github/copilot-sdk · error

invalid AskUserVariant

Error message

invalid AskUserVariant %q: expected %q, %q, or unset

What it means

validateAskUserVariant enforces that SessionConfig.AskUserVariant is either unset, AskUserVariantLegacy, or AskUserVariantElicitation. Any other string is rejected with this error before a session is created.

Solutions

1. Set AskUserVariant to one of the exported constants: AskUserVariantLegacy or AskUserVariantElicitation.
2. Leave AskUserVariant as the zero value ("") for default behavior.
3. Check the SDK version for the set of valid variants and update your value accordingly.

Example fix

// before
cfg.AskUserVariant = "elicitation-mode"
// after
cfg.AskUserVariant = AskUserVariantElicitation

if v := cfg.AskUserVariant; v != "" && v != AskUserVariantLegacy && v != AskUserVariantElicitation { return fmt.Errorf("invalid AskUserVariant %q", v) }

func validAskUserVariant(v AskUserVariant) bool { return v == "" || v == AskUserVariantLegacy || v == AskUserVariantElicitation }

if err := validateAskUserVariant(cfg.AskUserVariant); err != nil { return err }

When it happens

Trigger: Passing an arbitrary/typo'd string in config.AskUserVariant to Client.CreateSession or ResumeSessionWithOptions.

Common situations: Typo like "elicitaton" or "legacy-mode"; constructing the value dynamically from user input; SDK version change adding new variants not yet known to the caller.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• SessionFS.Conventions must be either 'posix' or 'windows'
• sessionFs.conventions must be either 'windows' or 'posix'
• Unknown AgentMode value: + value
• Unknown AskUserVariant value: + value
• Unknown AutoTier value: + value

AI-assisted analysis of github/copilot-sdk@cd8cf15dc3 (2026-09-09). Data as JSON: /api/errors/cf039c8770cfb2cc. Report an issue: GitHub.

Appendix: source

Thrown at go/client.go:829

	if len(callbacks) == 0 {
		return config, nil
	}

	wireConfig := &SystemMessageConfig{
		Mode:     config.Mode,
		Content:  config.Content,
		Sections: wireSections,
	}
	return wireConfig, callbacks
}

func hasManagedSettings(enableManagedSettings *bool, managedSettings *ManagedSettings) bool {
	return (enableManagedSettings != nil && *enableManagedSettings) || managedSettings != nil
}

func validateAskUserVariant(variant AskUserVariant) error {
	if variant != "" && variant != AskUserVariantLegacy && variant != AskUserVariantElicitation {
		return fmt.Errorf("invalid AskUserVariant %q: expected %q, %q, or unset", variant, AskUserVariantLegacy, AskUserVariantElicitation)
	}
	return nil
}

func (c *Client) CreateSession(ctx context.Context, config *SessionConfig) (*Session, error) {
	if config == nil {
		config = &SessionConfig{}
	}
	if config.GitHubToken != "" && config.GitHubTokenProvider != nil {
		return nil, fmt.Errorf("GitHubToken and GitHubTokenProvider cannot be used together")
	}
	if err := validateAskUserVariant(config.AskUserVariant); err != nil {
		return nil, err
	}

	if err := c.ensureConnected(ctx); err != nil {
		return nil, err
	}

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