Troubleshooting Gemini Integration with DSPex

Issue: “No LM is loaded” Despite Configuring Gemini

Even though Gemini is successfully configured (API key is shown), DSPy modules report “No LM is loaded” when trying to execute.

Root Cause

The issue occurs due to how DSPy/LiteLLM handles API keys for different providers:

1. DSPy uses LiteLLM under the hood for LLM connections
2. LiteLLM expects the Gemini API key to be in the environment variable GOOGLE_API_KEY or GEMINI_API_KEY
3. Even if you pass api_key to the LM constructor, LiteLLM might not use it correctly for Gemini
4. DSPy modules check for a configured LM at execution time, not creation time

Current Behavior

1. DSPex.LM.configure() successfully creates a dspy.LM instance
2. It calls dspy.configure(lm=...) to set it globally
3. BUT: When modules are created, they have lm=None by default
4. Execution fails because the module’s lm attribute is not set

Solutions

Solution 1: Ensure Correct API Key

# First, verify your API key works
export GOOGLE_API_KEY=your-actual-gemini-api-key

# Test with curl
curl -H "Content-Type: application/json" \
     -H "x-goog-api-key: $GOOGLE_API_KEY" \
     -X POST https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash-exp:generateContent \
     -d '{"contents":[{"parts":[{"text":"Hello"}]}]}'

Solution 2: Check DSPy Version

pip install --upgrade dspy-ai

Solution 3: Manual LM Configuration

In Python/DSPy directly:

import dspy
from dspy.clients import LM

# Configure Gemini
lm = LM(model="google/gemini-2.0-flash-exp", api_key="your-key")
dspy.configure(lm=lm)

# Now create modules
predict = dspy.Predict("question -> answer")
result = predict(question="What is 2+2?")

Current Workaround

The examples demonstrate what DSPex would do with a properly configured LM. To see real results:

1. Ensure your Gemini API key is valid
2. Use the Python DSPy directly to verify it works
3. The DSPex wrappers will work once the underlying connection is established

Future Improvements

1. Better LM Propagation: Ensure modules inherit the global LM configuration
2. Connection Validation: Add explicit LM connection testing
3. Error Messages: Provide clearer diagnostics when LM configuration fails

Testing Your Setup

Run this test to diagnose the issue:

mix run examples/dspy/test_lm_config.exs

This will show:

• Whether the LM instance is created successfully
• If DSPy’s global configuration is working
• Where the configuration breaks down