diff --git a/core/autocomplete/templating/index.ts b/core/autocomplete/templating/index.ts
index 3ebf29b71be..cb51ef55abb 100644
--- a/core/autocomplete/templating/index.ts
+++ b/core/autocomplete/templating/index.ts
@@ -204,7 +204,10 @@ function pruneLength(llm: ILLM, prompt: string): number {
   const contextLength = llm.contextLength;
   const reservedTokens = llm.completionOptions.maxTokens ?? DEFAULT_MAX_TOKENS;
   const safetyBuffer = getTokenCountingBufferSafety(contextLength);
-  const maxAllowedPromptTokens = contextLength - reservedTokens - safetyBuffer;
+  const maxAllowedPromptTokens = Math.max(
+    0,
+    contextLength - reservedTokens - safetyBuffer,
+  );
   const promptTokenCount = countTokens(prompt, llm.model);
   return promptTokenCount - maxAllowedPromptTokens;
 }