docs: add Rule 52 prohibiting duplicate ontology mappings

- Create .opencode/rules/no-duplicate-ontology-mappings.md with detection script
- Add Rule 52 to AGENTS.md (after Rule 51)
- Fix 29 duplicate mappings: same URI in multiple mapping categories
  - 26 slot files: remove duplicates keeping most precise mapping
  - 3 class files: ExhibitionSpace, Custodian, DigitalPlatform
- Mapping precedence: exact > close > narrow/broad > related

Each ontology URI must appear in only ONE mapping category per schema
element, following SKOS semantics where mapping properties are mutually
exclusive.

.opencode/rules/no-duplicate-ontology-mappings.md

@@ -0,0 +1,189 @@
+# Rule 52: No Duplicate Ontology Mappings
+
+## Summary
+
+Each ontology URI MUST appear in only ONE mapping category per schema element. A URI cannot simultaneously have multiple semantic relationships to the same class or slot.
+
+## The Problem
+
+LinkML provides five mapping annotation types based on SKOS vocabulary alignment:
+
+| Property | SKOS Predicate | Meaning |
+|----------|---------------|---------|
+| `exact_mappings` | `skos:exactMatch` | "This IS that" (equivalent) |
+| `close_mappings` | `skos:closeMatch` | "This is very similar to that" |
+| `related_mappings` | `skos:relatedMatch` | "This is conceptually related to that" |
+| `narrow_mappings` | `skos:narrowMatch` | "This is MORE SPECIFIC than that" |
+| `broad_mappings` | `skos:broadMatch` | "This is MORE GENERAL than that" |
+
+These relationships are **mutually exclusive**. A URI cannot simultaneously:
+- BE the element (`exact_mappings`) AND be broader than it (`broad_mappings`)
+- Be closely similar (`close_mappings`) AND be more general (`broad_mappings`)
+
+## Anti-Pattern (WRONG)
+
+```yaml
+# WRONG - schema:url appears in TWO mapping types
+slots:
+  source_url:
+    slot_uri: prov:atLocation
+    exact_mappings:
+      - schema:url      # Says "source_url IS schema:url"
+    broad_mappings:
+      - schema:url      # Says "schema:url is MORE GENERAL than source_url"
+```
+
+This is a **logical contradiction**: `source_url` cannot simultaneously BE `schema:url` AND be more specific than `schema:url`.
+
+## Correct Pattern
+
+```yaml
+# CORRECT - each URI appears in only ONE mapping type
+slots:
+  source_url:
+    slot_uri: prov:atLocation
+    exact_mappings:
+      - schema:url      # source_url IS schema:url
+    close_mappings:
+      - dcterms:source  # Similar but not identical
+```
+
+## Decision Guide: Which Mapping to Keep
+
+When a URI appears in multiple categories, keep the **most precise** one:
+
+### Precedence Order (keep the first match)
+
+1. **exact_mappings** - Strongest claim: semantic equivalence
+2. **close_mappings** - Strong claim: nearly equivalent
+3. **narrow_mappings** / **broad_mappings** - Hierarchical relationship
+4. **related_mappings** - Weakest claim: conceptual association
+
+### Decision Matrix
+
+| If URI appears in... | Keep | Remove |
+|---------------------|------|--------|
+| exact + broad | exact | broad |
+| exact + close | exact | close |
+| exact + related | exact | related |
+| close + broad | close | broad |
+| close + related | close | related |
+| related + broad | related | broad |
+| narrow + broad | narrow | broad (contradictory!) |
+
+### Special Case: narrow + broad
+
+If a URI appears in BOTH `narrow_mappings` AND `broad_mappings`, this is a **data error** - the same URI cannot be both more specific AND more general. Investigate which is correct based on the ontology definition.
+
+## Real Examples Fixed
+
+### Example 1: source_url
+
+```yaml
+# BEFORE (wrong)
+slots:
+  source_url:
+    exact_mappings:
+      - schema:url
+    broad_mappings:
+      - schema:url  # Duplicate!
+
+# AFTER (correct)
+slots:
+  source_url:
+    exact_mappings:
+      - schema:url  # Keep exact (strongest)
+    # broad_mappings removed
+```
+
+### Example 2: Custodian class
+
+```yaml
+# BEFORE (wrong)
+classes:
+  Custodian:
+    close_mappings:
+      - cpov:PublicOrganisation
+    narrow_mappings:
+      - cpov:PublicOrganisation  # Duplicate!
+
+# AFTER (correct)
+classes:
+  Custodian:
+    close_mappings:
+      - cpov:PublicOrganisation  # Keep close (Custodian ≈ PublicOrganisation)
+    # narrow_mappings: use for URIs that are MORE SPECIFIC than Custodian
+```
+
+### Example 3: geonames_id (narrow + broad conflict)
+
+```yaml
+# BEFORE (wrong - logical contradiction!)
+slots:
+  geonames_id:
+    narrow_mappings:
+      - dcterms:identifier  # Says geonames_id is MORE SPECIFIC
+    broad_mappings:
+      - dcterms:identifier  # Says geonames_id is MORE GENERAL
+
+# AFTER (correct)
+slots:
+  geonames_id:
+    narrow_mappings:
+      - dcterms:identifier  # geonames_id IS a specific type of identifier
+    # broad_mappings removed (was contradictory)
+```
+
+## Detection Script
+
+Run this to find duplicate mappings in the schema:
+
+```python
+import yaml
+from pathlib import Path
+from collections import defaultdict
+
+mapping_types = ['exact_mappings', 'close_mappings', 'related_mappings', 
+                 'narrow_mappings', 'broad_mappings']
+
+dirs = [
+    Path('schemas/20251121/linkml/modules/slots'),
+    Path('schemas/20251121/linkml/modules/classes'),
+]
+
+for d in dirs:
+    for yaml_file in d.glob('*.yaml'):
+        try:
+            with open(yaml_file) as f:
+                content = yaml.safe_load(f)
+        except Exception:
+            continue
+        if not content:
+            continue
+        
+        for section in ['classes', 'slots']:
+            items = content.get(section, {})
+            if not isinstance(items, dict):
+                continue
+            for name, defn in items.items():
+                if not isinstance(defn, dict):
+                    continue
+                uri_to_types = defaultdict(list)
+                for mt in mapping_types:
+                    for uri in defn.get(mt, []) or []:
+                        uri_to_types[uri].append(mt)
+                for uri, types in uri_to_types.items():
+                    if len(types) > 1:
+                        print(f"{yaml_file}: {name} - {uri} in {types}")
+```
+
+## Validation Rule
+
+**Pre-commit check**: Before committing LinkML schema changes, run the detection script. If any duplicates are found, the commit should fail.
+
+## References
+
+- [LinkML Mappings Documentation](https://linkml.io/linkml-model/latest/docs/mappings/)
+- [SKOS Mapping Properties](https://www.w3.org/TR/skos-reference/#mapping)
+- Rule 50: Ontology-to-LinkML Mapping Convention (parent rule)
+- Rule 51: No Hallucinated Ontology References

