• Screen: SCR-CCM.27 — Assignment Builder
• Sub-use case: SUC-CCM-12 — Build Assignment (demoted from UC-CCM.03 on 2026-06-23)
• Invoked by: UC-CCM.01 (Author Course Content), UC-CCM.10 (Manage Course Assets)
• Type: page · Primary actor: ACT-02 (Instructor)

Current returnUrl: (none — standalone preview)
Fallback: / when returnUrl is empty.
Propagation: Save (main flow step 9) → returnUrl. Cancel (AF 1A) / Delete (AF 1B) → returnUrl + &sub_cancelled=1.

Opens in two modes: "new" (empty form, Delete disabled) and "edit" (pre-filled, Delete enabled) via ?mode=edit.
Step 9 (save, pass validation) returns to a different screen depending on the caller: from UC-CCM.01 → SCR-CCM.02 (assignment appears in the lesson's content item list); from UC-CCM.10 → SCR-CCM.24 (assignment appears in the Assignment tab of the asset library). The prototype uses the generic returnUrl passed in by the caller for both destinations.

• course_title — text · read-only · session.current_course_title
• lesson_position — text · read-only · param.lesson_position_label
• title — text · required · max 255
• instructions_html — rich text · combined required* with scenario_prompt_html (SS-CCM.30) · sanitized (SS-CCM.27)
• scenario_prompt_html — rich text ("Case study") · optional · sanitized (SS-CCM.27)
• submission_format — enum [text, file, both] · required · default text
• character_limit — number · visible when text/both · min 0 · 0 = unlimited
• max_files — number · visible when file/both · min 1
• accepted_file_types — enum · visible when file/both · TBD (open issue)
• criterion_text — textarea per row · required
• criterion_max_points — number per row · required · min 1
• total_rubric_points — computed · read-only · real-time update

• Assessment type (Practice/Summative radio) — removed. Now a delivery setting on the content item in the lesson editor, not the assignment itself. Per SUC-CCM-12 additional_requirements #5: "the same assignment can be summative in one lesson and practice in another."
• Optional assignment (switch) — removed. Per SUC-CCM-12 additional_requirements #9: the optional toggle is a delivery setting on the content item (UC-CCM.01 AF 7A), independent from the summative setting.
• Maximum resubmission attempts (number field) — removed. Same additional_requirements #9: the resubmission count is also a per-lesson delivery setting, not part of SCR-CCM.27's current field list.

SCR-CCM.27 action #4 ("Preview") is still defined in the current screen spec — client-side only, shows the assignment from the learner's perspective with unsaved data, triggers_uc_step: null (no corresponding SUC-CCM-12 flow step). Kept in this build; not tied to any AF number.

1. Validation errors display inline below fields; scroll to first error on Save [refs: SS-CCM.30]
2. Rich text toolbar: bold/italic/underline/lists/image; HTML sanitized before save [refs: SS-CCM.27]
3. Rubric drag-drop reorder must have keyboard alternative (↑/↓ buttons) [WCAG 2.1 AA]
4. At least one of "Instructions" or "Case study" must have content [refs: SS-CCM.30]