01 / EXTRACT
Atomic claims
Separates dates, quantities, attributions and factual propositions while preserving their source spans.
MephistophelesEvidence verification for AI
Confidence isn’t truth.
Mephistopheles breaks AI output into atomic claims, retrieves inspectable evidence, and reports support, contradiction, dispute, uncertainty, and coverage—without turning a score into a guarantee.
SupportedThe checked source directly supports the atomic claim.
ContradictedA material component conflicts with suitable evidence.
DisputedCredible sources disagree or the context changes the conclusion.
UnverifiableSuitable evidence was not obtained. This is not support.
Not checkableThe sentence is opinion, instruction, or otherwise outside factual verification.
5explicit verdict states, including abstention
Atomicclaim-level findings instead of one opaque score
Visiblesource provenance, retrieval time and relationship
Versionedpolicy, engine and result schema records
The verification loop
From plausible prose to an inspectable decision.
02 / RETRIEVE
Independent evidence
Queries structured and public sources, then normalises canonical destinations and provenance.
03 / ADJUDICATE
Policy-aware verdicts
Applies a versioned profile, including source-class, freshness, jurisdiction and abstention rules.
04 / INSPECT
Coverage and risk
Shows what was examined, what may have been missed, and which material findings drive risk.
Try the real contract
Run a live verification.
This demonstration calls the same versioned verification endpoint used by the workbench. Results are generated, not pre-written.
Retrieval and model providers may take a little time. Do not submit secrets, personal health information, or other sensitive content in this public demo.
Evidence will appear here.
Every verdict includes its limits and provenance.
Designed for scrutiny
No “truth score” theatre.
A supported verdict is bounded.
It means the active policy obtained enough suitable evidence for the examined claim at the displayed time. It does not establish universal or permanent truth.
Contradiction, uncertainty, incomplete coverage and failure states remain visible. Material findings can be routed to a human review record without overwriting the machine result.
One evidence platform
Choose the surface. Keep the same truth contract.
Workbench
Map original passages to atomic claims, verdicts, evidence, corrections and review state.
Open workbenchDocuments
Validate PDF, DOCX and text uploads, follow durable processing, and export an annotated review.
Review a documentExtension
Verify text you explicitly select through a stable Manifest V3 side panel with narrow permissions.
Review permissionsAPI
Integrate the versioned result contract, asynchronous documents, webhooks and governed policies.
Read developer docsAccuracy and limits
Abstention is a result, not a defect to hide.
Coverage, risk and unresolved evidence are reported separately. A result remains qualified when material content was missed or suitable evidence was not obtained.
Current publication boundary
No historical benchmark percentage is presented as current until it reproduces from the recovered, versioned evaluation set under a frozen release configuration.
Known limitationsSecurity and privacy
Trust starts with an explicit data path.
Uploads are bounded, signature-checked and malware-scanned. Provider credentials and retained content use separate encrypted controls. Public documentation states what may leave the service boundary and what zero retention omits.
No certification theatre
The product does not imply SOC 2, ISO 27001, HIPAA or other independent assurance without the relevant evidence and agreements.
Review subprocessorsDeveloper integration
Verification as infrastructure.
Use typed Python and TypeScript clients, scoped keys, request IDs, rate-limit metadata, version discovery, owner-bound document jobs and replay-resistant webhooks.
Explore the API{
"coverage": { "status": "qualified" },
"risk": { "level": "medium" },
"abstention": { "count": 1 },
"claims": [
{ "verdict": "unverifiable" }
]
}
Pricing without surprises
Start bounded. Scale with controls.
The anonymous demonstration is deliberately limited. Account and API usage expose metering, quotas and hard cost ceilings; final public prices remain gated on measured provider cost and margin.
Review plans and billing boundaryReady to inspect an answer?
See exactly what was checked, what evidence was found, and where the system abstained.
Verify now