feat(core): Parse Multimodal MCP Tool responses (#5529)

Co-authored-by: Luccas Paroni <[email protected]>

1 files changed, 3 insertions, 1 deletions

diff --git a/docs/core/tools-api.md b/docs/core/tools-api.md
index e10333d2..0b52191c 100644
--- a/docs/core/tools-api.md
+++ b/docs/core/tools-api.md
@@ -15,9 +15,11 @@ The Gemini CLI core (`packages/core`) features a robust system for defining, reg
   - `execute()`: The core method that performs the tool's action and returns a `ToolResult`.
 
 - **`ToolResult` (`tools.ts`):** An interface defining the structure of a tool's execution outcome:
-  - `llmContent`: The factual string content to be included in the history sent back to the LLM for context.
+  - `llmContent`: The factual content to be included in the history sent back to the LLM for context. This can be a simple string or a `PartListUnion` (an array of `Part` objects and strings) for rich content.
   - `returnDisplay`: A user-friendly string (often Markdown) or a special object (like `FileDiff`) for display in the CLI.
 
+- **Returning Rich Content:** Tools are not limited to returning simple text. The `llmContent` can be a `PartListUnion`, which is an array that can contain a mix of `Part` objects (for images, audio, etc.) and `string`s. This allows a single tool execution to return multiple pieces of rich content.
+
 - **Tool Registry (`tool-registry.ts`):** A class (`ToolRegistry`) responsible for:
   - **Registering Tools:** Holding a collection of all available built-in tools (e.g., `ReadFileTool`, `ShellTool`).
   - **Discovering Tools:** It can also discover tools dynamically: