319,7 +1833,8 @@ def spawn_test(data: dict, timeout: float = 3.0) -> dict:
     args_list = [resolved_cmd] + [str(a) for a in (data.get("args") or [])]
 
     merged_env = {**os.environ, "PATH": augmented_path()}
-    merged_env.update(data.get("env") or {})
+    # Popen rejects non-string env values; pasted JSON may carry numbers.
+    merged_env.update({str(k): str(v) for k, v in (data.get("env") or {}).items()})
 
     stderr_chunks: list[bytes] = []
 
@@ -1347,6 +1862,10 @@ def spawn_test(data: dict, timeout: float = 3.0) -> dict:
     )
     if os.name != "nt":
         popen_kwargs["start_new_session"] = True  # own process group → clean kill
+    else:
+        # The packaged app is windowed (console=False); without this every
+        # spawn test of a console server flashes a console window.
+        popen_kwargs["creationflags"] = getattr(subprocess, "CREATE_NO_WINDOW", 0)
 
     try:
         proc = subprocess.Popen(args_list, **popen_kwargs)
@@ -1368,7 +1887,7 @@ def spawn_test(data: dict, timeout: float = 3.0) -> dict:
             if os.name != "nt":
                 os.killpg(os.getpgid(proc.pid), _signal.SIGKILL)
             else:
-                proc.kill()  # best-effort on Windows
+                _kill_process_tree_windows(proc.pid)
         except OSError:
             pass
         with contextlib.suppress(subprocess.TimeoutExpired):
@@ -1400,6 +1919,53 @@ def spawn_test(data: dict, timeout: float = 3.0) -> dict:
     }
 
 
+# --------------------------------------------------------------------------- #
+# Health status (maps a spawn_test() result to a simple tri-state for the
+# server-list UI's per-row status dot; see "Test all" in bcc.py)
+# --------------------------------------------------------------------------- #
+class HealthStatus:
+    """
+    Tri-state health for the server-list status dot. A plain class of string
+    constants -- not an Enum -- to match the plain-string status values used
+    elsewhere in this module (see check_dependency's 'status').
+    """
+
+    UNTESTED = "untested"
+    OK = "ok"
+    FAILED = "failed"
+
+
+def health_from_spawn_result(result: dict) -> tuple[str, str]:
+    """
+    Map a spawn_test() result dict to (HealthStatus, short_summary) for the
+    server-list status column. Reuses spawn_test's own outcome classification
+    rather than re-deriving pass/fail from returncode/stderr:
+
+      outcome "ok"             -> OK       (server started and kept running)
+      outcome "not_applicable" -> UNTESTED (remote server, or no command set)
+      anything else            -> FAILED   (exited, crashed, or not found)
+
+    The summary is short enough for a table cell/tooltip; when the process
+    wrote to stderr before dying, its first line is appended for context.
+    """
+    outcome = result.get("outcome", "")
+    detail = result.get("detail", "") or ""
+    stderr = (result.get("stderr") or "").strip()
+
+    if outcome == "ok":
+        return HealthStatus.OK, detail or "started"
+    if outcome == "not_applicable":
+        return HealthStatus.UNTESTED, detail or "not applicable"
+
+    # exited / crashed / not_found: the server didn't come up cleanly.
+    summary = detail or outcome
+    if stderr:
+        first_line = stderr.splitlines()[0].strip()
+        if first_line:
+            summary = f"{summary} — {first_line}"
+    return HealthStatus.FAILED, summary
+
+
 def test_remote(url: str, timeout: float = 5.0) -> tuple[bool, str]:
     """
     Reachability check for a url-based MCP server. ANY HTTP response (even 4xx/5xx)
@@ -1459,3 +2025,121 @@ def pin_command_path(data: dict, path: str | None = None) -> tuple[dict, str | N
                     out["args"] = args
                     return out, f"'{c}'  →  {resolved}"
     return data, None
+
+
+# --------------------------------------------------------------------------- #
+# Restart Claude Desktop (issue #9)
+#
+# Scoped strictly to Claude DESKTOP, the GUI app -- never Claude Code (the
+# CLI), which has no long-running process to bounce. Callers should gate this
+# behind profile_targets_claude_desktop() before offering it in the UI.
