Last verified against Google’s public Looker documentation in October 2026.
What each one is
LookML describes views, explores, dimensions and measures for Looker. Looker is a commercial BI product, and the model lives in a Looker project. Looker protects against two classic problems inside the tool:- Fanout. Symmetric aggregates keep sums, averages and counts correct when a join repeats rows, by counting each fact once through the primary key defined in the model.
- Rules and access.
sql_always_whereandaccess_filterapply filters that users cannot see or change.always_filterrequires a filter with a default value that users can change but not remove.
Where they differ
Both tools care about fanout. They take opposite routes. A correcting mechanism returns a number whatever the query. canonic refuses when it cannot prove the number is right and tells the caller what to change.
How canonic uses Looker
Thelooker connector is an evidence connector. It reads saved Looks through the Looker REST API 4.0 and turns each one into usage evidence, with a role derived from the Look’s visibility and view count. A public, frequently viewed Look becomes a trusted example. A private or rarely viewed one becomes an alternative. Evidence never becomes a canonical definition on its own.
canonic does not parse LookML files today, and it never runs the SQL of a Look. If a Looker-encoded metric is adopted, it is recompiled through the deterministic compiler like any other definition. See connectors for how evidence is normalized and ingestion and reconciliation for how a proposal becomes part of the project.
Using them together
- Keep LookML for the dashboards people already use.
- Add a
lookerconnection so that the metrics your teams actually look at show up as evidence when canonic drafts definitions. - Review the proposals, bind the canonical definition once, and let the agent ask canonic instead of guessing from the schema.
- If you want Looker’s own agents to see the same numbers, compare them with assertions on the canonic side.
canonic and other tools
The roles and a side-by-side table for dbt, Cube, LookML and Ossie.
Connectors
How warehouse, definition and evidence connectors differ.
Sources
- Google Cloud, Understanding symmetric aggregates
- Google Cloud,
always_filter,sql_always_whereandaccess_filter - Google Cloud, Use Looker with MCP, Gemini CLI and other agents
- Google Cloud, Looker updates for agentic BI