You have just executed dbt run on this model:select * from {{ source("{{ env_var('input') }}",...

This error is caused by invalid Jinja syntax, specifically by nesting {{ }} blocks inside another Jinja expression. The expression:

{{ source("{{ env_var('input') }}", 'table_name') }}

compiles to:

{{ source({{ env_var('input') }}, 'table_name') }}

Here, Jinja sees {{ inside another {{ ... }} block. Jinja does not allow nested print statements like this; instead, functions should be called directly inside a single pair of curly braces. The parser encounters an unexpected } where it expects part of a valid expression (hence “expected token ':', got '}'”), which is a classic symptom of mismatched or nested curly braces.

The correct usage is:

select * from {{ source(env_var('input'), 'table_name') }}

In this form, env_var('input') is evaluated first, and its result is passed as the first argument to source() within one Jinja expression.

Option C is therefore the correct debugging approach: inspect your Jinja and look for incorrectly nested curly brackets. Options A and D are generic and don’t address the root cause, while B talks about quoting in SQL, which is not the problem—the error arises before SQL compilation, at Jinja parse time.