+# --------------------------------------------------------------------------- #
+class RestartResult(NamedTuple):
+    """Outcome of a restart_claude_desktop() attempt."""
+
+    success: bool
+    detail: str
+
+
+def _run_quiet(cmd: list[str]) -> None:
+    """Best-effort fire-and-forget command. Never raises: a nonzero exit (e.g.
+    pkill finding nothing to kill) is expected and not an error."""
+    with contextlib.suppress(OSError):
+        subprocess.run(cmd, capture_output=True)
+
+
+def restart_supported() -> bool:
+    """
+    True only where restarting Claude Desktop makes sense (macOS, Windows).
+    There is no official Claude Desktop for Linux, and the obvious binary
+    name there ("claude") is the Claude Code CLI — killing or spawning it
+    would be actively harmful. GUI callers gate the Restart button on this.
+    """
+    return sys.platform == "darwin" or sys.platform.startswith("win")
+
+
+_MACOS_QUIT_WAIT_S = 5.0
+
+
+def _macos_claude_running() -> bool:
+    try:
+        return subprocess.run(["pgrep", "-x", "Claude"], capture_output=True).returncode == 0
+    except OSError:
+        return False
+
+
+def _restart_claude_desktop_macos() -> RestartResult:
+    _run_quiet(["pkill", "-x", "Claude"])
+    # Wait for the old instance to actually exit: `open -a` against a dying
+    # process can merely re-activate it, and the config is only re-read on a
+    # true relaunch. Blocks up to _MACOS_QUIT_WAIT_S — callers run this off
+    # the UI thread (see RestartWorker in bcc.py).
+    deadline = time.monotonic() + _MACOS_QUIT_WAIT_S
+    while _macos_claude_running():
+        if time.monotonic() > deadline:
+            return RestartResult(
+                False,
+                f"Claude Desktop didn't quit within {_MACOS_QUIT_WAIT_S:.0f}s — "
+                "quit it manually, then reopen it.",
+            )
+        time.sleep(0.15)
+    try:
+        result = subprocess.run(["open", "-a", "Claude"], capture_output=True, text=True)
+    except OSError as e:
+        return RestartResult(False, f"Couldn't launch Claude Desktop: {e}")
+    if result.returncode != 0:
+        detail = (result.stderr or result.stdout or "").strip() or "'open -a Claude' failed"
+        return RestartResult(False, detail)
+    return RestartResult(True, "Claude Desktop restarted.")
+
+
+def _claude_windows_start_menu_shortcut() -> Path:
+    appdata = os.environ.get("APPDATA", str(Path.home()))
+    return Path(appdata) / "Microsoft" / "Windows" / "Start Menu" / "Programs" / "Claude.lnk"
+
+
+def _restart_claude_desktop_windows() -> RestartResult:
+    shortcut = _claude_windows_start_menu_shortcut()
+    if not shortcut.is_file():
+        # Checked BEFORE killing: an MSIX/Store install has no Start-menu .lnk
+        # at this path, and killing without a relaunch path would leave the
+        # user with no running Claude at all.
+        return RestartResult(
+            False,
+            f"Claude's Start-menu shortcut wasn't found ({shortcut}). "
+            "If Claude Desktop is installed from the Microsoft Store, "
+            "quit and reopen it manually.",
+        )
+    _run_quiet(["taskkill", "/IM", "Claude.exe", "/F"])
+    try:
+        # `cmd /c start "" <target>` launches detached, the same as double-clicking
+        # the Start-menu shortcut, and returns immediately.
+        result = subprocess.run(
+            ["cmd", "/c", "start", "", str(shortcut)], capture_output=True, text=True
+        )
+    except OSError as e:
+        return RestartResult(False, f"Couldn't launch Claude Desktop: {e}")
+    if result.returncode != 0:
+        detail = (
+            result.stderr or result.stdout or ""
+        ).strip() or "failed to relaunch Claude Desktop"
+        return RestartResult(False, detail)
+    return RestartResult(True, "Claude Desktop restarted.")
