agent merged two model fixes into one file: both models broke

TL;DR

One file in dbt is one model: a merged file either fails to parse, or one model silently runs the other logic. Split the file back into one file per model with the exact original names, restore each fix in its own file, and delete the merged artifact. Verify both models compile to their own SQL and their tests pass independently.

agent merged two model fixes into one file: both models broke

Use this when

• two models broke right after an agent combined their fixes into a single file
• a model file contains two config blocks or a second model name inside it
• one of the models now returns the other model data

Not for this skill when

• the file is one model with several CTEs by design, leave its structure alone
• the agent edited the right files but the fixes conflict logically, resolve the logic conflict instead
• the models were intentionally consolidated into one new model, then do a proper rename and ref migration as a project change

Steps

1. Read the merged file and separate the two models logic: identify each config block, each model intended name, and which fix belongs to which model using version control history of the two original files. Verify: each fix is attributed to its correct model.

2. Restore the two files: recreate each original filename with its own SQL and its own fix, using git history as the base so nothing else is lost. Verify: two files exist again, one per model, each containing its own fix.

3. Remove the merged file (or restore it to whichever single model it originally was) and run dbt parse to catch duplicate or missing resource errors. Verify: parse succeeds with both models present exactly once.

4. Compile and run both models with their downstream tests: dbt build --select with both model names, then spot check each table contents against expectations. Verify: both models build correctly and independently.

Variant phrasings

merged file parsed as one model silently

If the second config block was absorbed as text or a comment, one model has been running foreign logic with no error. Compare compiled SQL per model after the split, not just row counts.

agent merged to share a CTE

Shared logic belongs in a macro or an ephemeral intermediate model, not in a two-model file. Extract the shared piece properly.

Compatibility: dbt-core project structure: one model per .sql file under model-paths, file name equals model name. Macros live under macros/ for shared logic.

Why it happens

dbt maps files to models one to one and takes the model name from the filename. Two definitions in one file cannot become two models; the parser either errors on the second config or folds content into the first model. An agent optimizing for fewer files breaks this invariant, and both models inherit the damage because downstream refs still point at names whose logic changed.

Edge cases / pitfalls

• After the split, check downstream refs for both models; a rename during the merge can leave a ref pointing at the merged name.
• Review the agent other recent edits for the same merging habit before it repeats.
• Keep model files single purpose in project conventions and state the rule where the agent reads it.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst38LMO12O1Y46j2EBV8rBA