Limitations and failure modes (descriptive)

Scenario: ND ANN execution with budget exhaustion, approximation, provenance, and replay mismatch.

Steps (CLI narrative):

1. bijux vex materialize --execution-contract non_deterministic
2. bijux vex execute --artifact-id art-1 --vector "[...]" --top-k 1 --execution-contract non_deterministic --execution-intent exploratory_search --execution-mode bounded --randomness-seed 1 --randomness-sources reference_ann_hnsw --randomness-bounded --max-latency-ms 1 --max-memory-mb 1 --max-error 0.2
3. Execution returns PARTIAL with BudgetExceededError provenance and DeterminismReport.
4. Ledger stores ExecutionResult + artifact signature.
5. bijux vex replay --request-text "..." → mismatch allowed but recorded; ReplayOutcome.details carries divergence and randomness sources.
6. bijux vex compare --vector "[...]" --execution-intent exact_validation → overlap/recall deltas highlight approximation loss.

What it proves:

• Budgets abort mid-plan, not post-hoc.
• ND replay is legal but must declare divergence.
• Provenance is required; replay without ledger state fails fast.
• Approximation is auditable, not silent.