+
+
+def restart_claude_desktop() -> RestartResult:
+    """
+    Kill and relaunch the Claude Desktop app so a freshly saved config takes
+    effect. The app not currently running is NOT a failure -- pkill/taskkill
+    exiting non-zero just means "nothing to kill", and we go straight to
+    relaunching. Only a failed relaunch is reported as success=False.
+
+    macOS blocks for up to _MACOS_QUIT_WAIT_S while the old instance exits —
+    run off the UI thread. Unsupported platforms (see restart_supported())
+    refuse without touching any process.
+    """
+    if sys.platform == "darwin":
+        return _restart_claude_desktop_macos()
+    if sys.platform.startswith("win"):
+        return _restart_claude_desktop_windows()
+    return RestartResult(False, "Restarting Claude Desktop isn't supported on this platform.")

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "better-claude-config"
-version = "1.1.0"
+version = "1.3.0"
 description = "Cross-platform GUI for editing the mcpServers block of Claude Desktop and Claude Code configs"
 readme = "README.md"
 license = { file = "LICENSE" }

requirements-dev.txt

@@ -8,3 +8,4 @@ pillow>=10.0        # generates icons/app.ico during CI (Windows build)
 # Test / lint
 pytest>=8.0
 ruff>=0.6
+cryptography>=42.0   # release checksum signing (scripts/sign_checksums.py)

scripts/sign_checksums.py

@@ -0,0 +1,235 @@
+#!/usr/bin/env python3
+"""
+Generate a SHA256SUMS file for release artifacts and sign it with Ed25519.
+
+BCC ships PyInstaller binaries that are not code-signed (no budget for a
+macOS Developer ID / Windows Authenticode certificate). This script provides
+the free half of supply-chain integrity: a checksum manifest, detached-signed
+so downloaders can verify the file they got is the file we published.
+
+This does NOT remove Gatekeeper/SmartScreen warnings and does NOT prove the
+binary is safe to run -- only that it matches what the release signing key
+attested to.
+
+Usage:
+    # Hash every file in a directory into a SHA256SUMS-format manifest.
+    python scripts/sign_checksums.py generate <dir> --out SHA256SUMS
+
+    # Sign a manifest, producing a detached signature.
+    # Private key comes from $RELEASE_SIGNING_KEY (base64 raw Ed25519 seed)
+    # unless --key-b64 is given explicitly (mostly for tests).
+    python scripts/sign_checksums.py sign --sums SHA256SUMS --out SHA256SUMS.sig
+
+    # Verify a manifest against a detached signature and a public key.
+    python scripts/sign_checksums.py verify --sums SHA256SUMS --sig SHA256SUMS.sig \
+        --pubkey-b64 <base64 raw Ed25519 public key>
+
+The private key is generated and rotated via the Catalog Console (#62) --
+this script never generates or stores a key itself.
+"""
+
+from __future__ import annotations
+
+import argparse
+import base64
+import hashlib
+import os
+import sys
+from pathlib import Path
+
+# Domain separation prefix: ties every signature to "a BCC release checksum
+# manifest" so a signature can never be replayed against an unrelated
+# message signed by the same key.
+DOMAIN_PREFIX = b"bcc-release-v1|"
+
+CHUNK_SIZE = 1024 * 1024
+
+
+def sha256_file(path: Path) -> str:
+    """Return the lowercase hex SHA-256 digest of a file's contents."""
+    digest = hashlib.sha256()
+    with open(path, "rb") as fh:
+        while chunk := fh.read(CHUNK_SIZE):
+            digest.update(chunk)
+    return digest.hexdigest()
+
+
+def build_checksums_text(files: dict[str, str]) -> str:
+    """Build a sha256sum(1)-compatible manifest body.
+
+    `files` maps filename -> hex digest. Entries are sorted by filename for
+    a deterministic, diffable output. Format matches `sha256sum` exactly:
+    "<hash>  <filename>\n" (two spaces, no path components).
+    """
+    lines = [f"{digest}  {name}" for name, digest in sorted(files.items())]
+    body = "\n".join(lines)
+    return body + "\n" if body else ""
+
+
+def generate_checksums(directory: Path, *, exclude: set[str] | None = None) -> str:
+    """Hash every regular file directly inside `directory` (non-recursive)
+    and return the SHA256SUMS text. Filenames are recorded without any
+    directory prefix so the manifest can be verified from inside the
+    directory it describes.
