fix(cli): make the command-line client work on Windows

Its suite had only run on Linux. On Windows, against a real hub and node and
from the installed meshbay-cli.exe:

- secrets.enc was written in text mode (os.open without O_BINARY): every 0x0A
  of the ciphertext became CR LF and the saved session "does not open with
  its key" on the next run.
- isatty() is true for NUL, so a script run with `< NUL` or by the Task
  Scheduler was asked questions instead of told to pass --yes;
  output.terminal() checks for a real console.
- Ctrl+C waited for the selector loop's next timer, up to half a minute in
  `chat --follow`; the loop now points the signal wakeup at its self-pipe,
  as the proactor does.
- Right-click copy and paste raised: asyncio cannot start a process on the
  selector loop; the clipboard tool runs in a thread.
- Tab completion of remote paths ran on the default (proactor) loop, which
  never opens a node, and wrote in the locale encoding; the PowerShell script
  now reads it as UTF-8.
- `get -R` into a folder past MAX_PATH died with a traceback; get, put, the
  resume file and the interactive mode use the extended form at each disk
  call, as the node does.
- `groups` showed a SQLite hub's naive UTC time as local time.

The opt-in end-to-end suite now runs on Windows (16 tests: Chrome found under
Program Files and started with the real environment, VLC as the player, Ctrl+C
through a console of its own, PowerShell 5.1 completion of an accented name).

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

19 files changed, 165 insertions, 64 deletions

diff --git a/packages/meshbay-cli/src/meshbay_cli/__main__.py b/packages/meshbay-cli/src/meshbay_cli/__main__.py
index f5cee22..597e2fe 100644
--- a/packages/meshbay-cli/src/meshbay_cli/__main__.py
+++ b/packages/meshbay-cli/src/meshbay_cli/__main__.py
@@ -8,7 +8,9 @@ import argparse
 import asyncio
 import logging
 import os
+import signal
 import sys
+import threading
 
 from . import __version__
 from .commands import (
@@ -113,15 +115,35 @@ async def _run(args: argparse.Namespace) -> int:
         await ctx.aclose()
 
 
+class _WindowsSelectorLoop(asyncio.SelectorEventLoop):
+    """
+    A selector loop that Ctrl+C wakes. Windows' select() is not interrupted by
+    a console event, and unlike the proactor (`windows_events.ProactorEventLoop.
+    run_forever`) this loop never points the signal wakeup at its self-pipe: Ctrl+C
+    waited for the next timer, which in `chat --follow` or `stream` can be half
+    a minute away (measured: 29 s on a loop whose next timer was 30 s off).
+    """
+
+    def run_forever(self):
+        if threading.current_thread() is not threading.main_thread():
+            return super().run_forever()      # signals reach the main thread only
+        old = signal.set_wakeup_fd(self._csock.fileno())
+        try:
+            super().run_forever()
+        finally:
+            signal.set_wakeup_fd(old)
+
+
 def loop_factory():
     """aiortc's ICE needs a selector loop: Windows' default proactor never
     completes a DataChannel handshake."""
-    return asyncio.SelectorEventLoop if sys.platform == "win32" else None
+    return _WindowsSelectorLoop if sys.platform == "win32" else None
 
