diff --git a/.cursor/skills/treatment-workspace/SKILL.md b/.cursor/skills/treatment-workspace/SKILL.md
index 932ab50..c0ba28b 100644
--- a/.cursor/skills/treatment-workspace/SKILL.md
+++ b/.cursor/skills/treatment-workspace/SKILL.md
@@ -45,7 +45,7 @@ Right-column entry is **not** a three-step wizard. Type dropdown + `TreatmentDet
 
 - Prosthesis uses `WizardStepper` (Treatment → Lab) with Back/Next. Lab dispatch keeps comments.
 - Detail chips show **type + teeth**, not “Detail N”. Lab-dependent chips use colored sent/unsent text (same size as the label); sent date stays on Lab dispatch.
-- Detail type may differ from appointment purpose. Purpose only seeds the **first** line of an empty draft — **Add detail** starts with an empty type.
+- Detail type may differ from appointment purpose. Purpose seeds the first line of an empty **appointment** draft (first open, and **Add detail** when the plan is `[]`). Later **Add detail** starts with an empty type. Unscheduled / New treatment still seeds a blank first line.
 - Switching `activeDetailId` resets to the treatment form, unless `pendingEntryStepRef` is set to `lab` first (lab shipments rail / “Go to dispatch” / load-with-focus).
 - Live draft is **not** duplicated in the left rail preview; preview is for history browse only.
 
diff --git a/AGENTS.md b/AGENTS.md
index 4cb937a..ee313a0 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -55,7 +55,7 @@ frontend/src/
 **Treatment lab rules (quick ref):**
 - Lab-dependent details (e.g. prosthesis) **without teeth** can save but **cannot ship** — same inline amber banner (`labShipmentBlockedBody`) on Treatment **and** Lab steps; toast on dispatch add.
 - New prosthesis dispatch lines start **empty** (no default lab, no apply-all / per-tooth prosthesis type), even for siblings in the same plan. Recent-lab chips are the last **3 sent** destinations — pick is explicit, never auto-selected.
-- Detail treatment type need **not** match appointment purpose — purpose only seeds the **first** line of an empty draft; **Add detail** starts with an empty type.
+- Detail treatment type need **not** match appointment purpose — purpose only seeds the **first** line of an empty **appointment** draft (first open, and **Add detail** when the plan is `[]`). Further **Add detail** starts with an empty type. Unscheduled / New treatment still seeds a blank first line.
 - **History filters** are client-side only (`treatmentHistoryFilters.ts`): “Not shipped to lab” + single date on already-fetched patient history; includes live current draft when filtering.
 - **Lab shipments rail**: unified list with scope toggle **This patient** vs **All updates** (unread across org for **this clinician's cases only**, includes patient name). Opening a case from the rail jumps to the **Lab** send sheet.
 - **Unread semantics**: Treatment tab badge = count of unread cases **for the user's own treatment plans** (per-case read cursor) and clears when a case is opened/marked read (not on tab visit).
diff --git a/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx b/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx
index 586a146..0d22bba 100644
--- a/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx
+++ b/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx
@@ -2438,7 +2438,14 @@ export function TreatmentWorkspace({
             saveStatus={saveStatus}
             uploadBusy={uploadBusyDetailId === activeDetailId}
             onAddDetail={() => {
-              const next = newDetail();
+              const seedFromAppointment =
+                details.length === 0 && selectedAppointment
+                  ? defaultTreatmentTypeForAppointment(
+                      selectedAppointment.purpose,
+                      treatmentCatalog,
+                    )
+                  : undefined;
+              const next = newDetail(seedFromAppointment);
               setDetails((prev) => [...prev, next]);
               setActiveDetailId(next.clientId);
               setEntryStep('treatment');