promptum 0.0.4

Async LLM benchmarking library with protocol-based extensibility

promptum

Test LLMs Like a Pro.

Stop writing boilerplate to test LLMs. Start getting results.

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What's This?

A dead-simple Python library for testing LLM providers. Write tests once, run them across any model, get structured results.

session = Session(provider=client, name="my_test")
session.add_test(Prompt(
    name="basic_math",
    prompt="What is 2+2?",
    model="gpt-3.5-turbo",
    validator=Contains("4")
))
report = await session.run_async()

That's it. No setup. No config files. Just results.

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Why You Need This

Before promptum:

# Custom API client for each provider
openai_client = OpenAI(api_key=...)
anthropic_client = Anthropic(api_key=...)

# Manual validation logic
if "correct answer" not in response:
    failed_tests.append(...)

# Track metrics yourself
latency = end_time - start_time
tokens = response.usage.total_tokens

# Write your own retry logic
for attempt in range(max_retries):
    try:
        response = client.chat.completions.create(...)
        break
    except Exception:
        sleep(2 ** attempt)

After promptum:

report = await session.run_async()
summary = report.get_summary()  # Metrics captured automatically

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Quick Start

pip install promptum  # (or: uv pip install promptum)
export OPENROUTER_API_KEY="your-key"

import asyncio
from promptum import Session, Prompt, OpenRouterClient, Contains

async def main():
    async with OpenRouterClient(api_key="your-key") as client:
        session = Session(provider=client, name="quick_test")

        session.add_test(Prompt(
            name="basic_math",
            prompt="What is 15 * 7? Reply with just the number.",
            model="openai/gpt-3.5-turbo",
            validator=Contains("105")
        ))

        report = await session.run_async()
        summary = report.get_summary()

        print(f"✓ {summary.passed}/{summary.total} tests passed")
        print(f"⚡ {summary.avg_latency_ms:.0f}ms average")
        print(f"💰 ${summary.total_cost_usd:.6f} total cost")

asyncio.run(main())

Run it:

python your_script.py

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What You Get

• 100+ Models via OpenRouter - One client for OpenAI, Anthropic, Google, and more
• Smart Validation - ExactMatch, Contains, Regex, JsonSchema, or write your own
• Automatic Retries - Exponential/linear backoff with configurable attempts
• Metrics Tracking - Latency, tokens, cost - automatically captured
• Async by Default - Run 100 tests in parallel without breaking a sweat
• Type Safe - Full type hints, catches errors before runtime
• Zero Config - No YAML files, no setup scripts, just Python

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Real Example

Compare GPT-4 vs Claude on your tasks:

import asyncio
from promptum import Session, Prompt, Contains, Regex, OpenRouterClient

async def main():
    async with OpenRouterClient(api_key="your-key") as client:
        session = Session(provider=client, name="model_comparison")

        session.add_tests([
            Prompt(
                name="json_output_gpt4",
                prompt='Output JSON: {"status": "ok"}',
                model="openai/gpt-4",
                validator=Regex(r'\{"status":\s*"ok"\}')
            ),
            Prompt(
                name="json_output_claude",
                prompt='Output JSON: {"status": "ok"}',
                model="anthropic/claude-3-5-sonnet",
                validator=Regex(r'\{"status":\s*"ok"\}')
            ),
            Prompt(
                name="creative_writing",
                prompt="Write a haiku about Python",
                model="openai/gpt-4",
                validator=Contains("Python", case_sensitive=False)
            ),
        ])

        report = await session.run_async()

        # Side-by-side model comparison
        for model, model_report in report.group_by(lambda r: r.test_case.model).items():
            summary = model_report.get_summary()
            print(f"{model}: {summary.pass_rate:.0%} pass rate, {summary.avg_latency_ms:.0f}ms avg")

asyncio.run(main())

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Use Cases

🔬 Model Evaluation - Compare GPT-4, Claude, Gemini on your specific tasks 🎯 Prompt Engineering - Test 100 prompt variations, find what works ⚡ Latency Testing - Measure real-world response times across providers 💰 Cost Analysis - Track spending per model/task before production 🔄 Regression Testing - Ensure model updates don't break your prompts 📊 A/B Testing - Data-driven model selection for your product

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Requirements

• Python 3.13+
• An OpenRouter API key (or implement your own provider)

That's it. No Docker, no complex setup.

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Why Protocol-Based?

Most libraries force inheritance:

class MyProvider(BaseProvider):  # Tightly coupled
    def generate(self): ...

We use protocols (structural typing):

class MyProvider:  # No inheritance needed
    async def generate(self) -> tuple[str, Metrics]:
        # Your implementation
        return response, metrics

# It just works
session = Session(provider=MyProvider())

Cleaner. More flexible. More Pythonic.

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Contributing

Found a bug? Want a feature? PRs welcome!

# Development setup
git clone https://github.com/deyna256/promptum.git
cd promptum
just sync       # Install dependencies
just test       # Run tests

# Development commands
just lint       # Check code style
just format     # Format code
just typecheck  # Type checking

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License

MIT - do whatever you want with it.

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⭐ Star on GitHub | 🐛 Report Bug | 💡 Request Feature

Made for developers who value their time.