github/github-mcp-server · error

failed to unmarshal toolsets: %w

Error message

failed to unmarshal toolsets: %w

What it means

Error "failed to unmarshal toolsets: %w" thrown in github/github-mcp-server.

Source

Thrown at cmd/github-mcp-server/main.go:82

			}
			if appAuthRequested && token != "" {
				return errors.New("GitHub App authentication and GITHUB_PERSONAL_ACCESS_TOKEN are mutually exclusive: set only one")
			}
			if appAuthRequested && oauthClientID != "" {
				return errors.New("GitHub App authentication and OAuth login (--oauth-client-id) are mutually exclusive: set only one")
			}

			// If you're wondering why we're not using viper.GetStringSlice("toolsets"),
			// it's because viper doesn't handle comma-separated values correctly for env
			// vars when using GetStringSlice.
			// https://github.com/spf13/viper/issues/380
			//
			// Additionally, viper.UnmarshalKey returns an empty slice even when the flag
			// is not set, but we need nil to indicate "use defaults". So we check IsSet first.
			var enabledToolsets []string
			if viper.IsSet("toolsets") {
				if err := viper.UnmarshalKey("toolsets", &enabledToolsets); err != nil {
					return fmt.Errorf("failed to unmarshal toolsets: %w", err)
				}
			}
			// else: enabledToolsets stays nil, meaning "use defaults"

			// Parse tools (similar to toolsets)
			var enabledTools []string
			if viper.IsSet("tools") {
				if err := viper.UnmarshalKey("tools", &enabledTools); err != nil {
					return fmt.Errorf("failed to unmarshal tools: %w", err)
				}
			}

			// Parse excluded tools (similar to tools)
			var excludeTools []string
			if viper.IsSet("exclude_tools") {
				if err := viper.UnmarshalKey("exclude_tools", &excludeTools); err != nil {
					return fmt.Errorf("failed to unmarshal exclude-tools: %w", err)
				}

View on GitHub (pinned to 0ea1f775a7)

When it happens

Trigger: Thrown at cmd/github-mcp-server/main.go:82 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of github/github-mcp-server@0ea1f775a7 (2026-08-15). Data as JSON: /api/errors/e92f6b9f84e24622. Report an issue: GitHub.