[Bug]: [Windows] cursor-agent fails when prompt contains CLI-like flags (e.g. go -ldflags -X)

[WitMiao]

Summary

On Windows, when a Cursor agent task prompt contains CLI-like flags (e.g. Go ldflags with -X), cursor-agent exits immediately with:

error: unknown option '-X'
cursor-agent exited with error: exit status 1

The task fails in ~1–2s with failure_reason=agent_error.process_failure and produces no agent output.

This is not the multi-line prompt truncation fixed by #1297 / PR #1709: daemon logs already show the PowerShell -File rewrite path is active (cursor-agent: routing through powershell -File to preserve argv tokens).

Environment

• OS: Windows 10/11 (amd64)
• Multica CLI/daemon: 0.4.2 (also reproduced on 0.4.4-era daemon behavior per local logs)
• cursor-agent: 2026.07.16-899851b
• Provider: cursor via Cursor runtime
• Launch path: pwsh.exe -NoProfile -ExecutionPolicy Bypass -File cursor-agent.ps1 -p <prompt> ...

Steps to reproduce

1. On Windows, run Multica daemon with a Cursor runtime.

2. Trigger a comment task whose prompt body includes a pasted build log containing:

   go build -ldflags "-X main.version=foo -X main.commit=bar" -o bin/server ./cmd/server

   (In our case this came from a user @mentioning an agent with CI build output in the issue comment.)

3. Observe the task fail within ~2 seconds.

Expected behavior

The full comment/prompt text should be passed to cursor-agent -p as prompt content. Flags inside the prompt (like -X main.version=...) must not be parsed as cursor-agent CLI options.

Actual behavior

Daemon stderr shows:

[cursor:stderr] error: unknown option '-X'
cursor-agent finished status=failed duration=~2s
agent finished status=failed tools=0 output_bytes=0

buildCursorArgs currently passes:

args := []string{
    "-p", prompt,
    "--output-format", "stream-json",
    "--yolo",
}

Even with Windows chooseCursorInvocation routing through powershell -File, prompt content that looks like CLI flags appears to leak into option parsing.

Related issues (not duplicates)

• [Bug]: [Windows] Multica-spawned cursor-agent always exits 1; manual run succeeds #1297 — Windows cursor-agent exit 1 due to cmd.exe %* mangling multi-line prompts; fixed by PR fix(agent/cursor): route Windows launcher through PowerShell -File to… #1709. Our repro already uses the PS -File path.
• [Bug]: When using Pi, the user's message was not sent normally. #3306 — Pi prompt truncation on Windows (same class of argv issue, different runtime).
• Two local daemons (CLI + desktop app) race to claim the same runtime's tasks #4862 — unknown option '--effort' from a stale Claude binary chosen by a racing daemon, not prompt content.
• [Bug]: Cursor task posts its final issue comment, then is marked failed with only "exit status 1" #5552 — Cursor task marked failed after posting a comment (stream finalization), different failure mode.

Suggested fixes

Any of these would likely work:

1. Pass prompt via stdin / temp file instead of -p <huge string> when it contains ambiguous tokens.
2. Insert -- after -p (if supported by cursor-agent) before prompt args.
3. Escape or quote prompt so cursor-agent.ps1 cannot re-tokenize embedded -X flags.
4. Regression test: Windows fake cursor-agent that asserts prompt argv containing -ldflags "-X main.version=..." arrives as a single -p value.

Minimal repro log excerpt

INF cursor-agent: routing through powershell -File to preserve argv tokens
INF agent command exec=pwsh.exe args=[-NoProfile -ExecutionPolicy Bypass -File .../cursor-agent.ps1 -p ... go build -ldflags "-X main.version=..." ...]
DBG [cursor:stderr] error: unknown option '-X'
INF cursor-agent finished status=failed duration=2.037s

Happy to provide full daemon debug logs on request.