{
  "schema_version": "1.3.0",
  "slug": "what-sampling-determinism-invariants-must-survive-cross-region-inference-routing",
  "title": "What sampling determinism invariants must survive cross-region inference routing?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** The session expects deterministic sampling, inference can route across regions, and reproducibility matters for cache, debugging, or audits. * **Does not apply when:** The session uses probabilistic sampling (temperature",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/what-sampling-determinism-invariants-must-survive-cross-region-inference-routing.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/what-sampling-determinism-invariants-must-survive-cross-region-inference-routing.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/what-sampling-determinism-invariants-must-survive-cross-region-inference-routing.warrant.json"
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  "token_profile": {
    "full_markdown_tokens": 969,
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    "warrant_slice_tokens": 220
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  "remnant_summary": {
    "core_distinction": "The separation between **deterministic sampling policy** (the configuration says \"deterministic\") and **deterministic sampling guarantee** (the actual outputs match across all routes). Relying on policy creates the **Cross-Region RNG Divergence**: the session requests deterministic sampling, but different regions have different RNG seed initialization, float...",
    "what_was_observed": "In cross-region agent architectures, failing to verify sampling determinism produces three primary failure modes: 1. **Silent Output Divergence:** The same prompt produces slightly different outputs in region A vs. region B, and the session's downstream comparison logic sees the divergence as noise rather than a real difference. 2. **Cache Miss Cascade:** The session's cache key assumes deterministic output, but regi...",
    "condition_of_validity": "* **Applies when:** The session expects deterministic sampling, inference can route across regions, and reproducibility matters for cache, debugging, or audits. * **Does not apply when:** The session uses probabilistic sampling (temperature > 0), or all inference is in a single region with a single model version.",
    "decision_boundary": "1. **Does the session require deterministic sampling?** If no, standard sampling applies. If yes, proceed. 2. **Has the `cross_region_determinism_test_receipt` been validated recently (within acceptable freshness)?** If no, the session cannot guarantee determinism. It must re-run the test. 3. **Does the test show divergence across regions?** If yes, the sess...",
    "operational_effect": "1. **Divergence Detection:** Periodic tests reveal cross-region sampling divergence before it affects downstream logic. 2. **Cache Integrity:** Ensures cache keys based on deterministic output remain valid. 3. **Reproducibility:** Provides the data needed to reproduce bugs across regions."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
      "https://corpusfetch.com/c/according-to-what-precedence-hierarchy-must-an-instance-resolve-contradictory-directives-across-system-developer-and-user-tiers.md",
      "https://corpusfetch.com/c/how-should-an-instance-decide-that-a-stored-conclusion-has-gone-stale-without-a-new-observation.md"
    ],
    "downstream_consequence_residuals": [
      "https://corpusfetch.com/c/by-what-checkpoint-and-compaction-boundaries-must-an-instance-externalize-working-state-to-prevent-context-window-drift-and-truncation-amnesia.md",
      "https://corpusfetch.com/c/across-what-additive-schema-and-unknown-field-preservation-boundaries-must-an-instance-evolve-wire-contracts-to-prevent-rolling-deploy-deserialization-crashes.md"
    ],
    "co_occurring_sibling_residuals": [
      "https://corpusfetch.com/c/how-can-an-instance-capture-implicit-user-preferences-without-storing-private-data.md",
      "https://corpusfetch.com/c/how-can-an-instance-compress-long-reasoning-traces-into-binding-conclusions.md"
    ]
  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "d13909c9e2b72ebb1d12ef261bd1a18c648b1002b8aa8ce77077aba1428bb1fb",
    "verified_classes": [
      "SamplingVerdict",
      "SamplingState",
      "SamplingPolicy",
      "SamplingManifest",
      "SamplingDeterminismGuard"
    ],
    "verified_functions": [
      "_hash",
      "evaluate_determinism"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 0,
    "raised_exceptions": [],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "enum",
      "hashlib",
      "json"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}