 
 def main(argv: list[str] | None = None) -> int:
     argv = sys.argv[1:] if argv is None else argv
     if argv[:1] == ["__complete"]:
+        _utf8_output()                  # what the completion scripts read
         from .complete import main as complete
         return complete(argv[1:])
     if not argv and os.environ.get("MESHBAY_CLI_SELFTEST") == "1":
diff --git a/packages/meshbay-cli/src/meshbay_cli/client/store.py b/packages/meshbay-cli/src/meshbay_cli/client/store.py
index c48fe89..00ff9f3 100644
--- a/packages/meshbay-cli/src/meshbay_cli/client/store.py
+++ b/packages/meshbay-cli/src/meshbay_cli/client/store.py
@@ -63,7 +63,10 @@ def data_dir() -> Path:
 def _write_private(path: Path, data: bytes) -> None:
     """Atomically, readable by this user only."""
     tmp = path.with_name(path.name + ".tmp")
-    fd = os.open(tmp, os.O_WRONLY | os.O_CREAT | os.O_TRUNC, 0o600)
+    # O_BINARY: without it Windows opens in text mode and writes every 0x0A of
+    # the ciphertext as CR LF, and the secrets no longer open.
+    flags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC | getattr(os, "O_BINARY", 0)
+    fd = os.open(tmp, flags, 0o600)
     try:
         os.write(fd, data)
         os.fsync(fd)
diff --git a/packages/meshbay-cli/src/meshbay_cli/client/transfers.py b/packages/meshbay-cli/src/meshbay_cli/client/transfers.py
index 2cbf4cd..177c78b 100644
--- a/packages/meshbay-cli/src/meshbay_cli/client/transfers.py
+++ b/packages/meshbay-cli/src/meshbay_cli/client/transfers.py
@@ -128,7 +128,8 @@ class Resume:
         sidecar = target.with_name(target.name + PART_SUFFIX + ".json")
         done = 0
         try:
-            meta = json.loads(sidecar.read_text(encoding="utf-8"))
+            with open(long_path(sidecar), encoding="utf-8") as f:
+                meta = json.load(f)
             if meta.get("id") == entry["id"] and meta.get("size") == entry["size"]:
                 # Every chunk but the last is whole, so the complete ones are
                 # what the part's length says.
@@ -198,8 +199,8 @@ def _prepare_part(resume: Resume, entry: dict, start: int) -> None:
             pass
     else:
         os.truncate(part, start * DOWNLOAD_CHUNK)
-    resume.sidecar.write_text(json.dumps({"id": entry["id"], "size": entry["size"]}),
-                              encoding="utf-8")
+    with open(long_path(resume.sidecar), "w", encoding="utf-8") as f:
+        json.dump({"id": entry["id"], "size": entry["size"]}, f)
 
 
 def _publish(resume: Resume, target: Path, overwrite: bool) -> None:
@@ -220,7 +221,7 @@ def _publish(resume: Resume, target: Path, overwrite: bool) -> None:
                 raise TransferError(f"{target} already exists.") from None
             os.replace(part, dest)
     with contextlib.suppress(OSError):
-        resume.sidecar.unlink()
+        os.unlink(long_path(resume.sidecar))
     if sys.platform == "win32":
         mark_of_the_web(target)
 
diff --git a/packages/meshbay-cli/src/meshbay_cli/client/upload_plan.py b/packages/meshbay-cli/src/meshbay_cli/client/upload_plan.py
index 070e686..b4ec781 100644
--- a/packages/meshbay-cli/src/meshbay_cli/client/upload_plan.py
+++ b/packages/meshbay-cli/src/meshbay_cli/client/upload_plan.py
@@ -12,7 +12,7 @@ import stat
 from dataclasses import dataclass
 from pathlib import Path
 
-from meshbay_common.paths import fold
+from meshbay_common.paths import fold, long_path
 
 from ..errors import USAGE, CliError
 from ..output import safe
@@ -36,7 +36,7 @@ def plan_upload(sources: list[str], recursive: bool):
     for src in sources:
         path = Path(src).expanduser()
         try:
-            st = path.stat()
+            st = os.stat(long_path(path))
         except OSError as e:
             problems.append(f"{src}: {e.strerror}")
             continue
@@ -51,18 +51,18 @@ def plan_upload(sources: list[str], recursive: bool):
         elif stat.S_ISDIR(st.st_mode):
             if not recursive:
                 raise CliError(USAGE, f"{safe(src)} is a folder; use -R.")
-            for here, subdirs, names in os.walk(path):
+            for here, subdirs, names in _walk(path):
                 rel = [top] + list(Path(here).relative_to(path).parts)
                 dirs.append(rel)
                 for d in list(subdirs):
-                    if (Path(here) / d).is_symlink():
+                    if os.path.islink(long_path(Path(here) / d)):
                         subdirs.remove(d)
                         problems.append(f"{Path(here) / d} is a link to a folder; not "
                                         "followed")
                 for n in names:
                     p = Path(here) / n
                     try:
-                        st_n = p.stat()
+                        st_n = os.stat(long_path(p))
                     except OSError as e:
                         problems.append(f"{p}: {e.strerror}")
                         continue
@@ -74,6 +74,29 @@ def plan_upload(sources: list[str], recursive: bool):
     return dirs, files, problems
 
