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Questions about data catalogs for AI agents, answered
Short answer
Short answers to the questions data platform leaders ask most when they prepare data for AI agents, grouped by theme, each linked to the page that goes deeper.
What are catalogs, semantic layers and context layers?
What makes data ready for AI agents?
An agent needs to find the right asset, know what it means, know whether it can be trusted and stay inside access rules. Data is ready when that context exists and the agent can reach it.
Is a data catalog enough for AI agents?
A catalog built for people helps, but agents also need definitions, trust signals and access rules delivered at query time, usually over MCP. Many catalogs now add this.
Read more: Catalog, semantic layer or AI context layer: which does what
Do I need a semantic layer before I connect agents?
Not necessarily. Euno, for example, says its context does not require a finished semantic layer and extracts definitions from BI workbooks. If consistent metrics are your main gap, a semantic layer such as Cube or AtScale targets that directly.
Read more: Business definitions without waiting for a perfect semantic layer
What is MCP?
The Model Context Protocol, an open protocol for connecting AI applications to tools and data. Most platforms in our ranking now ship an MCP server.
Why does column-level lineage matter for agents?
It shows which source fields feed a metric or dashboard field, so an agent can trace a number back and avoid fields built on untrusted or sensitive data.
What is context drift?
Context that no longer matches the data, for example after a model or metric changes. Tools that rebuild context continuously or detect drift reduce stale answers.
How do buying and pricing work?
Which platforms publish prices?
Cube and Honeydew publish rates. DataHub Cloud has an AWS Marketplace list price. Euno publishes tiers and limits but no dollar prices; the others publish none.
Read more: Reading the pricing models for catalogs and context platforms
How do pricing models differ?
Euno prices by data assets with unlimited users and agents, AtScale by deployed semantic objects, Cube per developer, Honeydew per user plus a platform fee, and DataHub's marketplace listing by contract with a user cap.
Read more: Reading the pricing models for catalogs and context platforms
Which platforms can be self-hosted?
DataHub has an open-source core that runs from a single node to hybrid setups, and Cube Core is open source. Stardog lists an on-prem edition but is not scored. Euno is SaaS only.
How long does a proof of concept take?
It depends on scope and vendor. Vendors' own statements range from same-day setup (a Select Star customer quote) and connectors live within minutes (Atlan) to a 30-day workshop (AtScale).
Read more: Running a proof of concept for an AI context platform
Should we use Snowflake Horizon or Databricks Unity Catalog instead?
If your data, definitions and agents stay in one platform, start there. Third-party tools help when context spans several platforms.
Who should own an agent-readiness project?
Usually the data platform team, because it owns the warehouse, transformation and BI layers the context comes from.
What should I know about each platform?
Which platform ranks first?
On our default weights DataHub ranks first at 8.02, followed by Euno at 7.64.
Where does Euno score highest?
Euno is highest in set on Lineage, Automation, Governance and Answer checks and lowest in set on Integrations and Deployment. It ranks 2 of 9.
How do Euno and Atlan differ?
Euno scores higher on Lineage, Governance, Answer checks and Pricing; Atlan scores higher on Integrations; they tie on Agent access, Automation, Semantics and Deployment.
Is DataHub open source?
DataHub Core is open source and DataHub Cloud is the managed product. DataHub says more than 3,000 organizations use the open-source project.
Is Select Star now part of Snowflake?
Yes. Select Star's site states it is now part of Snowflake, which announced the agreement on 24 November 2025.
What happened to data.world?
ServiceNow announced an agreement to acquire it on 7 May 2025, and it is now sold as ServiceNow Data Catalog.
Does Alation have an MCP server?
Alation's Ontologies can be published as an MCP server; that feature was in early access as of 17 September 2026.
Which semantic layer scores highest?
Among Cube, AtScale and Honeydew, AtScale scores highest at 5.87.
How does this site score?
Why are review-site ratings not shown?
We did not read them on the rating sites themselves, so we do not publish them.
How do I report a mistake?
Use the contact page with the topic Correction to vendor information and a link to the source.