ecto-constraint-debug
Debug Ecto constraint violations - trace triggers, check migrations, find duplicate data. Use when seeing unique_constraint, foreign_key_constraint, or check_constraint errors.
npx skills add oliver-kriska/claude-elixir-phoenix --skill ecto-constraint-debug --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# Ecto Constraint Debugging > **Ash projects**: Ash surfaces DB constraints through its own error DSL. Use the `ash-framework` skill — `mix usage_rules.search_docs "constraint" -p ash_postgres`. Systematic approach to diagnosing constraint violations. Load when you see `Ecto.ConstraintError`, `unique_constraint`, `foreign_key_constraint`, or constraint-related changeset errors. ## Iron Laws 1. **READ THE CONSTRAINT NAME** — The constraint name (e.g., `links_url_index`) tells you exactly which index/constraint failed. Parse it from the error message first 2. **CHECK MIGRATION BEFORE CODE** — Verify the constraint definition in `priv/repo/migrations/` matches what the schema expects 3. **TRACE ALL INSERT PATHS** — Find every code path that inserts into the constrained table. The bug is often in a path you didn't consider 4. **RACE CONDITION UNTIL PROVEN OTHERWISE** — If validation passes but constraint fails, assume concurrent inserts until you prove a single-request cause ## Step-by-Step Debugging ### Step 1: Parse the Error Extract from the error message: - **Constraint name** (e.g., `users_email_index`) - **Table name** (e.g., `users`) - **Operation** (insert, update, or delete) -
- Iron Laws
- Step-by-Step Debugging
- Step 1: Parse the Error
- Step 2: Find the Migration
- Step 3: Find the Schema
- Step 4: Trace Insert Paths
- Step 5: Identify the Cause
- Step 6: Apply Fix
- Quick Fixes by Constraint Type
- References
What does the ecto-constraint-debug skill do?
Debug Ecto constraint violations - trace triggers, check migrations, find duplicate data. Use when seeing unique_constraint, foreign_key_constraint, or check_constraint errors.
How do I install it?
Run `npx skills add oliver-kriska/claude-elixir-phoenix --skill ecto-constraint-debug --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From oliver-kriska/claude-elixir-phoenix, a repository with 515 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.