dbt-prune 0.1.0

Find orphaned dbt models and snapshots across multiple manifests and open Copilot-powered cleanup tasks.

dbt-prune

dbt-prune is a pip-installable dbt-core companion CLI for finding dbt models and snapshots that are no longer referenced by anything in your current project, configured sibling projects, or dbt exposures.

Installation

pip install dbt-prune

Optional integrations stay lightweight by default:

pip install 'dbt-prune[gcs]'
pip install 'dbt-prune[datahub]'

Configuration

By default dbt-prune looks for dbt_prune.config.yml in the dbt project root passed to --project-dir.

projects:
  - name: other_project
    manifest:
      type: local
      path: ../other_project/target/manifest.json

datahub:
  enabled: false
  gms_server_env_var: DATAHUB_GMS_SERVER
  token_env_var: DATAHUB_TOKEN

Important DataHub note

The config file stores the names of the environment variables only. The actual DataHub GMS server URL and token must come from the environment at runtime:

export DATAHUB_GMS_SERVER=https://datahub.example.com
export DATAHUB_TOKEN=...

How orphan detection works

dbt-prune only parses manifest.json files. It does not run dbt, compile models, or introspect a live warehouse.

It loads:

• the current project's target/manifest.json
• any configured external manifests from local paths or gs:// URIs
• exposure dependencies from every loaded manifest

A current-project model or snapshot is considered orphaned only when it has zero incoming references from any loaded manifest and is not referenced by any exposure. If DataHub checking is enabled, downstream lineage consumers also keep a node off the orphan list.

Usage

List all orphaned assets

dbt-prune ls --project-dir .

Inspect one specific model

dbt-prune ls --project-dir . -s my_model

When -s/--select is used, dbt-prune reports whether the named model or snapshot is orphaned and explains why.

JSON output

dbt-prune ls --format json

Open Copilot cleanup tasks for every orphan

dbt-prune run --project-dir .

Behavior:

• scans all current-project models and snapshots by default
• opens one GitHub Copilot coding-agent task per orphan
• auto-detects the target owner/repo from git remote get-url origin
• requires GITHUB_TOKEN for GitHub API authentication

Dry-run the cleanup plan

dbt-prune run --dry-run

Restrict cleanup to one model

dbt-prune run -s my_model

Limit the number of cleanup tasks

dbt-prune run --limit 5

DataHub integration

When datahub.enabled: true, dbt-prune queries DataHub for downstream lineage before marking an otherwise unreferenced asset as orphaned.

If the required environment variables are missing or DataHub is unreachable, dbt-prune warns and continues unless you pass --strict.

GitHub Copilot coding-agent PR automation

dbt-prune run generates a clear problem statement for each orphaned asset and sends it to GitHub through dbt_prune.pr_agent. The default implementation creates a GitHub issue payload intended for Copilot coding-agent workflows, and the module is designed to be replaceable if your organization uses a dedicated Copilot task/session endpoint.

Development

python -m pip install -e '.[dev]'
ruff check .
pytest
mypy dbt_prune