Action and integration
Tools connect model decisions to external observations and effects. Google's function-calling documentation explicitly assigns function execution to the application, while the model selects calls and arguments. This separation makes the tool boundary a place for validation and authority checks. gemini-function-calling
Interoperability
Interoperability lets independently implemented components discover capabilities and exchange requests and results. A compatible message format is only one layer: task meaning, authorization and recovery still need agreements. This page treats the boundary as core while identifying protocol-specific and cross-runtime behavior as evolving.