Enterprise data context layer · Apache Ossie

A working data context layer in days.

Every enterprise has a data agent mandate; very few can ship one. Datus turns the warehouse you already own into a governed data context layer — an Apache Ossie semantic layer and ontology, not a general-purpose memory. The context your data agents can trust, live in days and evolving with every query.

agent.run
$ datus init --datasource snowflake
↳ read schema · SQL history · lineage → OSI semantic models generated
✓ Apache Ossie context layer ready — ontology, metrics, governed SQL
Map our revenue ontology
compile → validate → govern → serve · via Dosi engine, 16 dialects
↻ evolve: refine the ontology & metrics from every query
· one governed definition, many surfaces
Bring your own warehouse Bring your own model
1.2k+
GitHub stars
Apache Ossie
Open semantic + ontology standard
16 dialects
One OSI spec, native SQL
Days, not quarters
Connect to a working context layer
The mandate

Every enterprise has a data agent mandate. Very few can ship one.

The blocker is not the model. It is decades of messy, siloed data no agent can safely navigate on its own — so the pilot stalls and the bill arrives anyway. Datus gives agents a governed path through it.

Without a context layer
With Datus
Agents guess at joins and definitions, then answer confidently wrong.
Agents query through a governed Apache Ossie semantic layer and ontology — no room to hallucinate.
A full data overhaul takes quarters, so the pilot dies on real data.
Fast start, zero overhaul — connect the warehouse you own and get a working data context layer in days.
Every team defines the same metric differently; the numbers never agree.
One shared, governed definition for producers, consumers and agents alike — one source of truth, many surfaces.
The stack

Open core, commercial studio

One standards-based stack: a commercial Studio on top, an open-source agent in the middle, the Apache Ossie standard and the Dosi engine underneath.

Datus Studio

L3

Commercial · where humans, BI and agents interact

Co-pilotBIAI agentsREST · MCP

Datus agent

L2

Open source · generates the models, runs the work

OSI modelstext-to-SQLCLI · SDKApache 2.0

Apache Ossie + Dosi engine

L1

The standard · defines and compiles the semantics

OntologyOSI → SQL16 dialectsOpen standard
agent
datus
01Connect
02Read schema & SQL
03Generate OSI models
04Map ontology
05Define metrics
06Govern access
07Agents query
08Evolve
How it builds

From a raw warehouse to a context layer agents trust

Datus reads what you already have and compiles it into a governed Apache Ossie context layer — then keeps refining it from real usage.

The wedge

Where the data context layer pays for itself

Start with one governed domain, prove it in an afternoon, then expand domain by domain.

Turn a stalled agent pilot into production

The demo worked on sample data and died on the real thing. Datus gives that pilot a governed context layer over the real warehouse, so it finally ships.

One definition across a fragmented BI estate

Same metric, three definitions, two platforms. Datus compiles one Apache Ossie semantic layer that BI, humans and agents all read.

Agents that reason over an ontology, not raw tables

Ontology teaches agents what things mean and how they connect, so they navigate the business instead of guessing at joins.

A semantic layer your agents call over MCP

Expose the governed context over native MCP, so Claude, Cursor or your own agents query through definitions, not raw SQL.
Interfaces

Same engine, same answers — everywhere your team works

CLI, REST with Apache Arrow, native MCP and a Python SDK. One data context layer, every surface — humans, BI and agents get the same governed answer.

01 / 04

Studio

The commercial context-aware co-pilot where teams drive the whole stack in natural language — map entities, define metrics and answer questions, grounded in your governed context layer.

▸ open studio.datus.ai

studio.datus.ai
chat
you
top 10 regions by MRR this quarter
datus
here you go 👇
sql
SELECT region,
  SUM(mrr) AS revenue
FROM subscriptions
GROUP BY 1
ORDER BY revenue DESC;
results · 4 rows · 128ms
NA$482K
EU$317K
APAC$184K
LATAM$96K

02 / 04

Datus agent

The open-source Datus agent reads your schema and SQL history, generates OSI semantic models with no hand-written YAML, then handles datasets, text-to-SQL and scheduling — all under Apache 2.0.

