diff --git a/docs/tools-custom/function-tools.md b/docs/tools-custom/function-tools.md
index 4a47cad74..f39bc5460 100644
--- a/docs/tools-custom/function-tools.md
+++ b/docs/tools-custom/function-tools.md
@@ -223,6 +223,14 @@ While you have considerable flexibility in defining your function, remember that
 * **Build for Parallel Execution:** Improve function calling performance when multiple tools are run by building for asynchronous operation. For information on enabling parallel execution for tools, see
 [Increase tool performance with parallel execution](/adk-docs/tools-custom/performance/).
 
+## Simplified Tool Declaration with JSON Schema (Experimental)
+
+ADK now offers a simplified way to declare function tools by generating a JSON schema from your function's signature using Pydantic. This feature can be enabled via a feature flag.
+
+When enabled, `build_function_declaration` will automatically generate a JSON schema for your function's parameters, which simplifies the declaration process and provides more accurate type information to the LLM.
+
+This feature is currently experimental and can be enabled by setting the `ADK_ENABLE_JSON_SCHEMA_FOR_FUNC_DECL` environment variable to `true`.
+
 ## Long Running Function Tools {#long-run-tool}
 
 This tool is designed to help you start and manage tasks that are handled outside the operation of your agent workflow, and require a significant amount of processing time, without blocking the agent's execution. This tool is a subclass of `FunctionTool`.
@@ -481,4 +489,4 @@ The `AgentTool` class provides the following attributes for customizing its beha
 3. Behind the scenes, the `main_agent` will call the `summary_agent` with the long text as input.  
 4. The `summary_agent` will process the text according to its instruction and generate a summary.  
 5. **The response from the `summary_agent` is then passed back to the `main_agent`.**  
-6. The `main_agent` can then take the summary and formulate its final response to the user (e.g., "Here's a summary of the text: ...")
+6. The `main_agent` can then take the summary and formulate its final response to the user (e.g., "Here's a summary of the text: ...")
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