+    """
+    exclude = exclude or set()
+    files: dict[str, str] = {}
+    for entry in sorted(directory.iterdir()):
+        if not entry.is_file():
+            continue
+        if entry.name in exclude:
+            continue
+        files[entry.name] = sha256_file(entry)
+    return build_checksums_text(files)
+
+
+def _signing_message(sums_text: str) -> bytes:
+    """The exact bytes that get signed: the domain prefix followed by the
+    raw bytes of the SHA256SUMS file content."""
+    return DOMAIN_PREFIX + sums_text.encode("utf-8")
+
+
+def sign_checksums(seed_b64: str, sums_text: str) -> bytes:
+    """Sign `sums_text` with the Ed25519 private key encoded (base64, raw
+    32-byte seed) in `seed_b64`. Returns the raw 64-byte signature."""
+    # Imported lazily so `generate` mode (used on every CI run) never
+    # requires the `cryptography` package to be installed.
+    from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
+
+    seed = base64.b64decode(seed_b64)
+    if len(seed) != 32:
+        raise ValueError(f"expected a 32-byte raw Ed25519 seed, got {len(seed)} bytes")
+    private_key = Ed25519PrivateKey.from_private_bytes(seed)
+    return private_key.sign(_signing_message(sums_text))
+
+
+def verify_checksums(pubkey_b64: str, sums_text: str, signature: bytes) -> bool:
+    """Verify `signature` over `sums_text` against the base64-encoded raw
+    32-byte Ed25519 public key. Returns True/False; never raises for a bad
+    signature (only for malformed inputs)."""
+    from cryptography.exceptions import InvalidSignature
+    from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PublicKey
+
+    pubkey_bytes = base64.b64decode(pubkey_b64)
+    if len(pubkey_bytes) != 32:
+        raise ValueError(
+            f"expected a 32-byte raw Ed25519 public key, got {len(pubkey_bytes)} bytes"
+        )
+    public_key = Ed25519PublicKey.from_public_bytes(pubkey_bytes)
+    try:
+        public_key.verify(signature, _signing_message(sums_text))
+        return True
+    except InvalidSignature:
+        return False
+
+
+def public_key_b64_from_seed(seed_b64: str) -> str:
+    """Derive the base64 raw public key from a base64 raw seed. Handy for
+    local key-pair sanity checks; not used by the release workflow."""
+    from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
+    from cryptography.hazmat.primitives.serialization import Encoding, PublicFormat
+
+    seed = base64.b64decode(seed_b64)
+    private_key = Ed25519PrivateKey.from_private_bytes(seed)
+    raw = private_key.public_key().public_bytes(Encoding.Raw, PublicFormat.Raw)
+    return base64.b64encode(raw).decode("ascii")
+
+
+# --------------------------------------------------------------------------- #
+# CLI
+# --------------------------------------------------------------------------- #
+def _cmd_generate(args: argparse.Namespace) -> int:
+    directory = Path(args.directory)
+    exclude = {"SHA256SUMS", "SHA256SUMS.sig"}
+    text = generate_checksums(directory, exclude=exclude)
+    out_path = Path(args.out)
+    out_path.write_text(text, encoding="utf-8")
+    print(f"Wrote {out_path} ({len(text.splitlines())} entries)")
+    return 0
+
+
+def _cmd_sign(args: argparse.Namespace) -> int:
+    seed_b64 = args.key_b64 or os.environ.get(args.key_env, "")
+    if not seed_b64:
+        print(
+            f"error: no signing key provided (checked --key-b64 and ${args.key_env})",
+            file=sys.stderr,
+        )
+        return 1
+    sums_text = Path(args.sums).read_text(encoding="utf-8")
+    signature = sign_checksums(seed_b64, sums_text)
+    Path(args.out).write_bytes(signature)
+    print(f"Wrote {args.out} ({len(signature)} bytes)")
+    return 0
+
+
+def _cmd_verify(args: argparse.Namespace) -> int:
+    pubkey_b64 = args.pubkey_b64 or os.environ.get(args.pubkey_env, "")
+    if not pubkey_b64:
+        print(
+            f"error: no public key provided (checked --pubkey-b64 and ${args.pubkey_env})",
+            file=sys.stderr,
+        )
+        return 1
+    sums_text = Path(args.sums).read_text(encoding="utf-8")
