Fabric data engineering agent (Project Osmos) capacity consumption - preview

Fabric data engineering agent (Project Osmos) uses language models to plan and refine work, and Spark compute to execute code, test implementation options, and validate results. To understand a task's compute consumption, review both components rather than language model tokens alone.

Important

The data engineering agent (Project Osmos) is in preview. Preview features are released with limited capabilities and are subject to separate supplemental preview terms. They're not intended for production use, aren't subject to service-level agreements, and might be available only in selected regions. For more information, see Microsoft Fabric preview information.

Understand task consumption

The following components use different consumption and billing rules:

Component What consumes resources Where to find guidance
Language models Input, cached input when reported separately, and output tokens used for planning, reasoning, and code generation. Refer to Copilot consumption and billing guidance. Language model usage appears under the Project Osmos operation and the Copilot and AI Azure billing meter.
Spark compute Code execution, implementation experiments, data processing, and validation runs. Review Apache Spark billing and utilization. Spark usage is reported separately from the Project Osmos language model operation.

Task complexity affects both components. More implementation attempts or validation runs can increase token usage and Spark execution. The amount of context processed affects token usage, while data volume and transformations such as joins and aggregations affect Spark work. Tasks with similar prompts can therefore consume different amounts of compute.

Other Fabric operations that a task uses have their own consumption rules. For more information, see Fabric operations.

Monitor usage

Use the Fabric Capacity Metrics app to inspect language model and Spark usage. If you don't have access to the app, ask your capacity administrator to review the usage with you.

In the app's default report:

  1. Open the Compute page and use Capacity Name to select the capacity assigned to the task's workspace.
  2. Select the period that includes the task run in the multimetric ribbon chart.
  3. Filter the item kind to Lakehouse. In the matrix by item and operation, locate the task's workspace and lakehouse.
  4. Hover over a value in that lakehouse's row to see the operation breakdown. Find Project Osmos for language model consumption. This Background operation uses the Copilot and AI Azure billing meter.
  5. Review the lakehouse's Spark usage separately. If you also run generated notebooks, review their Notebook items and Spark operations. Don't interpret the Project Osmos operation as the total compute consumption of the task.

For illustrated guidance on the report and operation breakdown, see Compute page in the Fabric Capacity Metrics app and Monitor Apache Spark capacity consumption. If you use the redesigned preview report, see Compute page in the Capacity Metrics app preview.

Note

Lakehouse totals can include activity from other tasks and users. Don't attribute all Spark usage for a shared lakehouse to one task. Usage also takes time to appear in the app; for refresh behavior, see Data latency.

Consumption rates

Language model usage is converted into Fabric capacity units (CUs). For published Copilot consumption rates and billing guidance, see Consumption rates and billing for Copilot in Fabric.

Account for Spark usage separately under the applicable Spark billing model. A token count alone doesn't determine the total cost of a task.

For capacity planning guidance, see Plan for shared-capacity usage.