▸ pip install datus-agent

~ / datus
$ pip install datus-agent
✓ installed datus-agent 0.3.5
$ datus
connected snowflake · dbt · datahub
1,284 tables loaded into context
datus> monthly active users, last 6 months
▸ SELECT date_trunc('month', event_at) AS m,
         COUNT(DISTINCT user_id) AS mau
  FROM events GROUP BY 1 ORDER BY 1;
✓ 6 rows · 42ms
2025-08   28,412
2025-09   31,207   ↑ 10%
2025-12   34,588   ↑ 11%
2026-01   38,904   ↑ 24%

03 / 04

Chatbot

Embed the context layer in Slack, Feishu or Microsoft Teams so every channel becomes a self-serve data interface — answers that match the governed definitions, not one-off SQL.

▸ /datus in Slack

#growth · slack
A
aria9:41
@datus what changed in signups this week?
D
datusAPP9:41
signups this week: 2,914 (+18% wow)
daily signups
MonTueWedThuFriSatSun
↑ mostly driven by google / cpc
open in studio ↗

04 / 04

MCP Server

Expose your entire governed context over the Model Context Protocol. Plug it into Claude, Cursor or Windsurf so any agent reasons over your ontology and metrics — same engine, same answers.

▸ datus mcp serve

claude · mcp
mcp servers
datusconnected
tools 6 · resources 1,284
> summarize the orders table
datus.get_schema (orders)
id           uuid          pk
user_id      uuid          fk → users
amount       numeric(10,2)
status       text
created_at   timestamptz
1.2M rows · fresh 4m ago
the orders table tracks purchases per user, ~1.2M rows, updated every few minutes from the ingestion pipeline.
Integrations

On the modern data stack you already run

Point Datus at your warehouse, catalog, semantic layer and BI. The Dosi engine compiles OSI to native SQL for 16 warehouse dialects, so nothing has to migrate.

ModelBYO
OpenAIAnthropicGeminiDeepSeekQwenOllamaBedrock
Warehouse
SnowflakeBigQueryRedshiftPostgresDuckDB
Modeling
dbtSQLMesh
Semantic Layer
Cubedbt Semantic LayerLookML
Catalog
DataHubOpenMetadataUnity Catalog
BI
MetabaseSupersetTableau
Orchestration
AirflowDagsterPrefect
FAQ

Frequently asked questions

The data context layer, Apache Ossie, the Dosi engine, open core and how Datus compares.

What is a data context layer?

A data context layer is a governed semantic layer and ontology built directly on your warehouse: it teaches AI what your entities, metrics and relationships mean, and gives it clean, governed paths to measure them. Unlike a general-purpose memory store, it is grounded in the data itself — the context an enterprise data agent needs to answer correctly instead of guessing at joins and definitions.

Why does an enterprise agent mandate stall without one?

The blocker is rarely the model. It is decades of messy, siloed data no LLM can safely navigate on its own, so the demo works on sample data and dies on the real thing. Datus connects to the warehouse you already own and compiles a governed context layer in days — agents get clear, governed paths through the business, so the pilot reaches production.

What is Apache Ossie (OSI) and why does Datus build on it?

OSI (Open Semantic Interchange), now Apache Ossie, is an open standard for defining ontology and semantic models — backed by 50+ organizations including Snowflake, Databricks, Salesforce and dbt Labs. Datus defines your models in OSI specs rather than a proprietary format, so your context layer is portable and vendor-neutral. The spec is open to everyone; our engine and our position in it are the product.

What is the Dosi engine?

Dosi is a Rust engine that compiles OSI YAML to native SQL for 16 warehouse dialects, with zero-copy Arrow streaming. It is on its way to open source and already free to download and use — the same engine and the same answers behind the CLI, REST, MCP and the SDK.

How does the open core relate to Datus Studio?

The open-source Datus agent, the Dosi engine and the Apache Ossie models are the core, free to run on your own warehouse. Datus Studio is the commercial layer on top: a context-aware co-pilot where humans, BI and agents drive the whole stack in natural language, with SSO, RBAC and private / VPC deployment for enterprises.

How does Datus compare to Snowflake Cortex, Databricks Genie or Cube?

Snowflake Semantic Views feed Cortex Analyst and Databricks Metric Views feed Genie, but neither reads the other — context inside one vendor stops there. Datus sits on neutral ground: an Apache Ossie semantic layer and ontology on the warehouse you already own, compiled to native SQL across 16 dialects, that agents call over MCP.

Give your data agents a context layer they can trust.

Open Datus Studio free in your browser, or self-host the open-source agent and Dosi engine on the warehouse you already own.