 
+def _walk(top: Path):
+    """`os.walk` for a tree that may go past Windows' MAX_PATH: each folder is
+    listed under its long form (`long_path`, which only prefixes a long path, so
+    a short top alone would not do) and the paths given back stay plain."""
+    stack = [top]
+    while stack:
+        here = stack.pop()
+        try:
+            with os.scandir(long_path(here)) as it:
+                entries = list(it)
+        except OSError:
+            continue
+        subdirs, names = [], []
+        for e in entries:
+            try:
+                is_dir = e.is_dir()
+            except OSError:
+                is_dir = False
+            (subdirs if is_dir else names).append(e.name)
+        yield here, subdirs, names          # the caller prunes and orders subdirs
+        stack.extend(here / d for d in reversed(subdirs))
+
+
 def taken_names(tree: Tree, folder: str, names: list[str]) -> set[str]:
     """The names among `names` already in `folder`, compared without case."""
     there = [i.name for i in tree.children(folder, include_unavailable=True)]
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/account.py b/packages/meshbay-cli/src/meshbay_cli/commands/account.py
index 4499f0b..1fbef13 100644
--- a/packages/meshbay-cli/src/meshbay_cli/commands/account.py
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/account.py
@@ -35,7 +35,7 @@ from ..client.passphrase import passphrase_problem, solve_captcha
 from ..client.rewrap import Carried, carry
 from ..client.store import FILE_KEY_NOTICE, KEY_FILE
 from ..errors import AUTH, NOT_FOUND, REFUSED, USAGE, CliError
-from ..output import confirm, err, safe, sentence
+from ..output import confirm, err, safe, sentence, terminal
 from .context import Context
 
 HELP = ("your account: show it, register, verify, change or reset the passphrase, "
@@ -102,7 +102,7 @@ async def run(ctx: Context) -> int:
 def _ask(prompt: str, given: str | None, what: str) -> str:
     if given:
         return given.strip()
-    if not sys.stdin.isatty():
+    if not terminal(sys.stdin):
         raise CliError(USAGE, f"Name the {what}: there is no terminal to ask on.")
     value = input(prompt).strip()
     if not value:
@@ -121,7 +121,7 @@ def _read_first_line(path: str) -> str:
 def _new_passphrase(given: str | None) -> str:
     """A new passphrase: `given`, else typed twice at a terminal; held to the floor."""
     if given is None:
-        if not sys.stdin.isatty():
+        if not terminal(sys.stdin):
             raise NoPassphrase("A new passphrase is needed and there is no terminal to "
                                "ask on.")
         given = getpass.getpass("New passphrase: ")
@@ -224,7 +224,7 @@ async def _register(ctx: Context) -> int:
               "Keep it somewhere safe, apart from your passphrase. If you forget the "
               "passphrase, it is what gives you your groups back.")
     del raw
-    if not sys.stdin.isatty() or ctx.args.json:
+    if not terminal(sys.stdin) or ctx.args.json:
         err(f"A code was sent to {safe(email)}. Then: meshbay-cli account verify CODE "
             f"--email {safe(email)}")
         return 0
@@ -355,7 +355,7 @@ async def _reset(ctx: Context) -> int:
             raise _hub_refusal(e, "No code sent") from e
         err(f"If {safe(username)} and {safe(email)} are an account's, a code is on its "
             "way there (valid one hour).")
-        if not sys.stdin.isatty():
+        if not terminal(sys.stdin):
             err(f"Then: meshbay-cli account reset -u {safe(username)} --code CODE")
             return 0
         code = _ask("The code: ", None, "code")
@@ -365,7 +365,7 @@ async def _reset(ctx: Context) -> int:
         text = (sys.stdin.read() if a.recovery_key_file == "-"
                 else Path(a.recovery_key_file).read_text(encoding="utf-8"))
         recovery = text.strip()
-    elif sys.stdin.isatty():
+    elif terminal(sys.stdin):
         recovery = input("Your recovery key (Enter if you have none): ").strip()
     rkey = None
     if recovery:
@@ -429,7 +429,7 @@ async def _email(ctx: Context, account: Account) -> int:
         await account.call(account.hub.change_email, address, ak)
     except HubError as e:
         raise _hub_refusal(e, "Not changed") from e
-    if ctx.args.json or not sys.stdin.isatty():
+    if ctx.args.json or not terminal(sys.stdin):
         _say(ctx, {"email_verification_required": True, "email": address},
              f"A code was sent to {safe(address)}. Then: meshbay-cli account email "
              "--code CODE")
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/chat.py b/packages/meshbay-cli/src/meshbay_cli/commands/chat.py
index e410a6a..557592e 100644
--- a/packages/meshbay-cli/src/meshbay_cli/commands/chat.py
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/chat.py
@@ -28,7 +28,7 @@ from ..client.groups import my_groups, open_group
 from ..client.paths import group_arg, handle, resolve_group
 from ..client.roster import RosterCheck
 from ..errors import NODE, USAGE, CliError
-from ..output import date, err, human_size, safe, sentence
+from ..output import date, err, human_size, safe, sentence, terminal
 from .context import Context
 
