Recursive Language Models - DSpy (RLM)

Using Python and DSpy’s Recursive Language Model implementation to handle unbounded context lengths.

Based on the paper by Alex Zhang and Omar Khattab (MIT, 2025)

Based on the source code by ysz

What is RLM?

RLM enables language models to process extremely long contexts (100k+ tokens) by:

• Storing context as a Python variable instead of in the prompt
• Allowing the LM to recursively explore and partition the context
• Avoiding "context rot" (performance degradation with long context)

Instead of this:

llm.complete(prompt="Summarize this", context=huge_document)  # Context rot!

RLM does this:

rlm = RLM(model="gpt-5-mini")
result = rlm.completion(
    query="Summarize this",
    context=huge_document  # Stored as variable, not in prompt
)

The LM can then peek, search, and recursively process the context adaptively.

Installation

Note: This package is not yet published to PyPI. Install from source:

# Clone the repository
git clone https://github.com/codecrack3/recursive-llm.git
cd recursive-llm

# Install in editable mode
pip install -e .

# Or install with dev dependencies
pip install -e ".[dev]"

Future: Once published to PyPI, you'll be able to install with pip install recursive-llm

Requirements

• Python 3.9 or higher
• An API key for your chosen LLM provider (OpenAI, Anthropic, etc.)
• Or a local model setup (Ollama, llama.cpp, etc.)

Quick Start

from rlm import RLM

# Initialize with any LLM (auto-selects best backend)
rlm = RLM(model="gpt-4o-mini")

# Process long context
result = rlm.completion(
    query="What are the main themes in this document?",
    context=long_document
)
print(result)

DSPy + E2B Sandbox

from rlm import RLM

# RLM uses DSPy for LLM orchestration with E2B cloud sandbox
rlm = RLM(
    model="gpt-4o-mini",
    sandbox='e2b'        # E2B cloud sandbox (or 'auto' to auto-detect)
)

result = rlm.completion(query, context)

API Keys Setup

Set your API key via environment variable or pass it directly:

export OPENAI_API_KEY="sk-..."  # or ANTHROPIC_API_KEY, etc.

Or pass directly in code:

rlm = RLM(model="gpt-5-mini", api_key="sk-...")

Supported Models

Works with 100+ LLM providers via DSPy and OpenRouter:

# OpenAI
rlm = RLM(model="gpt-4o-mini")
rlm = RLM(model="gpt-4o")

# Anthropic
rlm = RLM(model="claude-sonnet-4")
rlm = RLM(model="claude-sonnet-4-20250514")

# OpenRouter (100+ models with single API key)
rlm = RLM(model="openrouter/anthropic/claude-3.5-sonnet")
rlm = RLM(model="openrouter/openai/gpt-4o-mini")
rlm = RLM(model="openrouter/google/gemini-pro")
rlm = RLM(model="openrouter/meta-llama/llama-3.1-70b")

# Ollama (local)
rlm = RLM(model="ollama/llama3.2")
rlm = RLM(model="ollama/mistral")

# llama.cpp (local)
rlm = RLM(
    model="openai/local",
    api_base="http://localhost:8000/v1"
)

# Azure OpenAI
rlm = RLM(model="azure/gpt-4-deployment")

# And many more...

Advanced Usage

Two Models (Optimize Cost)

Use a cheaper model for recursive calls:

rlm = RLM(
    model="gpt-5",              # Root LM (main decisions)
    recursive_model="gpt-5-mini"  # Recursive calls (cheaper)
)

Async API

For better performance with parallel recursive calls:

import asyncio

async def main():
    rlm = RLM(model="gpt-5-mini")
    result = await rlm.acompletion(query, context)
    print(result)

asyncio.run(main())

Configuration

rlm = RLM(
    model="gpt-5-mini",
    max_depth=5,         # Maximum recursion depth
    max_iterations=20,   # Maximum REPL iterations
    temperature=0.7,     # LLM parameters
    timeout=60
)

How It Works

1. Context is stored as a variable in a Python REPL environment
2. Root LM gets only the query plus instructions
3. LM can explore context using Python code:

   # Peek at context
   context[:1000]
   
   # Search with regex
   import re
   re.findall(r'pattern', context)
   
   # Recursive processing
   recursive_llm("extract dates", context[1000:2000])

4. Returns final answer via FINAL(answer) statement

Graph Tracking & Visualization

Visualize recursive LLM calls with interactive NetworkX graphs:

from rlm import RLM

# Enable graph tracking
rlm = RLM(
    model="gpt-4o-mini",
    enable_graph_tracking=True,
    graph_output_path="./rlm_graph.html"
)

result = rlm.completion(query="Analyze this", context=document)
# Graph automatically saved to ./rlm_graph.html

The interactive HTML visualization shows:

• Hierarchical structure: See the complete call tree
• Node details: Input/output for each recursive call
• REPL iterations: Code generated and executed at each step
• Performance metrics: Iterations and LLM calls per node
• Error tracking: Which nodes encountered issues

Programmatic access:

import networkx as nx

# Get the graph object
graph = rlm.get_graph()
print(f"Total nodes: {graph.number_of_nodes()}")

# Analyze the graph structure
for node_id, node_data in graph.nodes(data=True):
    print(f"Depth {node_data['depth']}: {node_data['iterations']} iterations")

# Save to different location
rlm.save_graph("./analysis/custom_graph.html")

Learn more: See docs/GRAPH_TRACKING.md for full documentation.

