> ## Documentation Index
> Fetch the complete documentation index at: https://mcp-use.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
## Submitting Feedback
If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:
POST https://mcp-use.com/docs/feedback
```json
{
"path": "/python/api-reference/mcp_use_client_middleware_middleware",
"feedback": "Description of the issue"
}
```
Only submit feedback when you have something specific and actionable to report.
# Middleware
> Core middleware system for MCP requests API Documentation
export const RandomGradientBackground = ({className, color, children, grayscaled = false}) => {
const saturation = useMemo(() => {
if (color) {
const values = color.split("(")[1].split(")")[0].trim().split(/\s+/);
return parseFloat(values[1] || "0");
}
return grayscaled ? 0 : 0.2;
}, [color, grayscaled]);
const lightness = useMemo(() => {
if (color) {
const values = color.split("(")[1].split(")")[0].trim().split(/\s+/);
return parseFloat(values[0] || "0.5");
}
return grayscaled ? 0.3 : 0.4;
}, [color, grayscaled]);
const randomHue = useMemo(() => {
if (color) {
const values = color.split("(")[1].split(")")[0].trim().split(/\s+/);
return parseFloat(values[2] || "0");
}
return Math.floor(Math.random() * 360);
}, [color]);
const randomColor = useMemo(() => {
if (color) {
return color;
}
return `oklch(${Math.min(lightness, 1)} ${saturation} ${randomHue})`;
}, [randomHue, saturation, lightness]);
const lightColor = useMemo(() => {
return `oklch(${Math.min(lightness * 2, 1)} ${saturation} ${randomHue})`;
}, [randomHue, saturation, lightness, color]);
const direction = useMemo(() => {
return Math.floor(Math.random() * 360);
}, [randomHue]);
const brightnessFilter = useMemo(() => {
return "1000%";
}, []);
return ;
};
View the source code for this module on GitHub: [https://github.com/mcp-use/mcp-use/blob/main/libraries/python/mcp\_use/client/middleware/middleware.py](https://github.com/mcp-use/mcp-use/blob/main/libraries/python/mcp_use/client/middleware/middleware.py)
Core middleware system for MCP requests.
This module provides a robust and extensible middleware architecture:
* A typed MiddlewareContext to carry request data.
* A Middleware base class with a dispatcher that routes to strongly-typed hooks.
* A MiddlewareManager to build and execute the processing chain.
* A CallbackClientSession that acts as an adapter, creating the initial context
without requiring changes to upstream callers like HttpConnector.
## CallbackClientSession
class CallbackClientSession
ClientSession wrapper that uses callback-based middleware.
```python theme={null}
from mcp_use.client.middleware.middleware import CallbackClientSession
```
### `method` **init**
**Parameters**
> MCP session instance
> Connector instance
> Middleware instance
**Signature**
```python wrap theme={null}
def __init__(client_session: mcp.client.session.ClientSession, connector_id: str, middleware_manager: mcp_use.client.middleware.middleware.MiddlewareManager):
```
### `method` call\_tool
**Parameters**
> Name identifier
> Dictionary of key-value pairs
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def call_tool(name: str, arguments: dict[str, Any], args, kwargs):
```
### `method` get\_prompt
**Parameters**
> Name identifier
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def get_prompt(name: str, args, kwargs):
```
### `method` initialize
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def initialize(args, kwargs):
```
### `method` list\_prompts
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def list_prompts(args, kwargs):
```
### `method` list\_resources
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def list_resources(args, kwargs):
```
### `method` list\_tools
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def list_tools(args, kwargs):
```
### `method` read\_resource
**Parameters**
> Parameter value
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def read_resource(uri: pydantic.networks.AnyUrl, args, kwargs):
```
## MCPResponseContext
class MCPResponseContext
Extended context for MCP responses with middleware metadata.
```python theme={null}
from mcp_use.client.middleware.middleware import MCPResponseContext
```
**Attributes**
>
String value
Parameter value
Parameter value
Parameter value
Dictionary of key-value pairs
Parameter value
### `method` **init**
**Parameters**
> String value
> Parameter value
> Parameter value
> Parameter value
> Dictionary of key-value pairs
> Parameter value
**Signature**
```python wrap theme={null}
def __init__(request_id: str, result: Any, error: Exception | None, duration: float, metadata: dict[str, Any], jsonrpc_response: mcp.types.JSONRPCResponse | None = None):
```
## Middleware
class Middleware
Base class for middlewares with hooks.
```python theme={null}
from mcp_use.client.middleware.middleware import Middleware
```
### `method` **call**
Main entry point that orchestrates the chain
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def __call__(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
call_next: mcp_use.client.middleware.middleware.NextFunctionT
):
```
### `method` on\_call\_tool
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def on_call_tool(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
call_next: mcp_use.client.middleware.middleware.NextFunctionT
):
```
### `method` on\_get\_prompt
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def on_get_prompt(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
call_next: mcp_use.client.middleware.middleware.NextFunctionT
):
```
### `method` on\_initialize
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def on_initialize(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
call_next: mcp_use.client.middleware.middleware.NextFunctionT
):
```
### `method` on\_list\_prompts
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def on_list_prompts(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
call_next: mcp_use.client.middleware.middleware.NextFunctionT
):
```
### `method` on\_list\_resources
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def on_list_resources(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
call_next: mcp_use.client.middleware.middleware.NextFunctionT
):
```
### `method` on\_list\_tools
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def on_list_tools(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
call_next: mcp_use.client.middleware.middleware.NextFunctionT
):
```
### `method` on\_read\_resource
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def on_read_resource(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
call_next: mcp_use.client.middleware.middleware.NextFunctionT
):
```
### `method` on\_request
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def on_request(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
call_next: mcp_use.client.middleware.middleware.NextFunctionT
):
```
## MiddlewareContext
class MiddlewareContext
Unified, typed context for all middleware operations.
```python theme={null}
from mcp_use.client.middleware.middleware import MiddlewareContext
```
**Attributes**
>
String value
String value
Parameter value
String value
Parameter value
Dictionary of key-value pairs
### `method` **init**
**Parameters**
> String value
> String value
> Parameter value
> String value
> Parameter value
> Dictionary of key-value pairs
**Signature**
```python wrap theme={null}
def __init__(id: str, method: str, params: mcp_use.client.middleware.middleware.T, connection_id: str, timestamp: float, metadata: dict[str, Any] = ):
```
## MiddlewareManager
class MiddlewareManager
Manages middleware callbacks for MCP requests.
```python theme={null}
from mcp_use.client.middleware.middleware import MiddlewareManager
```
### `method` **init**
**Signature**
```python wrap theme={null}
def __init__():
```
### `method` add\_middleware
Add a middleware callback.
**Parameters**
> Callback function
**Signature**
```python wrap theme={null}
def add_middleware(callback: mcp_use.client.middleware.middleware.Middleware):
```
### `method` process\_request
Runs the full middleware chain, captures timing and errors,
and returns a structured MCPResponseContext.
**Parameters**
> Parameter value
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def process_request(
context: mcp_use.client.middleware.middleware.MiddlewareContext,
original_call: Callable
):
```
## NextFunctionT
class NextFunctionT
Protocol for the `call_next` function passed to middleware.
```python theme={null}
from mcp_use.client.middleware.middleware import NextFunctionT
```
### `method` **init**
**Parameters**
> Parameter value
> Parameter value
**Signature**
```python wrap theme={null}
def __init__(args, kwargs):
```
### `method` **call**
**Parameters**
> Parameter value
**Returns**
>
**Signature**
```python wrap theme={null}
def __call__(context: mcp_use.client.middleware.middleware.MiddlewareContext):
```