diff --git a/db/core/changelog-master.xml b/db/core/changelog-master.xml
index 9bf67ee..5a115c5 100644
--- a/db/core/changelog-master.xml
+++ b/db/core/changelog-master.xml
@@ -48,5 +48,6 @@
   <include file="changesets/036-fn-work-program-get-curve.sql" relativeToChangelogFile="true"/>
   <include file="changesets/037-fn-work-program-get-curve-vrow.sql" relativeToChangelogFile="true"/>
   <include file="changesets/038-fn-work-program-vs-cost.sql" relativeToChangelogFile="true"/>
+  <include file="changesets/039-fn-next-project-code-global.sql" relativeToChangelogFile="true"/>
 
 </databaseChangeLog>
diff --git a/db/core/changesets/039-fn-next-project-code-global.sql b/db/core/changesets/039-fn-next-project-code-global.sql
new file mode 100644
index 0000000..d08715f
--- /dev/null
+++ b/db/core/changesets/039-fn-next-project-code-global.sql
@@ -0,0 +1,119 @@
+--liquibase formatted sql
+-- PANELS · core · código PRY global (UNIQUE en projects.code) vs RLS por tenant
+
+--changeset panel:core-039a-fn-next-project-code-global splitStatements:false
+CREATE OR REPLACE FUNCTION core.fn_next_project_code(payload jsonb)
+RETURNS jsonb
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = core
+AS $$
+DECLARE
+  v_n integer;
+  v_code text;
+BEGIN
+  -- projects.code es UNIQUE en toda la base. Con RLS el tenant solo ve sus filas
+  -- y MAX+1 puede repetir PRY-0001 de otro tenant → projects_code_key.
+  -- SECURITY DEFINER (dueño del esquema) lee la secuencia global.
+  SELECT COALESCE(MAX(substring(code FROM 5)::integer), 0) + 1
+    INTO v_n
+    FROM projects
+   WHERE code ~ '^(PRY|OBR)-[0-9]+$';
+  v_code := 'PRY-' || lpad(v_n::text, 4, '0');
+  RETURN core.rpc_ok(
+    jsonb_build_object('code', v_code),
+    format('Siguiente código de proyecto asignado: %s', v_code),
+    jsonb_build_object('fn', 'fn_next_project_code', 'sequence', v_n)
+  );
+EXCEPTION WHEN OTHERS THEN
+  RETURN core.rpc_from_exception('fn_next_project_code', SQLSTATE, SQLERRM);
+END;
+$$;
+
+--changeset panel:core-039b-fn-project-create-code-lock splitStatements:false
+CREATE OR REPLACE FUNCTION core.fn_project_create(payload jsonb)
+RETURNS jsonb
+LANGUAGE plpgsql
+SECURITY INVOKER
+SET search_path = core
+AS $$
+DECLARE
+  v_tid integer := COALESCE(
+    (payload->>'tenant_id')::integer,
+    NULLIF(current_setting('app.tenant_id', true), '')::integer
+  );
+  v_name text := nullif(btrim(payload->>'name'), '');
+  v_address text := coalesce(nullif(btrim(payload->>'address'), ''), '');
+  v_theme_id text := coalesce(nullif(btrim(payload->>'theme_id'), ''), 'arctec-dos-logos-fold');
+  v_status text := coalesce(nullif(btrim(payload->>'status'), ''), 'activo');
+  v_company_id integer := (payload->>'company_id')::integer;
+  v_contract_amount numeric(14,2) := (payload->>'contract_amount')::numeric(14,2);
+  v_start_date date := nullif(btrim(payload->>'start_date'), '')::date;
+  v_end_date date := nullif(btrim(payload->>'end_date'), '')::date;
+  v_resident_name text := coalesce(nullif(btrim(payload->>'resident_name'), ''), '');
+  v_siroc text := upper(coalesce(nullif(btrim(payload->>'siroc'), ''), ''));
+  v_payroll_tax_pct numeric(5,2) := coalesce((payload->>'payroll_tax_pct')::numeric(5,2), 4);
+  v_code_env jsonb;
+  v_code text;
+  v_row projects%ROWTYPE;
+BEGIN
+  IF v_name IS NULL THEN
+    RETURN core.rpc_err(
+      'VALIDATION',
+      'fn_project_create: nombre de proyecto obligatorio',
+      jsonb_build_object('fn', 'fn_project_create', 'field', 'name')
+    );
+  END IF;
+  IF v_company_id IS NULL THEN
+    RETURN core.rpc_err(
+      'VALIDATION',
+      'fn_project_create: company_id es obligatorio',
+      jsonb_build_object('fn', 'fn_project_create', 'field', 'company_id')
+    );
