database-migrations
Creates safe database migrations with proper indexes and rollback strategies. Use when creating tables, adding columns, creating indexes, handling zero-downtime migrations, or when user mentions migrations, schema changes, or database structure.
Install with Tessl CLI
npx tessl i github:ThibautBaissac/rails_ai_agents --skill database-migrations90
Does it follow best practices?
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npx tessl skill review --optimize ./path/to/skillAgent success when using this skill
Validation for skill structure
Evaluation results
100%
16%Slow Query Performance on Orders Table
Safe concurrent index creation
disable_ddl_transaction!
100%
100%
algorithm: :concurrently
100%
100%
if_not_exists: true
0%
100%
Composite index column order
100%
100%
Partial index where clause
100%
100%
Foreign key indexed
100%
100%
Migration version [8.0]
100%
100%
Reversible migrations
100%
100%
No direct add_index without concurrently
100%
100%
Index name specified
0%
100%
Without context: $0.1515 · 32s · 8 turns · 9 in / 1,843 out tokens
With context: $0.2891 · 52s · 13 turns · 13 in / 2,666 out tokens
100%
20%Migrate Product Price Column to Decimal Precision
Safe column type change with batched backfill
No change_column
100%
100%
New column added first
100%
100%
Batched backfill
100%
100%
sleep in batch loop
0%
100%
disable_ddl_transaction! on data migration
100%
100%
safety_assured on remove_column
0%
100%
Old column removed
100%
100%
Migration version [8.0]
100%
100%
Reversible migrations
100%
100%
Separate migration files
100%
100%
Without context: $0.3236 · 1m 37s · 13 turns · 14 in / 5,203 out tokens
With context: $0.5268 · 1m 48s · 22 turns · 23 in / 5,614 out tokens
57%
31%Add Shipment Tracking to the Orders System
NOT NULL constraint and enum column migration
Two-step NOT NULL
0%
0%
Initial column nullable
0%
50%
Enum uses :integer type
0%
100%
Enum default: 0
0%
100%
Enum column indexed
100%
100%
on_delete specified
0%
0%
Migration version [8.0]
100%
100%
Reversible migrations
100%
100%
change_column_null usage
0%
0%
Enum model declaration
0%
100%
Without context: $0.1773 · 40s · 9 turns · 10 in / 2,241 out tokens
With context: $0.4194 · 1m 28s · 17 turns · 270 in / 4,084 out tokens
- Evaluated
- Agent
- Claude Code
Table of Contents
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