Preprint Open access
How Do Agentic LLMs Decide to Call Tools? A Tool-Call Vector Shaped by Suppression
Tool calling, invoking external tools on demand, is central to agentic LLMs, yet the mechanism that decides whether a model calls a tool or responds directly remains poorly understood. Agentic prompts are long and heavily scaffolded, combining role instructions, tool schemas, format templates, and the user's request ac …