Sealed Test Paradigm locks agent tests

This is a useful primitive even if the framing is heavier than the implementation: test immutability is one of the most practical guardrails for autonomous coding loops.

• –The key contribution is architectural, not model-specific: isolate test planning, append tests, seal them, then gate code generation on failing sealed tests
• –It targets a real failure mode in agentic coding systems where the agent optimizes the harness instead of the product behavior
• –The reference implementation is intentionally small, which makes it easier to adapt into local runners, CI gates, or custom orchestration layers
• –The bigger open question is ergonomics: teams still need a trusted blueprint authoring path and a way to handle legitimate test evolution without weakening the guarantee