MCP Server with HTTP transport fails after connection reset

[vugenti]

If connection to HTTP based MCP server is temporarily disrupted after the tools are initialized, the following errors appear in logs and no requests can be processed until after the agent is restarted and establishes a new connection to the MCP server:

time=2026-02-15T20:54:27.468-05:00 level=DEBUG msg="Agent is consuming a job" agent=test_agent job="&{Result:0xc000428120 ReasoningCallback:0x7ff653d0f180 ResultCallback:0x7ff653d0eb60 ConversationHistory:[{Role:user Content:tt Refusal: MultiContent:[] Name: ReasoningContent: FunctionCall:<nil> ToolCalls:[] ToolCallID:}] UUID:dc35e499-201a-4e8b-88a6-0b6955af6fb6 Metadata:map[] DoneFilter:false BuiltinTools:[] UserTools:[] ToolChoice: context:0xc000610050 fragment:<nil> cancel:0x7ff652e26ec0 Obs:0xc000580840}" source.file=C:/src/LocalAGI/core/agent/agent.go source.L=1315
time=2026-02-15T20:54:27.469-05:00 level=DEBUG msg="No filters" source.file=C:/src/LocalAGI/core/agent/agent.go source.L=588
time=2026-02-15T20:54:27.469-05:00 level=DEBUG msg="Processing user inputs" agent=test_agent conversation="user: tt\n" source.file=C:/src/LocalAGI/core/agent/agent.go source.L=512
time=2026-02-15T20:54:27.469-05:00 level=DEBUG msg="[Knowledge Base Lookup] Disabled, skipping" agent=test_agent source.file=C:/src/LocalAGI/core/agent/knowledgebase.go source.L=21
time=2026-02-15T20:54:27.478-05:00 level=ERROR msg="Error listing tools: %v" !BADKEY="connection closed: calling \"tools/list\": client is closing: standalone SSE stream: failed to connect: Bad Request" source.file=C:/Users/user/go/pkg/mod/github.com/mudler/cogito@v0.8.2-0.20260215230740-d1c0dc9bd9dc/mcp.go source.L=108
time=2026-02-15T21:50:08.960-05:00 level=ERROR msg="Error executing cogito" error="failed to get relevant guidelines: failed to get MCP tools: connection closed: calling \"tools/list\": client is closing: standalone SSE stream: failed to connect: Bad Request" source.file=C:/src/LocalAGI/core/agent/agent.go source.L=1162
time=2026-02-15T21:50:08.960-05:00 level=DEBUG msg="Agent has finished" agent=test_agent source.file=C:/src/LocalAGI/core/agent/agent.go source.L=238

[vugenti]

I've been trying to find the right place to re-establish the connection but because of the way the control flows between cogito and LocalAGI, and the way the error is structured, I am not sure how to best intercept and re-establish a new connection. I was thinking about just throwing a call to re-init the mcp tools every time the agent runs periodically as an ugly hack.

[tekhedd]

I am seeing a similar, probably related issue: if a remote (HTTP) MCP server is offline or fails during startup, there is no way to use it until you restart.

(Similar fail if a stdio MCP fails at the "initialize" call...)

Yes this requires architectural changes to make the connection stateful, which I fully understand is not a minor bugfix. :)

[vugenti]

I am seeing a similar, probably related issue: if a remote (HTTP) MCP server is offline or fails during startup, there is no way to use it until you restart.

(Similar fail if a stdio MCP fails at the "initialize" call...)

Yes this requires architectural changes to make the connection stateful, which I fully understand is not a minor bugfix. :)

#419 demonstrates how to resolve this. I don't know if it can still cleanly merge with the main branch though.