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+# Scheduler Phase 1 Payload Notes
+
+Phase 1 keeps HumanCompiler runtime behavior unchanged. This document records
+the payload that HumanCompiler can already send today, and the equivalent shape
+expected by the external `Scheduler` repository's experimental Human daily
+fixtures.
+
+## Current Daily Schedule Request
+
+`POST /api/schedule/daily` keeps the existing request shape:
+
+```json
+{
+  "date": "2026-05-20",
+  "task_source": {
+    "type": "all_tasks"
+  },
+  "time_slots": [
+    {
+      "start": "09:00",
+      "end": "12:00",
+      "kind": "focused_work",
+      "capacity_hours": 2.5
+    },
+    {
+      "start": "13:00",
+      "end": "16:00",
+      "kind": "study",
+      "capacity_hours": 2.5
+    },
+    {
+      "start": "16:30",
+      "end": "18:00",
+      "kind": "light_work"
+    }
+  ],
+  "preferences": {},
+  "fixed_assignments": [
+    {
+      "task_id": "task-standup-notes",
+      "slot_index": 1,
+      "duration_hours": 0.5
+    }
+  ]
+}
+```
+
+The API adapter expands this request with database task data before calling the
+current optimizer. Regular tasks and quick tasks are both converted to
+`SchedulerTask`; quick task IDs are prefixed with `quick_`.
+
+## Equivalent External Scheduler Fixture
+
+The same scheduling intent can be represented in the external Scheduler repo as
+an editable YAML fixture:
+
+```yaml
+date: "2026-05-20"
+metadata:
+  name: humancompiler_payload_sample
+
+time_slots:
+  - index: 0
+    start: "09:00"
+    end: "12:00"
+    work_kind: focused_work
+    capacity_minutes: 150
+  - index: 1
+    start: "13:00"
+    end: "16:00"
+    work_kind: study
+    capacity_minutes: 150
+  - index: 2
+    start: "16:30"
+    end: "18:00"
+    work_kind: light_work
+
+fixed_assignments:
+  - task_id: task-standup-notes
+    slot_index: 1
+    duration_minutes: 30
+
+tasks:
+  - id: task-proposal
+    title: Draft product proposal
+    remaining_minutes: 90
+    priority: 1
+    work_kind: focused_work
+    due_at: "2026-05-22T17:00:00"
+    project_id: project-alpha
+    goal_id: goal-launch
+    source: task
+  - id: quick-inbox
+    title: Clear inbox and small replies
+    remaining_minutes: 30
+    priority: 4
+    work_kind: light_work
+    source: quick_task
+
+task_dependencies:
+  task-proposal:
+    - task-research
+```
+
+## Input Mapping
+
+| HumanCompiler field | External Scheduler fixture field | Notes |
+| --- | --- | --- |
+| `DailyScheduleRequest.date` | `date` | Same calendar day. |
+| `time_slots[].start` / `end` | `time_slots[].start` / `end` | Same `HH:MM` strings. |
+| `time_slots[].kind` | `time_slots[].work_kind` | Values map directly: `light_work`, `focused_work`, `study`. |
+| `time_slots[].capacity_hours` | `time_slots[].capacity_minutes` | Convert hours to minutes. If omitted, slot duration is used. |
+| `time_slots[].assigned_project_id` | `time_slots[].assigned_project_id` | Project-specific slot constraint. |
+| `fixed_assignments[].task_id` | `fixed_assignments[].task_id` | Same task identifier after quick task prefixing. |
+| `fixed_assignments[].slot_index` | `fixed_assignments[].slot_index` | Same zero-based slot index. |
+| `fixed_assignments[].duration_hours` | `fixed_assignments[].duration_minutes` | Convert hours to minutes. |
+| regular `Task.id` | `tasks[].id` | UUID string from HumanCompiler. |
+| quick task ID | `tasks[].id` | Prefix with `quick_`, matching current API adapter behavior. |
+| task title | `tasks[].title` | Safe to anonymize for exported fixtures later. |
+| estimate minus actual logged hours | `tasks[].remaining_minutes` | Current API already computes remaining hours for regular tasks. |
+| `Task.priority` / `QuickTask.priority` | `tasks[].priority` | Quick task priority is already passed. Regular task priority is still a known gap in the current adapter. |
+| `work_type` | `tasks[].work_kind` | Falls back to title-based kind inference only when regular tasks lack `work_type`. |
+| `due_date` | `tasks[].due_at` | Use ISO datetime when present. |
+| task goal | `tasks[].goal_id` | Regular tasks only. |
+| goal project | `tasks[].project_id` | Derived from the task goal for regular tasks. |
+| task dependencies | `task_dependencies` | Map dependent task ID to prerequisite task IDs. |
+
+## Output Mapping
+
+| Current API response field | External Scheduler result field | Notes |
+| --- | --- | --- |
+| `success` | report status | HumanCompiler should continue returning the current boolean when integrated later. |
+| `date` | fixture `date` | Same requested date. |
+| `assignments[].task_id` | `plan.blocks[].task_id` | Same task ID. |
+| `assignments[].slot_index` | `plan.blocks[].slot_index` | Same slot index. |
+| `assignments[].start_time` | `plan.blocks[].start` | External timeline blocks have concrete sequential start times. |
+| `assignments[].duration_hours` | `plan.blocks[].duration_minutes` | Convert minutes to hours. |
+| `assignments[].is_fixed` | `plan.blocks[].is_fixed` | Same meaning. |
+| `unscheduled_tasks[]` | `unscheduled_tasks[]` | External result adds `reason`; current API does not expose it yet. |
+| `optimization_status` | `plan.status` | Exact status values do not need to match during Phase 1. |
+| `objective_value` | `score_breakdown[]` | External review output is richer than the current single objective value. |
+
+## Current Gaps For Later Phases
+
+- Regular task priority is still hardcoded to `3` before the daily optimizer.
+  Quick tasks already pass their real priority.
+- The current daily API does not expose unscheduled reasons, score breakdowns,
+  or constraint violations.
+- Current assignments are slot-shaped. Multiple tasks in one slot can still
+  share the same `start_time`.
+- Phase 1 does not import the external package into HumanCompiler and does not
+  change persisted schedule data.