PrysmProof: verifiable receipts for every AI call

AI-generated content is increasingly used in compliance workflows, financial analysis, legal research, and medical information. When an automated system acts on an LLM output, you need to be able to prove:

This specific prompt was sent (not a different one).
This specific model ran it (not a cheaper substitute).
At this specific time (not cached or replayed).
With this output (not modified after the fact).

PRYSM’s PrysmProof system provides a cryptographic receipt for every call. It’s included automatically — no configuration needed.

The receipt

Every PRYSM response includes a prysm.proof extension field:

from prysm import Prysm

client = Prysm()
resp = client.chat.completions.create(
    model="auto",
    messages=[{"role": "user", "content": "Summarize this contract clause: ..."}],
)

proof = resp.extensions["prysm"]["proof"]
print(proof)
# {
#   "request_id": "f9a3b2c1-1234-5678-abcd-ef0123456789",
#   "timestamp": "2026-06-13T14:32:11.456Z",
#   "model": "claude-sonnet-4.5",
#   "provider": "anthropic",
#   "mode": "balanced",
#   "proof_hash": "sha256:a1b2c3d4e5f67890",
#   "verifiable": true
# }

The hash

proof_hash is a truncated SHA-256 of the concatenated fields:

import hashlib

def compute_proof(request_id, timestamp, model, provider, mode, prompt, response):
    prompt_sha = hashlib.sha256(prompt.encode()).hexdigest()
    response_sha = hashlib.sha256(response.encode()).hexdigest()
    raw = f"{request_id}{timestamp}{model}{provider}{mode}{prompt_sha}{response_sha}"
    return "sha256:" + hashlib.sha256(raw.encode()).hexdigest()[:16]

You can reconstruct and verify the hash yourself — no trust required.

Verify via the API

# Verify by request_id — the API recomputes the hash from stored data
is_valid = client.verify_proof(
    proof["request_id"],
    resp.choices[0].message.content,
)
print(is_valid)  # True

Or via the public endpoint (no API key):

curl https://api.prysm1.com/v1/proof/f9a3b2c1-1234-5678-abcd-ef0123456789
# {
#   "verified": true,
#   "request_id": "f9a3b2c1-...",
#   "entry": {"model": "claude-sonnet-4.5", "timestamp": "...", ...}
# }

Offline verification (Ed25519 signatures)

When PRYSM_SIGNING_SEED is set on the server, every receipt is signed with an Ed25519 private key. You can verify receipts offline without any API call:

import nacl.signing
import nacl.encoding

# Fetch the public key once — cache it, it changes rarely
pubkey_hex = client._get("/proof/pubkey")["public_key"]
verify_key = nacl.signing.VerifyKey(bytes.fromhex(pubkey_hex))

# Verify a receipt offline
message = proof["request_id"].encode()
signature = bytes.fromhex(proof["signature"])
verify_key.verify(message, signature)   # raises if invalid
print("Offline verification: OK")

PrysmProof v2 (orchestration)

For multi-model orchestration runs (POST /v2/orchestrate), PrysmProof v2 attests to the full cascade of models:

result = client.orchestrate("Analyze these three architectural options", policy="depth")
proof_v2 = result["prysm"]["proof"]
print(proof_v2["models_used"])    # ["gpt-5.2", "claude-sonnet-4.5", "gemini-3.1-pro"]
print(proof_v2["strategy"])       # "ensemble_moa"
print(proof_v2["confidence"])     # 0.94
print(proof_v2["agreement"])      # 0.87
print(proof_v2["proof_hash"])     # sha256:...

The v2 hash covers all model outputs, the synthesis step, and the final response — proving the entire cascade, not just the final answer.

Compliance attestations

For regulated workloads, PRYSM can bind a compliance policy decision to the PrysmProof receipt:

resp = client.orchestrate(
    "Review this loan application for FCRA compliance",
    compliance={"frameworks": ["FCRA"], "jurisdiction": ["US"], "data_residency": ["US"]},
)
attestation = resp["prysm"]["compliance"]["attestation"]
# {
#   "sha256": "7a3f...",
#   "policy_hash": "e5c2...",
#   "chosen_model": "gpt-5.2",
#   "approved_provider": "openai",
#   "cost_actual_usd": 0.0043,
#   "timestamp": "2026-06-13T..."
# }

The attestation hash covers the policy decision, the chosen model, the actual cost, and the timestamp — a single artifact you can store in an audit log.

​The receipt

​The hash

​Verify via the API

​Offline verification (Ed25519 signatures)

​PrysmProof v2 (orchestration)

​Compliance attestations