charmbracelet/crush · warning

failed to marshal api key string: %w

Error message

failed to marshal api key string: %w

What it means

SetProviderAPIKey marshals a string API key to JSON before sending it. json.Marshal on a plain Go string cannot realistically fail, so this error is defensive; if it ever occurs the JSON encoding layer itself is broken (e.g. corrupted encoding state via custom marshalers).

Source

Thrown at internal/client/config.go:94

	}
	return nil
}

// SetProviderAPIKey sets a provider API key on the server. The wire
// format tags the credential with an explicit Kind so the server can
// decode it back into the right Go type — JSON's `any` loses that
// information across the socket.
func (c *Client) SetProviderAPIKey(ctx context.Context, id string, scope config.Scope, providerID string, apiKey any) error {
	var (
		kind proto.APIKeyKind
		raw  json.RawMessage
	)
	switch v := apiKey.(type) {
	case string:
		kind = proto.APIKeyKindString
		b, err := json.Marshal(v)
		if err != nil {
			return fmt.Errorf("failed to marshal api key string: %w", err)
		}
		raw = b
	case *oauth.Token:
		if v == nil {
			return fmt.Errorf("oauth token is nil")
		}
		kind = proto.APIKeyKindOAuth
		b, err := json.Marshal(v)
		if err != nil {
			return fmt.Errorf("failed to marshal oauth token: %w", err)
		}
		raw = b
	default:
		return fmt.Errorf("unsupported api key type %T", apiKey)
	}

	rsp, err := c.post(ctx, fmt.Sprintf("/workspaces/%s/config/provider-key", id), nil, jsonBody(proto.ConfigProviderKeyRequest{
		Scope:      scope,

View on GitHub (pinned to 7944b8e522)

Solutions

1. Inspect the wrapped %w error for details from json.Marshal
2. If apiKey is a custom string type, check whether it defines a MarshalJSON method that errors
3. Retry the call; if it persists, report a bug in the client

if _, err := json.Marshal(apiKey); err != nil {
    return fmt.Errorf("key not serializable: %w", err)
}
// proceed with SetProviderAPIKey

When it happens

Trigger: Calling SetProviderAPIKey with a string apiKey where json.Marshal(v) returns an error — practically never for a plain string.

Common situations: Essentially unreachable in normal use; would indicate a corrupted runtime or a custom string type with a failing MarshalJSON method.

Related errors

• failed to marshal oauth token: %w
• failed to decode workspaces: %w
• failed to decode MCP pending auth: %w
• failed to decode MCP auth URL: %w
• marshal request: %w

AI-assisted analysis of charmbracelet/crush@7944b8e522 (2026-08-29). Data as JSON: /api/errors/1d7bdd0e05680d43. Report an issue: GitHub.