The Windows desktop GUI runs its backend headless via pythonw.exe. Several
auxiliary subprocess sites that run inside that windowless backend spawned
console-subsystem children (git, gh, wmic, powershell, bash, rg, taskkill)
WITHOUT CREATE_NO_WINDOW, so Windows allocated a fresh conhost per call and
flashed a black window on screen — sometimes continuously (the dashboard
Projects-tree git probe alone fired ~118 spawns in 60s on startup).
The terminal tool, cron, browser, code_execution, and gateway-spawn paths
already carry windows_hide_flags(); these auxiliary probe/scan/launcher legs
were missed. Wire the existing helper into them:
- tui_gateway/git_probe.py: run_git (+ encoding=utf-8/errors=replace, fixes the
cp950 UnicodeDecodeError on CJK paths from the same site)
- agent/coding_context.py: _git (per-turn git status/log/diff)
- agent/context_references.py: _run_git + _rg_files (@file/@ref resolution)
- hermes_cli/copilot_auth.py: gh auth token probe (auxiliary provider:auto)
- hermes_cli/gateway.py: wmic + PowerShell Get-CimInstance PID scan
- hermes_cli/main.py: wmic stale-dashboard PID scan
- gateway/status.py: taskkill /T /F force-kill
windows_hide_flags() returns 0 on POSIX, so every changed call is a no-op on
Linux/macOS (verified: real git/rg probes still work; Windows-simulated calls
all pass creationflags=CREATE_NO_WINDOW).
Scoped to the windowless-backend paths that cause the reported flashing. The
Electron updater-handoff leg (main.cjs windowsHide:false) and the
interactive-CLI banner probes (cli.py) are intentionally NOT touched here —
the former needs a Windows-tested change of its own, the latter runs in a
visible console anyway.
Tracking: #54220
Refs: #53178#53631#53781#53957#49602#52982#53424#53053#53016
Follow-up to #53791 addressing review feedback: the footgun checker treated
capture_output=/stdout=/stderr=/check_output as proof a subprocess can't pop a
Windows console. That invariant is false — stream redirection controls where a
child's output goes, not whether a console is allocated. From a console-less
parent (Desktop/Electron, pythonw.exe, detached gateway/cron) a console-subsystem
child still flashes a window even when fully captured.
- check-windows-footguns.py: capture/redirect/check_output is no longer a blanket
safe-pass. Added _WINDOWS_FLASHING_PROGRAMS (git/gh/npm/node/python/uv/ffmpeg/
docker/powershell/…); calls to those are flagged even when captured. Non-flashing
programs keep the capture exemption (no 271-site noise). _subprocess_compat.run/
popen calls are inherently safe (wrapper injects CREATE_NO_WINDOW).
- Routed the 35 genuine flashing git/gh/npm/uv/ffmpeg/docker spawns through the
_subprocess_compat.run/popen chokepoint (Brooklyn's wrapper from #53810) — the
durable fix, not per-site annotations. cmd.exe /c start stays # ok (intentional).
- Updated tests + CONTRIBUTING.md rule #17 to the corrected invariant.
A binary @file: ref (PDF, docx, spreadsheet, …) expanded to a bare
"binary files are not supported" warning with no content. The model saw a
failure and gave up — e.g. a dropped PDF came back as a text note claiming the
type was unsupported, even though the file was staged on disk right next to it.
Inject an actionable content block instead: the path, mime type, size, and a
nudge to use its tools to read/convert/view the file (and explicitly not to tell
the user the type is unsupported). General across every binary type — not
PDF-specific. The file already resolves where the agent's tools run (local cwd
or the staged copy in a remote session workspace), so it can act on it directly.
When Hermes runs in TUI mode, the gateway child process communicates with
the Node.js parent over a JSON-RPC protocol on stdin. Subprocess calls that
inherit this stdin fd can trigger a race condition where the child's stdin
read returns EOF, causing the gateway to exit cleanly (exit code 0) mid-tool-
execution.
This is the same root cause as issue #14036 (byterover plugin) and PR #39257
(SSH environment backend). This commit applies the fix — stdin=subprocess.DEVNULL
— to all 85 subprocess.run() and subprocess.Popen() calls that execute inside
the TUI gateway child process.
Scope: TUI-context code only (agent/, tools/, plugins/, tui_gateway/server.py).
CLI code (cli.py, hermes_cli/), tests, scripts, and gateway process management
are excluded — they don't run inside the TUI child and inherit the terminal's
stdin, not the JSON-RPC pipe.
85 call sites across 28 files. All files pass syntax check.
16 callsites across 14 files were re-deriving the hermes home path
via os.environ.get('HERMES_HOME', ...) instead of using the canonical
get_hermes_home() from hermes_constants. This breaks profiles — each
profile has its own HERMES_HOME, and the inline fallback defaults to
~/.hermes regardless.
Fixed by importing and calling get_hermes_home() at each site. For
files already inside the hermes process (agent/, hermes_cli/, tools/,
gateway/, plugins/), this is always safe. Files that run outside the
process context (mcp_serve.py, mcp_oauth.py) already had correct
try/except ImportError fallbacks and were left alone.
Skipped: hermes_constants.py (IS the implementation), env_loader.py
(bootstrap), profiles.py (intentionally manipulates the env var),
standalone scripts (optional-skills/, skills/), and tests.
Follow-up to PR #4305 — .config/gh was added to the write-deny list
but missed from _SENSITIVE_HOME_DIRS, leaving GitHub CLI OAuth tokens
exposed via @file:~/.config/gh/hosts.yml context injection.
_expand_git_reference() and _rg_files() called subprocess.run()
without a timeout. On a large repository, @diff, @staged, or
@git:N references could hang the agent indefinitely while git
or ripgrep processes slow output.
- Add timeout=30 to git subprocess in _expand_git_reference()
with a user-friendly error message on TimeoutExpired
- Add timeout=10 to rg subprocess in _rg_files() returning
None on timeout (falls back to os.walk folder listing)
Co-authored-by: memosr.eth <96793918+memosr@users.noreply.github.com>
Add @file:path, @folder:dir, @diff, @staged, @git:N, and @url:
references that expand inline before the message reaches the LLM.
Supports line ranges (@file:main.py:10-50), token budget enforcement
(soft warn at 25%, hard block at 50%), and path sandboxing for gateway.
Core module from PR #2090 by @kshitijk4poor. CLI and gateway wiring
rewritten against current main. Fixed asyncio.run() crash when called
from inside a running event loop (gateway).
Closes#682.
