Extending Agent Capabilities: Tools vs. Agents

The main aim of this paper is to motivate extending the formal definition of "capability\´\´ to incorporate the capabilities of external entities, i.e. external capability. The title points to the idea that an external entity may be either a tool or an agent, and only in the latter case does collaboration becomes relevant. This is the starting point for viewing the previously introduced "tool\´\´ concept and tool use, as complementary to the agent concept and collaboration respectively. We argue that the tool concept fits between the single agent case and true multi-agent systems where the agents collaborate. According to our view, tool-use is distinguishable both from using internal capabilities and from collaborating with other agents. We also present a formalization of external capability and show this definition preserves desirable \´rationality\´ properties.