🔍 LLM Call History (Debugging)

Track and inspect all LLM calls for debugging prompts and responses:

# Enable history tracking
rlm = RLM(
    model="gpt-4o-mini",
    enable_history=True,  # Enable LLM call history
    history_output_path="./logs/history.json"  # Auto-save to JSON (optional)
)

result = rlm.completion(query="Your query", context=document)

# Print history summary (shows model, messages, outputs)
rlm.print_history(detailed=False)

# Print detailed history with full prompts/responses
rlm.print_history(detailed=True, max_length=2000)

# Get raw history for programmatic access
history = rlm.get_history()
print(f"Total LLM calls: {len(history)}")

# Save history to JSON manually
rlm.save_history("./my_history.json", pretty=True)

# Clear history for new run
rlm.clear_history()

Use cases:

• 🐛 Debug prompts: See exactly what's being sent to the LLM (shows full messages/inputs)
• 📊 Analyze responses: Inspect the raw outputs from each call
• 🔧 Optimize prompts: Iterate on prompt engineering
• 📈 Monitor usage: Track token usage and costs (exports to JSON)
• 💾 Export logs: Auto-save or manually export history as JSON
• 🔄 Combine with graph tracking: Visualize + inspect LLM calls

Tip: Combine enable_history=True and enable_graph_tracking=True for comprehensive debugging!

Examples

See the examples/ directory for complete working examples:

• basic_usage.py - Simple completion with OpenAI
• dspy_usage.py - DSPy backend with E2B sandbox
• openrouter_usage.py - OpenRouter multi-model access
• e2b_usage.py - E2B cloud sandbox features
• ollama_local.py - Using Ollama locally
• two_models.py - Cost optimization with two models
• long_document.py - Processing 50k+ token documents
• data_extraction.py - Extract structured data from text
• multi_file.py - Process multiple documents
• custom_config.py - Advanced configuration
• graph_tracking.py - NetworkX visualization of recursive calls

Run an example:

# Set your API key first
export OPENAI_API_KEY="sk-..."

# Run example
python examples/basic_usage.py

Performance

Paper Results

On OOLONG benchmark (132k tokens):

• GPT-5: baseline
• RLM(GPT-5-Mini): 33% better than GPT-5 at similar cost

Our Benchmark Results

Tested with GPT-5-Mini on structured data queries (counting, filtering) across 5 different test cases:

60k token contexts:

• RLM: 80% accurate (4/5 correct)
• Direct OpenAI: 0% accurate (0/5 correct, all returned approximations)

RLM wins on accuracy. Both complete requests, but only RLM gives correct answers.

150k+ token contexts:

• Direct OpenAI: Fails (rate limit errors)
• RLM: Works (processes 1M+ tokens successfully)

Token efficiency: RLM uses ~2-3k tokens per query vs 95k+ for direct approach, since context is stored as a variable instead of being sent in prompts.

Development

# Clone repository
git clone https://github.com/codecrack3/recursive-llm.git
cd recursive-llm

# Install with dev dependencies
pip install -e ".[dev]"

# Run tests
pytest tests/ -v

# Run tests with coverage
pytest tests/ -v --cov=src/rlm --cov-report=term-missing

# Type checking
mypy src/rlm

# Linting
ruff check src/rlm

# Format code
black src/rlm tests examples

Architecture

RLM uses DSPy for LLM orchestration with flexible sandbox options:

RLM (DSPy Backend)
├── Custom RLMModule (DSPy module for REPL pattern)
├── E2B Sandbox (cloud code execution)
└── RestrictedPython Fallback (local execution)

Key Features:

• Programmatic LLM orchestration via DSPy
• Better prompt optimization and composability
• Supports E2B cloud sandboxes for enhanced security
• Custom RLMModule optimized for recursive REPL pattern
• RestrictedPython fallback for local execution

Sandbox Selection

Automatic Selection (Recommended)

# Auto-selects E2B if API key set, otherwise RestrictedPython
rlm = RLM(model="gpt-4o-mini")

Explicit Sandbox Selection

# Use E2B cloud sandbox (requires E2B_API_KEY)
rlm = RLM(model="gpt-4o-mini", sandbox='e2b')

# Use RestrictedPython (no API key needed, runs locally)
rlm = RLM(model="gpt-4o-mini", sandbox='restricted')

Environment Variables

Configure sandbox preferences via environment variables:

# Sandbox selection
export RLM_SANDBOX=e2b         # or 'restricted', 'auto'

# E2B API key (get from https://e2b.dev)
export E2B_API_KEY=your-key-here

What's New in v0.2.0

Simplified Architecture

• DSPy Only: Removed legacy LiteLLM backend for simpler codebase
• Cleaner API: No more backend selection - DSPy is the only backend
• Better Maintainability: Reduced complexity and dependencies

