letsping 0.1.3

The Human-in-the-Loop SDK for AI Agents

LetsPing Python SDK

The official state management infrastructure for Human-in-the-Loop (HITL) AI agents. LetsPing provides a durable "pause button" for autonomous agents, decoupling the agent's execution logic from the human's response time. It handles state serialization, secure polling, and notification routing (Slack, Email) automatically.

Installation

pip install letsping

Configuration

Set your API key as an environment variable (recommended) or pass it directly.

export LETSPING_API_KEY="lp_live_..."

Usage

1. The "Ask" Primitive (Blocking)

Use this when you want to pause a script until a human approves.

from letsping import LetsPing

client = LetsPing()

# Pauses here for up to 24 hours (default)
decision = client.ask(
    service="payments-agent",
    action="transfer_funds",
    payload={
        "amount": 5000,
        "currency": "USD",
        "recipient": "acct_99"
    },
    priority="critical"
)

# Execution resumes only after approval
print(f"Transfer approved by {decision['metadata']['actor_id']}")

2. Async / Non-Blocking (FastAPI/LangGraph)

For high-concurrency environments or event loops.

import asyncio
from letsping import LetsPing

async def main():
    client = LetsPing()
    
    # Non-blocking wait
    decision = await client.aask(
        service="github-agent",
        action="merge_pr",
        payload={"pr_id": 42},
        timeout=3600 # 1 hour timeout
    )

asyncio.run(main())

3. LangChain / Agent Integration

LetsPing provides a compliant tool interface that can be injected directly into LLM agent toolkits (LangChain, CrewAI, etc). This allows the LLM to decide when to ask for help.

from letsping import LetsPing

client = LetsPing()

tools = [
    # ... your other tools (search, calculator) ...
    
    # Inject the human as a tool
    client.tool(
        service="research-agent",
        action="review_draft",
        priority="high"
    )
]

Error Handling

The SDK uses typed exceptions for control flow.

• ApprovalRejectedError: Raised when the human explicitly clicks "Reject".
• TimeoutError: Raised when the duration (default 24h) expires without a decision.
• LetsPingError: Base class for API or network failures.

License

MIT