fix(models): allow distinct protocols on one provider base URL

Author: bobleer

src/crates/assembly/core/AGENTS.md

@@ -212,6 +212,12 @@ or test-target layout. Workspace checks and product-wide tests are CI-backed and
 are not the default Core precheck. For documentation-only changes, run
 `git diff --check`.
 
+For built-in provider overlay, trusted endpoint validation, and reasoning catalog changes:
+
+```bash
+cargo test -p openbitfun-core --no-default-features --features ai-adapter-runtime --lib infrastructure::ai::
+```
+
 Configuration persistence, account settings import, backup restore, legacy
 field/deletion compatibility, local-change notifications, and save/reload/model
 concurrency regressions have feature-free fixtures:

src/crates/assembly/core/src/infrastructure/ai/provider_catalog.rs

@@ -212,6 +212,7 @@ fn validate_overlay(overlay: &ProviderOverlayDocument) -> Result<(), String> {
     let mut provider_ids = BTreeSet::new();
     let mut catalog_provider_owners = BTreeMap::<String, String>::new();
     let mut trusted_urls = BTreeMap::<String, String>::new();
+    let mut trusted_routes = BTreeSet::new();
     for provider in &overlay.providers {
         if provider.id.trim().is_empty() || !provider_ids.insert(provider.id.as_str()) {
             return Err(format!("duplicate or empty provider ID '{}'", provider.id));
@@ -339,11 +340,19 @@ fn validate_overlay(overlay: &ProviderOverlayDocument) -> Result<(), String> {
                             provider.id, endpoint.id
                         ));
                     }
+                    // One provider may expose multiple protocols at the same base,
+                    // but ownership and each protocol's binding must be unambiguous.
+                    let unique_route = trusted_routes.insert((
+                        normalized.clone(),
+                        endpoint.api_format.trim().to_ascii_lowercase(),
+                    ));
                     if let Some(previous) = trusted_urls.insert(normalized, provider.id.clone()) {
-                        return Err(format!(
-                            "trusted endpoint is claimed by providers '{previous}' and '{}'",
-                            provider.id
-                        ));
+                        if previous != provider.id || !unique_route {
+                            return Err(format!(
+                                "trusted endpoint is claimed by providers '{previous}' and '{}'",
+                                provider.id
+                            ));
+                        }
                     }
                 }
             }
@@ -572,10 +581,32 @@ mod tests {
     use super::{parse_overlay, resolve_builtin_provider_catalog, trusted_models_dev_binding};
     use openbitfun_ai_adapters::models_dev::ModelsDevCatalog;
 
+    #[test]
+    fn trusted_urls_allow_distinct_protocols_only_within_one_provider() {
+        let overlay = parse_overlay().expect("valid overlay with MiMo protocols");
+        let index = overlay
+            .providers
+            .iter()
+            .position(|p| p.id == "xiaomi")
+            .unwrap();
+        let mut duplicate = overlay.clone();
+        // A second spelling of the same protocol/normalized URL is ambiguous.
+        duplicate.providers[index].endpoints[1].api_format = " OpenAI ".into();
+        assert!(super::validate_overlay(&duplicate).is_err());
+
+        let mut cross_provider = overlay.clone();
+        let mut other = overlay.providers[index].clone();
+        other.id = "other-provider".into();
+        other.endpoints.truncate(1);
+        other.endpoints[0].api_format = "gemini".into();
+        cross_provider.providers.push(other);
+        assert!(super::validate_overlay(&cross_provider).is_err());
+    }
+
     #[test]
     fn overlay_is_valid_and_keeps_product_endpoint_decisions() {
         let overlay = parse_overlay().expect("valid overlay");
-        assert_eq!(overlay.providers.len(), 14);
+        assert_eq!(overlay.providers.len(), 15);
         let go = overlay
             .providers
             .iter()
@@ -812,7 +843,7 @@ mod tests {
             "bundle".to_string(),
             ProviderCatalogSource::Bundle,
         );
-        assert_eq!(resolved.providers.len(), 14);
+        assert_eq!(resolved.providers.len(), 15);
         let go = resolved
             .providers
             .iter()