Claude Code agent returns empty reply with exit code -4058 on Windows

[Kieutran26]

Environmen

t

• OS: Windows 11
• Claude Code: v2.1.168
• html-video studio: v0.7

Problem

After successfully detecting Claude Code as the agent, sending
any prompt results in an empty reply with exit code -4058.

Error message in Studio

"The agent returned an empty reply. Try rephrasing your request"
"agent exit code -4058"

Steps to reproduce

1. Install Claude Code globally via npm
2. Start html-video studio
3. Select Claude Code as agent
4. Send any prompt (e.g. "create a 30s video about vibe coding")
5. Agent returns empty reply

Notes

Exit code -4058 on Windows typically indicates the process was
terminated or could not spawn correctly. May be related to how
the studio invokes claude --print on Windows (missing .cmd extension).

[lefarcen]

Hi @Kieutran26 — thanks for the crisp Windows repro, especially the note about claude --print and the possible .cmd path.

This looks related to the current Windows runtime gap in main: the runtime still resolves agents with which and spawns the raw claude binary name, which is a likely match for the -4058 empty-reply failure you're seeing on Windows. We already have PR #10 open against this area, covering Windows agent detection / .cmd / .exe probing and spawn behavior.

One quick data point that would help confirm it's the same path on your machine: could you run where claude in PowerShell or Command Prompt and paste the output here? If it resolves to claude.cmd, that would line up very closely with the current fix path.

[Kieutran26]

Hi @lefarcen, here is the output of where claude on my machine:

C:\Users\khoav\AppData\Roaming\npm\claude
C:\Users\khoav\AppData\Roaming\npm\claude.cmd
C:\Users\khoav\AppData\Roaming\npm\claude.ps1

So yes, it resolves to claude.cmd. This confirms the issue
you described with PR #10.

[lefarcen]

Thanks — that’s very helpful, @Kieutran26.

The where claude output is exactly the confirmation I needed: Windows is resolving both claude and claude.cmd, while the current main runtime still uses the Unix-style lookup/spawn path. That makes PR #10 the right fix track for this issue.

I’m going to keep this issue open and tied to #10 until that PR lands. Once there’s an updated branch or merge on that path, we can use this issue as the verification point for the Windows fix.

[lefarcen]

A PR is now open in #29 for the Windows path behind this report. It switches agent detection to where on win32 and resolves the real CLI path before spawning, so .cmd shims like claude.cmd can launch instead of falling into the -4058 / empty-reply path.

Keeping this issue open until the PR lands and the fix is verified on the shipped build.

[lefarcen]

Quick update, @Kieutran26 — PR #29 is still under review. Once it merges and ships, we'll post back here with the build version so you can verify the -4058 is cleared. Nothing needed from you in the meantime.

[lefarcen]

Hey @Kieutran26 — PR #29 (fix/windows-agent-spawn) is still awaiting its first review. It targets the exact .cmd path you confirmed, and your Windows setup is the right environment to validate it. If you're up for testing the fix branch ahead of the official build, that would move this forward quickly. Let us know!

[lefarcen]

Hey @Kieutran26 — one more concrete sync on the path you confirmed.

Your where claude output (claude + claude.cmd + claude.ps1) is still the key evidence for this bug, and the current fix branch for that Windows launch path is PR #29. That PR is still open, so this issue will stay open with it until we have a landed change to verify against your Windows setup.

Nothing new needed from you right now — once that branch lands or there’s a testable update worth trying, we’ll post back here for verification.

[lefarcen]

Hey @Kieutran26 — one useful update since the last sync.

Another Windows tester has now confirmed the full path locally on the related fix work: CLI launch, video generation, and export all succeed once the Windows runtime changes are applied. That’s stronger evidence that the .cmd / Windows spawn path you helped confirm is the right fix area for this issue.

The blocker is still that the current PRs in this area need maintainer resolution before anything can ship, so I’m keeping this issue open until there’s a landed build or a refreshed branch worth validating against your setup. Once we have that, we’ll post back here for verification.

[lefarcen]

Hey @Kieutran26 — one concrete update on the Windows path you helped confirm.

PR #29 has now merged, and it lands the runtime-side Windows CLI launch fix that matches your where claude output (claude / claude.cmd / claude.ps1). That means the .cmd detection/spawn path is no longer just under review; it is now in the codebase.

When you have a chance, could you test again against the latest build that includes PR #29 and let us know whether Claude Code now returns a normal reply instead of the -4058 empty-response error? If it still fails, the most useful follow-up would be the exact new error text plus whether Studio detects claude.cmd on that build.