routine create fails to parse API response after accepting valid folder_id

[garoldot]

Environment

• hevycli installed via Homebrew cask on macOS
• Command run from terminal
• API key configured and other commands work

Problem

hevycli routine create appears to accept a valid folder_id, but then fails with a response parsing error:

error: failed to create routine: NETWORK_ERROR: failed to create routine: json: cannot unmarshal array into Go struct field RoutineResponse.routine of type api.Routine

Observed behavior

1. If folder_id is omitted or null, the API returns:

   [public-post-routine] Invalid routine folder id: undefined
   

2. If an invalid folder ID like 1 is provided, the API returns:

   [public-post-routine] Invalid routine folder id: 1
   

3. If a valid folder ID is provided, the request gets past folder validation, but hevycli crashes parsing the response with:

   json: cannot unmarshal array into Go struct field RoutineResponse.routine of type api.Routine
   

This suggests:

• request payload is accepted
• response schema from API may now return an array where hevycli expects a single object
• or the client is decoding the wrong shape for the create response

Reproduction

Command:

hevycli -o plain routine create --file chest-next-workout.json

Example payload:

{
  "routine": {
    "title": "Next Chest Workout",
    "folder_id": 2607603,
    "notes": "Chest hypertrophy focus. Minimum standard: log the full session and beat at least one metric next time.",
    "exercises": [
      {
        "exercise_template_id": "79D0BB3A",
        "rest_seconds": 150,
        "notes": "2 warm-up sets, then 3 work sets. Leave 1-2 reps in reserve on the first two work sets.",
        "sets": [
          {"type": "warmup", "reps": 15},
          {"type": "warmup", "reps": 8},
          {"type": "normal", "reps": 10},
          {"type": "normal", "reps": 8},
          {"type": "normal", "reps": 6}
        ]
      },
      {
        "exercise_template_id": "07B38369",
        "rest_seconds": 90,
        "notes": "Controlled eccentric. Full range.",
        "sets": [
          {"type": "normal", "reps": 12},
          {"type": "normal", "reps": 10},
          {"type": "normal", "reps": 8}
        ]
      },
      {
        "exercise_template_id": "78683336",
        "rest_seconds": 75,
        "notes": "Stretch and squeeze. No sloppy reps.",
        "sets": [
          {"type": "normal", "reps": 15},
          {"type": "normal", "reps": 12},
          {"type": "normal", "reps": 12}
        ]
      },
      {
        "exercise_template_id": "392887AA",
        "rest_seconds": 60,
        "notes": "Take sets close to failure with clean form.",
        "sets": [
          {"type": "normal", "reps": 15},
          {"type": "normal", "reps": 12}
        ]
      }
    ]
  }
}

Expected behavior

• Routine should be created successfully
• CLI should print created routine details or at least succeed silently

Actual behavior

• CLI returns a Go JSON unmarshal error after the request is accepted

Possible root cause

The API response shape for create may be returning:

• routine: []
• or another array/object layout that no longer matches the client struct:
  • RoutineResponse.routine api.Routine

Suggested fix

• inspect raw response body for routine create
• update the response struct to match current API behavior
• ideally add a fallback parser for object/array compatibility