Produce STRICT JSON with the schema: {"specs": [{"spec": string, "category": string, "output_mode": string}]}.
Generate {{num}} diverse specs for the category: {{category}}.
All specs must have difficulty level: {{difficulty}}.
Guidelines:
- Each spec describes a self-contained function: given text input, produce text output.
- Specs should be precise enough that a developer knows what to implement, including edge cases and output format.
- Keep each spec concise (1-3 sentences). Do NOT include input/output examples in the spec.
- Vary the complexity and real-world applicability across specs.
- category must be "{{category}}" for all specs.
- output_mode must be one of: "string" (plain text output), "json_object" (JSON object output), "json_array" (JSON array output), "answer" (short factual answer).
Return ONLY JSON.