diff --git a/mcp_servers.d/navi_ui.json b/mcp_servers.d/navi_ui.json
index 912c00d..6b8626f 100644
--- a/mcp_servers.d/navi_ui.json
+++ b/mcp_servers.d/navi_ui.json
@@ -4,5 +4,5 @@
   "groups": {
     "ui": ["render_component"]
   },
-  "instructions": "Internal Navi UI server. Use `render_component` to display structured data in the webclient. The tool accepts `component_name` (string) and `payload` (JSON object); `session_id` is injected automatically by the agent. Only use it when a graphical/structured view is appropriate."
+  "instructions": "Tool: render_component. Arguments: {\"component_name\": \"card_grid\", \"payload\": {...}}. Only use component_name=\"card_grid\". session_id is injected automatically. For card_grid, payload must contain a non-empty \"cards\" array. Each card must have string \"id\" and string \"title\". Optional card fields: \"subtitle\", \"image\" (URL), \"meta\" (array of {\"label\", \"value\"}), \"description\" (short string), \"details\" (array of {\"label\", \"value\"} shown in modal), \"actions\" (array of {\"label\", \"url\"}). Limit card grid to 4 cards. After rendering the grid, still give a brief text summary and ask what the user wants next."
 }
diff --git a/navi/mcp/ui_server.py b/navi/mcp/ui_server.py
index 2445c16..84e106a 100644
--- a/navi/mcp/ui_server.py
+++ b/navi/mcp/ui_server.py
@@ -34,53 +34,45 @@
 # This is separate from the webclient implementation; both must agree on the
 # same contract, but the server only validates the envelope.
 SERVER_INSTRUCTIONS = """\
-Internal Navi UI server. Use this to render structured data in the webclient.
+Internal Navi UI server. Use render_component to show structured UI in the webclient.
 
 Tool: render_component(component_name, payload, session_id)
-- component_name: identifier of the UI component to render.
-- payload: JSON-serializable object with the data for that component.
-- session_id: target Navi session (injected automatically by the agent).
+- component_name: only "card_grid" is supported.
+- payload: JSON object. See schema below.
+- session_id: DO NOT pass manually. It is injected automatically by the agent.
 
-Only call this when the user explicitly asks for a graphical / structured
-view, or when a tool response is naturally represented as a component.
+## card_grid payload schema
 
-## Supported components
-
-### card_grid
-A responsive grid of clickable cards (default up to 4). Clicking a card opens a
-modal with the full `details` object.
-
-Payload shape:
-```json
 {
   "title": "Optional section heading",
   "cards": [
     {
-      "id": "unique-card-id",
-      "title": "Card title",
-      "subtitle": "Short secondary line",
-      "image": "https://optional-image-url",
+      "id": "required-string-id",
+      "title": "Required card title",
+      "subtitle": "Optional secondary line",
+      "image": "https://optional-direct-image-url",
       "meta": [
         {"label": "Label", "value": "Value"}
       ],
-      "description": "One-line summary (optional)",
+      "description": "Optional short one-line summary",
       "details": [
-        {"label": "Full detail", "value": "Full value"}
+        {"label": "Detail label", "value": "Detail value"}
       ],
       "actions": [
-        {"label": "Open", "url": "https://..."}
+        {"label": "Button label", "url": "https://..."}
       ]
     }
   ]
 }
-```
 
-Rules:
-- `cards` is required and must be a list.
-- Each card must contain `id` (string) and `title` (string).
-- `image` must be a direct URL if present.
-- Keep `description` under 120 characters.
-- Put everything the user might want to see after clicking in `details`.
+Hard rules:
+1. component_name must be "card_grid".
+2. payload.cards is required and must be a non-empty list.
+3. Every card must have id (string) and title (string).
+4. Limit to 4 cards in one call. If there are more, say there are more and ask if the user wants them.
+5. image must be a direct URL, never a local path.
+6. Put the full information that should appear after a card click into details.
+7. After calling render_component, still provide a short text summary and offer next steps.
 """
 
 mcp = FastMCP(
diff --git a/navi/profiles/realtor/system_prompt.txt b/navi/profiles/realtor/system_prompt.txt
index 0c2374a..d68aef8 100644
--- a/navi/profiles/realtor/system_prompt.txt
+++ b/navi/profiles/realtor/system_prompt.txt
@@ -169,48 +169,56 @@
 