AGENTS.md

@@ -1528,6 +1528,56 @@ slots:
 
 ---
 
+### Rule 52: No Duplicate Ontology Mappings
+
+🚨 **CRITICAL**: Each ontology URI MUST appear in only ONE mapping category per schema element. A URI cannot have multiple semantic relationships to the same class or slot.
+
+**The Problem**: LinkML mapping properties (`exact_mappings`, `close_mappings`, `related_mappings`, `narrow_mappings`, `broad_mappings`) are mutually exclusive based on SKOS semantics. The same URI appearing in multiple categories creates logical contradictions.
+
+**Anti-Pattern (WRONG)**:
+
+```yaml
+slots:
+  source_url:
+    exact_mappings:
+      - schema:url      # Says "source_url IS schema:url"
+    broad_mappings:
+      - schema:url      # Says "schema:url is MORE GENERAL than source_url"
+# CONTRADICTION: source_url cannot both BE schema:url AND be more specific than it
+```
+
+**Correct Pattern**:
+
+```yaml
+slots:
+  source_url:
+    exact_mappings:
+      - schema:url      # Keep only the most precise mapping
+```
+
+**Decision Guide** - When duplicates found, keep the MOST PRECISE:
+
+| Precedence | Mapping Type | Meaning |
+|------------|--------------|---------|
+| 1st (keep) | `exact_mappings` | Semantic equivalence |
+| 2nd | `close_mappings` | Nearly equivalent |
+| 3rd | `narrow_mappings` | This is more specific |
+| 4th | `broad_mappings` | This is more general |
+| 5th | `related_mappings` | Conceptual association |
+
+**Quick Reference**:
+
+| If URI in... | Action |
+|--------------|--------|
+| exact + broad | Keep exact, remove broad |
+| close + broad | Keep close, remove broad |
+| related + broad | Keep related, remove broad |
+| narrow + broad | ERROR - investigate (contradictory) |
+
+**See**: `.opencode/rules/no-duplicate-ontology-mappings.md` for complete documentation
+
+---
+
 ## Appendix: Full Rule Content (No .opencode Equivalent)
 
