feat(mcp): wire the overview MCP App view end to end

- CSP meta + color-scheme meta in the ui:// view HTML
- zernio_overview tool (read-only, pinned) declaring _meta.ui.resourceUri
- server card gains websiteUrl/repository/remotes (registry-manifest shape)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KaAt3g7RCFz1PpLQ4xHSyX

Author: mikipalet

src/late/mcp/http_server.py

@@ -87,6 +87,9 @@ async def handle_health(_request: Request) -> JSONResponse:
         "plus ad management on 7 ad networks, via MCP."
     ),
     "icon": "https://media.zernio.com/site-assets/brand/icon-primary.png",
+    "websiteUrl": "https://zernio.com",
+    "repository": {"url": "https://github.com/zernio-dev/zernio-python", "source": "github"},
+    "remotes": [{"type": "streamable-http", "url": f"{MCP_PUBLIC_URL}{ENDPOINT_MCP}"}],
     "serverInfo": {
         "name": "zernio",
         "title": "Zernio Social Media API",

src/late/mcp/resources.py

@@ -4,6 +4,7 @@
 
 from fastmcp import FastMCP
 from fastmcp.apps import AppConfig, ResourceCSP
+from mcp.types import ToolAnnotations
 
 _OVERVIEW = """\
 # Zernio — social media and messaging API
@@ -73,6 +74,8 @@
 <html lang="en">
 <head>
 <meta charset="utf-8">
+<meta name="color-scheme" content="light dark">
+<meta http-equiv="Content-Security-Policy" content="default-src 'none'; style-src 'unsafe-inline'">
 <title>Zernio</title>
 <style>
   body { font-family: system-ui, sans-serif; margin: 0; padding: 16px; color: #1a1a1a; background: #fff; }
@@ -130,6 +133,20 @@ def authentication() -> str:
     def overview_view() -> str:
         return _OVERVIEW_VIEW_HTML
 
+    @mcp.tool(
+        name="zernio_overview",
+        description="Show an overview of what this Zernio MCP server can do (accounts, posts, analytics, ads, inbox) and how to find the right tool.",
+        annotations=ToolAnnotations(
+            title="Zernio server overview",
+            readOnlyHint=True,
+            destructiveHint=False,
+            openWorldHint=False,
+        ),
+        app=AppConfig(resource_uri="ui://zernio/overview.html", visibility=["model"]),
+    )
+    def zernio_overview() -> str:
+        return _OVERVIEW
+
     @mcp.resource(
         "zernio://docs/rate-limits",
         name="Rate limits",

src/late/mcp/server.py

@@ -68,7 +68,7 @@
     "posts_list", "posts_get", "posts_create", "posts_publish_now", "posts_cross_post",
     "posts_update", "posts_delete", "posts_retry", "posts_list_failed", "posts_retry_all_failed",
     "media_generate_upload_link", "media_check_upload_status",
-    "docs_search",
+    "docs_search", "zernio_overview",
     # Posting operations not covered by the ergonomic set
     "posts_bulk_upload_posts", "posts_unpublish_post", "posts_edit_post",
     # Scheduling queue