diff --git a/schemas/04_log.sql b/schemas/04_log.sql
index 0add790..79f818b 100644
--- a/schemas/04_log.sql
+++ b/schemas/04_log.sql
@@ -1,6 +1,8 @@
 -- ============================================
 -- SCHEMA LOG - Sistema TZZR
 -- Log inmutable de mensajes
+-- Versión: 2.0
+-- Fecha: 2026-01-01
 -- ============================================
 
 DROP SCHEMA IF EXISTS log CASCADE;
@@ -13,7 +15,7 @@ CREATE EXTENSION IF NOT EXISTS pgcrypto;
 CREATE TYPE log.ref_type AS ENUM ('context', 'accountant', 'secretary');
 
 -- ============================================
--- Tabla 1: messages
+-- Tabla principal: messages
 -- ============================================
 CREATE TABLE log.messages (
     id              BIGSERIAL PRIMARY KEY,
@@ -21,7 +23,7 @@ CREATE TABLE log.messages (
     session_hash    CHAR(64) NOT NULL,
     thread_hash     CHAR(64),
     owner_id        CHAR(64) NOT NULL,
-    players_id      CHAR(64)[] DEFAULT '{}',
+    players_id      CHAR(64)[] NOT NULL DEFAULT '{}',
     master_player   CHAR(64),
     role            TEXT,
     content         TEXT NOT NULL,
@@ -36,21 +38,23 @@ CREATE TABLE log.messages (
     created_at      TIMESTAMPTZ DEFAULT NOW()
 );
 
+-- Índices messages
 CREATE INDEX idx_messages_session ON log.messages(session_hash);
 CREATE INDEX idx_messages_thread ON log.messages(thread_hash);
 CREATE INDEX idx_messages_owner ON log.messages(owner_id);
-CREATE INDEX idx_messages_master_player ON log.messages(master_player);
-CREATE INDEX idx_messages_prev ON log.messages(prev_hash);
-CREATE INDEX idx_messages_created ON log.messages(created_at);
-CREATE INDEX idx_messages_hashtags ON log.messages USING gin(hashtags);
 CREATE INDEX idx_messages_players ON log.messages USING gin(players_id);
-CREATE INDEX idx_messages_items ON log.messages USING gin(item_id);
+CREATE INDEX idx_messages_master ON log.messages(master_player);
+CREATE INDEX idx_messages_prev ON log.messages(prev_hash);
+CREATE INDEX idx_messages_hashtags ON log.messages USING gin(hashtags);
 CREATE INDEX idx_messages_flag ON log.messages(flag_id);
+CREATE INDEX idx_messages_master_item ON log.messages(master_item_id);
+CREATE INDEX idx_messages_items ON log.messages USING gin(item_id);
 CREATE INDEX idx_messages_loc ON log.messages(loc_id);
+CREATE INDEX idx_messages_created ON log.messages(created_at);
 
 -- ============================================
--- Tabla 2: message_refs
--- Relaciona mensaje con contexto y conocimiento
+-- Tabla relacional: message_refs
+-- Referencias a contexto y conocimiento
 -- ============================================
 CREATE TABLE log.message_refs (
     id              BIGSERIAL PRIMARY KEY,
@@ -59,9 +63,10 @@ CREATE TABLE log.message_refs (
     ref_type        log.ref_type NOT NULL,
     position        INT NOT NULL,
     thread_hash     CHAR(64),
-    UNIQUE(message_hash, ref_hash)
+    UNIQUE(message_hash, ref_hash, ref_type)
 );
 
+-- Índices message_refs
 CREATE INDEX idx_refs_message ON log.message_refs(message_hash);
 CREATE INDEX idx_refs_ref ON log.message_refs(ref_hash);
 CREATE INDEX idx_refs_type ON log.message_refs(ref_type);
@@ -89,7 +94,7 @@ END;
 $$ LANGUAGE plpgsql;
 
 -- ============================================
--- Triggers de protección
+-- Triggers de protección (inmutabilidad)
 -- ============================================
 CREATE TRIGGER protect_messages_update BEFORE UPDATE ON log.messages
     FOR EACH ROW EXECUTE FUNCTION log.prevent_update();
@@ -110,4 +115,5 @@ GRANT SELECT, INSERT ON log.message_refs TO tzzr;
 GRANT USAGE ON SEQUENCE log.messages_id_seq TO tzzr;
 GRANT USAGE ON SEQUENCE log.message_refs_id_seq TO tzzr;
 
-SELECT 'Schema log: 2 tablas creadas' as status;
+-- Verificación
+SELECT 'Schema log v2.0: 2 tablas creadas' as status;