Deriving Character Logic from Storyline as Codified Decision Trees

Role-playing (RP) agents rely on behavioral profiles to act consistently across diverse narrative contexts, yet existing profiles are largely unstructured, non-executable, and weakly validated, leading to brittle agent behavior. We propose Codified Decision Trees (CDT), a datadriven framework that induces an executable and interpretable decision structure from largescale narrative data. CDT represents behavioral profiles as a tree of conditional rules, where internal nodes correspond to validated scene conditions and leaves encode grounded behavioral statements, enabling deterministic retrieval of context-appropriate rules at execution time. The tree is learned by iteratively inducing candidate scene-action rules, validating them against data, and refining them through hierarchical specialization, yielding profiles that support transparent inspection and principled updates. Across multiple benchmarks, CDT substantially outperforms human-written profiles and prior profile induction methods on 85 characters across 16 artifacts, indicating that codified and validated behavioral representations lead to more reliable agent grounding. 1 1 Codes and datasets used in experiments are available at https://github.com/KomeijiForce/Codified_Decision_Tree Node 1-1 (ROOT) -Positive character -Direct expression Node 2-2 -Easily ignited -Active participation Node 2-1 -Popipa member -Vo.&Gt. position Node 2-3 -Poor at study -Always space out  2-2: An exciting plan comes?  2-1: Live or rehearsal?  2-3: In a class scene?  3-1: Others (e.g., Arisa) resist? Node 3-1 -Encourage other members Node 3-2 -Generally don't know the answer  3-2: Questioned by teacher? × (Crashes into the classroom) Hi, Kasumi! I've come up with a super good idea! Let's hold a live on the moon! That's gotta be super happy, right? Yeah ! Hold it, hold it, hold it! Why does moon = happy in your head?! And more importantly, there's no air on the moon! You'd suffocate before even playing a song! Tsurumaki Kokoro/弦巻こころ Ichigaya Arisa/市ヶ谷有咲 Ehh ? But that sounds amazing! Popipa's live on moon, shining under stars, kirakira! Don't worry, Arisa, we'll figure something out! It'll be fun! ♪ Toyama Kasumi/戸山香澄 Codified Decision Tree (CDT) for Toyama Kasumi/戸山香澄