This study aims to develop and validate a tool for examining and diagnosing the internal attachment patterns in middle childhood for use in clinical interventions and social work. A total of 100 children from five educational centers in different districts of Tehran were selected through multi-stage cluster random sampling. Initially, the children completed the Finzi‑Dottan et al. (2012)' attachment questionnaire, followed by the story completion test based on the MacArthur approach. The stories were designed around stressful life situations for elementary school children, reviewed by experts, illustrated, and implemented. Responses were recorded and coded. Content validity was confirmed by 12 experts, and internal consistency was verified using Cronbach's alpha (0.83 for all items). The validity of the tool was established through concurrent validation, comparing the results of the story completion tool with the 'Finzi‑Dottan et al. (2012)' attachment questionnaire (0.897), as well as through exploratory and confirmatory factor analysis (p<0.05). The advantage of this tool is that, beyond determining attachment styles, it provides a deeper understanding of the child's psychological state, including their history, potential traumas, and the role of family members beyond parents in attachment formation or even mistreatment. For a comprehensive understanding of its benefits and limitations, further studies with larger sample sizes are needed.