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Sandstone vs Luminance: Enterprise Contract AI or In-House Legal Operations?
Luminance is enterprise contract AI, built on legal-specific models, and markets autonomous negotiation of routine agreements. Sandstone solves a different problem: getting legal requests captured, routed, and resolved with the business context behind them. Here's where each one fits.
Sandstone vs Luminance
| Capability | Sandstone |  Luminance |
|---|---|---|
| Primary focus | Operating system for in-house legal work, from request to resolution | Enterprise contract AI: review, negotiation, and contract intelligence |
| Underlying technology | Selects across frontier models by task, grounded in your legal and business context | Proprietary legal-specific models, described as Legal-Grade AI |
| Negotiation model | Playbook-driven redlining with an attorney approving what goes to the counterparty | Autonomous negotiation, which Luminance markets as running routine NDA negotiations end to end |
| Intake and triage | Agents capture requests from Slack, email, and business systems, then route them | Contract-centric workflows, beginning with the document |
| Business context | Counterparty history, relationships, and prior decisions attached to each request | Shared context and negotiation memory carried across the contract portfolio |
| Scope of work covered | All inbound legal work, contracts included | Contract touchpoints across the lifecycle |
| Language coverage | Review and drafting across languages | Review and analysis across a wide range of languages, which Luminance cites as 80+ |
| Legal research | Research grounded in your own playbooks, precedent, and prior decisions; not a replacement for Westlaw or Lexis | Citation-backed research inside the platform via a LexisNexis alliance announced in 2026 |
| Permissions across systems | Permissions mapped across every connected integration | Platform access controls |
| Internal collaboration | Legal works a request together in the app or the plugins, with comments and drafts staying behind the scenes until you choose otherwise | Shared negotiation context |
| Acting back in source systems | Replies and actions go back to Slack, procurement, and contract systems under a shared team identity, with permissions mapped across those integrations centrally | Collaboration channels |
| Buyer profile | In-house legal teams, roughly 5 to 100 lawyers | Large enterprises and law firms; Luminance cites 1,000+ organizations across 70+ countries |
| Best fit for | Teams drowning in inbound requests across channels | Enterprises with high-volume contract review, due diligence, or multilingual portfolios |
Based on publicly available information as of September 2026. Names and trademarks belong to their respective owners. If anything here is inaccurate or out of date, contact us and we'll update it.
Frequently asked questions
Sandstone applies your playbooks to redlining and drafting with an attorney approving anything that goes to a counterparty. That's a design choice rather than a missing feature — Sandstone lets you set exactly where a human sign-off is required. Some platforms market fully autonomous negotiation for routine agreements; whether you want that is a real question for your risk posture, not a checkbox.
Yes — that's the middle of the range Sandstone is built for, roughly five to a hundred lawyers. Smaller teams tend to feel the request volume more sharply because there's nobody to absorb the overflow.
Yes. Large-scale document review and diligence is supported, with playbooks and context applied across the document set rather than each file being reviewed in isolation. Bring us a live example of the kind of diligence you run and we'll walk through it against your own documents.
Capture the request before it's a document. A question in Slack about whether a clause can move, a procurement query that never becomes a contract, a review forwarded by email — those never reach a contract-AI platform at all.
