feat(core): add tools to list and read MCP resources (#25395)

docs/cli/plan-mode.md

@@ -130,7 +130,9 @@ These are the only allowed tools:
   [`cli_help`](../core/subagents.md#cli-help-agent)
 - **Interaction:** [`ask_user`](../tools/ask-user.md)
 - **MCP tools (Read):** Read-only [MCP tools](../tools/mcp-server.md) (for
-  example, `github_read_issue`, `postgres_read_schema`) are allowed.
+  example, `github_read_issue`, `postgres_read_schema`) and core
+  [MCP resource tools](../tools/mcp-resources.md) (`list_mcp_resources`,
+  `read_mcp_resource`) are allowed.
 - **Planning (Write):**
   [`write_file`](../tools/file-system.md#3-write_file-writefile) and
   [`replace`](../tools/file-system.md#6-replace-edit) only allowed for `.md`

docs/reference/tools.md

@@ -92,6 +92,13 @@ each tool.
 | [`ask_user`](../tools/ask-user.md) | `Communicate` | Requests clarification or missing information via an interactive dialog.               |
 | [`write_todos`](../tools/todos.md) | `Other`       | Maintains an internal list of subtasks. The model uses this to track its own progress. |
 
+### MCP
+
+| Tool                                              | Kind     | Description                                                            |
+| :------------------------------------------------ | :------- | :--------------------------------------------------------------------- |
+| [`list_mcp_resources`](../tools/mcp-resources.md) | `Search` | Lists all available resources exposed by connected MCP servers.        |
+| [`read_mcp_resource`](../tools/mcp-resources.md)  | `Read`   | Reads the content of a specific Model Context Protocol (MCP) resource. |
+
 ### Memory
 
 | Tool                                             | Kind    | Description                                                                          |

docs/sidebar.json

@@ -122,7 +122,14 @@
               }
             ]
           },
-          { "label": "MCP servers", "slug": "docs/tools/mcp-server" },
+          {
+            "label": "MCP servers",
+            "collapsed": true,
+            "items": [
+              { "label": "Overview", "slug": "docs/tools/mcp-server" },
+              { "label": "Resource tools", "slug": "docs/tools/mcp-resources" }
+            ]
+          },
           { "label": "Model routing", "slug": "docs/cli/model-routing" },
           { "label": "Model selection", "slug": "docs/cli/model" },
           {

docs/tools/mcp-resources.md

@@ -0,0 +1,44 @@
+# MCP resource tools
+
+MCP resource tools let Gemini CLI discover and retrieve data from contextual
+resources exposed by Model Context Protocol (MCP) servers.
+
+## 1. `list_mcp_resources` (ListMcpResources)
+
+`list_mcp_resources` retrieves a list of all available resources from connected
+MCP servers. This is primarily a discovery tool that helps the model understand
+what external data sources are available for reference.
+
+- **Tool name:** `list_mcp_resources`
+- **Display name:** List MCP Resources
+- **Kind:** `Search`
+- **File:** `list-mcp-resources.ts`
+- **Parameters:**
+  - `serverName` (string, optional): An optional filter to list resources from a
+    specific server.
+- **Behavior:**
+  - Iterates through all connected MCP servers.
+  - Fetches the list of resources each server exposes.
+  - Formats the results into a plain-text list of URIs and descriptions.
+- **Output (`llmContent`):** A formatted list of available resources, including
+  their URI, server name, and optional description.
+- **Confirmation:** No. This is a read-only discovery tool.
+
+## 2. `read_mcp_resource` (ReadMcpResource)
+
+`read_mcp_resource` retrieves the content of a specific resource identified by
+its URI.
+
+- **Tool name:** `read_mcp_resource`
+- **Display name:** Read MCP Resource
+- **Kind:** `Read`
+- **File:** `read-mcp-resource.ts`
+- **Parameters:**
+  - `uri` (string, required): The URI of the MCP resource to read.
+- **Behavior:**
+  - Locates the resource and its associated server by URI.
+  - Calls the server's `resources/read` method.
+  - Processes the response, extracting text or binary data.
+- **Output (`llmContent`):** The content of the resource. For binary data, it
+  returns a placeholder indicating the data type.
+- **Confirmation:** No. This is a read-only retrieval tool.

docs/tools/mcp-server.md

@@ -64,7 +64,8 @@ Gemini CLI supports three MCP transport types:
 
 Some MCP servers expose contextual “resources” in addition to the tools and
 prompts. Gemini CLI discovers these automatically and gives you the possibility
-to reference them in the chat.
+to reference them in the chat. For more information on the tools used to
+interact with these resources, see [MCP resource tools](mcp-resources.md).
 
 ### Discovery and listing