+    signature = Path(args.sig).read_bytes()
+    ok = verify_checksums(pubkey_b64, sums_text, signature)
+    if ok:
+        print("OK: signature is valid")
+        return 0
+    print("FAILED: signature is invalid", file=sys.stderr)
+    return 1
+
+
+def build_parser() -> argparse.ArgumentParser:
+    parser = argparse.ArgumentParser(
+        description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter
+    )
+    sub = parser.add_subparsers(dest="mode", required=True)
+
+    p_gen = sub.add_parser(
+        "generate", help="hash every file in a directory into a SHA256SUMS manifest"
+    )
+    p_gen.add_argument("directory", help="directory whose files should be hashed (non-recursive)")
+    p_gen.add_argument("--out", required=True, help="path to write the SHA256SUMS manifest to")
+    p_gen.set_defaults(func=_cmd_generate)
+
+    p_sign = sub.add_parser("sign", help="detached-sign a SHA256SUMS manifest with Ed25519")
+    p_sign.add_argument("--sums", required=True, help="path to the SHA256SUMS manifest to sign")
+    p_sign.add_argument("--out", required=True, help="path to write the detached signature to")
+    p_sign.add_argument(
+        "--key-b64", default=None, help="base64 raw Ed25519 seed (overrides --key-env)"
+    )
+    p_sign.add_argument(
+        "--key-env",
+        default="RELEASE_SIGNING_KEY",
+        help="environment variable holding the base64 seed (default: RELEASE_SIGNING_KEY)",
+    )
+    p_sign.set_defaults(func=_cmd_sign)
+
+    p_verify = sub.add_parser(
+        "verify", help="verify a SHA256SUMS manifest against a detached signature"
+    )
+    p_verify.add_argument("--sums", required=True, help="path to the SHA256SUMS manifest")
+    p_verify.add_argument("--sig", required=True, help="path to the detached signature")
+    p_verify.add_argument(
+        "--pubkey-b64", default=None, help="base64 raw Ed25519 public key (overrides --pubkey-env)"
+    )
+    p_verify.add_argument(
+        "--pubkey-env",
+        default="RELEASE_SIGNING_PUBKEY",
+        help="environment variable holding the base64 public key (default: RELEASE_SIGNING_PUBKEY)",
+    )
+    p_verify.set_defaults(func=_cmd_verify)
+
+    return parser
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = build_parser()
+    args = parser.parse_args(argv)
+    return args.func(args)
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

tests/test_checksums.py

@@ -0,0 +1,234 @@
+"""Tests for scripts/sign_checksums.py: SHA256SUMS generation and detached
+Ed25519 signing/verification for release artifacts."""
+
+from __future__ import annotations
+
+import base64
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent / "scripts"))
+
+import sign_checksums as sc
+
+cryptography = pytest.importorskip("cryptography")
+from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey  # noqa: E402
+from cryptography.hazmat.primitives.serialization import Encoding, PublicFormat  # noqa: E402
+
+
+def _make_keypair() -> tuple[str, str]:
+    """Return (seed_b64, pubkey_b64) for a fresh Ed25519 keypair."""
+    private_key = Ed25519PrivateKey.generate()
+    seed = private_key.private_bytes_raw()
+    pubkey = private_key.public_key().public_bytes(Encoding.Raw, PublicFormat.Raw)
+    return base64.b64encode(seed).decode("ascii"), base64.b64encode(pubkey).decode("ascii")
+
+
+# --------------------------------------------------------------------------- #
+# sha256_file / build_checksums_text / generate_checksums
+# --------------------------------------------------------------------------- #
+def test_sha256_file_matches_hashlib(tmp_path):
+    f = tmp_path / "a.txt"
+    f.write_bytes(b"hello world")
+    import hashlib
+
+    assert sc.sha256_file(f) == hashlib.sha256(b"hello world").hexdigest()
+
+
+def test_build_checksums_text_sorted_and_formatted():
+    files = {"zeta.zip": "aa" * 32, "alpha.zip": "bb" * 32}
+    text = sc.build_checksums_text(files)
+    lines = text.splitlines()
+    assert lines[0].endswith("alpha.zip")
+    assert lines[1].endswith("zeta.zip")
+    # Standard sha256sum format: hash, two spaces, filename.
