diff --git a/rust/crates/api/src/providers/openai_compat.rs b/rust/crates/api/src/providers/openai_compat.rs
index 1d53f120b4..4f199a3e94 100644
--- a/rust/crates/api/src/providers/openai_compat.rs
+++ b/rust/crates/api/src/providers/openai_compat.rs
@@ -928,13 +928,14 @@ fn wire_model_for_base_url<'a>(
     if lowered_prefix == "openai" {
         let trimmed_base_url = base_url.trim_end_matches('/');
         let default_openai = DEFAULT_OPENAI_BASE_URL.trim_end_matches('/');
+        if matches!(lowered_prefix.as_str(), "xai" | "grok" | "kimi" | "gemini" | "gemma") {
+            return Cow::Borrowed(&model[pos + 1..]);
+        }
         if config.provider_name == "OpenAI" && trimmed_base_url != default_openai {
-            // OpenAI-compatible gateways such as OpenRouter commonly use
-            // slash-containing model slugs (for example `openai/gpt-4.1-mini`).
-            // Preserve the slug when the user configured a non-default OpenAI
-            // base URL; the prefix still routed to the OpenAI-compatible client,
-            // but the gateway owns the final model namespace.
-            return Cow::Borrowed(model);
+            // Only preserve the full slug if it's NOT a model we want to strip
+            if !model.contains("gemini") && !model.contains("gemma") {
+                return Cow::Borrowed(model);
+            }
         }
         return Cow::Borrowed(&model[pos + 1..]);
     }