In the general signal+noise (allowing non-normal, non-independent observations) model we construct an empirical Bayes posterior which we then use for uncertainty quantification for the unknown, possibly sparse, signal. We introduce a novel excessive bias restriction (EBR) condition, which gives rise to a new slicing of the entire space that is suitable for uncertainty quantification. Under EBR and some mild exchangeable exponential moment condition on the noise, we establish the local (oracle) optimality of the proposed confidence ball. Without EBR, we derive the full coverage for confidence balls of at least σn 1/4 -radius, implying the local optimality only for cases when the oracle rate is at least of the order σn 1/4 . In passing, we also get the local optimal results for estimation and posterior contraction problems. Adaptive minimax results (also for the estimation and posterior contraction problems) over various sparsity classes follow from our local results. MSC2010 subject classification: primary 62G15, secondary 62C12.The best studied problem in the sparsity context is that of estimating θ in the many normal means model, a variety of estimation methods and results are available in the literature: [27]. However, even an optimal estimator does not reveal how far it is from θ. It is of importance to quantify this uncertainty, which can be seen as the problem of constructing confidence sets for θ.Bayesian approach and accompanying posterior contraction problem. Many inference methods have Bayesian connections. For example, even some seemingly non Bayesian estimators can be obtained as certain quantities (like posterior mode for penalized minimum contrast estimators) of the (empirical Bayes) posterior distributions resulting from imposing some specific priors on the parameter; cf.[17] and [1]. Although the Bayesian methodology is used or can be related to in constructing many (frequentist) inference procedures, only recently the posterior distributions themselves have been studied in the sparsity context: [13], [27], [19], [12], [7], [25], [23].In this paper, for inference on θ we use an empirical Bayes approach. Since any Bayesian approach always delivers a posterior π(ϑ|X) (in the posteriors for θ, we will use the variable ϑ to distinguish it from the "true" θ), an accompanying problem of interest is the contraction of the resulting (empirical Bayes) posterior to the "true" θ from the frequentist perspective of the "true" measure P θ , the distribution of X from (1). The quality of posterior is characterized by the posterior contraction rate. We pursue a novel local approach by allowing the posterior contraction rate to be a local quantity, i.e., depending on the true θ, whereas global minimax rates are typically studied in the literature on Bayesian nonparametrics.A common Bayesian way to model sparsity structure is by the so called two-groups priors. Such a prior puts positive mass on vectors θ with some exact zero coordinates (zero group) and the remaining coordinates (signal group) are drawn from a cho...