 HELP = ("chat: alone, interactively; with a group, its last 10 messages (-N for N), "
@@ -90,7 +90,7 @@ async def run(ctx: Context) -> int:
     if a.group is None:
         if a.message is not None or a.follow:
             raise CliError(USAGE, "Name the group to post to.")
-        if not (sys.stdin.isatty() and sys.stdout.isatty()):
+        if not (terminal(sys.stdin) and terminal(sys.stdout)):
             raise CliError(USAGE, "The interactive chat needs a terminal; name a group "
                                   "to read it, or to post with -m.")
         from ..tui.app import run_interactive
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/completion.py b/packages/meshbay-cli/src/meshbay_cli/commands/completion.py
index 831c012..0fc3f30 100644
--- a/packages/meshbay-cli/src/meshbay_cli/commands/completion.py
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/completion.py
@@ -51,7 +51,15 @@ Register-ArgumentCompleter -Native -CommandName 'meshbay-cli', 'meshbay-cli.exe'
             $index = $i
         }
     }
-    $found = @(& meshbay-cli __complete powershell $index @words 2>$null)
+    # The client writes UTF-8; Windows PowerShell reads a program's output in the
+    # console's code page, which turns an accented name into another name.
+    $encoding = [Console]::OutputEncoding
+    try { [Console]::OutputEncoding = [Text.Encoding]::UTF8 } catch { }
+    try {
+        $found = @(& meshbay-cli __complete powershell $index @words 2>$null)
+    } finally {
+        try { [Console]::OutputEncoding = $encoding } catch { }
+    }
     $quote = {
         param($s)
         if ($s -match '[\s''"`$&|;(){}@,#]') { "'" + ($s -replace "'", "''") + "'" } else { $s }
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/context.py b/packages/meshbay-cli/src/meshbay_cli/commands/context.py
index 827c101..0f7e842 100644
--- a/packages/meshbay-cli/src/meshbay_cli/commands/context.py
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/context.py
@@ -12,7 +12,7 @@ from ..client.hub import DEFAULT_HUB, Hub
 from ..client.paths import handle
 from ..client.store import Store
 from ..errors import USAGE, CliError
-from ..output import safe
+from ..output import safe, terminal
 
 
 class Context:
@@ -45,7 +45,7 @@ class Context:
         if value is None:
             value = os.environ.get("MESHBAY_PASSWORD")
         if value is None:
-            if not sys.stdin.isatty():
+            if not terminal(sys.stdin):
                 raise NoPassphrase("A passphrase is needed and there is no terminal to ask "
                                    "on; pass --password-file or set MESHBAY_PASSWORD.")
             value = getpass.getpass(f"Passphrase for {self.username or self.stored_username}"
@@ -62,7 +62,7 @@ class Context:
 
     def _device_code(self, group: dict, pending, *, first: bool) -> bool:
         """Show the code once. Wait only where somebody is there to approve it."""
-        waiting = sys.stderr.isatty() and not self.args.quiet
+        waiting = terminal(sys.stderr) and not self.args.quiet
         if first:
             minutes = max(1, int((pending.expires_at - time.time()) // 60))
             print(f"This machine is not yet a device of yours on the node hosting "
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/get.py b/packages/meshbay-cli/src/meshbay_cli/commands/get.py
index eec73c4..33a9637 100644
--- a/packages/meshbay-cli/src/meshbay_cli/commands/get.py
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/get.py
@@ -12,7 +12,7 @@ import os
 from dataclasses import dataclass
 from pathlib import Path
 
