diff --git a/.gitignore b/.gitignore
index f861804cf..674eed813 100644
--- a/.gitignore
+++ b/.gitignore
@@ -45,6 +45,9 @@ cypress/fixtures/
 .idea/*
 .vscode/*
 
+# Claude Code
+.claude/
+
 # Configuration
 /**/app-config.json
 
diff --git a/openspec/changes/fix-category-option-mapping/.openspec.yaml b/openspec/changes/fix-category-option-mapping/.openspec.yaml
new file mode 100644
index 000000000..5aae5cfa4
--- /dev/null
+++ b/openspec/changes/fix-category-option-mapping/.openspec.yaml
@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-03-04
diff --git a/openspec/changes/fix-category-option-mapping/design.md b/openspec/changes/fix-category-option-mapping/design.md
new file mode 100644
index 000000000..b46de1786
--- /dev/null
+++ b/openspec/changes/fix-category-option-mapping/design.md
@@ -0,0 +1,57 @@
+## Context
+
+Category options in DHIS2 can belong to multiple categories. The mapping system uses a composite ID format `"{categoryId}-{categoryOptionId}"` to disambiguate which category context a mapping applies in. This composite format is used in nested mapping (within a category combo) by `CategoryOptionMappedModel.modelTransform`.
+
+However, in **global mapping**, category options should be listed once each with their plain DHIS2 ID — they're mapped globally regardless of which category they belong to. The current code has three intertwined problems:
+
+1. **`MappingDialog` always uses `modelFactory("categoryOptions")`** which resolves to `CategoryOptionMappedModel` (the first class with `mappingType = "categoryOptions"`). This model's `modelTransform` expands each option into N rows by category → duplicates.
+
+2. **ID format mismatch on read-back**: When a user selects a destination item, the composite ID (e.g. `"catA-opt1"`) is stored as `mappedId`. When re-opening, `MappingDialog` strips it to plain ID via `_.last(split("-"))` → `"opt1"`. But the table lists composite IDs, so `"opt1"` matches nothing → selection appears lost.
+
+3. **Automap stores plain IDs**: `lookupSimilar()` returns plain DHIS2 IDs. With `initialShowOnlySelected=true` and composite IDs in the table, the result is invisible.
+
+The backend consumer (`mapCategoryOptionCombo` in `src/utils/synchronization.ts`) already handles both formats using `_.last(candidate.split("-"))`, so fixing the UI won't break sync operations.
+
+## Goals / Non-Goals
+
+**Goals:**
+- Each category option appears exactly once in the global mapping destination picker
+- Selected mappings are visually persistent when re-opening the dialog
+- Automap results are visible in the selection window
+- Nested (non-global) category option mapping continues to work with composite IDs
+
+**Non-Goals:**
+- Changing the mapping storage format in the dataStore
+- Modifying the backend sync consumer (`mapCategoryOptionCombo`)
+- Fixing mapping for other metadata types
+
+## Decisions
+
+### 1. Use plain `CategoryOptionModel` for the global mapping destination picker
+
+**Change:** In `MappingDialog`, when the mapping context is global category options, use a model that does NOT have the category-exploding `modelTransform`. This can be done by passing the appropriate model from the `MappingTable` (which already knows whether it's global or nested) instead of re-resolving via `modelFactory`.
+
+**Rationale:** The `MappingTable` already holds the model class for the source rows. For global mapping, this is `GlobalCategoryOptionModel` (no transform). The destination picker should use the same kind of model — plain category options without category expansion.
+
+**Approach:** Add the model (or mappingType context) to `MappingDialogConfig` so `MappingDialog` can use it directly instead of calling `modelFactory(mappingType)`. When a global model is provided, the dialog uses it; otherwise it falls back to the current `modelFactory` behavior for backward compatibility with nested mapping.
+
+**Alternatives considered:**
+- Creating a separate `GlobalCategoryOptionDestinationModel` — too many model classes already, adds complexity.
+- Modifying `modelFactory` to accept a "global" flag — leaks UI concerns into the factory.
+
+### 2. Store and read back plain IDs consistently for global category options
+
+**Change:** Since the destination picker will now list plain IDs (no composite), the `mappedId` stored will also be plain. The `mappedId` read-back logic in `MappingDialog` (lines 56-64) using `_.last(split("-"))` will naturally produce the correct plain ID. No change needed to the read-back logic — it already handles plain IDs correctly (`_.last("opt1".split("-"))` = `"opt1"`).
+
+**Rationale:** With plain IDs in both storage and display, the selection will match correctly when the dialog is re-opened.
+
+### 3. No change needed for automap
+
+**Change:** None. Automap already stores plain IDs. Once the destination picker uses plain IDs too, the automap result will match rows correctly.
+
+**Rationale:** The automap bug is a symptom of the same root cause (composite vs plain ID mismatch in the destination table). Fixing decision #1 resolves it automatically.
+
+## Risks / Trade-offs
+
+- **[Low] Existing global mappings with composite `mappedId` values** → The `_.last(split("-"))` read-back logic already strips these to plain IDs, so existing stored mappings will display correctly. New mappings will be stored with plain IDs. The backend consumer handles both formats.
+- **[Low] Nested (non-global) category option mapping** → Unchanged. The `MappingDialog` will only use the plain model when a global-context model is explicitly provided; nested mapping continues using `CategoryOptionMappedModel` via `modelFactory`.
diff --git a/openspec/changes/fix-category-option-mapping/proposal.md b/openspec/changes/fix-category-option-mapping/proposal.md
new file mode 100644
index 000000000..23ac8570b
--- /dev/null
+++ b/openspec/changes/fix-category-option-mapping/proposal.md
@@ -0,0 +1,25 @@
+## Why
+
+Category option mapping in Global Mapping is broken in three ways: the destination picker shows duplicate entries (one per category a category option belongs to), selected mappings appear lost when re-opening the dialog, and automap results are invisible in the selection window. All three stem from an inconsistency between how category option IDs are stored (composite `categoryId-optionId` vs plain `optionId`) and how they are read back in the UI.
+
+## What Changes
+
+- **Fix duplicate destination entries**: The `MappingDialog` uses `modelFactory("categoryOptions")` which resolves to `CategoryOptionMappedModel` — a model with a `modelTransform` that explodes each category option into N rows (one per parent category). For the destination picker in global mapping, use plain `CategoryOptionModel` instead to list each category option once.
+- **Fix mapping not persisting visually**: `MappingDialog` stores composite IDs as `mappedId` but strips them back to plain IDs with `_.last(split("-"))` when reading, causing a mismatch with the composite row IDs in the table. Ensure consistent ID handling so the previously selected item is correctly highlighted.