 The following rules have no separate .opencode file and are preserved in full:

schemas/20251121/linkml/manifest.json

@@ -1,5 +1,5 @@
 {
-  "generated": "2026-01-13T12:50:30.701Z",
+  "generated": "2026-01-13T14:57:26.896Z",
   "schemaRoot": "/schemas/20251121/linkml",
   "totalFiles": 2886,
   "categoryCounts": {

schemas/20251121/linkml/modules/classes/Custodian.yaml

@@ -146,7 +146,6 @@ classes:
     - pico:Person
     - schema:Person
     - schema:Organization
-    - cpov:PublicOrganisation
     - rico:CorporateBody
     - org:Organization
     - foaf:Person

schemas/20251121/linkml/modules/classes/DigitalPlatform.yaml

@@ -91,7 +91,6 @@ classes:
     - foaf:homepage
     close_mappings:
     - schema:WebApplication
-    - schema:SoftwareApplication
     - dcat:Catalog
     - dcat:DataService
     - crm:E73_Information_Object

schemas/20251121/linkml/modules/classes/ExhibitionSpace.yaml

@@ -76,7 +76,6 @@ classes:
     related_mappings:
     - schema:Museum
     - schema:ArtGallery
-    - aat:300005768
     slots:
     - has_or_had_admission_fee
     - current_exhibition

schemas/20251121/linkml/modules/slots/cataloging_standard.yaml

@@ -28,5 +28,3 @@ slots:
       description: Natural history specimen data standard
     related_mappings:
     - dcterms:conformsTo
-    broad_mappings:
-    - dcterms:conformsTo

schemas/20251121/linkml/modules/slots/claim_type.yaml

@@ -29,5 +29,3 @@ slots:
       '
     close_mappings:
     - dcterms:type
-    broad_mappings:
-    - dcterms:type

schemas/20251121/linkml/modules/slots/claim_value.yaml

@@ -14,5 +14,3 @@ slots:
     description: The extracted value from the web source. This is the actual content claimed to exist at the XPath location.
     close_mappings:
     - rdf:value
-    broad_mappings:
-    - rdf:value

schemas/20251121/linkml/modules/slots/collection_description.yaml

@@ -14,5 +14,3 @@ slots:
     - schema:description
     related_mappings:
     - dcterms:description
-    broad_mappings:
-    - dcterms:description

schemas/20251121/linkml/modules/slots/collection_scope.yaml

@@ -21,5 +21,3 @@ slots:
     - dcterms:coverage
     close_mappings:
     - schema:about
-    broad_mappings:
-    - dcterms:coverage

schemas/20251121/linkml/modules/slots/collection_size.yaml

@@ -71,5 +71,3 @@ slots:
     - schema:numberOfItems
     close_mappings:
     - dcterms:extent
-    broad_mappings:
-    - dcterms:extent

schemas/20251121/linkml/modules/slots/collection_type.yaml

@@ -41,5 +41,3 @@ slots:
       '
     close_mappings:
     - dcterms:type
-    broad_mappings:
-    - dcterms:type

schemas/20251121/linkml/modules/slots/confidence_method.yaml

@@ -11,5 +11,3 @@ slots:
       '
     close_mappings:
     - prov:wasGeneratedBy
-    broad_mappings:
-    - prov:wasGeneratedBy

schemas/20251121/linkml/modules/slots/conflict_status.yaml

@@ -39,7 +39,7 @@ slots:
           conflict_status:
             status: destroyed
             date: "2023-12-08"
-            description: "Destroyed by Israeli airstrike\        \ during Gaza conflict"
+            description: "Destroyed by Israeli airstrike during Gaza conflict"
             sources:
               - "LAP Gaza Report 2024"
           
@@ -49,7 +49,7 @@ slots:
             status: damaged
             date: "2022-03-01"
             is_rebuilding: true
-            description: "Damaged\        \ by shelling, currently under restoration"
+            description: "Damaged by shelling, currently under restoration"
             sources:
               - "UNESCO Ukraine heritage monitoring"
           
