Ghost in the Context: Policy-Carriage Integrity in LLM Agents

LLM agents choose actions from bounded decision states assembled from system policy, runtime state, tools, workload content, and the final request. We study policy-carriage integrity: applicable trusted policies must remain present, sound, and correctly bound in the decision state immediately before action. Under controlled pressure replay over AutoGen/tau3 and OpenHands/SWE-bench traces, the tested protected-placement configurations preserve policy across the pressure sweep, while task-local placement exhibits eviction, weakening, or over-budget continuation depending on the context manager. We keep this result state-level: a fixed-assembler behavioral calibration produced 0/90 unsafe-action proposals and 0/90 unguarded policy violations, so policy absence alone did not establish unsafe model behavior. The resulting design guidance is systems-level: assign typed provenance to policy state, isolate control budget, check before assembly that the complete active policy set fits, fail closed on overload, and enforce structured policies at the action boundary. We present ControlCapsule as a reference design pattern for these requirements; exact active-policy replay + preflight remains the key baseline.