| 1 | package plugin |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "io" |
| 7 | "strings" |
| 8 | |
| 9 | mcpjsonrpc "github.com/modelcontextprotocol/go-sdk/jsonrpc" |
| 10 | mcpsdk "github.com/modelcontextprotocol/go-sdk/mcp" |
| 11 | ) |
| 12 | |
| 13 | func isExplicitMCPSessionMissing(err error) bool { |
| 14 | if errors.Is(err, mcpsdk.ErrSessionMissing) { |
| 15 | return true |
| 16 | } |
| 17 | if !isMCPHTTPNotFound(err) || !hasMCPTransportRejection(err) { |
| 18 | return false |
| 19 | } |
| 20 | found := false |
| 21 | visitMCPRPCErrors(err, func(rpcErr *mcpjsonrpc.Error) { |
| 22 | message := strings.ToLower(strings.TrimSpace(rpcErr.Message)) |
| 23 | for _, marker := range []string{ |
| 24 | "session not found", |
| 25 | "session missing", |
| 26 | "session expired", |
| 27 | "invalid session", |
| 28 | "unknown session", |
| 29 | } { |
| 30 | if strings.Contains(message, marker) { |
| 31 | found = true |
| 32 | } |
| 33 | } |
| 34 | }) |
| 35 | return found |
| 36 | } |
| 37 | |
| 38 | // isMCPHTTPNotFound recognizes the status-only error emitted by newer Go MCP |
| 39 | // SDKs for a plain HTTP 404 when no session ID exists. It intentionally does |
| 40 | // not match arbitrary "not found" prose so a tool-level domain error cannot be |
| 41 | // mistaken for an endpoint or protocol mismatch. |
| 42 | func isMCPHTTPNotFound(err error) bool { |
| 43 | if err == nil { |
| 44 | return false |
| 45 | } |
| 46 | hasRPCError := false |
| 47 | visitMCPRPCErrors(err, func(*mcpjsonrpc.Error) { |
| 48 | hasRPCError = true |
| 49 | }) |
| 50 | if hasRPCError && !hasMCPTransportRejection(err) { |
| 51 | return false |
| 52 | } |
| 53 | message := strings.ToLower(strings.TrimSpace(err.Error())) |
| 54 | return message == "not found" || |
| 55 | strings.HasSuffix(message, ": not found") || |
| 56 | strings.Contains(message, "http 404") || |
| 57 | strings.Contains(message, "status 404") |
| 58 | } |
| 59 | |
| 60 | func hasMCPTransportRejection(err error) bool { |
| 61 | found := false |
| 62 | visitMCPRPCErrors(err, func(rpcErr *mcpjsonrpc.Error) { |
| 63 | if rpcErr.Code == -32005 && strings.EqualFold(strings.TrimSpace(rpcErr.Message), "rejected by transport") { |
| 64 | found = true |
| 65 | } |
| 66 | }) |
| 67 | return found |
| 68 | } |
| 69 | |
| 70 | // visitMCPRPCErrors walks every concrete error-tree node because errors.As |
| 71 | // returns only the first matching RPC error and would hide transport evidence. |
| 72 | // |
| 73 | //nolint:errorlint // Direct inspection distinguishes server errors from the SDK transport sentinel. |
| 74 | func visitMCPRPCErrors(err error, visit func(*mcpjsonrpc.Error)) { |
| 75 | if err == nil { |
| 76 | return |
| 77 | } |
| 78 | if rpcErr, ok := err.(*mcpjsonrpc.Error); ok && rpcErr != nil { |
| 79 | visit(rpcErr) |
| 80 | } |
| 81 | switch wrapped := err.(type) { |
| 82 | case interface{ Unwrap() []error }: |
| 83 | for _, child := range wrapped.Unwrap() { |
| 84 | visitMCPRPCErrors(child, visit) |
| 85 | } |
| 86 | case interface{ Unwrap() error }: |
| 87 | visitMCPRPCErrors(wrapped.Unwrap(), visit) |
| 88 | } |
| 89 | } |
| 90 | |
| 91 | func (t *sdkSessionTransport) isStreamableHTTPNotFound(err error) bool { |
| 92 | return canonicalMCPRuntimeTransport(t.spec.Type) == "streamable-http" && isMCPHTTPNotFound(err) |
| 93 | } |
| 94 | |
| 95 | func isTerminalSDKError(err error) bool { |
| 96 | return errors.Is(err, mcpsdk.ErrConnectionClosed) || errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) |
| 97 | } |
| 98 | |
| 99 | func isAmbiguousTransportError(err error) bool { |
