SPR SDK for Python

SPR, the Sealed Payment Record, in Python: seal your AI agents' payments on your own machine with your company's own key, and check any SPR record or package without Luca. Apache-2.0. Needs cryptography.

from spr import SprBook

book = SprBook(dir="books", agent_id="agt_research", entity="Example Co")

# Before paying: declare, and sign the nonce as the payment's nonce where the rail lets you (x402, EIP-3009).
intent = book.declare(purpose="Market data for the pricing model", max_amount_minor=20000, currency="USDC")
nonce = book.nonce_for(intent["intent_id"])
if book.check_payment(10000, "USDC", nonce=nonce)["decision"] != "approve":
    raise SystemExit("declined")

# After paying: seal it.
record = book.seal(rail="x402", source_id=tx_hash, amount_minor=10000, currency="USDC", nonce=nonce)

The folder, files and records are the same as the JavaScript SDK's, so either language opens the other's book.

The book runs on your machine and makes no call to Luca. A check against the book's own mandate.json reports authority: "self-declared", because whoever keeps the book writes it. Times need their offset; a time without one is refused. Different facts for a payment already sealed return conflict and seal nothing, unless you pass correction={"reason": ...}.

Check a package, or run the test vectors that come with the package:

python -m spr <package folder>
python -m spr --vectors

Send the book to Luca's hosted service (optional), which checks every seal, then classifies each payment and posts it to your ERP:

book.register_with_luca("acme-us", url="https://sandbox.luca.network", api_key=FINANCE_KEY)   # once, by finance
book.send_to_luca(url="https://sandbox.luca.network", api_key=LUCA_API_KEY)                    # sending it again changes nothing

url and api_key default to LUCA_URL and LUCA_API_KEY. Only the package's files are sent, never the private key.

Tests: python -m unittest discover -s tests, from this folder.