What causes "allocate plugin response buffer: %w" in router-for-me/CLIProxyAPI?

Reduce memory pressure: lower concurrency, restart the process, or raise the container/job memory limit

allocate plugin response buffer: %w

Error message

allocate plugin response buffer: %w

What it means

Before invoking the Windows plugin call pointer, the host allocates a windowsBuffer via LocalAlloc to receive the response. If LocalAlloc returns an error (wrapped here), the call cannot proceed. This is a local memory-allocation failure, not a plugin failure.

Source

Thrown at internal/pluginhost/loader_windows.go:277

		case <-ctx.Done():
			return nil, ctx.Err()
		default:
		}
	}
	methodBytes, errMethod := syscall.BytePtrFromString(method)
	if errMethod != nil {
		return nil, errMethod
	}
	var requestPtr uintptr
	if len(request) > 0 {
		requestPtr = uintptr(unsafe.Pointer(&request[0]))
	}
	responseMem, errAlloc := windows.LocalAlloc(
		windows.LMEM_FIXED|windows.LMEM_ZEROINIT,
		uint32(unsafe.Sizeof(windowsBuffer{})),
	)
	if errAlloc != nil {
		return nil, fmt.Errorf("allocate plugin response buffer: %w", errAlloc)
	}
	if responseMem == 0 {
		return nil, fmt.Errorf("allocate plugin response buffer")
	}
	defer func() {
		_, _ = windows.LocalFree(windows.Handle(responseMem))
	}()
	response := (*windowsBuffer)(unsafe.Pointer(responseMem))
	rc, _, _ := syscall.SyscallN(
		c.api.call,
		uintptr(unsafe.Pointer(methodBytes)),
		requestPtr,
		uintptr(len(request)),
		responseMem,
	)
	var out []byte
	if response.ptr != 0 && response.len > 0 {
		out = unsafe.Slice((*byte)(unsafe.Pointer(response.ptr)), response.len)

View on GitHub (pinned to 78f0c4079e)

Solutions

Reduce memory pressure: lower concurrency, restart the process, or raise the container/job memory limit
Rate-limit concurrent plugin calls so response-buffer allocations stay bounded
Capture the wrapped error code to confirm it is allocation-related before deeper debugging

Defensive patterns

Strategy: retry

Try / catch

out, err := client.Call(ctx, method, body)
if err != nil && strings.Contains(err.Error(), "allocate plugin response buffer") {
    // transient memory pressure: shed load and retry once
    time.Sleep(50 * time.Millisecond)
    out, err = client.Call(ctx, method, body)
}

Prevention

Cap concurrent plugin calls with a semaphore
Monitor process memory and restart on sustained growth
Run with adequate container memory limits

When it happens

Trigger: Extreme process memory pressure causing LocalAlloc to fail; handle/memory quota exhaustion; extremely large numbers of concurrent plugin calls each allocating response buffers.

Common situations: Host process near its memory limit (many plugins + heavy traffic); running under a job object or container with a tight memory cap.

Related errors

AI-assisted analysis of router-for-me/CLIProxyAPI@78f0c4079e (2026-08-15). Data as JSON: /api/errors/689ce49d89105076. Report an issue: GitHub.