Agent skill
cosmos-dbt-fusion
Use when running a dbt Fusion project with Astronomer Cosmos. Covers Cosmos 1.11+ configuration for Fusion on Snowflake/Databricks with ExecutionMode.LOCAL. Before implementing, verify dbt engine is Fusion (not Core), warehouse is supported, and local execution is acceptable. Does not cover dbt Core.
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/cosmos-dbt-fusion
SKILL.md
Cosmos + dbt Fusion: Implementation Checklist
Execute steps in order. This skill covers Fusion-specific constraints only.
Version note: dbt Fusion support was introduced in Cosmos 1.11.0. Requires Cosmos ≥1.11.
Reference: See reference/cosmos-config.md for ProfileConfig, operator_args, and Airflow 3 compatibility details.
Before starting, confirm: (1) dbt engine = Fusion (not Core → use cosmos-dbt-core), (2) warehouse = Snowflake, Databricks, Bigquery and Redshift only.
Fusion-Specific Constraints
| Constraint | Details |
|---|---|
| No async | AIRFLOW_ASYNC not supported |
| No virtualenv | Fusion is a binary, not a Python package |
| Warehouse support | Snowflake, Databricks, Bigquery and Redshift support while in preview |
1. Confirm Cosmos Version
CRITICAL: Cosmos 1.11.0 introduced dbt Fusion compatibility.
# Check installed version
pip show astronomer-cosmos
# Install/upgrade if needed
pip install "astronomer-cosmos>=1.11.0"
Validate: pip show astronomer-cosmos reports version ≥ 1.11.0
2. Install the dbt Fusion Binary (REQUIRED)
dbt Fusion is NOT bundled with Cosmos or dbt Core. Install it into the Airflow runtime/image.
Determine where to install the Fusion binary (Dockerfile / base image / runtime).
Example Dockerfile Install
USER root
RUN apt-get update && apt-get install -y curl
ENV SHELL=/bin/bash
RUN curl -fsSL https://public.cdn.getdbt.com/fs/install/install.sh | sh -s -- --update
USER astro
Common Install Paths
| Environment | Typical path |
|---|---|
| Astro Runtime | /home/astro/.local/bin/dbt |
| System-wide | /usr/local/bin/dbt |
Validate: The dbt binary exists at the chosen path and dbt --version succeeds.
3. Choose Parsing Strategy (RenderConfig)
Parsing strategy is the same as dbt Core. Pick ONE:
| Load mode | When to use | Required inputs |
|---|---|---|
dbt_manifest |
Large projects; fastest parsing | ProjectConfig.manifest_path |
dbt_ls |
Complex selectors; need dbt-native selection | Fusion binary accessible to scheduler |
automatic |
Simple setups; let Cosmos pick | (none) |
from cosmos import RenderConfig, LoadMode
_render_config = RenderConfig(
load_method=LoadMode.AUTOMATIC, # or DBT_MANIFEST, DBT_LS
)
4. Configure Warehouse Connection (ProfileConfig)
Reference: See reference/cosmos-config.md for full ProfileConfig options and examples.
from cosmos import ProfileConfig
from cosmos.profiles import SnowflakeUserPasswordProfileMapping
_profile_config = ProfileConfig(
profile_name="default",
target_name="dev",
profile_mapping=SnowflakeUserPasswordProfileMapping(
conn_id="snowflake_default",
),
)
5. Configure ExecutionConfig (LOCAL Only)
CRITICAL: dbt Fusion with Cosmos requires
ExecutionMode.LOCALwithdbt_executable_pathpointing to the Fusion binary.
from cosmos import ExecutionConfig
from cosmos.constants import InvocationMode
_execution_config = ExecutionConfig(
invocation_mode=InvocationMode.SUBPROCESS,
dbt_executable_path="/home/astro/.local/bin/dbt", # REQUIRED: path to Fusion binary
# execution_mode is LOCAL by default - do not change
)
6. Configure Project (ProjectConfig)
from cosmos import ProjectConfig
_project_config = ProjectConfig(
dbt_project_path="/path/to/dbt/project",
# manifest_path="/path/to/manifest.json", # for dbt_manifest load mode
# install_dbt_deps=False, # if deps precomputed in CI
)
7. Assemble DAG / TaskGroup
Option A: DbtDag (Standalone)
from cosmos import DbtDag, ProjectConfig, ProfileConfig, ExecutionConfig, RenderConfig
from cosmos.profiles import SnowflakeUserPasswordProfileMapping
from pendulum import datetime
_project_config = ProjectConfig(
dbt_project_path="/usr/local/airflow/dbt/my_project",
)
_profile_config = ProfileConfig(
profile_name="default",
target_name="dev",
profile_mapping=SnowflakeUserPasswordProfileMapping(
conn_id="snowflake_default",
),
)
_execution_config = ExecutionConfig(
dbt_executable_path="/home/astro/.local/bin/dbt", # Fusion binary
)
_render_config = RenderConfig()
my_fusion_dag = DbtDag(
dag_id="my_fusion_cosmos_dag",
project_config=_project_config,
profile_config=_profile_config,
execution_config=_execution_config,
render_config=_render_config,
start_date=datetime(2025, 1, 1),
schedule="@daily",
)
Option B: DbtTaskGroup (Inside Existing DAG)
from airflow.sdk import dag, task # Airflow 3.x
# from airflow.decorators import dag, task # Airflow 2.x
from airflow.models.baseoperator import chain
from cosmos import DbtTaskGroup, ProjectConfig, ProfileConfig, ExecutionConfig
from pendulum import datetime
_project_config = ProjectConfig(dbt_project_path="/usr/local/airflow/dbt/my_project")
_profile_config = ProfileConfig(profile_name="default", target_name="dev")
_execution_config = ExecutionConfig(dbt_executable_path="/home/astro/.local/bin/dbt")
@dag(start_date=datetime(2025, 1, 1), schedule="@daily")
def my_dag():
@task
def pre_dbt():
return "some_value"
dbt = DbtTaskGroup(
group_id="dbt_fusion_project",
project_config=_project_config,
profile_config=_profile_config,
execution_config=_execution_config,
)
@task
def post_dbt():
pass
chain(pre_dbt(), dbt, post_dbt())
my_dag()
8. Final Validation
Before finalizing, verify:
- Cosmos version: ≥1.11.0
- Fusion binary installed: Path exists and is executable
- Warehouse supported: Snowflake, Databricks, Bigquery or Redshift only
- Secrets handling: Airflow connections or env vars, NOT plaintext
Troubleshooting
If user reports dbt Core regressions after enabling Fusion:
AIRFLOW__COSMOS__PRE_DBT_FUSION=1
User Must Test
- The DAG parses in the Airflow UI (no import/parse-time errors)
- A manual run succeeds against the target warehouse (at least one model)
Reference
- Cosmos dbt Fusion docs: https://astronomer.github.io/astronomer-cosmos/configuration/dbt-fusion.html
- dbt Fusion install: https://docs.getdbt.com/docs/core/pip-install#dbt-fusion
Related Skills
- cosmos-dbt-core: For dbt Core projects (not Fusion)
- authoring-dags: General DAG authoring patterns
- testing-dags: Testing DAGs after creation
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