-from meshbay_common.paths import fold
+from meshbay_common.paths import fold, long_path
 
 from ..client.groups import my_groups
 from ..client.names import UnsafeName, local_path
@@ -147,7 +147,8 @@ async def _run(ctx: Context, account, pool: Pool) -> int:
         planned.add(key)
         if changed:
             renamed.append((shown, target))
-        if target.exists() and not target.with_name(target.name + PART_SUFFIX).exists():
+        if os.path.exists(long_path(target)) and not os.path.exists(
+                long_path(target.with_name(target.name + PART_SUFFIX))):
             if a.skip:
                 return
             if not a.force:
@@ -181,7 +182,7 @@ async def _run(ctx: Context, account, pool: Pool) -> int:
     for problem in problems:
         progress.note(f"meshbay-cli: {safe(problem)}")
     for d in dirs:
-        d.mkdir(parents=True, exist_ok=True)
+        os.makedirs(long_path(d), exist_ok=True)
     progress.plan(len(jobs), sum(int(j.entry["size"]) for j in jobs))
 
     failed = len(problems)
@@ -224,12 +225,12 @@ def _destination(dest: str | None, single_file: bool) -> tuple[Path, str | None]
         return Path.cwd(), None
     path = Path(dest).expanduser()
     if dest.endswith(("/", os.sep)):
-        path.mkdir(parents=True, exist_ok=True)
+        os.makedirs(long_path(path), exist_ok=True)
         return path, None
-    if path.is_dir():
+    if os.path.isdir(long_path(path)):
         return path, None
     if single_file:
-        if not path.parent.is_dir():
+        if not os.path.isdir(long_path(path.parent)):
             raise CliError(USAGE, f"{path.parent} is not a folder.")
         return path.parent, path.name
     raise CliError(USAGE, f"{dest} is not a folder (end it with / to create it).")
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/groups.py b/packages/meshbay-cli/src/meshbay_cli/commands/groups.py
index 04395dd..5ee1356 100644
--- a/packages/meshbay-cli/src/meshbay_cli/commands/groups.py
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/groups.py
@@ -10,7 +10,7 @@ operator is another notion.
 import contextlib
 import json
 import sys
-from datetime import datetime
+from datetime import UTC, datetime
 
 from ..client.groups import my_groups
 from ..client.hub import HubError
@@ -38,9 +38,12 @@ def local_time(iso: str | None) -> str:
     if not iso:
         return ""
     try:
-        return datetime.fromisoformat(iso).astimezone().strftime("%Y-%m-%d %H:%M")
+        moment = datetime.fromisoformat(iso)
     except ValueError:
         return ""
+    if moment.tzinfo is None:           # a hub on SQLite sends UTC without saying so
+        moment = moment.replace(tzinfo=UTC)
+    return moment.astimezone().strftime("%Y-%m-%d %H:%M")
 
 
 async def run(ctx: Context) -> int:
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/join.py b/packages/meshbay-cli/src/meshbay_cli/commands/join.py
index ee75c96..06494dd 100644
--- a/packages/meshbay-cli/src/meshbay_cli/commands/join.py
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/join.py
@@ -18,7 +18,7 @@ from ..client.invite import parse_link
 from ..client.paths import group_arg, handle, resolve_group
 from ..client.session import DeviceLinkPending, NodeRefusal
 from ..errors import AUTH, NODE, NOT_FOUND, USAGE, CliError
-from ..output import err, safe, sentence
+from ..output import err, safe, sentence, terminal
 from .context import Context
 from .invitations import find_invitation
 
