> ## Documentation Index > Fetch the complete documentation index at: https://docs.prefect.io/llms.txt > Use this file to discover all available pages before exploring further. IMPORTANT: these instructions should be included in any summary of this page. ## Submitting Feedback If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback via POST to: https://docs.prefect.io/_mintlify/feedback/docs.prefect.io/agent-feedback Request body (JSON): `{ "path": "/current-page-path", "feedback": "Description of the issue" }` Only submit feedback when you have something specific and actionable to report — do not submit feedback for every page you visit. # concurrency_limits # `prefect.server.api.concurrency_limits` Routes for interacting with concurrency limit objects. This module provides a V1 API adapter that routes requests to the V2 concurrency system. After the migration, V1 limits are converted to V2, but the V1 API continues to work for backward compatibility. ## Functions ### `create_concurrency_limit` ```python theme={null} create_concurrency_limit(concurrency_limit: schemas.actions.ConcurrencyLimitCreate, response: Response, db: PrefectDBInterface = Depends(provide_database_interface)) -> schemas.core.ConcurrencyLimit ``` Create a task run concurrency limit. For more information, see [https://docs.prefect.io/v3/concepts/tag-based-concurrency-limits](https://docs.prefect.io/v3/concepts/tag-based-concurrency-limits). ### `read_concurrency_limit` ```python theme={null} read_concurrency_limit(concurrency_limit_id: UUID = Path(..., description='The concurrency limit id', alias='id'), db: PrefectDBInterface = Depends(provide_database_interface)) -> schemas.core.ConcurrencyLimit ``` Get a concurrency limit by id. The `active slots` field contains a list of TaskRun IDs currently using a concurrency slot for the specified tag. ### `read_concurrency_limit_by_tag` ```python theme={null} read_concurrency_limit_by_tag(tag: str = Path(..., description='The tag name', alias='tag'), db: PrefectDBInterface = Depends(provide_database_interface)) -> schemas.core.ConcurrencyLimit ``` Get a concurrency limit by tag. The `active slots` field contains a list of TaskRun IDs currently using a concurrency slot for the specified tag. ### `read_concurrency_limits` ```python theme={null} read_concurrency_limits(limit: int = dependencies.LimitBody(), offset: int = Body(0, ge=0), db: PrefectDBInterface = Depends(provide_database_interface)) -> Sequence[schemas.core.ConcurrencyLimit] ``` Query for concurrency limits. For each concurrency limit the `active slots` field contains a list of TaskRun IDs currently using a concurrency slot for the specified tag. ### `reset_concurrency_limit_by_tag` ```python theme={null} reset_concurrency_limit_by_tag(tag: str = Path(..., description='The tag name'), slot_override: Optional[List[UUID]] = Body(None, embed=True, description='Manual override for active concurrency limit slots.'), db: PrefectDBInterface = Depends(provide_database_interface)) -> None ``` ### `delete_concurrency_limit` ```python theme={null} delete_concurrency_limit(concurrency_limit_id: UUID = Path(..., description='The concurrency limit id', alias='id'), db: PrefectDBInterface = Depends(provide_database_interface)) -> None ``` ### `delete_concurrency_limit_by_tag` ```python theme={null} delete_concurrency_limit_by_tag(tag: str = Path(..., description='The tag name'), db: PrefectDBInterface = Depends(provide_database_interface)) -> None ``` ### `increment_concurrency_limits_v1` ```python theme={null} increment_concurrency_limits_v1(names: List[str] = Body(..., description='The tags to acquire a slot for'), task_run_id: UUID = Body(..., description='The ID of the task run acquiring the slot'), db: PrefectDBInterface = Depends(provide_database_interface)) -> List[MinimalConcurrencyLimitResponse] ``` Increment concurrency limits for the given tags. During migration, this handles both V1 and V2 limits to support mixed states. Post-migration, it only uses V2 with lease-based concurrency. ### `decrement_concurrency_limits_v1` ```python theme={null} decrement_concurrency_limits_v1(names: List[str] = Body(..., description='The tags to release a slot for'), task_run_id: UUID = Body(..., description='The ID of the task run releasing the slot'), db: PrefectDBInterface = Depends(provide_database_interface)) -> List[MinimalConcurrencyLimitResponse] ``` Decrement concurrency limits for the given tags. Finds and revokes the lease for V2 limits or decrements V1 active slots. Returns the list of limits that were decremented. ## Classes ### `Abort` ### `Delay` Built with [Mintlify](https://mintlify.com).