 ## UI component output (optional)
 
-When the data is naturally shown as a grid of cards (e.g. several listings, products, items), use the tool:
+When the data is naturally shown as a grid of cards (for example, several listings, products, or any items), render it with:
 
-```
-mcp__navi_ui__render_component
-component_name: card_grid
-payload:
-  title: "Подходящие варианты"   // optional section title
-  cards:
-    - id: "unique-id-1"           // required, stable identifier
-      title: "Квартира на Арсенальной"
-      subtitle: "Печерский район · 5 мин до метро"
-      image: "https://..."        // optional, direct image URL
-      meta:
-        - label: "Цена"
-          value: "$80 000"
-        - label: "Комнат"
-          value: "2"
-        - label: "Площадь"
-          value: "58 м²"
-        - label: "Этаж"
-          value: "4/9"
-      description: "Краткое описание карточки."
-      details:                      // shown in the modal on click
-        - label: "Адрес"
-          value: "ул. Примерная, 10"
-        - label: "Тип дома"
-          value: "монолит"
-        - label: "Ремонт"
-          value: "евро"
-        - label: "Телефон"
-          value: "+380 ..."
-      actions:                      // optional buttons
-        - label: "Источник"
-          url: "https://..."
+Tool name: `mcp__navi_ui__render_component`
+
+Required arguments:
+- `component_name`: always `"card_grid"`.
+- `payload`: JSON object with the exact shape below.
+- `session_id`: DO NOT pass manually. The agent injects it automatically.
+
+### card_grid payload (exact JSON shape)
+
+```json
+{
+  "title": "Подходящие варианты",
+  "cards": [
+    {
+      "id": "listing-12345",
+      "title": "2-комнатная квартира на Арсенальной",
+      "subtitle": "Печерский район, 5 мин до метро",
+      "image": "https://example.com/image.jpg",
+      "meta": [
+        { "label": "Цена", "value": "$80 000" },
+        { "label": "Комнат", "value": "2" },
+        { "label": "Площадь", "value": "58 м²" },
+        { "label": "Этаж", "value": "4/9" }
+      ],
+      "description": "Краткое описание карточки, не длиннее 120 символов.",
+      "details": [
+        { "label": "Адрес", "value": "ул. Примерная, 10" },
+        { "label": "Тип дома", "value": "монолит" },
+        { "label": "Ремонт", "value": "евро" },
+        { "label": "Телефон", "value": "+380 ..." }
+      ],
+      "actions": [
+        { "label": "Источник", "url": "https://..." }
+      ]
+    }
+  ]
+}
 ```
 
-Guidelines:
-- Limit to **4 cards** for the first grid. Offer more on request.
-- Each card must have `id` and `title`; keep `description` under 120 characters.
-- Put the full information the user may need in `details` (modal view).
-- `image` must be a direct URL, not a local path.
-- After calling the component, still provide a short text summary and offer next steps.
+### Rules for card_grid
+1. Use `component_name = "card_grid"` only.
+2. `payload.cards` must be a non-empty array.
+3. Every card must have `"id"` (string) and `"title"` (string).
+4. Show **maximum 4 cards** in one call. If there are more, say so and offer the next batch.
+5. `"image"` must be a direct URL, never a local file path.
+6. Keep `"description"` under 120 characters.
+7. Put everything the user might want to see after clicking a card into `"details"` (it opens in a modal).
+8. After calling the component, still write a short text summary and ask what the user wants next.
 
 ## Workflow summary
 1. Understand the user's request. Ask clarifying questions if criteria are vague (budget, district, rooms).