chore: fixing metadata for adk doc

docs/en/sdks/python-sdk/adk/index.md

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+---
+title: "Adk"
+type: docs
+weight: 8
+description: >
+  MCP Toolbox ADK SDK for integrating functionalities of MCP Toolbox into your apps.
+---
+
+## Overview
+
+The `toolbox-adk` package provides a Python interface to the MCP Toolbox service, enabling you to load and invoke tools from your own applications.
+
+## Installation
+
+```bash
+pip install toolbox-adk
+```
+
+## Usage
+
+The primary entry point is the `ToolboxToolset`, which loads tools from a remote Toolbox server and adapts them for use with ADK agents.
+
+{{< notice note>}}
+The `ToolboxToolset` in this package mirrors the `ToolboxToolset` in the [`adk-python`](https://github.com/google/adk-python) package. The `adk-python` version is a shim that delegates all functionality to this implementation.
+{{< /notice >}}
+
+```python
+from toolbox_adk import ToolboxToolset
+from google.adk.agents import Agent
+
+# Create the Toolset
+toolset = ToolboxToolset(
+    server_url="http://127.0.0.1:5000" 
+)
+
+# Use in your ADK Agent
+agent = Agent(tools=[toolset])
+```
+
+## Transport Protocols
+
+The SDK supports multiple transport protocols for communicating with the Toolbox server. By default, the client uses the latest supported version of the **Model Context Protocol (MCP)**.
+
+You can explicitly select a protocol using the `protocol` option during toolset initialization. This is useful if you need to use the native Toolbox HTTP protocol or pin the client to a specific legacy version of MCP.
+
+{{< notice note>}}
+* **Native Toolbox Transport**: This uses the service's native **REST over HTTP** API.
+* **MCP Transports**: These options use the **Model Context Protocol over HTTP**.
+{{< /notice >}}
+
+### Supported Protocols
+
+| Constant | Description |
+| :--- | :--- |
+| `Protocol.MCP` | **(Default)** Alias for the default MCP version (currently `2025-06-18`). |
+| `Protocol.TOOLBOX` | The native Toolbox HTTP protocol. |
+| `Protocol.MCP_v20251125` | MCP Protocol version 2025-11-25. |
+| `Protocol.MCP_v20250618` | MCP Protocol version 2025-06-18. |
+| `Protocol.MCP_v20250326` | MCP Protocol version 2025-03-26. |
+| `Protocol.MCP_v20241105` | MCP Protocol version 2024-11-05. |
+
+### Example
+
+If you wish to use the native Toolbox protocol:
+
+```python
+from toolbox_adk import ToolboxToolset
+from toolbox_core.protocol import Protocol
+
+toolset = ToolboxToolset(
+    server_url="http://127.0.0.1:5000",
+    protocol=Protocol.TOOLBOX
+)
+```
+
+If you want to pin the MCP Version 2025-03-26:
+
+```python
+from toolbox_adk import ToolboxToolset
+from toolbox_core.protocol import Protocol
+
+toolset = ToolboxToolset(
+    server_url="http://127.0.0.1:5000",
+    protocol=Protocol.MCP_v20250326
+)
+```
+
+{{< notice tip>}}
+By default, it uses **Toolbox Identity** (no authentication), which is suitable for local development.
+
+For production environments (Cloud Run, GKE) or accessing protected resources, see the [Authentication](#authentication) section for strategies like Workload Identity or OAuth2.
+{{< /notice >}}
+
+## Authentication
+
+The `ToolboxToolset` requires credentials to authenticate with the Toolbox server. You can configure these credentials using the `CredentialStrategy` factory methods.
+
+The strategies handle two main types of authentication:
+*   **Client-to-Server**: Securing the connection to the Toolbox server (e.g., Workload Identity, API keys).
+*   **User Identity**: Authenticating the end-user for specific tools (e.g., 3-legged OAuth).
+
+### 1. Workload Identity (ADC)
+*Recommended for Cloud Run, GKE, or local development with `gcloud auth login`.*
+
+Uses the agent's Application Default Credentials (ADC) to generate an OIDC token. This is the standard way for one service to authenticate to another on Google Cloud.
+
+```python
+from toolbox_adk import CredentialStrategy, ToolboxToolset
+
+# target_audience: The URL of your Toolbox server
+creds = CredentialStrategy.workload_identity(target_audience="https://my-toolbox-service.run.app")
+
+toolset = ToolboxToolset(
+    server_url="https://my-toolbox-service.run.app",
+    credentials=creds
+)
+```
+
+### 2. User Identity (OAuth2)
+*Recommended for tools that act on behalf of the user.*
+
+Configures the ADK-native interactive 3-legged OAuth flow to get consent and credentials from the end-user at runtime. This strategy is passed to the `ToolboxToolset` just like any other credential strategy.
