What causes "--input-json must be a JSON object" in Hmbown/CodeWhale?

Wrap the payload in a JSON object, e.g. `{"action": "run", ...}`.

--input-json must be a JSON object

Error message

--input-json must be a JSON object

What it means

After passing the approval-source check, `workflow-tool` parses `--input-json` with serde_json and additionally requires the parsed value to be a JSON object (`input.is_object()`). Non-object JSON (arrays, strings, numbers) is rejected even though it is valid JSON.

Solutions

Wrap the payload in a JSON object, e.g. `{"action": "run", ...}`.
Quote the whole `--input-json` value in single quotes in the shell to survive quoting.
Validate with `echo '<payload>' | jq -e 'type == "object"'` before invoking.

Example fix

// before
codewhale workflow-tool --input-json '[{"action":"run"}]'
// after
codewhale workflow-tool --approval-source explicit-workflow-command --input-json '{"action":"run"}'

Defensive patterns

Strategy: validation

Validate before calling

const input = JSON.parse(inputJson);
if (typeof input !== 'object' || input === null || Array.isArray(input)) {
  throw new Error('--input-json must be a JSON object');
}

Type guard

function isJsonObject(v) {
  return typeof v === 'object' && v !== null && !Array.isArray(v);
}

Try / catch

match serde_json::from_str::<serde_json::Value>(&args.input_json) {
    Ok(v) if v.is_object() => run(v),
    Ok(_) => bail!("--input-json must be a JSON object"),
    Err(e) => bail!("invalid JSON: {e}"),
}

Prevention

Validate payloads with `jq -e 'type == "object"'` before invoking.
Single-quote the whole --input-json value in shells to survive quoting.
Always model workflow input as a top-level object with an `action` field.

When it happens

Trigger: Passing `--input-json` that is a JSON array, scalar, or null — or unparseable text, which fails earlier with the `.context(...)` message — so `is_object()` returns false.

Common situations: Shell quoting mangling the JSON (quotes stripped so `{action:"run"}` is not valid JSON), or passing a top-level array of actions instead of a single object.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/7198d76cc57f13f4. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/lib.rs:12229

            exit_workflow_tool_failure();
        }
    }
}

async fn run_workflow_tool_command_inner(
    cli: &Cli,
    args: WorkflowToolArgs,
    plugin_registry: std::sync::Arc<crate::plugins::PluginRegistry>,
) -> Result<()> {
    use crate::tools::spec::ToolSpec;

    if args.approval_source != "explicit-workflow-command" {
        bail!("workflow-tool requires --approval-source explicit-workflow-command");
    }
    let input: serde_json::Value = serde_json::from_str(&args.input_json)
        .context("--input-json must be a valid Workflow tool input object")?;
    if !input.is_object() {
        bail!("--input-json must be a JSON object");
    }
    if !input
        .get("action")
        .and_then(serde_json::Value::as_str)
        .is_some_and(|action| action.eq_ignore_ascii_case("run"))
    {
        bail!("workflow-tool accepts only action=run");
    }

    let workspace = resolve_workspace(cli);
    let mut config = load_config_from_cli(cli)?;
    merge_user_workspace_config(&mut config, cli.config.clone(), &workspace);
    if let Ok(env_url) =
        std::env::var("CODEWHALE_BASE_URL").or_else(|_| std::env::var("DEEPSEEK_BASE_URL"))
    {
        let trimmed = env_url.trim();
        if !trimmed.is_empty() {
            config.base_url = Some(trimmed.to_string());

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