Tencent/WeKnora · error

invalid response from server

Error message

invalid response from server

What it means

Sentinel returned when the MCP server sends a response that cannot be parsed or does not match the expected JSON-RPC shape (missing fields, wrong types, error payload where a result was expected). It indicates a protocol-level mismatch rather than a business error.

Source

Thrown at internal/mcp/errors.go:25

	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. Log the raw response payload to diagnose the protocol mismatch
2. Verify client and server MCP protocol versions are compatible
3. Retry the request in case of a truncated/corrupted transport frame
4. Upgrade the MCP client library or server if the wire format changed

When it happens

Trigger: Thrown at internal/mcp/errors.go:25 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/7673e691b68c4115. Report an issue: GitHub.