Budibase/budibase · error · Error

Budibase bash automation failed: Args must be a JSON array o

Error message

Budibase bash automation failed: Args must be a JSON array of strings.

What it means

The Bash automation step validates its `args` input through `validateArgs`, which requires the value to be an array whose every element is a string. If args is not an array at all, or contains a non-string element (number, object, boolean), it throws ARGS_VALIDATION_ERROR, surfaced as 'Args must be a JSON array of strings'. This guards against injecting malformed argv into the spawned bash process.

Source

Thrown at packages/server/src/automations/steps/bash.ts:19

import execa from "execa"
import { findHBSBlocks, processStringSync } from "@budibase/string-templates"
import * as automationUtils from "../automationUtils"
import environment from "../../environment"
import { BashStepInputs, BashStepOutputs } from "@budibase/types"

const INVALID_INPUTS = "Budibase bash automation failed: Invalid inputs"
const COMMAND_BINDINGS_ERROR =
  "Budibase bash automation failed: Command bindings are not supported. Use the args field for dynamic values."
const ARGS_VALIDATION_ERROR =
  "Budibase bash automation failed: Args must be a JSON array of strings."

interface JsonEditorInput {
  value?: unknown
}

const validateArgs = (args: unknown): string[] => {
  if (!Array.isArray(args) || args.some(arg => typeof arg !== "string")) {
    throw new Error(ARGS_VALIDATION_ERROR)
  }

  return args
}

const parseArgs = (args: unknown) => {
  if (args == null) {
    return []
  }

  if (Array.isArray(args)) {
    return validateArgs(args)
  }

  if (typeof args === "object" && "value" in (args as JsonEditorInput)) {
    const value = (args as JsonEditorInput).value

    if (Array.isArray(value)) {

View on GitHub (pinned to a81a902e9a)

Solutions

1. Change args to a JSON array of strings, e.g. ["-la", "/tmp"] instead of "-la /tmp" or ["-la", 123].
2. If args come from a previous step, wrap the value in a JS/string-template step that coerces each element with String(...) before passing it on.
3. If the value is a JSON string like '["-la"]', note parseArgs already JSON.parses strings, so the JSON itself must parse to a string array; fix the inner JSON, not the quoting.

Example fix

// before
{ "step": "bash", "inputs": { "args": "-la /tmp" } }
// after
{ "step": "bash", "inputs": { "args": ["-la", "/tmp"] } }

const isValidArgs = (args: unknown): args is string[] =>
  Array.isArray(args) && args.every(a => typeof a === "string")
if (!isValidArgs(inputs.args)) throw new Error("args must be a JSON array of strings")

const isStringArray = (v: unknown): v is string[] =>
  Array.isArray(v) && v.every((x): x is string => typeof x === "string")

try {
  await runBashStep({ args })
} catch (err) {
  if (err.message.includes("JSON array of strings")) {
    args = [String(args)].filter(Boolean)
    return runBashStep({ args })
  }
  throw err
}

When it happens

Trigger: Calling the bash step with `args` set to a plain string, a JSON object, null, or an array containing non-string items (e.g. [1,2] or ["ls", {"flag":true}]) passes the first Array.isArray/typeof check as false and throws.

Common situations: Configuring the step in the UI with a comma-separated string like 'ls, -la' instead of a JSON array; binding args from an automation context where a previous step returned a single string or numbers; hand-editing the automation definition JSON and using ["echo", 123].

Related errors

• Automation ID is required to test a saved password
• No trigger found for automation
• IMAP password is required when connection details change
• Template name is required
• Template description is required

AI-assisted analysis of Budibase/budibase@a81a902e9a (2026-08-29). Data as JSON: /api/errors/1779597af2787148. Report an issue: GitHub.