diff --git a/docs/memory/component-registry.md b/docs/memory/component-registry.md
index c2bf705..bdf5845 100644
--- a/docs/memory/component-registry.md
+++ b/docs/memory/component-registry.md
@@ -40,7 +40,7 @@ duplicates) and MUST update it after completing one.
 | ProviderCard | review | Card + Typography + Badge + Tooltip | Provider listing card. Verified: image + logo (64px rounded rect) + "Verified" badge. Unverified: text-only with top accent bar. Capability badges with info icon + tooltip. Price split typography. No footer. 4 component tokens. |
 | VenueCard | review | Card + Typography | Venue listing card. Always has photo + location + capacity ("X guests") + price ("From $X"). No verification tiers, no logo, no badges. 3 component tokens. Critique: 33/40. |
 | MapCard | planned | Card + Typography + Badge | Compact horizontal map popup card. Deferred until map integration. |
-| ServiceOption | planned | Card + Typography + Chip + Icon | Selectable service item |
+| ServiceOption | review | Card (interactive, selected) + Typography | Selectable service option for arrangement flow. Heading + optional price (right-aligned) + optional description. role="radio" + aria-checked. Disabled state with opacity token. Maps to Figma ListItemPurchaseOption. |
 | SearchBar | planned | Input + Icon + Button | Search with submit |
 | StepIndicator | planned | Typography + Badge + Divider | Multi-step flow progress |
 
diff --git a/docs/memory/session-log.md b/docs/memory/session-log.md
index 088f35e..611ddee 100644
--- a/docs/memory/session-log.md
+++ b/docs/memory/session-log.md
@@ -661,7 +661,46 @@ Each entry follows this structure:
 - **Planned (5 organisms):** ServiceSelector, PricingTable, ArrangementForm, Navigation, Footer
 
 **Next steps:**
-- User to review IconButton, Divider, Link in Storybook
-- Build ServiceOption molecule (core arrangement flow interaction)
-- Consider building Navigation organism (now that IconButton + Link are available)
+- ~~User to review IconButton, Divider, Link in Storybook~~ ✓ Approved
+- ~~Build ServiceOption molecule~~ ✓ Done
+
+### Session 2026-03-25n (continued) — ServiceOption molecule
+
+**Agent(s):** Claude Opus (via conversation)
+
+**Work completed:**
+- Reviewed 2 Figma components: ListItemPurchaseOption (2349:39505) and ListItemAddItem (2350:40658)
+  - ListItemPurchaseOption: click-to-select card with 4 states (inactive, hover, active, active hover)
+  - ListItemAddItem: toggle with Switch — deferred as a future AddOnOption molecule
+- Built ServiceOption molecule (`src/components/molecules/ServiceOption/ServiceOption.tsx`):
+  - Composes Card (interactive, selected) + Typography
+  - Heading row: name (h6) + optional price (h6, brand colour, right-aligned, nowrap)
+  - Optional description below (body2, text.secondary)
+  - Selected state via Card's built-in brand border + warm bg
+  - Disabled state with opacity token (--fa-opacity-disabled) + pointer-events: none
+  - role="radio" + aria-checked for proper single-select group semantics
+  - Uses card.padding.compact (16px) for content padding
+- Created 7 stories: Default, Selected, ServiceTypeSelection (interactive radiogroup),
+  CoffinSelection (interactive 4-option), WithoutPrice, Disabled, EdgeCases
+- No new tokens — ServiceOption reuses Card tokens (padding.compact, border.selected, etc.)
+
+**Decisions made:**
+- ServiceOption uses role="radio" + aria-checked — correct for single-select groups within a radiogroup. Parent wraps in role="radiogroup".
+- Price right-aligned in heading row — natural scanning pattern (name on left, cost on right, like a menu)
+- No component-specific tokens needed — Card's existing tokens handle all visual states
+- AddOnOption (ListItemAddItem with Switch) deferred — will compose Card + Switch when arrangement form organisms are built
+
+**Component status at end of session:**
+- **Done (8):** Button, Typography, Input, Card, Badge, Chip, Switch, Radio
+- **Review (3 atoms):** IconButton, Divider, Link
+- **Review (3 molecules):** ProviderCard, VenueCard, ServiceOption
+- **Planned (3 atoms):** Icon, Avatar, ColourToggle, Slider
+- **Planned (3 molecules):** MapCard, SearchBar, StepIndicator, FormField
+- **Planned (5 organisms):** ServiceSelector, PricingTable, ArrangementForm, Navigation, Footer
+
+**Next steps:**
+- User to review ServiceOption in Storybook
+- Build Navigation organism (IconButton + Link + Divider are now available)
+- Build SearchBar molecule (Input + IconButton)
+- Consider AddOnOption molecule (Card + Switch) when arrangement form is needed
 - Remaining P3s: InfoOutlinedIcon sizing in ProviderCard, image loading placeholder, accent bar 3px→4px