Migration Guide: From LeMUR to LLM Gateway

Overview

This guide helps you migrate from LeMUR to AssemblyAI’s LLM Gateway. While LeMUR was designed specifically for processing transcripts, LLM Gateway provides a more flexible, unified interface for working with multiple language models.

Key differences

Migration steps

Step 1: Replace transcript processing

Before (LeMUR): LeMUR automatically retrieved transcript text using transcript IDs.

After (LLM Gateway): You need to include the transcript text directly in your request.

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# LeMUR automatically fetched transcript content
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result = transcript.lemur.task(
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    prompt="What was the emotional sentiment of the phone call?",
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    final_model=aai.LemurModel.claude_sonnet_4_20250514
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)

Step 2: Update model names

LLM Gateway uses different model identifiers:

Step 3: Modify response handling

Before: LeMUR returned a simple response object. After: LLM Gateway returns OpenAI-compatible response format.

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result = transcript.lemur.task(prompt)
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print(result.response)  # Direct access to response text

Complete migration example

Here’s a complete example showing how to migrate a LeMUR sentiment analysis task:

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import assemblyai as aai
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aai.settings.api_key = "<YOUR_API_KEY>"
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# Step 1: Transcribe an audio file
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audio_file = "https://assembly.ai/call.mp4"
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transcriber = aai.Transcriber()
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transcript = transcriber.transcribe(audio_file)
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# Step 2: Apply LeMUR
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prompt = "What was the emotional sentiment of the phone call?"
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result = transcript.lemur.task(
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    prompt, final_model=aai.LemurModel.claude_sonnet_4_20250514
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)
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print(result.response)

Migration benefits

Moving to LLM Gateway provides several advantages:

More model choices

• 15+ models including Claude 4.5 Sonnet, GPT-5, and Gemini 2.5 Pro
• Better performance with newer, more capable models

Flexible input handling

• Multi-turn conversations for complex interactions
• Custom system prompts for better context control

Enhanced capabilities

• Tool calling for function execution
• Agentic workflows for multi-step reasoning
• OpenAI-compatible API for easier integration

Next steps

After migrating to LLM Gateway, explore additional capabilities:

• Multi-turn Conversations - Build conversational experiences
• Tool Calling - Enable function execution
• Agentic Workflows - Create multi-step reasoning

Need help?

If you encounter issues during migration:

1. Check model availability - Ensure your chosen model is supported
2. Verify API endpoints - LLM Gateway uses different URLs than LeMUR
3. Update response parsing - Response format follows OpenAI standards
4. Review token limits - Different models have different context windows