diff --git a/src/core/ai/dims.ts b/src/core/ai/dims.ts
index ab8b7ab95..b88a4e175 100644
--- a/src/core/ai/dims.ts
+++ b/src/core/ai/dims.ts
@@ -244,10 +244,9 @@ export function dimsProviderOptions(
       // configured for a smaller width (e.g. 1536) hard-fail at first embed.
       // Azure/OpenAI-compat embeddings are symmetric — inputType ignored.
       // v0.36.0.0 (D13): same range validation as native-openai path.
-      const bareModelId = modelId.includes('/') ? modelId.split('/').pop()! : modelId;
-      if (bareModelId.startsWith('text-embedding-3')) {
-        if (isOpenAITextEmbedding3Model(bareModelId) && !isValidOpenAITextEmbedding3Dim(bareModelId, dims)) {
-          const max = maxOpenAITextEmbedding3Dim(bareModelId)!;
+      if (modelId.startsWith('text-embedding-3')) {
+        if (isOpenAITextEmbedding3Model(modelId) && !isValidOpenAITextEmbedding3Dim(modelId, dims)) {
+          const max = maxOpenAITextEmbedding3Dim(modelId)!;
           throw new AIConfigError(
             `OpenAI model "${modelId}" supports embedding_dimensions in 1..${max}, got ${dims}.`,
             `Set \`embedding_dimensions\` to a value between 1 and ${max} ` +
diff --git a/test/ai/dims-openai.test.ts b/test/ai/dims-openai.test.ts
index 2d05a4dcb..c1359fdfc 100644
--- a/test/ai/dims-openai.test.ts
+++ b/test/ai/dims-openai.test.ts
@@ -134,30 +134,3 @@ describe('dimsProviderOptions — OpenAI on openai-compatible adapter (Azure cas
     expect(JSON.stringify(opts)).not.toContain('input_type');
   });
 });
-
-describe('dimsProviderOptions — prefixed model IDs (OpenRouter / proxy providers)', () => {
-  test('openai/text-embedding-3-large at 1536d returns dimensions=1536', () => {
-    const opts = dimsProviderOptions('openai-compatible', 'openai/text-embedding-3-large', 1536);
-    expect(opts).toEqual({ openaiCompatible: { dimensions: 1536 } });
-  });
-
-  test('openai/text-embedding-3-small at 768d returns dimensions=768', () => {
-    const opts = dimsProviderOptions('openai-compatible', 'openai/text-embedding-3-small', 768);
-    expect(opts).toEqual({ openaiCompatible: { dimensions: 768 } });
-  });
-
-  test('openai/text-embedding-3-large at 5000d throws AIConfigError', () => {
-    expect(() => dimsProviderOptions('openai-compatible', 'openai/text-embedding-3-large', 5000))
-      .toThrow(AIConfigError);
-  });
-
-  test('error message preserves full prefixed model ID for clarity', () => {
-    try {
-      dimsProviderOptions('openai-compatible', 'openai/text-embedding-3-large', 5000);
-      throw new Error('should have thrown');
-    } catch (err) {
-      expect(err).toBeInstanceOf(AIConfigError);
-      expect((err as Error).message).toContain('openai/text-embedding-3-large');
-    }
-  });
-});