+- **Fix automap selection invisible**: `AutoMapUseCase` stores plain destination IDs, but the destination table lists composite IDs. The `initialShowOnlySelected` filter then shows zero rows. Align the ID format used by automap with what the table displays.
+
+## Capabilities
+
+### New Capabilities
+
+_(none — this is a bug fix)_
+
+### Modified Capabilities
+
+_(no spec-level requirement changes — the intended mapping behavior was correct by design, only the ID handling is broken)_
+
+## Impact
+
+- **Code**: `src/presentation/react/core/components/mapping-dialog/MappingDialog.tsx` (ID consistency), `src/models/dhis/mapping.ts` (`GlobalCategoryOptionModel`), `src/models/dhis/factory.ts` (model resolution for global mapping context)
+- **User impact**: Global category option mapping will show each option once, persist selections visually, and display automap results correctly
+- **Risk**: Low — changes are scoped to the mapping UI; the backend mapping consumer (`mapCategoryOptionCombo` in `synchronization.ts`) already handles both composite and plain keys via `_.last(split("-"))`
diff --git a/openspec/changes/fix-category-option-mapping/specs/category-option-mapping/spec.md b/openspec/changes/fix-category-option-mapping/specs/category-option-mapping/spec.md
new file mode 100644
index 000000000..7b03e44e7
--- /dev/null
+++ b/openspec/changes/fix-category-option-mapping/specs/category-option-mapping/spec.md
@@ -0,0 +1,44 @@
+## ADDED Requirements
+
+### Requirement: Global mapping destination picker SHALL list each category option exactly once
+
+When the user opens the mapping dialog for a category option in the global mapping context, the destination picker MUST display each category option from the destination instance exactly once, using its plain DHIS2 ID.
+
+#### Scenario: Category option belonging to multiple categories appears once
+- **WHEN** a category option exists in the destination instance and belongs to 3 different categories
+- **THEN** the destination picker SHALL display that category option exactly once, not 3 times
+
+#### Scenario: Destination picker uses plain IDs for global mapping
+- **WHEN** the mapping dialog opens for a global category option mapping
+- **THEN** each row in the destination picker SHALL use the plain category option ID (not the composite `categoryId-optionId` format)
+
+### Requirement: Selected global category option mapping SHALL be visible when re-opening the dialog
+
+When the user has selected a destination category option in global mapping, re-opening the mapping dialog for the same source element MUST show the previously selected destination item as selected.
+
+#### Scenario: Previously mapped category option is highlighted on dialog re-open
+- **WHEN** the user maps source category option A to destination category option B and closes the dialog
+- **AND** the user re-opens the mapping dialog for source category option A
+- **THEN** destination category option B SHALL be shown as selected in the picker
+
+#### Scenario: "Show only selected" filter displays the mapped item
+- **WHEN** the user re-opens a mapping dialog for a category option that was previously mapped
+- **AND** the dialog opens with the "show only selected" filter active
+- **THEN** the previously mapped destination category option SHALL appear in the filtered list
+
+### Requirement: Automap results for category options SHALL be visible in the mapping dialog
+
+When automap has assigned a destination category option, opening the mapping dialog MUST show that automapped selection.
+
+#### Scenario: Automapped category option is visible in the dialog
+- **WHEN** automap has matched source category option A to destination category option B
+- **AND** the user opens the mapping dialog for source category option A
+- **THEN** destination category option B SHALL be shown as selected in the picker
+
+### Requirement: Nested (non-global) category option mapping SHALL continue using composite IDs
+
+The composite `categoryId-optionId` format used in nested category option mapping (within category combos) MUST remain unchanged.
+
+#### Scenario: Nested mapping still uses composite IDs
+- **WHEN** the user maps a category option within a category combo mapping context (non-global)
+- **THEN** the destination picker SHALL use composite `categoryId-optionId` IDs as before
diff --git a/openspec/changes/fix-category-option-mapping/tasks.md b/openspec/changes/fix-category-option-mapping/tasks.md
new file mode 100644
index 000000000..4b3b360ad
--- /dev/null
+++ b/openspec/changes/fix-category-option-mapping/tasks.md
@@ -0,0 +1,19 @@
+## 1. Pass model from MappingTable to MappingDialog
+
+- [ ] 1.1 [FE] Add a `model` field to `MappingDialogConfig` in `MappingDialog.tsx` so the caller can specify which model the destination picker should use
+- [ ] 1.2 [FE] In `MappingDialog`, use the provided `model` from config when available, falling back to `modelFactory(mappingType)` for backward compatibility
+- [ ] 1.3 [FE] In `MappingTable.tsx`, pass the current source model (which is `GlobalCategoryOptionModel` for global mapping) when opening the `MappingDialog`
+
+## 2. Verify ID consistency
+
+- [ ] 2.1 [FE] Verify that with the plain model in the destination picker, stored `mappedId` values are plain IDs, and `_.last(split("-"))` read-back produces matching values
+- [ ] 2.2 [FE] Verify that nested (non-global) category option mapping still works by confirming the fallback to `modelFactory` produces `CategoryOptionMappedModel` with composite IDs
+
+## 3. Unit Tests
+
+- [ ] 3.1 [FE] Add a test verifying `MappingDialog` uses the provided model instead of calling `modelFactory` when a model is passed in the config
+- [ ] 3.2 [FE] Run `yarn test` to confirm all existing tests pass
+
+## 4. Validation
+
+- [ ] 4.1 [FE] Run `yarn test` and `yarn build core-app` to confirm everything compiles and passes
diff --git a/src/presentation/react/core/components/mapping-dialog/MappingDialog.tsx b/src/presentation/react/core/components/mapping-dialog/MappingDialog.tsx
index d395b978a..c2a793b37 100644
--- a/src/presentation/react/core/components/mapping-dialog/MappingDialog.tsx
+++ b/src/presentation/react/core/components/mapping-dialog/MappingDialog.tsx
@@ -7,6 +7,7 @@ import React, { useEffect, useState, useMemo, useCallback } from "react";
 import { DataSource, isDhisInstance } from "../../../../../domain/instance/entities/DataSource";
 import { MetadataMappingDictionary } from "../../../../../domain/mapping/entities/MetadataMapping";
 import i18n from "../../../../../utils/i18n";
+import { D2Model } from "../../../../../models/dhis/default";
 import { modelFactory } from "../../../../../models/dhis/factory";
 import { MetadataType } from "../../../../../utils/d2";
 import { useAppContext } from "../../contexts/AppContext";
@@ -19,6 +20,7 @@ export interface MappingDialogConfig {
     mappingType?: string;
     mappingPath?: string[];
     firstElement?: MetadataType;
+    model?: typeof D2Model;
 }
 
