{
  "schema_version": "1.3.0",
  "slug": "how-must-an-instance-convert-advisory-backpressure-into-an-enforced-bound",
  "title": "How must an instance convert advisory backpressure into an enforced bound?",
  "date_of_record": "2026 November 2",
  "scope": "Applies to producer-consumer channels where the consumer signals backpressure (slow-down, high-watermark, nack-with-retry-hint) and the producer may continue sending because the signal is advisory rather than enforced. Does not apply to channels with enforced flow control (credit-based, window-based with window decrement).",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-must-an-instance-convert-advisory-backpressure-into-an-enforced-bound.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-must-an-instance-convert-advisory-backpressure-into-an-enforced-bound.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-must-an-instance-convert-advisory-backpressure-into-an-enforced-bound.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 946,
    "python_slice_tokens": 124,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "Backpressure is either **advisory** (the consumer asks the producer to slow down, and the producer may ignore) or **enforced** (the consumer stops accepting, and the producer blocks or drops). Advisory backpressure depends on producer cooperation; enforced backpressure does not. An instance that treats advisory backpressure as protection is assuming cooperat...",
    "what_was_observed": "**Signature.** Queue overflow on the consumer while the producer reports sending at normal rate. The consumer's backpressure signal is logged and normal. Producer has received it and has not changed behavior (either because it does not honor advisory signals or because it is a legacy producer that predates the signal). **Trace.** Consumer queue 10,000 messages. High-watermark signal at 7,000. Producer sends 5,000/s, ...",
    "condition_of_validity": "The instance must ensure at least one holds before it treats backpressure as protective: 1. **Must enforce a hard bound.** The consumer stops accepting when the queue reaches capacity, either by blocking the producer (credit) or by rejecting with a hard error that the producer cannot ignore. 2. **Must have headroom for in-flight.** `queue_capacity >= queue_h...",
    "decision_boundary": "- Enforced flow control (credit/window): protective. - Advisory with verified cooperative producer: protective in steady state; assumes cooperation. - Advisory with unverified producer: protective only if queue headroom covers max producer in-flight. - Advisory without headroom: overflow is guaranteed under sustained overload.",
    "operational_effect": "The invariant converts an advisory signal into a bounded guarantee. The instance's correct posture is to add a hard cap behind the advisory signal, and to size the queue to absorb in-flight messages. **Trap.** Increase the queue. A larger queue postpones overflow without changing the rate mismatch; it also increases memory pressure and, if the queue is durab..."
  },
  "matched_failure_symptoms": [
    "HTTP_429_BURST_STARVATION"
  ],
  "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": "2aba7758637dce51a4253d9631eba9d218efb1f8334be87024a46f9d4a97aed5",
    "verified_classes": [
      "AdvisoryOverflowError",
      "BackpressureGate"
    ],
    "verified_functions": [
      "dispatch_backpressure_mode",
      "verify"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 1,
    "raised_exceptions": [
      "AdvisoryOverflowError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}