+  END IF;
+  IF NOT EXISTS (SELECT 1 FROM companies WHERE id = v_company_id) THEN
+    RETURN core.rpc_err(
+      'VALIDATION',
+      format('fn_project_create: empresa id=%s no encontrada', v_company_id),
+      jsonb_build_object('fn', 'fn_project_create', 'company_id', v_company_id)
+    );
+  END IF;
+  IF v_status NOT IN ('activo', 'pausado', 'concluido', 'cancelado') THEN
+    RETURN core.rpc_err(
+      'VALIDATION',
+      format('fn_project_create: estado inválido %s', v_status),
+      jsonb_build_object('fn', 'fn_project_create', 'field', 'status', 'value', v_status)
+    );
+  END IF;
+  IF v_start_date IS NOT NULL AND v_end_date IS NOT NULL AND v_end_date < v_start_date THEN
+    RETURN core.rpc_err(
+      'VALIDATION',
+      'fn_project_create: la fecha de término no puede ser anterior al inicio',
+      jsonb_build_object('fn', 'fn_project_create', 'field', 'end_date')
+    );
+  END IF;
+
+  PERFORM pg_advisory_xact_lock(41092001);
+
+  v_code_env := core.fn_next_project_code('{}'::jsonb);
+  IF NOT COALESCE((v_code_env->>'ok')::boolean, false) THEN
+    RETURN v_code_env;
+  END IF;
+  v_code := v_code_env->'data'->>'code';
+  INSERT INTO projects (
+    code, name, address, theme_id, status, company_id, contract_amount,
+    start_date, end_date, resident_name, siroc, payroll_tax_pct, tenant_id
+  ) VALUES (
+    v_code, v_name, v_address, v_theme_id, v_status, v_company_id, v_contract_amount,
+    v_start_date, v_end_date, v_resident_name, v_siroc, v_payroll_tax_pct, v_tid
+  )
+  RETURNING * INTO v_row;
+  RETURN core.rpc_created(
+    jsonb_build_object('id', v_row.id, 'code', v_row.code, 'status', v_row.status),
+    format('Proyecto %s (%s) creado', v_row.code, v_row.name),
+    jsonb_build_object('fn', 'fn_project_create', 'id', v_row.id, 'code', v_row.code)
+  );
+EXCEPTION WHEN OTHERS THEN
+  RETURN core.rpc_from_exception('fn_project_create', SQLSTATE, SQLERRM);
+END;
+$$;
diff --git a/scripts/verify-project-code-next-run.sql b/scripts/verify-project-code-next-run.sql
new file mode 100644
index 0000000..31867aa
--- /dev/null
+++ b/scripts/verify-project-code-next-run.sql
@@ -0,0 +1,45 @@
+SET search_path = core;
+SELECT set_config('app.tenant_id', '2', true);
+
+CREATE OR REPLACE FUNCTION fn_next_project_code_old()
+RETURNS text
+LANGUAGE plpgsql
+SECURITY INVOKER
+SET search_path = core
+AS $$
+DECLARE v_n integer; v_code text;
+BEGIN
+  SELECT COALESCE(MAX(substring(code FROM 5)::integer), 0) + 1 INTO v_n
+    FROM projects WHERE code ~ '^PRY-[0-9]{4}' OR code ~ '^OBR-[0-9]{4}';
+  RETURN 'PRY-' || lpad(v_n::text, 4, '0');
+END;
+$$;
+
+CREATE OR REPLACE FUNCTION fn_next_project_code_new()
+RETURNS text
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = core
+AS $$
+DECLARE v_n integer; v_code text;
+BEGIN
+  SELECT COALESCE(MAX(substring(code FROM 5)::integer), 0) + 1 INTO v_n
+    FROM projects WHERE code ~ '^(PRY|OBR)-[0-9]+$';
+  RETURN 'PRY-' || lpad(v_n::text, 4, '0');
+END;
+$$;
+
+DO $$
+DECLARE old_code text; new_code text;
+BEGIN
+  old_code := fn_next_project_code_old();
+  new_code := fn_next_project_code_new();
+  IF old_code <> 'PRY-0001' THEN
+    RAISE EXCEPTION 'RLS bug demo: old should propose PRY-0001, got %', old_code;
+  END IF;
+  IF new_code <> 'PRY-0002' THEN
+    RAISE EXCEPTION 'fix should propose PRY-0002, got %', new_code;
+  END IF;
+  RAISE NOTICE 'OK old=% (conflict) new=% (safe)', old_code, new_code;
+END;
+$$;
diff --git a/scripts/verify-project-code-next.sql b/scripts/verify-project-code-next.sql
new file mode 100644
index 0000000..34ba1f3
--- /dev/null
+++ b/scripts/verify-project-code-next.sql
@@ -0,0 +1,44 @@
+-- Simula RLS: tenant B no ve PRY-0001 de tenant A pero el código debe ser global.