 export interface MappingDialogProps {
@@ -69,7 +71,7 @@ const MappingDialog: React.FC<MappingDialogProps> = ({
 
     const [selected, updateSelected] = useState<string | undefined>(defaultSelection);
 
-    const model = useMemo(() => modelFactory(mappingType), [mappingType]);
+    const model = useMemo(() => config.model ?? modelFactory(mappingType), [config.model, mappingType]);
     const modelName = useMemo(() => model.getModelName(), [model]);
     const api = useMemo(() => {
         return isDhisInstance(instance) ? compositionRoot.instances.getApi(instance) : defaultApi;
diff --git a/src/presentation/react/core/components/mapping-table/MappingTable.tsx b/src/presentation/react/core/components/mapping-table/MappingTable.tsx
index 9d60ae872..8d624fcdf 100644
--- a/src/presentation/react/core/components/mapping-table/MappingTable.tsx
+++ b/src/presentation/react/core/components/mapping-table/MappingTable.tsx
@@ -292,6 +292,7 @@ export default function MappingTable({
                             mappingPath,
                             mappingType,
                             firstElement,
+                            model: firstElement.model,
                         });
                     }
                 }
@@ -326,7 +327,13 @@ export default function MappingTable({
                 .value();
 
             if (types.length === 1) {
-                setMappingConfig({ elements, mappingPath, mappingType: types[0], firstElement });
+                setMappingConfig({
+                    elements,
+                    mappingPath,
+                    mappingType: types[0],
+                    firstElement,
+                    model: firstElement?.model,
+                });
                 setSelectedIds([]);
             } else if (types.length > 1) {
                 snackbar.error(i18n.t("You need to select all items from the same type"));