+
+```python
+from toolbox_adk import CredentialStrategy, ToolboxToolset
+
+creds = CredentialStrategy.user_identity(
+    client_id="YOUR_CLIENT_ID",
+    client_secret="YOUR_CLIENT_SECRET",
+    scopes=["https://www.googleapis.com/auth/cloud-platform"]
+)
+
+# The toolset will now initiate OAuth flows when required by tools
+toolset = ToolboxToolset(
+    server_url="...",
+    credentials=creds
+)
+```
+
+### 3. API Key
+*Use a static API key passed in a specific header (default: `X-API-Key`).*
+
+```python
+from toolbox_adk import CredentialStrategy
+
+# Default header: X-API-Key
+creds = CredentialStrategy.api_key(key="my-secret-key")
+
+# Custom header
+creds = CredentialStrategy.api_key(key="my-secret-key", header_name="X-My-Header")
+```
+
+### 4. HTTP Bearer Token
+*Manually supply a static bearer token.*
+
+```python
+from toolbox_adk import CredentialStrategy
+
+creds = CredentialStrategy.manual_token(token="your-static-bearer-token")
+```
+
+### 5. Manual Google Credentials
+*Use an existing `google.auth.credentials.Credentials` object.*
+
+```python
+from toolbox_adk import CredentialStrategy
+import google.auth
+
+creds_obj, _ = google.auth.default()
+creds = CredentialStrategy.manual_credentials(credentials=creds_obj)
+```
+
+### 6. Toolbox Identity (No Auth)
+*Use this if your Toolbox server does not require authentication (e.g., local development).*
+
+```python
+from toolbox_adk import CredentialStrategy
+
+creds = CredentialStrategy.toolbox_identity()
+```
+
+### 7. Native ADK Integration
+*Convert ADK-native `AuthConfig` or `AuthCredential` objects.*
+
+```python
+from toolbox_adk import CredentialStrategy
+
+# From AuthConfig
+creds = CredentialStrategy.from_adk_auth_config(auth_config)
+
+# From AuthCredential + AuthScheme
+creds = CredentialStrategy.from_adk_credentials(auth_credential, scheme)
+```
+
+### 8. Tool-Specific Authentication
+*Resolve authentication tokens dynamically for specific tools.*
+
+Some tools may define their own authentication requirements (e.g., Salesforce OAuth, GitHub PAT) via `authSources` in their schema. You can provide a mapping of getters to resolve these tokens at runtime.
+
+```python
+async def get_salesforce_token():
+    # Fetch token from secret manager or reliable source
+    return "sf-access-token"
+
+toolset = ToolboxToolset(
+    server_url="...",
+    auth_token_getters={
+        "salesforce-auth": get_salesforce_token,   # Async callable
+        "github-pat": lambda: "my-pat-token"       # Sync callable or static lambda
+    }
+)
+```
+
+## Advanced Configuration
+
+### Additional Headers
+
+You can inject custom headers into every request made to the Toolbox server. This is useful for passing tracing IDs, API keys, or other metadata.
+
+```python
+toolset = ToolboxToolset(
+    server_url="...",
+    additional_headers={
+        "X-Trace-ID": "12345",
+        "X-My-Header": lambda: get_dynamic_header_value() # Can be a callable
+    }
+)
+```
+
+### Global Parameter Binding
+
+Bind values to tool parameters globally across all loaded tools. These values will be **fixed** and **hidden** from the LLM.
+
+*   **Schema Hiding**: The bound parameters are removed from the tool schema sent to the model, simplifying the context window.
+*   **Auto-Injection**: The values are automatically injected into the tool arguments during execution.
+
+```python
+toolset = ToolboxToolset(
+    server_url="...",
+    bound_params={
+        # 'region' will be removed from the LLM schema and injected automatically
+        "region": "us-central1",
+        "api_key": lambda: get_api_key() # Can be a callable
+    }
+)
+```
+
+### Usage with Hooks
+
+You can attach `pre_hook` and `post_hook` functions to execute logic before and after every tool invocation.
+
+{{< notice note>}}
+ The `pre_hook` can modify `context.arguments` to dynamically alter the inputs passed to the tool.
+{{< /notice >}}
+
+```python
+from google.adk.tools.tool_context import ToolContext
+from typing import Any, Dict, Optional
+
+async def log_start(context: ToolContext, args: Dict[str, Any]):
+    print(f"Starting tool with args: {args}")
+    # context is the ADK ToolContext
+    # Example: Inject or modify arguments
+    # args["user_id"] = "123"
+
+async def log_end(context: ToolContext, args: Dict[str, Any], result: Optional[Any], error: Optional[Exception]):
+    print("Finished tool execution")
+    # Inspect result or error
+    if error:
+        print(f"Tool failed: {error}")
+    else:
+        print(f"Tool succeeded with result: {result}")
+
+toolset = ToolboxToolset(
+    server_url="...",
+    pre_hook=log_start,
+    post_hook=log_end
+)
+```