opencode serve fails immediately with generic 'ServeError' on Windows, no stack trace even at DEBUG level

Summary

opencode serve fails immediately on every attempt on Windows 11, with a generic error and zero diagnostic detail:

Warning: OPENCODE_SERVER_PASSWORD is not set; server is unsecured.
Error: Unexpected error

ServeError

opencode (interactive TUI mode) works completely fine on the same machine, same install, same config — this is isolated specifically to serve.

Environment

• OS: Windows 11 Home (build 26200)
• opencode-ai: reproduced on both 1.18.15 and 1.18.18 (latest at time of filing)
• Install: npm install -g opencode-ai
• Shell: tested from both Git Bash and PowerShell (Administrator), identical result

Steps to reproduce

opencode serve --port 4096

Fails immediately (well under a second after the config-loading log lines), no port ever binds.

What I've ruled out (extensive isolation testing)

• Not port-specific — identical failure on ports 4096, 4097, 4098, 4099, and others. None were pre-bound (confirmed via netstat before each attempt).
• Not a plugin issue — identical failure with --pure (no external plugins loaded).
• Not a version issue — identical failure on 1.18.15 and 1.18.18.
• Not a corrupted install — full clean npm uninstall -g opencode-ai + npm cache clean --force + fresh npm install -g opencode-ai@latest, still fails identically. Confirmed the fresh install works for everything else (opencode --version, opencode run "..." both succeed and return real model output).
• Not config-related — identical failure with the two local config files (opencode.json, opencode.jsonc) both temporarily removed entirely (zero custom config).
• Not the local MCP entry — identical failure with the mcp block in config disabled.
• Not hostname/binding-specific — identical failure with --hostname 127.0.0.1 (default), --hostname 0.0.0.0, and --hostname localhost.
• Not verbosity-related — --print-logs --log-level DEBUG and DEBUG=* env var both produce the exact same three-line output, no additional detail.

Expected behavior

opencode serve starts a headless server and binds the given port, same as it presumably does on other platforms / for other users, enabling API-based integrations (e.g. opencode-telegram-bot, which requires opencode serve to function and is currently completely blocked by this).

Actual behavior

Immediate failure with a generic wrapped error, no stack trace, no indication of what actually threw.

Additional context

Given the error is a clean, immediate return (not a hang or timeout), this looks like an exception being thrown and caught by the CLI's own generic error handler during server construction, with the real underlying error swallowed rather than surfaced. Happy to run additional diagnostics or a debug build if that would help narrow it down further — I've exhausted what's reachable from the public CLI surface.