zeroclaw-labs/zeroclaw · error · anyhow::Error

Declarative cron job '{id}': agent job requires a non-empty

Error message

Declarative cron job '{id}': agent job requires a non-empty 'prompt'

What it means

validate_decl enforces that declarative cron jobs with job_type = "agent" carry a non-empty prompt. The prompt is the instruction sent to the LLM when the job fires, so an agent job without one has nothing to run; validation fails during sync_declarative_jobs before any DB write.

Source

Thrown at crates/zeroclaw-runtime/src/cron/store.rs:1411

}

/// Validate a declarative cron job definition.
fn validate_decl(id: &str, decl: &zeroclaw_config::schema::CronJobDecl) -> Result<()> {
    if id.trim().is_empty() {
        anyhow::bail!("Declarative cron job has empty id");
    }

    match decl.job_type.to_lowercase().as_str() {
        "shell" => {
            if decl.command.as_deref().is_none_or(|c| c.trim().is_empty()) {
                anyhow::bail!(
                    "Declarative cron job '{id}': shell job requires a non-empty 'command'"
                );
            }
        }
        "agent" => {
            if decl.prompt.as_deref().is_none_or(|p| p.trim().is_empty()) {
                anyhow::bail!(
                    "Declarative cron job '{id}': agent job requires a non-empty 'prompt'"
                );
            }
            if decl.shell_output_format != zeroclaw_config::schema::CronShellOutputFormat::default()
            {
                anyhow::bail!(
                    "Declarative cron job '{id}': shell_output_format is shell-only and cannot be set on an agent job"
                );
            }
        }
        other => {
            anyhow::bail!(
                "Declarative cron job '{id}': invalid job_type '{other}', expected 'shell' or 'agent'"
            );
        }
    }

    Ok(())

View on GitHub (pinned to 88bb9c8533)

Solutions

1. Add prompt = "<instruction for the agent>" to the [cron.<id>] table
2. If the job should run a command instead, set job_type = "shell" and provide a non-empty command
3. Make sure prompt is not only whitespace

Example fix

# before
[cron.summarize]
job_type = "agent"
schedule = { kind = "cron", expression = "0 9 * * *" }

# after
[cron.summarize]
job_type = "agent"
schedule = { kind = "cron", expression = "0 9 * * *" }
prompt = "Summarize yesterday's commits and post a digest."

for (id, decl) in &decls {
    if decl.job_type.eq_ignore_ascii_case("agent")
        && decl.prompt.as_deref().is_none_or(|p| p.trim().is_empty())
    {
        anyhow::bail!("cron job '{id}': agent job needs a non-empty 'prompt'");
    }
}

fn agent_decl_is_runnable(decl: &zeroclaw_config::schema::CronJobDecl) -> bool {
    !decl.job_type.eq_ignore_ascii_case("agent")
        || decl.prompt.as_deref().is_some_and(|p| !p.trim().is_empty())
}

if let Err(err) = zeroclaw_runtime::cron::sync_declarative_jobs(&config, &decls) {
    if err.to_string().contains("agent job requires") {
        eprintln!("config error: an agent [cron.<id>] table is missing 'prompt'");
    }
    return Err(err);
}

When it happens

Trigger: A [cron.<id>] table with job_type = "agent" and no prompt key, prompt = "", or prompt containing only whitespace.

Common situations: Converting a shell job to an agent job and replacing command with prompt only partially; filling in model and allowed_tools but forgetting the prompt; expecting the heartbeat fallback message to apply to cron agent jobs (it does not).

Understand the failure class

Background: Config validation failed: what "invalid value for {key}" and settings-rejection errors mean across 19 open-source libraries — this error's family across 19 libraries.

Related errors

• Declarative cron job '{id}': shell_output_format is shell-on
• Declarative cron job has empty id
• Declarative cron job '{id}': shell job requires a non-empty
• Declarative cron job '{id}': invalid job_type '{other}', exp
• ACP request_permission failed: {} ({})

AI-assisted analysis of zeroclaw-labs/zeroclaw@88bb9c8533 (2026-08-23). Data as JSON: /api/errors/253ef45da9961ae7. Report an issue: GitHub.