Treating random masking as a performance plug-in for large language models (LLMs) offers three advantages: low coupling to the task, the model, and training resources. However, the critical drawback is that its gains are highly stochastic. Motivated by this, we propose play-it-by-ear masking performance plug-in (PibE-MPP), which enables LLMs to adaptively select masking target combinations for each task, retaining these advantages and mitigating the drawback. Specifically, we pose two core questions—what are the masking targets and what is the masking strategy under 7 constraints obtained from these advantages and a drawback. For the first question, we select all attention heads in the last layer as masking targets by constructing a first-order Markov process with alternating hidden state and information fusion. The feasibility of this target is validated by random masking experiments. For the second question, we first construct a small yet interpretable candidate set by proposing a three-axis mapping and a mean-based criterion for fusion features of masking targets. We then propose an axis-variance minimization to select a compact masking-target combination, reducing sensitivity to outlier targets. Experiments on 6 LLMs (Qwen and LLaMA) and 24 datasets demonstrate PibE-MPP’s effectiveness and generality, gain stability, and domain performance, and verify the necessity of its final module, providing empirical evidence of its transferability across tasks and models. The code is available at https://github.com/wtctcop/PibE-MPP.

Role-playing agents(RPAs) are widely used to steer large language models(LLMs) toward role-consistent behavior, yet existing benchmarks mainly evaluate surface-level fidelity and offer limited insight into decision making under role–alignment value conflicts. To address this gap, we introduce RoleCDE, the first benchmark designed to evaluate RPAs under structured conflicts between role-specific values and alignment-oriented constraints. RoleCDE formulates role-aware decision making as cognitive dilemma scenarios, jointly evaluating role–scenario grounding, value conflict resolution, and decision tendencies. The benchmark is constructed at scale, covering approximately 8k diverse role profiles and scenarios and nearly 240k dilemma instances across three difficulty levels and eight role categories. Evaluation of several mainstream LLMs reveals a "Role Value Decoupling" phenomenon, where agents systematically default to alignment- and morality-consistent decisions rather than role-specific values when the two conflict, even under explicit role conditioning. This behavior is largely invariant to dilemma difficulty but varies substantially across role categories. We further show that RoleCDE-based fine-tuning effectively mitigates this decoupling by improving value trade-off reasoning, while preserving general role-playing fidelity and general reasoning performance. Code is available at: https://github.com/rabbitrose/RoleCDE.