Exercise the SEP-2575 stateless probes and SEP-2243 resource/prompt headers in the conformance fixtures (#3442)

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Max 2026-09-04 17:11:00 +01:00 • committed by GitHub
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@ -20,7 +20,7 @@ Scenarios:
json-schema-ref-no-deref - Connect, list tools (no $ref deref)
json-schema-2020-12-preservation - List tools, echo the focal inputSchema back verbatim
request-metadata - Connect with all callbacks; client stamps _meta
http-standard-headers - Connect, call a tool (Mcp-* headers checked)
http-standard-headers - Tool, resource and prompt round-trips (Mcp-* headers checked)
http-invalid-tool-headers - List tools, call every surfaced tool (x-mcp-header filter)
http-custom-headers - Replay the harness's toolCalls (x-mcp-header -> Mcp-Param-*)
elicitation-sep1034-client-defaults - Elicitation with default accept callback
@ -311,11 +311,24 @@ async def run_request_metadata(server_url: str) -> None:
@register("http-standard-headers")
async def run_http_standard_headers(server_url: str) -> None:
"""Connect on the modern path so Mcp-Method / Mcp-Name / MCP-Protocol-Version are sent (SEP-2243)."""
"""Touch tools, resources and prompts on the modern path so each standard header is checked (SEP-2243).
The scenario inspects Mcp-Method on each request and Mcp-Name on tools/call,
resources/read and prompts/get, and reports methods the client never sent as
SKIPPED rather than failed, so exercise one of each. initialize and
notifications/initialized stay SKIPPED: the modern path discovers via
server/discover and never sends them.
"""
async with Client(server_url, mode=client_mode()) as client:
await client.list_tools()
result = await client.call_tool("add_numbers", {"a": 5, "b": 3})
logger.debug(f"add_numbers result: {result}")
tools = await client.list_tools()
if tools.tools:
await client.call_tool(tools.tools[0].name, _stub_required_args(tools.tools[0].input_schema))
resources = await client.list_resources()
if resources.resources:
await client.read_resource(resources.resources[0].uri)
prompts = await client.list_prompts()
if prompts.prompts:
await client.get_prompt(prompts.prompts[0].name)
def _stub_required_args(input_schema: dict[str, Any]) -> dict[str, Any]:

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@ -0,0 +1,113 @@
# MCP Simple Chatbot
This example demonstrates how to integrate the Model Context Protocol (MCP) into a simple CLI chatbot. The implementation showcases MCP's flexibility by supporting multiple tools through MCP servers and is compatible with any LLM provider that follows OpenAI API standards.
## Requirements
- Python 3.10
- `python-dotenv`
- `requests`
- `mcp`
- `uvicorn`
## Installation
1. **Install the dependencies:**
```bash
pip install -r requirements.txt
```
2. **Set up environment variables:**
Create a `.env` file in the root directory and add your API key:
```plaintext
LLM_API_KEY=your_api_key_here
```
**Note:** The current implementation is configured to use the Groq API endpoint (`https://api.groq.com/openai/v1/chat/completions`) with the `llama-3.2-90b-vision-preview` model. If you plan to use a different LLM provider, you'll need to modify the `LLMClient` class in `main.py` to use the appropriate endpoint URL and model parameters.
3. **Configure servers:**
The `servers_config.json` follows the same structure as Claude Desktop, allowing for easy integration of multiple servers.
Here's an example:
```json
{
"mcpServers": {
"sqlite": {
"command": "uvx",
"args": ["mcp-server-sqlite", "--db-path", "./test.db"]
},
"puppeteer": {
"command": "npx",
"args": ["-y", "@modelcontextprotocol/server-puppeteer"]
}
}
}
```
Environment variables are supported as well. Pass them as you would with the Claude Desktop App.
Example:
```json
{
"mcpServers": {
"server_name": {
"command": "uvx",
"args": ["mcp-server-name", "--additional-args"],
"env": {
"API_KEY": "your_api_key_here"
}
}
}
}
```
## Usage
1. **Run the client:**
```bash
python main.py
```
2. **Interact with the assistant:**
The assistant will automatically detect available tools and can respond to queries based on the tools provided by the configured servers.
3. **Exit the session:**
Type `quit` or `exit` to end the session.
## Architecture
- **Tool Discovery**: Tools are automatically discovered from configured servers.
- **System Prompt**: Tools are dynamically included in the system prompt, allowing the LLM to understand available capabilities.
- **Server Integration**: Supports any MCP-compatible server, tested with various server implementations including Uvicorn and Node.js.
### Class Structure
- **Configuration**: Manages environment variables and server configurations
- **Server**: Handles MCP server initialization, tool discovery, and execution
- **Tool**: Represents individual tools with their properties and formatting
- **LLMClient**: Manages communication with the LLM provider
- **ChatSession**: Orchestrates the interaction between user, LLM, and tools
### Logic Flow
1. **Tool Integration**:
- Tools are dynamically discovered from MCP servers
- Tool descriptions are automatically included in system prompt
- Tool execution is handled through standardized MCP protocol
2. **Runtime Flow**:
- User input is received
- Input is sent to LLM with context of available tools
- LLM response is parsed:
- If it's a tool call → execute tool and return result
- If it's a direct response → return to user
- Tool results are sent back to LLM for interpretation
- Final response is presented to user

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@ -12,7 +12,7 @@ from typing import Annotated, Any
import click
from mcp.server import ServerRequestContext
from mcp.server.mcpserver import Context, MCPServer, RequestStateSecurity
from mcp.server.mcpserver import Context, Elicit, ElicitationResult, MCPServer, RequestStateSecurity, Resolve
from mcp.server.mcpserver.exceptions import ToolError
from mcp.server.mcpserver.prompts.base import Prompt, UserMessage
from mcp.server.streamable_http import EventCallback, EventMessage, EventStore
@ -350,6 +350,9 @@ def test_x_mcp_header(
return f"region={region}"
# SEP-2575 server-stateless diagnostics (the conformance scenario probes these tools by name)
@mcp.tool()
async def test_missing_capability(ctx: Context) -> str:
"""Tests that a handler-raised MISSING_REQUIRED_CLIENT_CAPABILITY surfaces as a top-level JSON-RPC error.
@ -370,6 +373,33 @@ async def test_missing_capability(ctx: Context) -> str:
return "Client declared sampling capability; proceeding."
def _ask_stream_probe() -> Elicit[UserResponse]:
return Elicit("The stateless streaming probe asks for a word", UserResponse)
@mcp.tool()
async def test_streaming_elicitation(
answer: Annotated[ElicitationResult[UserResponse], Resolve(_ask_stream_probe)],
) -> str:
"""A tool that needs elicitation, asked through a resolver (SEP-2575 / SEP-2322).
On 2026-07-28 the question is returned as an InputRequiredResult rather than sent
on the response stream; on earlier versions it is a mid-call elicitation request.
"""
return f"elicitation {answer.action}"
@mcp.tool()
async def test_logging_tool(ctx: Context) -> str:
"""Logs once on the request-scoped channel (SEP-2575).
On 2026-07-28 the message is delivered only when the request's `_meta` sets
`io.modelcontextprotocol/logLevel`.
"""
await ctx.info("test_logging_tool ran") # pyright: ignore[reportDeprecated]
return "logged through the request-scoped, logLevel-gated channel"
# SEP-2322 InputRequiredResult fixtures (multi-round-trip / ephemeral workflow)
NAME_SCHEMA = {"type": "object", "properties": {"name": {"type": "string"}}, "required": ["name"]}