tethered-trust (Python)

Fit, compatibility and recall checks for AI agents before they buy. Every answer is a decision (supported, conditional, incompatible, insufficient_evidence) with the rules checked, manufacturer sources and a signed receipt.

• Standard library only (Python 3.8+)
• Tool definitions for OpenAI, Anthropic and LangChain
• Same tools as the Tethered Trust MCP server (https://tetheredtrust.com/mcp)

pip install tethered-trust            # add [langchain] for LangChain tools

Quick start

from tethered_trust import TetheredTrust

tt = TetheredTrust(sandbox=True)  # sandbox: free, never charged
cart = tt.check_cart({
    "owned": ["Sony PlayStation 5 Pro"],
    "line_items": [{"id": "li_1", "title": "Samsung 990 PRO with Heatsink 2TB", "quantity": 1}],
})
if cart["safe_to_checkout"]:
    # place the order, then link the receipt to it (free)
    tt.call("attach_order", {"receipt_id": cart["receipt"]["id"], "order_id": "112-5550001"})
else:
    print(cart["action"], cart["questions"])

Drop sandbox=True for live answers. Without a key you get a small free daily allowance; after that use an API key with prepaid credits (TetheredTrust(api_key="tt_..."), buy at tetheredtrust.com/credits) or pay per answer in USDC with x402.

Give the tools to your model

from openai import OpenAI
from tethered_trust import TetheredTrust, to_openai_tools, run_tool, SHOPPING_TOOLS

tt = TetheredTrust(api_key="tt_...")
res = OpenAI().chat.completions.create(
    model="gpt-4.1",
    messages=[{"role": "user", "content": "Will this charger work with my Pixel 10? Anker Nano Charger 30W"}],
    tools=to_openai_tools(SHOPPING_TOOLS),
)
for call in res.choices[0].message.tool_calls or []:
    print(run_tool(tt, call.function.name, call.function.arguments))

Anthropic: to_anthropic_tools(SHOPPING_TOOLS) gives the tools list for client.messages.create(...); run each tool_use block with run_tool(tt, block.name, block.input).

LangChain: to_langchain_tools(tt, SHOPPING_TOOLS) returns StructuredTools you can bind to any chat model.

What to do with the answer

Keep the receipt; after ordering, attach_order makes it a Decision Record. If an answer was wrong, file_claim within 60 days refunds the fee.

Docs: https://tetheredtrust.com/agents · Pricing: https://tetheredtrust.com/pricing · Terms: https://tetheredtrust.com/api-terms

Answers are informational; confirm with the manufacturer before buying. MIT licensed. © Chimes In LLC.