| 100 | if err == nil { |
| 101 | return false |
| 102 | } |
| 103 | message := strings.ToLower(err.Error()) |
| 104 | for _, marker := range []string{"connection reset", "broken pipe", "connection aborted", "connection refused", "transport is closing"} { |
| 105 | if strings.Contains(message, marker) { |
| 106 | return true |
| 107 | } |
| 108 | } |
| 109 | return false |
| 110 | } |
| 111 | |
| 112 | func classifySessionError(err error) SessionErrorKind { |
| 113 | if err == nil { |
| 114 | return SessionErrorNone |
| 115 | } |
| 116 | switch { |
| 117 | case isExplicitMCPSessionMissing(err): |
| 118 | return SessionErrorSessionMissing |
| 119 | case errors.Is(err, context.DeadlineExceeded): |
| 120 | return SessionErrorTimeout |
| 121 | case isTerminalSDKError(err): |
| 122 | return SessionErrorStreamClosed |
| 123 | } |
| 124 | lower := strings.ToLower(err.Error()) |
| 125 | switch { |
| 126 | case strings.Contains(lower, "unauthorized"), strings.Contains(lower, "forbidden"), strings.Contains(lower, "authorize again"), strings.Contains(lower, "authentication"): |
| 127 | return SessionErrorAuthRequired |
| 128 | case strings.Contains(lower, "protocol version"), strings.Contains(lower, "method not found"): |
| 129 | return SessionErrorProtocol |
| 130 | default: |
| 131 | return SessionErrorTransport |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | type sanitizedMCPError struct { |
| 136 | message string |
| 137 | cause error |
| 138 | } |
| 139 | |
| 140 | func (e *sanitizedMCPError) Error() string { return e.message } |
| 141 | func (e *sanitizedMCPError) Unwrap() error { return e.cause } |
| 142 | |
| 143 | func (t *sdkSessionTransport) sanitizeError(err error, managed *managedMCPSession) error { |
| 144 | if err == nil { |
| 145 | return nil |
| 146 | } |
| 147 | sessionID := "" |
| 148 | if managed != nil && managed.session != nil { |
| 149 | sessionID = managed.session.ID() |
| 150 | } |
| 151 | return &sanitizedMCPError{message: t.safeErrorText(err, sessionID), cause: err} |
| 152 | } |
| 153 | |
| 154 | func (t *sdkSessionTransport) safeErrorText(err error, sessionID string) string { |
| 155 | return redactMCPConfigValues(safeMCPErrorText(err, sessionID), t.spec) |
| 156 | } |
| 157 | |
| 158 | func redactMCPConfigValues(message string, spec Spec) string { |
| 159 | values := make([]string, 0, len(spec.Headers)+len(spec.Env)+2) |
| 160 | values = append(values, spec.WorkspaceRoot, spec.Dir) |
| 161 | for _, value := range spec.Headers { |
| 162 | values = append(values, value) |
| 163 | } |
| 164 | for _, value := range spec.Env { |
| 165 | values = append(values, value) |
| 166 | } |
| 167 | for _, value := range values { |
| 168 | value = strings.TrimSpace(value) |
| 169 | if value != "" { |
| 170 | message = strings.ReplaceAll(message, value, "[redacted]") |
| 171 | } |
| 172 | } |
| 173 | return message |
| 174 | } |
| 175 | |
| 176 | func safeMCPErrorText(err error, sessionID string) string { |
| 177 | if err == nil { |
| 178 | return "" |
| 179 | } |
| 180 | message := summarizeFailureError(err) |
| 181 | if sessionID != "" { |
| 182 | message = strings.ReplaceAll(message, sessionID, "[redacted]") |
| 183 | } |
| 184 | if index := strings.Index(strings.ToLower(message), "session id:"); index >= 0 { |
| 185 | start := index + len("session id:") |
| 186 | end := strings.IndexByte(message[start:], ')') |
| 187 | if end >= 0 { |
| 188 | message = message[:start] + " [redacted]" + message[start+end:] |
| 189 | } |
| 190 | } |
| 191 | return message |
| 192 | } |
| 193 |