---

Note: This package is a general-purpose LLM context management toolkit and is not related to Microsoft's LayoutLM multimodal models.

Why LLM Context Forge?

Every production AI application eventually hits the same infrastructure problems:

Problem	Impact	LLM Context Forge Solution
Context window overflow	Silent failures, truncated responses	Priority-based assembly with overflow tracking
Inaccurate token counting	Budget overruns, dropped requests	Deterministic counting via tiktoken + heuristic fallbacks
Naive text splitting	Broken semantics, degraded LLM reasoning	5 chunking strategies (sentence, paragraph, semantic, code, fixed)
Unpredictable API costs	Surprise bills, no cost governance	Pre-flight cost estimation across 15+ models
Oversized prompts	Wasted tokens, slow responses	4 compression strategies (extractive, truncate, middle-out, map-reduce)

Installation

pip install llm-context-forge

With API server support:

pip install "llm-context-forge[api]"

Quick Start

Token Counting

from llm_context_forge import TokenCounter

counter = TokenCounter("gpt-4o")
tokens = counter.count("Hello, world!")
print(f"Tokens: {tokens}")  # Tokens: 4

# Check context window fit
fits = counter.fits_in_window("Your prompt...", reserve_output=500)

# Estimate cost before sending
cost = counter.estimate_cost("Your prompt...", direction="input")
print(f"Cost: ${cost:.6f}")

Intelligent Chunking

from llm_context_forge import DocumentChunker, ChunkStrategy

chunker = DocumentChunker("gpt-4o")

# Chunk respecting paragraph boundaries
chunks = chunker.chunk(
    long_document,
    strategy=ChunkStrategy.PARAGRAPH,
    max_tokens=500,
    overlap_tokens=50,
)

# Specialized chunkers
code_chunks = chunker.chunk_code(source_code, language="python")
md_chunks = chunker.chunk_markdown(readme_text)

Priority-Based Context Assembly

The core pattern for RAG applications — guarantee critical context fits while gracefully dropping lower-priority content:

from llm_context_forge import ContextWindow, Priority

window = ContextWindow("gpt-4o")

# System instructions — always included
window.add_block("You are a legal assistant.", Priority.CRITICAL, "system")

# User query — high priority
window.add_block("What is the statute of limitations?", Priority.HIGH, "query")

# RAG search results — included if space permits
window.add_block(search_result_1, Priority.MEDIUM, "rag_1")
window.add_block(search_result_2, Priority.LOW, "rag_2")

# Assemble: packs highest-priority blocks first
prompt = window.assemble(max_tokens=4096)

# See what was included/dropped
usage = window.usage()
print(f"Included: {usage['num_included']} blocks ({usage['included_tokens']} tokens)")
print(f"Dropped:  {usage['num_excluded']} blocks")

Cost Estimation

from llm_context_forge import CostCalculator

calc = CostCalculator("gpt-4o")

# Single prompt cost
cost = calc.estimate_prompt("Your prompt text here")
print(f"Input cost: ${cost.usd:.6f}")

# Compare models
comparison = calc.compare_models(
    texts=["Document 1...", "Document 2..."],
    models=["gpt-4o", "gpt-4o-mini", "claude-3.5-sonnet", "gemini-flash"],
)
for model, analysis in comparison.items():
    print(f"{model}: ${analysis.total_usd:.6f} for {analysis.total_tokens} tokens")

Context Compression

from llm_context_forge import ContextCompressor, CompressionStrategy

compressor = ContextCompressor("gpt-4o")

# Extractive: keeps most important sentences via TF-IDF scoring
result = compressor.compress(long_text, target_tokens=200)
print(f"Compressed: {result.original_tokens} → {result.compressed_tokens} tokens")
print(f"Savings: {result.savings_pct:.1f}%")

# Middle-out: preserves start and end, removes middle
result = compressor.compress(log_text, target_tokens=300, strategy=CompressionStrategy.MIDDLE_OUT)

Conversation Management

from llm_context_forge import ConversationManager

manager = ConversationManager("gpt-4o")

manager.add_message("system", "You are a helpful Python tutor.")
manager.add_message("user", "Explain decorators")
manager.add_message("assistant", "Decorators are...")
# ... many more turns ...