+    assert lines[0] == f"{'bb' * 32}  alpha.zip"
+
+
+def test_build_checksums_text_empty():
+    assert sc.build_checksums_text({}) == ""
+
+
+def test_generate_checksums_from_directory(tmp_path):
+    (tmp_path / "b.bin").write_bytes(b"second")
+    (tmp_path / "a.bin").write_bytes(b"first")
+    (tmp_path / "subdir").mkdir()
+    (tmp_path / "subdir" / "ignored.bin").write_bytes(b"nested, not hashed")
+
+    text = sc.generate_checksums(tmp_path)
+    lines = text.splitlines()
+    assert len(lines) == 2
+    assert lines[0].endswith("a.bin")
+    assert lines[1].endswith("b.bin")
+    assert "subdir" not in text
+
+
+def test_generate_checksums_excludes_manifest_files(tmp_path):
+    (tmp_path / "archive.zip").write_bytes(b"payload")
+    (tmp_path / "SHA256SUMS").write_text("stale")
+    (tmp_path / "SHA256SUMS.sig").write_bytes(b"stale-sig")
+
+    text = sc.generate_checksums(tmp_path, exclude={"SHA256SUMS", "SHA256SUMS.sig"})
+    assert "archive.zip" in text
+    assert "SHA256SUMS" not in text.replace("archive.zip", "")
+
+
+# --------------------------------------------------------------------------- #
+# sign_checksums / verify_checksums
+# --------------------------------------------------------------------------- #
+def test_sign_then_verify_roundtrip():
+    seed_b64, pubkey_b64 = _make_keypair()
+    sums_text = "deadbeef" * 8 + "  BetterClaudeConfig-Linux.tar.gz\n"
+
+    signature = sc.sign_checksums(seed_b64, sums_text)
+    assert len(signature) == 64
+    assert sc.verify_checksums(pubkey_b64, sums_text, signature) is True
+
+
+def test_verify_rejects_tampered_checksums():
+    seed_b64, pubkey_b64 = _make_keypair()
+    sums_text = "aa" * 32 + "  file.zip\n"
+    signature = sc.sign_checksums(seed_b64, sums_text)
+
+    tampered = "bb" * 32 + "  file.zip\n"
+    assert sc.verify_checksums(pubkey_b64, tampered, signature) is False
+
+
+def test_verify_rejects_wrong_key():
+    seed_b64, _ = _make_keypair()
+    _, other_pubkey_b64 = _make_keypair()
+    sums_text = "cc" * 32 + "  file.zip\n"
+    signature = sc.sign_checksums(seed_b64, sums_text)
+
+    assert sc.verify_checksums(other_pubkey_b64, sums_text, signature) is False
+
+
+def test_domain_prefix_is_applied():
+    """The signed message must be prefixed, not the raw manifest bytes --
+    otherwise a signature over this manifest could be replayed as a
+    signature over an unrelated message with the same bytes elsewhere."""
+    seed_b64, pubkey_b64 = _make_keypair()
+    sums_text = "11" * 32 + "  file.zip\n"
+
+    from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey as PK
+
+    seed = base64.b64decode(seed_b64)
+    raw_signature = PK.from_private_bytes(seed).sign(sums_text.encode("utf-8"))
+
+    # A signature over the raw (unprefixed) bytes must NOT verify via our
+    # domain-separated verify function.
+    assert sc.verify_checksums(pubkey_b64, sums_text, raw_signature) is False
+
+    # But our own sign_checksums() output does verify.
