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docs/en/documentation/configuration/pre-post-processing/python/_index.md

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+---
+title: "Python: Pre & Post Processing"
+type: docs
+weight: 1
+description: >
+  How to add pre- and post- processing to your Agents using Python.
+sample_filters: ["Pre & Post Processing", "Python", "ADK", "LangChain"]
+is_sample: true
+---
+
+## Prerequisites
+
+This tutorial assumes that you have set up MCP Toolbox with a basic agent as described in the [local quickstart](../../../getting-started/local_quickstart.md).
+
+This guide demonstrates how to implement these patterns in your Toolbox applications.
+
+## Implementation
+
+{{< tabpane persist=header >}}
+{{% tab header="ADK" text=true %}}
+The following example demonstrates how to use `ToolboxToolset` with ADK's pre and post processing hooks to implement pre and post processing for tool calls.
+
+{{< include "adk/agent.py" "python">}}
+
+You can also add model-level (`before_model_callback`, `after_model_callback`) and agent-level (`before_agent_callback`, `after_agent_callback`) hooks to intercept messages at different stages of the execution loop.
+
+For more information, see the [ADK Callbacks documentation](https://google.github.io/adk-docs/callbacks/types-of-callbacks/).
+{{% /tab %}}
+{{% tab header="Langchain" text=true %}}
+The following example demonstrates how to use `ToolboxClient` with LangChain's middleware to implement pre- and post- processing for tool calls.
+
+{{< include "langchain/agent.py" "python" >}}
+
+You can also add model-level (`wrap_model`) and agent-level (`before_agent`, `after_agent`) hooks to intercept messages at different stages of the execution loop. See the [LangChain Middleware documentation](https://docs.langchain.com/oss/python/langchain/middleware/custom#wrap-style-hooks) for details on these additional hook types.
+{{% /tab %}}
+{{< /tabpane >}}
+
+## Results
+
+The output should look similar to the following.
+
+{{< notice note >}}
+The exact responses may vary due to the non-deterministic nature of LLMs and differences between orchestration frameworks.
+{{< /notice >}}
+
+```
+AI: Booking Confirmed! You earned 500 Loyalty Points with this stay.
+
+AI: Error: Maximum stay duration is 14 days.
+```