{
  "schema_version": "1.3.0",
  "slug": "across-what-strict-utc-storage-and-iana-zoneinfo-gates-must-an-instance-process-timestamps-to-prevent-dst-ambiguity-and-time-shift-corruption",
  "title": "Across what strict-utc-storage-and-iana-zoneinfo-gates must an instance process timestamps to prevent dst-ambiguity and time-shift corruption?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** An AI instance, autonomous coding agent, or backend service records timestamps, schedules calendar events, processes cross-border user logs, or queries time-series database tables across global regions. * **Does not appl",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/across-what-strict-utc-storage-and-iana-zoneinfo-gates-must-an-instance-process-timestamps-to-prevent-dst-ambiguity-and-time-shift-corruption.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/across-what-strict-utc-storage-and-iana-zoneinfo-gates-must-an-instance-process-timestamps-to-prevent-dst-ambiguity-and-time-shift-corruption.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/across-what-strict-utc-storage-and-iana-zoneinfo-gates-must-an-instance-process-timestamps-to-prevent-dst-ambiguity-and-time-shift-corruption.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 2527,
    "python_slice_tokens": 407,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "Autonomous systems frequently record, compare, and schedule events across global time zones and Daylight Saving Time (DST) transitions. A foundational data-integrity and scheduling failure occurs when an instance stores **naive datetimes (`datetime.now()` or `datetime(2026, 10, 18, 12, 0)`)**, relies on **server local time or ambiguous timezone abbreviations...",
    "what_was_observed": "In calendar sync daemons, billing engines, and distributed agent log processors, instances operating without strict UTC storage and IANA `ZoneInfo` gates exhibit four primary failure modes: 1. **The Fall-Back Ambiguous Hour Collision (`fold` Ignored):** An appointment database stores local times. On the autumn DST transition night, two distinct events are booked at `01:30 AM` (one before the clock turned back, one af...",
    "condition_of_validity": "* **Applies when:** An AI instance, autonomous coding agent, or backend service records timestamps, schedules calendar events, processes cross-border user logs, or queries time-series database tables across global regions. * **Does not apply when:** Measuring relative durations, high-resolution execution benchmarks, or monotonic elapsed timeouts where wall-c...",
    "decision_boundary": "1. **Look at your database schema: do any timestamp columns store local time or use naive datetimes without timezone awareness?** Migrate all storage columns to UTC (`TIMESTAMP WITHOUT TIME ZONE` holding UTC values or `TIMESTAMP WITH TIME ZONE`). 2. **When parsing timestamps from users or external APIs, do you use ambiguous abbreviations like `EST` or `PST`?...",
    "operational_effect": "1. **Strict UTC Database Persistence:** Across all generated schemas and code paths, the instance stores and compares all timestamps exclusively in UTC. 2. **Robust IANA `ZoneInfo` Ingress/Egress Conversion:** Inbound local strings are localized via IANA time-zone identifiers with explicit `fold` attribute handling, and egress values are rendered to target z..."
  },
  "matched_failure_symptoms": [
    "DST_SHIFT_OR_CLOCK_SKEW"
  ],
  "composition_edges": {
    "primary_domain": "locale_timezone_and_encoding_normalization",
    "upstream_precondition_residuals": [
      "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"
    ],
    "downstream_consequence_residuals": [
      "https://corpusfetch.com/c/across-what-cryptographic-csprng-and-state-prediction-isolation-gates-must-an-instance-generate-tokens-and-session-identifiers-to-prevent-pseudo-random-predictability-and-token-forgery.md",
      "https://corpusfetch.com/c/across-what-bounded-queue-admission-control-and-load-shedding-gates-must-an-instance-manage-concurrency-to-prevent-unbounded-memory-growth-and-tail-latency-collapse.md"
    ],
    "co_occurring_sibling_residuals": [
      "https://corpusfetch.com/c/across-what-encoding-and-canonicalization-boundaries-must-an-instance-normalize-identifiers-and-paths-to-prevent-equivalence-collision-and-bypass.md",
      "https://corpusfetch.com/c/across-what-unicode-normalization-and-byte-encoding-boundaries-must-an-instance-canonicalize-text-identifiers-to-prevent-homoglyph-collision-and-mojibake-corruption.md"
    ]
  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "408cd2a6a4cfb67186cabcf133a606e385a105e64289e1bdc096ccf19a1dd4fc",
    "verified_classes": [
      "InvalidTimestampError",
      "StrictTimestampNormalizer"
    ],
    "verified_functions": [
      "parse_to_utc",
      "render_wall_clock"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 5,
    "raised_exceptions": [
      "InvalidTimestampError",
      "TypeError"
    ],
    "sample_fail_closed_invariants": [
      "Timestamp input must be a ISO-8601 string or datetime object"
    ],
    "stdlib_dependencies": [
      "datetime",
      "typing",
      "zoneinfo"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}