# Auto-trim older messages to fit budget, preserving system prompt
trimmed = manager.get_context(max_tokens=4096, preserve_system=True)

Supported Models

Provider	Models	Token Counting	Pricing
OpenAI	GPT-4, GPT-4 Turbo, GPT-4o, GPT-4o-mini, GPT-3.5 Turbo	✅ tiktoken	✅
Anthropic	Claude 3 Opus, Claude 3.5 Sonnet, Claude 3 Haiku	✅ anthropic	✅
Google	Gemini Pro, Gemini Flash	✅ transformers	✅
Meta	Llama 3 8B, Llama 3 70B, Llama 3.1 405B	✅ transformers	✅
Mistral	Mistral Large	✅ mistral-common	✅
Cohere	Command R+	✅ transformers	✅

Production-Grade Tokenizer Fallback

In production environments, external tokenizer packages (transformers, mistral-common) might fail to download or initialize due to network errors. llm-context-forge provides a robust, production-grade fallback:

• If a native tokenizer fails to load, the system degrades to OpenAI's fast cl100k_base (tiktoken).
• Since most modern LLMs utilize similar Byte-Pair Encoding (BPE), cl100k_base offers a highly accurate baseline.
• llm-context-forge automatically applies structural safety multipliers (e.g. 1.05x) specifically tuned to each backend before throwing an overflow warning.
• A one-time warning is emitted via standard python logging to notify infrastructure teams of the fallback engagement.

Register custom models:

from llm_context_forge import ModelRegistry, ModelInfo, TokenizerBackend

ModelRegistry.register(ModelInfo(
    name="my-fine-tuned-model",
    backend=TokenizerBackend.OPENAI,
    context_window=16_384,
    encoding_name="cl100k_base",
    input_cost_per_1k=0.002,
    output_cost_per_1k=0.006,
))

CLI

# Count tokens
llm_context_forge count "Hello world" --model gpt-4o

# Chunk a document
llm_context_forge chunk document.md --strategy semantic --max-tokens 500

# Estimate cost
llm_context_forge cost document.txt --model claude-3.5-sonnet

# List all models
llm_context_forge models

# Health check
llm_context_forge doctor

# Start API server
llm_context_forge serve --port 8000

# Interactive demo
llm_context_forge demo

REST API

Start the server and access interactive docs at http://localhost:8000/docs:

pip install "llm_context_forge[api]"
llm_context_forge serve

Endpoint	Method	Description
/health	GET	System health + version
/api/v1/tokens/count	POST	Count tokens
/api/v1/tokens/validate	POST	Check context window fit
/api/v1/chunks/	POST	Chunk text
/api/v1/context/assemble	POST	Priority-based assembly
/api/v1/compress/	POST	Compress text
/api/v1/cost/estimate	POST	Estimate cost

Architecture

llm_context_forge/
├── models.py        # Model registry (15+ models, pricing, backends)
├── tokenizer.py     # Multi-provider token counter (tiktoken + heuristics)
├── chunker.py       # 5-strategy document chunker with overlap
├── context.py       # Priority-based context assembly + conversation manager
├── compressor.py    # 4-strategy compression engine (TF-IDF, middle-out, etc.)
├── cost.py          # Cost estimation engine with model comparison
├── cli/main.py      # Typer CLI with Rich output
└── api/             # FastAPI server with versioned routes

Docker

docker build -t llm_context_forge .
docker-compose up

Development

git clone https://github.com/dhruv-atomic-mui21/llm_context_forge.git
cd llm_context_forge
pip install -e ".[dev]"
pytest

Contributing

See CONTRIBUTING.md for development workflow guidelines.

License

MIT — see LICENSE.