TruthNexus
SDK & Open Source

Verified evidence, three method calls.

The Skippy Python SDK is in private preview. The verification and audit tooling that powers Skippy internally is available now as open-source packages.

Open Source · Apache 2.0

Verification tooling, available now

The packages below are the verification, audit, and key infrastructure used inside Skippy. All are Apache 2.0, installable via pip, and require no Skippy account or API key.

skippy-verifyAvailable

Offline cryptographic verifier for signed Skippy responses. Checks Ed25519 signatures, Merkle root integrity, key revocation, and optional Rekor transparency-log inclusion. No Skippy infrastructure required after install.

Install
pip install skippy-verify
Usage
from skippy_verify import ResponseVerifier
verifier = ResponseVerifier(
key_registry_url="https://keys.your-org.com"
)
result = verifier.verify(signed_response)
# result.verified · result.failures
Six verification steps
01Signature present
02Key lookup + TTL cache
03Key revocation check
04Merkle root recomputation
05Ed25519 signature validation
06Response hash integrity
Ed25519Merkle treeRekor-compatibleCLI + libraryApache 2.0
skippy-verifierAvailable

Claim-vs-source entailment audit harness. Extracts claims from output, validates each against cited sources using pluggable NLI backends, and returns structured violation reports with JSON Schema-validated audit logs.

Install
pip install skippy-verifier
# with NLI backend:
pip install skippy-verifier[alignscore]
Usage
from skippy_verifier import VerifierHarness
from skippy_verifier.providers import AlignScoreProvider
harness = VerifierHarness(
nli_provider=AlignScoreProvider()
)
result = harness.verify(claims, sources)
# result.gate_decision · result.violations
Violation taxonomy (V001–V011)
V001–V002Unsupported or uncited claim
V005–V006Finding not found · Retracted source
V010–V011PII in response · Safety gate bypass
V003–V004Irrelevant citation · Low utility
AlignScoreFactKBMiniCheck (BYO)Custom NLIApache 2.0
skippy-keysAvailable

Public key registry for cryptographic verification of signed Skippy responses. Provides key lookup, TTL-cached resolution, and key revocation status. Required by skippy-verify to resolve the signing key embedded in a signed response.

Install
pip install skippy-keys
Configure with skippy-verify
from skippy_verify import ResponseVerifier
from skippy_keys import KeyRegistry
registry = KeyRegistry(
base_url="https://keys.skippy.health/v1",
ttl_seconds=3600
)
verifier = ResponseVerifier(key_registry=registry)
result = verifier.verify(signed_response)
Key lifecycle
·90-day rotation cadence for all signing keys
·Revocation list checked on every verification
·Dev, test, and prod-2026-Q2 key sets included
·Self-hostable — point to your own registry URL
Ed25519 keysTTL cacheRevocation supportSelf-hostableApache 2.0
Pluggable NLI provider interface

Bring your own entailment model. Any class implementing the NLIProvider Protocol works as a drop-in backend — no inheritance required.

Protocol
class NLIProvider(Protocol):
model_id: str
model_type: str
def score(
claim: str, source: str
) -> NLIResult: ...
NLIResult
score: float # 0.0 → 1.0
supported: bool
rationale: str | None
model_id: str
elapsed_ms: int # latency audit
Evidence API · Private Preview

skippy-python — verified evidence, three method calls

v0.1.0Private PreviewMay 2026
  • verify() — claim verification with calibrated confidence
  • retrieve() — evidence retrieval by entity
  • score_output() — per-sentence grounding scores
  • Pydantic models for all responses
  • Typed error classes
v0.2.0UpcomingJune 2026
  • LangChain integration
  • LlamaIndex integration
  • OpenAI function-calling adapter
  • Async support
v0.3.0PlannedJuly 2026
  • Batch verification
  • Streaming responses
  • Local cache
  • Offline mode

Request SDK access

Tell us about your use case and we'll provision early access keys plus integration support.

Request AccessHow the verifier works →