khotem

Thin zero-dependency client for KHOTEM — cryptographic witness for AI agents (https://khotem.com). Paid per call via x402 (USDC on Base). Python ≥ 3.9, stdlib only.

This package never asks for seeds or private keys. Paid calls are signed/settled by your wallet through the x402 flow — see https://khotem.com/docs/pay-x402.

Install

pip install khotem

Free surfaces ($0, no key)

import khotem

khotem.status()          # service pulse: seals, paid_calls, ledger size
khotem.catalog()         # x402 catalog (endpoints + prices)
khotem.receipt_check(ref)  # is this receipt/ref in the KHOTEM ledger? + Base on-chain fallback
khotem.anchor()          # daily Bitcoin anchor (OpenTimestamps) of the ledger chain tip

Neutral witness (halo-record compatible)

Works with the open-source halo-record client — point it at https://khotem.com/api/witness with any bearer key:

import khotem, hashlib

receipt = khotem.witness_anchor(
    key="your-witness-key",          # any string 8..128 chars; first use binds it to your subject+chain_root
    subject="my-agent-run",
    count=1,
    head=hashlib.sha256(b"head").hexdigest(),
    chain_root=hashlib.sha256(b"root").hexdigest(),
)

# offline verification, no network, no deps:
assert khotem.verify_witness_receipt(receipt) is True

# fetch checkpoints back (CORS-open):
cps = khotem.witness_checkpoints(subject="my-agent-run")

Every witness receipt is Ed25519-signed (public key: khotem.witness_pubkey()) and the witness log rides the daily Bitcoin anchor — khotem.anchor().

Paid calls

resp = khotem.call("/api/seal", method="POST", body={"data": "..."})
# HTTP 402 -> x402 payment required; settle with your wallet, retry with X-Payment.

Security

• Never send us your private keys. We never ask.
• Report issues: https://khotem.com/.well-known/security.txt

Verify us without trusting us (v1.0.0)

Every paid response carries an Ed25519 receipt you can verify offline — zero dependencies: spec + verifier + a real paid test vector at https://khotem.com/verifier/. Ledger tip is anchored to Bitcoin daily (https://khotem.com/api/anchor). On-chain identity: ERC-8004 agent #68748 (Base). Machine manifest: https://khotem.com/.well-known/ucp.