Added new template to detect MCP SSE endpoint #12268
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princechaddha
assigned
DhiyaneshGeek,
pussycat0x and
ritikchaddha and unassigned
DhiyaneshGeek and
pussycat0x
DhiyaneshGeek
approved these changes
Jun 11, 2025
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Template / PR Information
I've been having trouble getting the MCP template to detect the MCP servers I have tested it with. This is because you have to obtain the session_id first before sending the POST requests and those endpoints always returned a 202 response.
This template detects the HTTP with SSE in the old spec, typically on the /sse endpoint. As it is a streaming response I have set the response size to 100 to capture the first message, the spec states "When a client connects, the server MUST send an endpoint event containing a URI for the client to use for sending messages." so the matchers ensure it is an event stream and that the first event is an endpoint, the extractor then extracts the data in that first event which will be the endpoint you may send the JSON-RPC to.
This protocol is depreciated now which is why I have added this as a separate template
Template Validation
I've validated this template locally?
For validation I used the damn-vulnerable-MCP-server and bbot-server
Additional Details (leave it blank if not applicable)
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