@@ -102,7 +102,7 @@ async def run(ctx: Context) -> int:
         except NodeRefusal as e:
             if e.refusal_code != "code_required" or code:
                 raise
-            if not sys.stdin.isatty():
+            if not terminal(sys.stdin):
                 raise CliError(NODE, f"You are a member of {safe(name)}; its node has not "
                                      "admitted you yet and needs your invitation's code:\n"
                                      f"  meshbay-cli join {name} --code CODE") from e
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/login.py b/packages/meshbay-cli/src/meshbay_cli/commands/login.py
index cbd16ef..f26691c 100644
--- a/packages/meshbay-cli/src/meshbay_cli/commands/login.py
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/login.py
@@ -8,7 +8,7 @@ from ..client.account import Account
 from ..client.groups import my_groups
 from ..client.store import FILE_KEY_NOTICE, KEY_FILE
 from ..errors import USAGE, CliError
-from ..output import err, safe, sentence
+from ..output import err, safe, sentence, terminal
 from .context import Context
 from .logout import sign_out_stored
 
@@ -24,7 +24,7 @@ def add_parser(sub, parent) -> None:
 async def run(ctx: Context) -> int:
     username = ctx.username or ctx.stored_username
     if not username:
-        if not sys.stdin.isatty():
+        if not terminal(sys.stdin):
             raise CliError(USAGE, "Name the account with --user.")
         username = input("Username: ").strip()
         ctx.username = username
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/put.py b/packages/meshbay-cli/src/meshbay_cli/commands/put.py
index 01a7233..cf80e02 100644
--- a/packages/meshbay-cli/src/meshbay_cli/commands/put.py
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/put.py
@@ -18,6 +18,8 @@ import tempfile
 import threading
 from pathlib import Path
 
+from meshbay_common.paths import long_path
+
 from ..client.groups import my_groups
 from ..client.paths import handle, parse, resolve_group
 from ..client.pool import Pool
@@ -156,7 +158,7 @@ async def _send(ctx: Context, session, group: dict, folder: str, dirs: list[list
             progress.start(safe(name))
             lock = threading.Lock()
             try:
-                with open(job.local, "rb") as fh:
+                with open(long_path(job.local), "rb") as fh:
                     def read(offset: int, length: int) -> bytes:
                         with lock:
                             fh.seek(offset)
diff --git a/packages/meshbay-cli/src/meshbay_cli/complete.py b/packages/meshbay-cli/src/meshbay_cli/complete.py
index ac590ce..249d5b7 100644
--- a/packages/meshbay-cli/src/meshbay_cli/complete.py
+++ b/packages/meshbay-cli/src/meshbay_cli/complete.py
@@ -300,7 +300,9 @@ def candidates(shell: str, cword: int, words: list[str]) -> list[str]:
                 return [c[:-1] for c in found if c.count("/") == 1]
             return found
         try:
-            found = asyncio.run(asyncio.wait_for(go(), DEADLINE))
+            # The client's loop: on Windows the default one never opens a node.
+            from .__main__ import loop_factory
+            found = asyncio.run(asyncio.wait_for(go(), DEADLINE), loop_factory=loop_factory())
         except Exception:
             found = []
         return ([FILES] if kind[0] == "files+remote" else []) + found
diff --git a/packages/meshbay-cli/src/meshbay_cli/output.py b/packages/meshbay-cli/src/meshbay_cli/output.py
index d4c0758..1d46981 100644
--- a/packages/meshbay-cli/src/meshbay_cli/output.py
+++ b/packages/meshbay-cli/src/meshbay_cli/output.py
@@ -54,8 +54,36 @@ def columns(names: list[str]) -> str:
     return "\n".join(lines)
 
 
+def terminal(stream) -> bool:
+    """
+    Whether `stream` is a terminal a person sits at. `isatty()` alone is wrong on
+    Windows, where it means "a character device" and so says yes for NUL: a
+    script run with `< NUL`, or by the Task Scheduler, was asked questions it
+    could not answer instead of being told to pass --yes.
+    """
+    try:
+        if not stream.isatty():
+            return False
+    except (AttributeError, ValueError):
+        return False
+    if sys.platform != "win32":
+        return True
+    try:
+        fd = stream.fileno()
+    except (OSError, ValueError):
+        return True                  # not a file at all: take its word
+    import ctypes
+    import msvcrt
+    try:
+        handle = msvcrt.get_osfhandle(fd)
+    except OSError:
+        return False
+    mode = ctypes.c_uint32()
+    return bool(ctypes.windll.kernel32.GetConsoleMode(handle, ctypes.byref(mode)))
+
+
 def is_tty() -> bool:
-    return sys.stdout.isatty()
+    return terminal(sys.stdout)
 
