diff --git a/backend/llm.txt b/backend/llm.txt
index f7c8b51..32bfcf9 100644
--- a/backend/llm.txt
+++ b/backend/llm.txt
@@ -20,6 +20,7 @@ This file condenses `backend/docs/dev/http_api.md` + `backend/docs/dev/model.md`
 - DO NOT manually write route declarations (only `atomctl gen route`).
 - DO keep Swagger annotations consistent with actual Fiber route paths (including `:param`).
 - MUST: route path parameter placeholders MUST be `camelCase` (e.g. `:tenantCode`), never `snake_case` (e.g. `:tenant_code`).
+- MUST: when creating/generating Go `struct` definitions (DTOs/requests/responses/etc.), add detailed per-field comments describing meaning, usage scenario, and validation/usage rules (do not rely on “self-explanatory” names).
 
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