+    good_signature = sc.sign_checksums(seed_b64, sums_text)
+    assert sc.verify_checksums(pubkey_b64, sums_text, good_signature) is True
+
+
+def test_sign_checksums_rejects_bad_seed_length():
+    bad_seed_b64 = base64.b64encode(b"too-short").decode("ascii")
+    with pytest.raises(ValueError):
+        sc.sign_checksums(bad_seed_b64, "irrelevant\n")
+
+
+def test_verify_checksums_rejects_bad_pubkey_length():
+    seed_b64, _ = _make_keypair()
+    sig = sc.sign_checksums(seed_b64, "irrelevant\n")
+    bad_pubkey_b64 = base64.b64encode(b"too-short").decode("ascii")
+    with pytest.raises(ValueError):
+        sc.verify_checksums(bad_pubkey_b64, "irrelevant\n", sig)
+
+
+def test_public_key_b64_from_seed_matches_generated_pubkey():
+    seed_b64, pubkey_b64 = _make_keypair()
+    assert sc.public_key_b64_from_seed(seed_b64) == pubkey_b64
+
+
+# --------------------------------------------------------------------------- #
+# CLI (end-to-end, via subprocess so argparse wiring is exercised too)
+# --------------------------------------------------------------------------- #
+SCRIPT = Path(__file__).resolve().parent.parent / "scripts" / "sign_checksums.py"
+
+
+def _run(*args, env=None):
+    return subprocess.run(
+        [sys.executable, str(SCRIPT), *args],
+        capture_output=True,
+        text=True,
+        env=env,
+    )
+
+
+def test_cli_generate_sign_verify_roundtrip(tmp_path, monkeypatch):
+    seed_b64, pubkey_b64 = _make_keypair()
+
+    release_dir = tmp_path / "release-files"
+    release_dir.mkdir()
+    (release_dir / "BetterClaudeConfig-Linux.tar.gz").write_bytes(b"fake archive contents")
+    (release_dir / "BetterClaudeConfig-macOS.zip").write_bytes(b"fake zip contents")
+
+    sums_path = release_dir / "SHA256SUMS"
+    sig_path = release_dir / "SHA256SUMS.sig"
+
+    gen = _run("generate", str(release_dir), "--out", str(sums_path))
+    assert gen.returncode == 0, gen.stderr
+    assert sums_path.exists()
+    body = sums_path.read_text()
+    assert "BetterClaudeConfig-Linux.tar.gz" in body
+    assert "BetterClaudeConfig-macOS.zip" in body
+
+    sign = _run("sign", "--sums", str(sums_path), "--out", str(sig_path), "--key-b64", seed_b64)
+    assert sign.returncode == 0, sign.stderr
+    assert sig_path.exists()
+    assert sig_path.stat().st_size == 64
+
+    verify = _run(
+        "verify",
+        "--sums",
+        str(sums_path),
+        "--sig",
+        str(sig_path),
+        "--pubkey-b64",
+        pubkey_b64,
+    )
+    assert verify.returncode == 0, verify.stderr
+    assert "OK" in verify.stdout
+
+
+def test_cli_sign_without_key_fails_loudly(tmp_path):
+    sums_path = tmp_path / "SHA256SUMS"
+    sums_path.write_text("aa" * 32 + "  file.zip\n")
+    sig_path = tmp_path / "SHA256SUMS.sig"
+
+    import os
+
+    env = {k: v for k, v in os.environ.items() if k != "RELEASE_SIGNING_KEY"}
+    result = _run("sign", "--sums", str(sums_path), "--out", str(sig_path), env=env)
+
+    assert result.returncode != 0
+    assert not sig_path.exists(), "must never write a bogus/empty signature file"
+    assert "no signing key" in result.stderr.lower()
+
+
+def test_cli_verify_detects_tampering(tmp_path):
+    seed_b64, pubkey_b64 = _make_keypair()
+    sums_path = tmp_path / "SHA256SUMS"
+    sums_path.write_text("aa" * 32 + "  file.zip\n")
+    sig_path = tmp_path / "SHA256SUMS.sig"
+
+    _run("sign", "--sums", str(sums_path), "--out", str(sig_path), "--key-b64", seed_b64)
+
+    sums_path.write_text("bb" * 32 + "  file.zip\n")  # tamper after signing
+    verify = _run(
+        "verify",
+        "--sums",
+        str(sums_path),
+        "--sig",
+        str(sig_path),
+        "--pubkey-b64",
+        pubkey_b64,
+    )
+    assert verify.returncode != 0
+    assert "FAILED" in verify.stdout + verify.stderr