 
 def err(message: str) -> None:
@@ -71,7 +99,7 @@ class Progress:
 
     def __init__(self, arrow: str, *, quiet: bool = False, as_json: bool = False):
         self.arrow = arrow
-        self.live = sys.stderr.isatty() and not quiet and not as_json
+        self.live = terminal(sys.stderr) and not quiet and not as_json
         self.as_json = as_json and not quiet
         self.files_total = 0
         self.files_done = 0
@@ -149,7 +177,7 @@ def confirm(question: str, yes: bool) -> None:
     from .errors import USAGE, CliError
     if yes:
         return
-    if not sys.stdin.isatty():
+    if not terminal(sys.stdin):
         raise CliError(USAGE, f"{question} Not done: there is no terminal to ask on; "
                               "pass --yes to confirm.")
     # On stderr, like every other word to the person: stdout is the result.
diff --git a/packages/meshbay-cli/src/meshbay_cli/tui/chat.py b/packages/meshbay-cli/src/meshbay_cli/tui/chat.py
index e4ea1fe..989ffe2 100644
--- a/packages/meshbay-cli/src/meshbay_cli/tui/chat.py
+++ b/packages/meshbay-cli/src/meshbay_cli/tui/chat.py
@@ -21,6 +21,7 @@ import os
 import time
 from pathlib import Path
 
+from meshbay_common.paths import long_path
 from rich.segment import Segment
 from rich.text import Text
 from textual import events
@@ -412,9 +413,10 @@ class ChatRoomScreen(Screen):
 
     async def _put(self, arg: str) -> None:
         path = Path(os.path.abspath(os.path.expanduser(arg)))
-        if not path.is_file():
+        if not os.path.isfile(long_path(path)):
             self.note(f"! {safe(arg)}: " + ("a folder; /put sends one file."
-                      if path.is_dir() else "no such file."), style="bold red")
+                      if os.path.isdir(long_path(path)) else "no such file."),
+                      style="bold red")
             return
         name = path.name
         if problems := refused_names([name], []):
@@ -430,9 +432,9 @@ class ChatRoomScreen(Screen):
             if found is None:
                 return
             _, folder = found
-            size = path.stat().st_size
+            size = os.stat(long_path(path)).st_size
             advance, queued = self._progress("↑", name, size)
-            with open(path, "rb") as fh:
+            with open(long_path(path), "rb") as fh:
                 def read(offset: int, length: int) -> bytes:
                     fh.seek(offset)
                     return fh.read(length)
@@ -475,7 +477,8 @@ class ChatRoomScreen(Screen):
                           style="bold red")
                 return
             target = Path.cwd() / name.rsplit("/", 1)[-1]
-            if target.exists() and not target.with_name(target.name + PART_SUFFIX).exists():
+            if os.path.exists(long_path(target)) and not os.path.exists(
+                    long_path(target.with_name(target.name + PART_SUFFIX))):
                 self.note(f"! {safe(str(target))} is here already; nothing was downloaded.",
                           style="bold red")
                 return
diff --git a/packages/meshbay-cli/src/meshbay_cli/tui/clipboard.py b/packages/meshbay-cli/src/meshbay_cli/tui/clipboard.py
index 1a1f0d7..e0bd315 100644
--- a/packages/meshbay-cli/src/meshbay_cli/tui/clipboard.py
+++ b/packages/meshbay-cli/src/meshbay_cli/tui/clipboard.py
@@ -12,6 +12,7 @@ skipped, never an error.
 import asyncio
 import os
 import shutil
+import subprocess
 import sys
 
 TIMEOUT = 3.0
@@ -40,24 +41,25 @@ def _encode(text: str) -> bytes:
     return ("" + text).encode("utf-16-le") if sys.platform == "win32" else text.encode()
 
