Scope Toolboxes preview header to skills + management REST only

The Foundry-Features: Toolboxes=V1Preview header is not required for
regular tool consumption over the toolbox MCP endpoint. Remove it from
the verify, Microsoft Agent Framework, Copilot SDK, and hosted-agent
samples, and correct the prose that claimed it was mandatory on every
request. Keep it only where it is actually needed: consuming skills as
MCP resources (10b) and the preview management REST API (5).

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: lindazqli

notebooks/mastering-foundry-toolbox.ipynb

@@ -185,8 +185,9 @@
     "  starts with `if skip(...): ...`.\n",
     "- `mcp_token()` - a bearer token scoped to `https://ai.azure.com/.default`, the audience the\n",
     "  toolbox MCP endpoint expects.\n",
-    "- `TOOLBOX_HEADERS` - **every** call to a toolbox MCP endpoint must carry\n",
-    "  `Foundry-Features: Toolboxes=V1Preview`. Forgetting it is the #1 cause of 404s.\n",
+    "- `TOOLBOX_HEADERS` - the `Foundry-Features: Toolboxes=V1Preview` header. Needed **only** for consuming\n",
+    "  **skills** as MCP resources (section 10b) and the preview management REST API (section 5) - regular\n",
+    "  tool calls don't need it.\n",
     "- `created_resources` - a tracker the cleanup section walks in reverse."
    ]
   },
@@ -242,7 +243,7 @@
     "# The MCP endpoint audience is ai.azure.com (NOT management.azure.com).\n",
     "TOOLBOX_SCOPE = \"https://ai.azure.com/.default\"\n",
     "\n",
-    "# Mandatory on every toolbox MCP request while the feature is in preview.\n",
+    "# Only needed for skills MCP resources (10b) and the preview management REST API (5); not tool calls.\n",
     "TOOLBOX_HEADERS = {\"Foundry-Features\": \"Toolboxes=V1Preview\"}\n",
     "\n",
     "credential = DefaultAzureCredential()\n",
@@ -1765,8 +1766,8 @@
     "| **Developer** | `{project}/toolboxes/{name}/versions/{version}/mcp?api-version=v1` | one pinned version |\n",
     "| **Consumer** | `{project}/toolboxes/{name}/mcp?api-version=v1` | the **default** version |\n",
     "\n",
-    "Both require the bearer token (scope `https://ai.azure.com/.default`) **and** the\n",
-    "`Foundry-Features: Toolboxes=V1Preview` header on every request."
+    "Both require the bearer token (scope `https://ai.azure.com/.default`). The\n",
+    "`Foundry-Features: Toolboxes=V1Preview` header is only needed for skills-resource calls (section 10b), not for regular tool calls."
    ]
   },
   {
@@ -1818,8 +1819,8 @@
     "claim (tool count *and* input-schema payload size). Then we run a `tool_search` -> `call_tool`\n",
     "round-trip and read each tool's `_meta.tool_configuration` (which carries `require_approval`).\n",
     "\n",
-    "We use the `mcp` SDK's streamable-HTTP client, passing the bearer token and the mandatory\n",
-    "preview header. If a tool's connection uses `oauth2`, the first call returns `CONSENT_REQUIRED`\n",
+    "We use the `mcp` SDK's streamable-HTTP client, passing the bearer token (no preview\n",
+    "header is needed for tool calls). If a tool's connection uses `oauth2`, the first call returns `CONSENT_REQUIRED`\n",
     "(`-32006`) with a consent URL - we surface it so you can consent and retry."
    ]
   },
@@ -1844,7 +1845,7 @@
     "\n",
     "async def _list_tools(url: str):\n",
     "    \"\"\"tools/list against a specific toolbox MCP endpoint.\"\"\"\n",
-    "    headers = {**TOOLBOX_HEADERS, \"Authorization\": f\"Bearer {mcp_token()}\"}\n",
+    "    headers = {\"Authorization\": f\"Bearer {mcp_token()}\"}\n",
     "    async with streamablehttp_client(url, headers=headers) as (read, write, _):\n",
     "        async with ClientSession(read, write) as session:\n",
     "            await session.initialize()\n",
@@ -1869,7 +1870,7 @@