+DROP SCHEMA IF EXISTS core CASCADE;
+CREATE SCHEMA core;
+SET search_path = core;
+
+CREATE FUNCTION rpc_assert_message(p_message text) RETURNS void LANGUAGE plpgsql IMMUTABLE AS $$
+BEGIN IF p_message IS NULL OR btrim(p_message) = '' THEN RAISE EXCEPTION 'empty'; END IF; END; $$;
+CREATE FUNCTION rpc_ok(p_data jsonb, p_message text, p_ctx jsonb DEFAULT '{}'::jsonb) RETURNS jsonb
+LANGUAGE plpgsql IMMUTABLE AS $$
+BEGIN PERFORM rpc_assert_message(p_message);
+RETURN jsonb_build_object('ok', true, 'data', p_data); END; $$;
+CREATE FUNCTION rpc_created(p_data jsonb, p_message text, p_ctx jsonb DEFAULT '{}'::jsonb) RETURNS jsonb
+LANGUAGE plpgsql IMMUTABLE AS $$
+BEGIN PERFORM rpc_assert_message(p_message);
+RETURN jsonb_build_object('ok', true, 'data', p_data); END; $$;
+CREATE FUNCTION rpc_err(p_code text, p_message text, p_ctx jsonb DEFAULT '{}'::jsonb, p_errors jsonb DEFAULT NULL) RETURNS jsonb
+LANGUAGE plpgsql IMMUTABLE AS $$
+BEGIN PERFORM rpc_assert_message(p_message);
+RETURN jsonb_build_object('ok', false, 'message', p_message); END; $$;
+CREATE FUNCTION rpc_from_exception(p_fn text, p_sqlstate text, p_message text, p_detail text DEFAULT NULL) RETURNS jsonb
+LANGUAGE plpgsql IMMUTABLE AS $$
+BEGIN RETURN rpc_err('INTERNAL', format('%s %s', p_fn, p_message), '{}'::jsonb); END; $$;
+
+CREATE TABLE companies (id BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY, name text);
+CREATE TABLE projects (
+  id BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+  code text NOT NULL UNIQUE,
+  name text NOT NULL,
+  address text DEFAULT '',
+  theme_id text NOT NULL DEFAULT 'arctec-dos-logos-fold',
+  status text DEFAULT 'activo',
+  company_id bigint,
+  tenant_id int
+);
+ALTER TABLE projects ENABLE ROW LEVEL SECURITY;
+CREATE POLICY tenant_isolation ON projects
+  USING (tenant_id = NULLIF(current_setting('app.tenant_id', true), '')::integer)
+  WITH CHECK (tenant_id = NULLIF(current_setting('app.tenant_id', true), '')::integer);
+
+INSERT INTO companies (name) VALUES ('Co A'), ('Co B');
+
+-- PRY-0001 ya existe (otro tenant / seed)
+INSERT INTO projects (code, name, theme_id, company_id, tenant_id)
+VALUES ('PRY-0001', 'Obra seed', 'arctec-dos-logos-fold', 1, 1);