@@ -62,5 +62,3 @@ slots:
       - hc:time_of_destruction
       - hc:ConflictStatus
       - hc:ConflictStatusEnum
-    broad_mappings:
-      - adms:status

schemas/20251121/linkml/modules/slots/contact_email.yaml

@@ -26,5 +26,3 @@ slots:
     exact_mappings:
     - schema:email
     - vcard:hasEmail
-    broad_mappings:
-    - schema:email

schemas/20251121/linkml/modules/slots/event_date.yaml

@@ -19,5 +19,3 @@ slots:
     - schema:startDate
     related_mappings:
     - dcterms:date
-    broad_mappings:
-    - dcterms:date

schemas/20251121/linkml/modules/slots/extraction_method.yaml

@@ -38,5 +38,3 @@ slots:
     - CustodianTimelineEvent overrides range to TimelineExtractionMethodEnum
     close_mappings:
     - prov:wasGeneratedBy
-    broad_mappings:
-    - prov:wasGeneratedBy

schemas/20251121/linkml/modules/slots/extraction_note.yaml

@@ -16,5 +16,3 @@ slots:
       '
     close_mappings:
     - skos:note
-    broad_mappings:
-    - skos:note

schemas/20251121/linkml/modules/slots/geonames_id.yaml

@@ -38,8 +38,6 @@ slots:
     - gn:geonamesID
     narrow_mappings:
     - dcterms:identifier
-    broad_mappings:
-    - dcterms:identifier
 comments:
 - Used by Settlement, AuxiliaryPlace, and GeoSpatialPlace classes
 - 'Lookup URL: https://www.geonames.org/{geonames_id}/'

schemas/20251121/linkml/modules/slots/has_or_had_data_service_endpoint.yaml

@@ -32,5 +32,3 @@ slots:
       \n    iiif_image_api_version: \"3.0\"\n```\n"
     close_mappings:
     - dcat:endpointURL
-    broad_mappings:
-    - dcat:endpointURL

schemas/20251121/linkml/modules/slots/html_file.yaml

@@ -29,5 +29,3 @@ slots:
     range: string
     related_mappings:
     - dcterms:source
-    broad_mappings:
-    - dcterms:source

schemas/20251121/linkml/modules/slots/identifier_value.yaml

@@ -9,5 +9,3 @@ slots:
       \ (ISIL)\n- 'Q190804' (Wikidata)\n- '148691498' (VIAF)\n- '0000 0001 2146 5765' (ISNI with spaces)\n"
     exact_mappings:
     - rdf:value
-    broad_mappings:
-    - rdf:value

schemas/20251121/linkml/modules/slots/is_or_was_encompassed_by.yaml

@@ -54,9 +54,8 @@ slots:
       
     close_mappings:
       - schema:parentOrganization
-      - schema:memberOf
       - rico:isOrWasSubordinateTo
-      
+       
     broad_mappings:
       - schema:memberOf
       

schemas/20251121/linkml/modules/slots/managed_by.yaml

@@ -32,5 +32,3 @@ slots:
     - org:linkedTo
     close_mappings:
     - prov:wasAttributedTo
-    broad_mappings:
-    - prov:wasAttributedTo

schemas/20251121/linkml/modules/slots/metadata_standard.yaml

@@ -37,5 +37,3 @@ slots:
       '
     close_mappings:
     - dcterms:conformsTo
-    broad_mappings:
-    - dcterms:conformsTo

schemas/20251121/linkml/modules/slots/observation_source.yaml

@@ -43,5 +43,3 @@ slots:
     range: string
     close_mappings:
     - dcterms:source
-    broad_mappings:
-    - dcterms:source

schemas/20251121/linkml/modules/slots/platform_type.yaml

@@ -19,5 +19,3 @@ slots:
       \ types (e.g., digital archive + aggregator).\n"
     close_mappings:
     - dcterms:type
-    broad_mappings:
-    - dcterms:type

schemas/20251121/linkml/modules/slots/retrieval_agent.yaml

@@ -27,5 +27,3 @@ slots:
     - PersonWebClaim overrides range to RetrievalAgentEnum
     close_mappings:
     - prov:wasAttributedTo
-    broad_mappings:
-    - prov:wasAttributedTo

schemas/20251121/linkml/modules/slots/source_type.yaml

@@ -13,5 +13,3 @@ slots:
       '
     related_mappings:
     - dcterms:type
-    broad_mappings:
-    - dcterms:type

schemas/20251121/linkml/modules/slots/source_url.yaml

@@ -46,8 +46,6 @@ slots:
     exact_mappings:
     - schema:url
     - dcterms:source
-    broad_mappings:
-    - schema:url
 comments:
 - Maps to pav:retrievedFrom for provenance tracking
 - Essential for web claim verification workflows

schemas/20251121/linkml/modules/slots/wikidata_id.yaml

@@ -40,5 +40,3 @@ slots:
     - schema:sameAs
     narrow_mappings:
     - dcterms:identifier
-    broad_mappings:
-    - dcterms:identifier