Tencent/WeKnora · error

client already connected

Error message

client already connected

What it means

Sentinel returned by mcpGoClient.Connect when c.connected is already true, i.e. Connect was called twice on the same client without an intervening Close. It is a pure state guard against duplicate connection establishment.

Source

Thrown at internal/mcp/errors.go:13

package mcp

import "errors"

var (
	// ErrUnsupportedTransport is returned when transport type is not supported
	ErrUnsupportedTransport = errors.New("unsupported transport type")

	// ErrNotConnected is returned when operation requires connection but client is not connected
	ErrNotConnected = errors.New("client not connected")

	// ErrAlreadyConnected is returned when trying to connect an already connected client
	ErrAlreadyConnected = errors.New("client already connected")

	// ErrInitializeFailed is returned when MCP initialize handshake fails
	ErrInitializeFailed = errors.New("MCP initialize handshake failed")

	// ErrToolNotFound is returned when requested tool is not found
	ErrToolNotFound = errors.New("tool not found")

	// ErrResourceNotFound is returned when requested resource is not found
	ErrResourceNotFound = errors.New("resource not found")

	// ErrInvalidResponse is returned when server response is invalid
	ErrInvalidResponse = errors.New("invalid response from server")

	// ErrTimeout is returned when operation times out
	ErrTimeout = errors.New("operation timed out")

	// ErrConnectionClosed is returned when connection is closed unexpectedly
	ErrConnectionClosed = errors.New("connection closed")

View on GitHub (pinned to 988cbb0330)

Solutions

1. Guard Connect calls with the client's connected state or a sync.Once
2. Close the existing connection before reconnecting
3. Treat this error as benign and reuse the existing connection instead of reconnecting

When it happens

Trigger: Thrown at internal/mcp/errors.go:13 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Tencent/WeKnora@988cbb0330 (2026-09-02). Data as JSON: /api/errors/6b0005ed04aa2bef. Report an issue: GitHub.