diff --git a/supabase/migrations/20251002192359_2917df33-335f-47a9-a747-59cf6fc20cb8.sql b/supabase/migrations/20251002192359_2917df33-335f-47a9-a747-59cf6fc20cb8.sql
new file mode 100644
index 00000000..95631a6f
--- /dev/null
+++ b/supabase/migrations/20251002192359_2917df33-335f-47a9-a747-59cf6fc20cb8.sql
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+-- Add size constraint to prevent JSON blob storage in content_submissions
+-- This enforces the architectural rule: "NEVER STORE JSON IN SQL COLUMNS"
+-- Content should only contain: action + max 2 reference IDs (< 500 bytes)
+
+ALTER TABLE public.content_submissions 
+ADD CONSTRAINT content_size_check 
+CHECK (pg_column_size(content) < 500);
+
+COMMENT ON CONSTRAINT content_size_check ON public.content_submissions 
+IS 'Prevents large JSON blobs in content column. Content should only contain action and reference IDs. All actual data goes in submission_items.item_data or specialized relational tables.';
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