DSPy Integration

• Programmatic LLM Orchestration: Use DSPy for better prompt engineering
• Custom RLMModule: Purpose-built DSPy module for recursive REPL pattern
• Automatic Optimization: DSPy's optimization capabilities (optional)

E2B Sandbox

• Cloud Execution: Secure sandboxed code execution in isolated containers
• Enhanced Security: Better isolation than local RestrictedPython
• Package Installation: Install Python packages on-the-fly if needed
• Auto-Fallback: Gracefully falls back to RestrictedPython if E2B unavailable

Migration Guide

From v0.1.0 to v0.2.0

The LiteLLM backend has been removed in v0.2.0. If you were using the backend parameter, simply remove it:

Before (v0.1.0):

from rlm import RLM
rlm = RLM(model="gpt-4o-mini", backend='dspy')
result = rlm.completion(query, context)

After (v0.2.0):

from rlm import RLM
rlm = RLM(model="gpt-4o-mini")  # backend parameter removed
result = rlm.completion(query, context)

Breaking Changes:

• Removed backend parameter (only DSPy is supported now)
• Removed RLMLiteLLM class
• Removed Backend type from exports
• Removed litellm dependency

Setting Up E2B

1. Get API key from https://e2b.dev
2. Add to .env file:

   E2B_API_KEY=your-key-here

3. RLM will automatically use E2B when available

Setting Up OpenRouter

OpenRouter provides access to 100+ models through a single API key:

1. Sign up at https://openrouter.ai
2. Get your API key at https://openrouter.ai/keys
3. Add to .env file:

   OPENROUTER_API_KEY=your-key-here

Usage:

# Anthropic Claude via OpenRouter
rlm = RLM(model="openrouter/anthropic/claude-3.5-sonnet")

# OpenAI GPT via OpenRouter
rlm = RLM(model="openrouter/openai/gpt-4o-mini")

# Google Gemini via OpenRouter
rlm = RLM(model="openrouter/google/gemini-pro")

# Meta Llama via OpenRouter
rlm = RLM(model="openrouter/meta-llama/llama-3.1-70b-instruct")

Benefits:

• ✅ Access 100+ models with single API key
• ✅ No rate limits on most models
• ✅ Competitive pricing
• ✅ Automatic fallback if model unavailable
• ✅ Easy model switching for testing

Cost optimization:

# Use premium model for root, economical for recursion
rlm = RLM(
    model="openrouter/anthropic/claude-3.5-sonnet",
    recursive_model="openrouter/anthropic/claude-3-haiku"
)

See full model list: https://openrouter.ai/models

Limitations

• REPL execution is sequential (no parallel code execution yet)
• No prefix caching (future enhancement)
• Recursion depth is limited (configurable via max_depth)
• No streaming support yet
• E2B requires API key for cloud sandboxes (free tier available)

Troubleshooting

"Max iterations exceeded"

• Increase max_iterations parameter
• Simplify your query
• Check if the model is getting stuck in a loop

"API key not found"

• Set the appropriate environment variable (e.g., OPENAI_API_KEY)
• Or pass api_key parameter to RLM constructor

"Model not found"

• Check model name format for your provider
• See DSPy docs: https://dspy-docs.vercel.app/

Using Ollama

• Make sure Ollama is running: ollama serve
• Pull a model first: ollama pull llama3.2
• Use model format: ollama/model-name

Contributing

Contributions welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Add tests for new features
4. Ensure all tests pass (pytest tests/)
5. Follow code style (use black and ruff)
6. Submit a pull request

Citation

This implementation is based on the RLM paper by Alex Zhang and Omar Khattab.

To cite this implementation:

@software{rlm_python,
  title = {recursive-llm-dspy: Using Python and DSpy’s Recursive Language Model implementation to handle unbounded context lengths},
  author = {codecrack3},
  year = {2025},
  url = {https://github.com/codecrack3/recursive-llm}
}

@software{rlm_python,
  title = {recursive-llm: Python Implementation of Recursive Language Models},
  author = {ysz},
  year = {2025},
  url = {https://github.com/ysz/recursive-llm}
}

@software{rlm_python,
  title = {Recursive Language Models (minimal version)},
  author = {alexzhang13},
  year = {2025},
  url = {https://github.com/alexzhang13/rlm}
}

To cite the original paper:

@misc{zhang2025rlm,
  title = {Recursive Language Models},
  author = {Zhang, Alex and Khattab, Omar},
  year = {2025},
  month = {October},
  url = {https://alexzhang13.github.io/blog/2025/rlm/}
}

License

MIT License - see LICENSE file for details

Acknowledgments

Based on the Recursive Language Models paper by Alex Zhang and Omar Khattab from MIT CSAIL.

Built using:

• DSPy for LLM orchestration
• E2B for cloud code execution
• RestrictedPython for safe local code execution

Links

• Paper: https://alexzhang13.github.io/blog/2025/rlm/
• DSPy Docs: https://dspy-docs.vercel.app/
• E2B Docs: https://e2b.dev/docs
• Issues: https://github.com/codecrack3/recursive-llm/issues