     "    assert \"tool_search\" in after_names, \"Tool Search not active - is the default version search-first?\"\n",
     "\n",
     "    # Drive the meta-tool, then read approval config off a listed tool.\n",
-    "    headers = {**TOOLBOX_HEADERS, \"Authorization\": f\"Bearer {mcp_token()}\"}\n",
+    "    headers = {\"Authorization\": f\"Bearer {mcp_token()}\"}\n",
     "    async with streamablehttp_client(CONSUMER_URL, headers=headers) as (read, write, _):\n",
     "        async with ClientSession(read, write) as session:\n",
     "            await session.initialize()\n",
@@ -1958,7 +1959,7 @@
     "\n",
     "The whole point of one governed endpoint is that *any* MCP client can use it unchanged. Here are\n",
     "three: **Microsoft Agent Framework**, **LangGraph**, and the **Copilot SDK**. Each just needs the\n",
-    "consumer URL, a bearer token, and the preview header."
+    "consumer URL and a bearer token."
    ]
   },
   {
@@ -1985,8 +1986,8 @@
    "source": [
     "# --- Microsoft Agent Framework -------------------------------------------------\n",
     "# MAF speaks MCP natively via MCPStreamableHTTPTool. Point it at the consumer URL.\n",
-    "# Auth note: the toolbox MCP endpoint needs a bearer token + the preview header on\n",
-    "# EVERY request, including the initialize handshake. MAF's header_provider only injects\n",
+    "# Auth note: the toolbox MCP endpoint needs a bearer token on every request, including the\n",
+    "# initialize handshake. MAF's header_provider only injects\n",
     "# on tool *calls*, so we hand it a pre-authenticated http_client whose default headers\n",
     "# cover connect + initialize. load_prompts=False skips a prompts/list the endpoint\n",
     "# doesn't serve, and we build FoundryChatClient from the endpoint + credential (the\n",
@@ -1997,7 +1998,7 @@
     "\n",
     "async def run_maf():\n",
     "    http = httpx.AsyncClient(\n",
-    "        headers={**TOOLBOX_HEADERS, \"Authorization\": f\"Bearer {mcp_token()}\"},\n",
+    "        headers={\"Authorization\": f\"Bearer {mcp_token()}\"},\n",
     "        follow_redirects=True,\n",
     "        timeout=httpx.Timeout(30.0, read=300.0),\n",
     "    )\n",
@@ -2105,7 +2106,7 @@
    "source": [
     "# --- Copilot SDK ---------------------------------------------------------------\n",
     "# The GitHub Copilot SDK (pip install github-copilot-sdk; Python 3.11+) consumes the toolbox as a\n",
-    "# remote MCP server - same consumer URL, same bearer token + preview header. Remote MCP servers are\n",
+    "# remote MCP server - same consumer URL, same bearer token. Remote MCP servers are\n",
     "# configured through create_session(..., mcp_servers={...}) with type \"http\".\n",
     "# Docs: https://docs.github.com/copilot/how-tos/copilot-sdk/features/mcp\n",
     "if not os.getenv(\"PROJECT_ENDPOINT\"):\n",
@@ -2127,7 +2128,7 @@
     "                    \"foundry_toolbox\": {\n",
     "                        \"type\": \"http\",\n",
     "                        \"url\": CONSUMER_URL,\n",
-    "                        \"headers\": {**TOOLBOX_HEADERS, \"Authorization\": f\"Bearer {mcp_token()}\"},\n",
+    "                        \"headers\": {\"Authorization\": f\"Bearer {mcp_token()}\"},\n",
     "                        \"tools\": [\"*\"],  # expose every toolbox tool (tool_search included)\n",
     "                    },\n",
     "                },\n",
@@ -2188,7 +2189,6 @@
     "#     toolbox_tool = MCPStreamableHTTPTool(\n",
     "#         name=\"foundry_toolbox\",\n",
     "#         url=CONSUMER_URL,                       # same consumer URL as local\n",
-    "#         headers=TOOLBOX_HEADERS,                # token injected by the runtime\n",
     "#     )\n",
     "#     return ChatAgent(\n",
     "#         chat_client=AzureAIAgentClient(project_client=project, model=MODEL_DEPLOYMENT),\n",