argoproj/argo-workflows · error

incorrect number of arguments

Error message

incorrect number of arguments

What it means

The `argo cp` command requires exactly two positional arguments: the workflow name and the output directory. When a different number is supplied, the help text is printed and this error is returned so the command exits non-zero instead of silently misinterpreting arguments.

Source

Thrown at cmd/argo/commands/cp.go:47

		artifactName string // --artifact-name
		customPath   string // --path
	)
	command := &cobra.Command{
		Use:   "cp my-wf output-directory ...",
		Short: "copy artifacts from workflow",
		Example: `# Copy a workflow's artifacts to a local output directory:

  argo cp my-wf output-directory

# Copy artifacts from a specific node in a workflow to a local output directory:

  argo cp my-wf output-directory --node-id=my-wf-node-id-123
`,
		SilenceUsage: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			if len(args) != 2 {
				cmd.HelpFunc()(cmd, args)
				return fmt.Errorf("incorrect number of arguments")
			}
			workflowName := args[0]
			outputDir := args[1]

			ctx := cmd.Context()
			ctx, apiClient, err := client.NewAPIClient(ctx)
			if err != nil {
				return err
			}
			serviceClient := apiClient.NewWorkflowServiceClient(ctx)
			if len(namespace) == 0 {
				namespace = client.Namespace(ctx)
			}
			workflow, err := serviceClient.GetWorkflow(ctx, &workflowpkg.WorkflowGetRequest{
				Name:      workflowName,
				Namespace: namespace,
			})
			if err != nil {

View on GitHub (pinned to 35bff19146)

Solutions

1. Provide both arguments: `argo cp <workflow-name> <output-directory>`.
2. Quote paths containing spaces: `argo cp my-wf "/tmp/my output"`.
3. Check that flags use `--flag=value` syntax so they are not consumed as positional args.
4. Run `argo cp --help` to review expected usage.

Example fix

// before
argo cp my-wf
// after
argo cp my-wf ./output-directory

# shell: check arg count before invoking
if [ "$#" -ne 2 ]; then echo "usage: argo cp <workflow> <outdir>"; exit 1; fi
argo cp "$1" "$2"

// in Go (exec wrapper)
out, err := exec.Command("argo", "cp", wf, dir).CombinedOutput()
if err != nil && strings.Contains(string(out), "incorrect number of arguments") {
  return fmt.Errorf("argo cp needs <workflow> <outdir>: %s", out)
}

When it happens

Trigger: Running `argo cp` with zero, one, or three-plus positional arguments, e.g. forgetting the output directory (`argo cp my-wf`) or accidentally passing flag values positionally.

Common situations: Copy-pasting examples with line breaks that drop an argument; putting flags after positional args and quoting issues splitting words; forgetting to quote an output directory containing spaces so only part is seen as one arg.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• requires either selector or workflow
• expected labels of the form: NAME1=VALUE2,NAME2=VALUE2. Rece
• expected Annotations of the form: NAME1=VALUE2,NAME2=VALUE2.
• expected parameter of the form: NAME=VALUE. Received: %s
• requires either selector or workflow

AI-assisted analysis of argoproj/argo-workflows@35bff19146 (2026-09-03). Data as JSON: /api/errors/e3a0a1f78b3aa310. Report an issue: GitHub.