What causes "either prompt or exec is required" in chenhg5/cc-connect?

Add a non-empty "prompt" (for agent-driven jobs) OR "exec" (for shell commands) to the request JSON

either prompt or exec is required

Error message

either prompt or exec is required

What it means

handleCronAdd validates cron-job creation requests in the HTTP API. A cron job must be driven by either a natural-language prompt or an exec command; the server rejects requests that carry neither, preventing creation of a job that would do nothing when fired.

Source

Thrown at core/api.go:351

		http.Error(w, "POST only", http.StatusMethodNotAllowed)
		return
	}
	if s.cron == nil {
		http.Error(w, "cron scheduler not available", http.StatusServiceUnavailable)
		return
	}

	var req CronAddRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "invalid JSON: "+err.Error(), http.StatusBadRequest)
		return
	}
	if req.CronExpr == "" {
		http.Error(w, "cron_expr is required", http.StatusBadRequest)
		return
	}
	if req.Prompt == "" && req.Exec == "" {
		http.Error(w, "either prompt or exec is required", http.StatusBadRequest)
		return
	}
	if req.Prompt != "" && req.Exec != "" {
		http.Error(w, "prompt and exec are mutually exclusive", http.StatusBadRequest)
		return
	}

	// Resolve project: use provided, or pick single engine
	project := req.Project
	if project == "" {
		s.mu.RLock()
		if len(s.engines) == 1 {
			for name := range s.engines {
				project = name
			}
		}
		s.mu.RUnlock()
	}

View on GitHub (pinned to 4000b2338a)

Solutions

Add a non-empty "prompt" (for agent-driven jobs) OR "exec" (for shell commands) to the request JSON
Check the client code that builds the body — an empty variable is likely being serialized as "" and omitted downstream
Confirm you are not sending both later; note prompt and exec are mutually exclusive (next validation)
Inspect the response of a prior step that was supposed to supply the prompt/exec value

Example fix

// before
{"cron_expr": "0 9 * * *"}
// after
{"cron_expr": "0 9 * * *", "prompt": "summarize open issues"}

Defensive patterns

Strategy: validation

Validate before calling

const body = { cron_expr: expr, prompt, exec };
if (!body.prompt && !body.exec) throw new Error('cron job needs a prompt or exec');
if (body.prompt && body.exec) throw new Error('prompt and exec are mutually exclusive');

Type guard

function hasCronAction(b) { return (typeof b?.prompt === 'string' && b.prompt.length > 0) || (typeof b?.exec === 'string' && b.exec.length > 0); }

Prevention

Validate the request body client-side before POSTing
Never build the body from possibly-empty variables without a default
Remember prompt and exec are mutually exclusive — enforce that in your client model

When it happens

Trigger: POST to the cron-add endpoint where req.Prompt == "" and req.Exec == "" (both omitted or empty strings) while cron_expr is present.

Common situations: Clients building the JSON body dynamically omit both fields when a variable is empty; tooling sends only {"cron_expr": "0 9 * * *"}; copy-pasted curl examples drop the prompt field.

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

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/12942f23f260c47a. Report an issue: GitHub.