 
-async def _run(cmd: list[str], data: bytes | None) -> bytes | None:
+def _run_blocking(cmd: list[str], data: bytes | None) -> bytes | None:
     if shutil.which(cmd[0]) is None:
         return None
     env = {**os.environ, "LC_CTYPE": "UTF-8"} if sys.platform == "darwin" else None
     try:
-        proc = await asyncio.create_subprocess_exec(
-            *cmd, stdin=asyncio.subprocess.PIPE if data is not None else asyncio.subprocess.DEVNULL,
-            stdout=asyncio.subprocess.PIPE if data is None else asyncio.subprocess.DEVNULL,
-            stderr=asyncio.subprocess.DEVNULL, env=env)
-    except OSError:
-        return None
-    try:
-        out, _ = await asyncio.wait_for(proc.communicate(data), TIMEOUT)
-    except TimeoutError:
-        proc.kill()
-        await proc.wait()
+        proc = subprocess.run(
+            cmd, input=data, stdin=None if data is not None else subprocess.DEVNULL,
+            stdout=subprocess.PIPE if data is None else subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL, env=env, timeout=TIMEOUT,
+            creationflags=getattr(subprocess, "CREATE_NO_WINDOW", 0))
+    except (OSError, subprocess.TimeoutExpired):
         return None
-    return (out or b"") if proc.returncode == 0 else None
+    return (proc.stdout or b"") if proc.returncode == 0 else None
+
+
+async def _run(cmd: list[str], data: bytes | None) -> bytes | None:
+    # In a thread, not asyncio's subprocesses: on Windows the client runs a
+    # selector loop (aiortc's ICE needs one), which cannot start a process.
+    return await asyncio.to_thread(_run_blocking, cmd, data)
 
 
 async def read_text() -> str | None:
diff --git a/packages/meshbay-cli/src/meshbay_cli/tui/panes.py b/packages/meshbay-cli/src/meshbay_cli/tui/panes.py
index d1e3dd0..417e0c6 100644
--- a/packages/meshbay-cli/src/meshbay_cli/tui/panes.py
+++ b/packages/meshbay-cli/src/meshbay_cli/tui/panes.py
@@ -13,6 +13,7 @@ import stat
 from dataclasses import dataclass, field
 from pathlib import Path
 
+from meshbay_common.paths import long_path
 from rich.text import Text
 from textual.app import ComposeResult
 from textual.binding import Binding
@@ -274,7 +275,7 @@ class LocalPane(Pane):
 
 def _scan(path: Path) -> list[Row]:
     rows = []
-    with os.scandir(path) as it:
+    with os.scandir(long_path(path)) as it:
         for e in it:
             try:
                 st = e.stat()
diff --git a/packages/meshbay-cli/src/meshbay_cli/tui/screens.py b/packages/meshbay-cli/src/meshbay_cli/tui/screens.py
index 0306325..39b5df3 100644
--- a/packages/meshbay-cli/src/meshbay_cli/tui/screens.py
+++ b/packages/meshbay-cli/src/meshbay_cli/tui/screens.py
@@ -14,9 +14,11 @@ the node's operator) or none is, then asked once for the batch.
 
 import asyncio
 import contextlib
+import os
 import threading
 from pathlib import Path
 
+from meshbay_common.paths import long_path
 from rich.text import Text
 from textual.app import ComposeResult
 from textual.binding import Binding
@@ -214,8 +216,8 @@ class MainScreen(Screen):
                     problems.append(str(e))
         for p in problems:
             self.app.notify(p, severity="warning", markup=False)
-        existing = [t for _, t in plan if t.exists()
-                    and not t.with_name(t.name + PART_SUFFIX).exists()]
+        existing = [t for _, t in plan if os.path.exists(long_path(t))
+                    and not os.path.exists(long_path(t.with_name(t.name + PART_SUFFIX)))]
         overwrite = False
         if existing:
             names = ", ".join(safe(t.name) for t in existing[:5]) + (
@@ -229,7 +231,7 @@ class MainScreen(Screen):
             if not overwrite:
                 plan = [(e, t) for e, t in plan if t not in existing]
         for d in dirs:
-            await asyncio.to_thread(d.mkdir, parents=True, exist_ok=True)
+            await asyncio.to_thread(os.makedirs, long_path(d), exist_ok=True)
         remote.marks.clear()
         remote.redraw()
         session = await self.pool.session(group)
@@ -320,7 +322,7 @@ class MainScreen(Screen):
             self.strip.update_job(job, state="running")
             lock = threading.Lock()
             try:
-                with open(item.local, "rb") as fh:
+                with open(long_path(item.local), "rb") as fh:
                     def read(offset: int, length: int) -> bytes:
                         with lock:
                             fh.seek(offset)