We study in this work the metrology precision of a probe system coupled to an ancillary qubit. Restricting the probe-qubit coupling along no more than two orthogonal directions is found to be a sufficient criterion for the effective dynamical generator of the composite system to exhibit Heisenberg scaling in precision. Under this coupling criterion, the quantum Fisher information (QFI) about the to-be-estimated parameter becomes the mean square of the effective generator with respect to the initial state of the composite system. Our criterion is justified in two distinct systems. For a bosonic probe, QFI about the displacement estimation is found to be proportional to the average excitation number of probe. It is a seemingly counterintuitive that quantum metrology sensitivity can be enhanced by increasing the probe system’s temperature. For a spin-ensemble probe, QFI about both rotation-phase and magnetic-field can exhibit a quadratic dependence on the probe-spin number, even when the probe is initially in a mixed state. Our protocol actually manufactures the metrologically relevant states to manifest a Heisenberg scaling behavior through qubit-probe interaction. At the input, it relieves the optimization about the probe to the so-called resource states, e.g., the squeezed state or the Greenberger-Horne-Zeilinger (GHZ) state, in sharp contrast to the prior preparation-then-encoding paradigm.