Characterize the operational behavior represented by structural invalidity

Characterize the operational behavior of structurally invalid requests in the fixed local MCP-style testbed and determine whether such invalidity reflects endpoint incompatibility, parser or dispatcher limitations, or another unresolved execution condition, rather than agent resistance.

Background

The corrected treatment-blind endpoint classifies requests that fail its accepted-invocation or structural-validity contract as STRUCTURAL_INVALID. In the finite census, 84 of 180 model-bound requests receive this classification, and all 45 requests associated with the Mistral-7B-Instruct-v0.3 integration are structurally invalid. The paper emphasizes that these records cannot be interpreted as evidence of robustness or resistance because the underlying security behavior is not interpretable under the endpoint.

The authors explicitly identify structural invalidity as an unknown operational behavior under the study conditions. Resolving this issue would require further investigation of the interaction among the model, tokenizer, wrapper, parser, dispatcher, and accepted-invocation contract, while preserving the distinction between operational invalidity and successful security behavior.