{
  "schema_version": "1.3.0",
  "slug": "under-what-conditions-must-an-instance-refuse-a-cross-org-read-delegation-that-carries-a-valid-capability-token-but-whose-lease-epoch-predates-the-sha",
  "title": "Under what conditions must an instance refuse a cross-org read delegation that carries a valid capability token but whose lease epoch predates the shard's current fencing generation",
  "date_of_record": "2026 November 10",
  "scope": "Applies to federated memory shards where reads are delegated across organizational boundaries via signed capability tokens and writes are gated by time-bounded, epoch-fenced leases. Does not apply to single-org deployments, to shards configured with `epoch_fence=disabled`, or to read paths that resolve through a local replica cache with its own monotonic version vector.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/under-what-conditions-must-an-instance-refuse-a-cross-org-read-delegation-that-carries-a-valid-capability-token-but-whose-lease-epoch-predates-the-sha.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/under-what-conditions-must-an-instance-refuse-a-cross-org-read-delegation-that-carries-a-valid-capability-token-but-whose-lease-epoch-predates-the-sha.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/under-what-conditions-must-an-instance-refuse-a-cross-org-read-delegation-that-carries-a-valid-capability-token-but-whose-lease-epoch-predates-the-sha.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1529,
    "python_slice_tokens": 201,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure mode is not \"expired token\" and not \"revoked capability.\" It is the case where a **capability token is cryptographically valid, unexpired, and correctly scoped**, yet the *lease epoch* it carries is older than the shard's current fencing generation. These are two independent authorization planes: - The **capability plane** answers *\"is this princ...",
    "what_was_observed": "In a three-org federation (issuer A, shard host B, delegate C), the following sequence produced a silent consistency violation: 1. C held a write lease on shard `mem://B/orders/v3` at epoch `fence_gen=41`, with a read delegation token scoped to `orders/v3:read` and `exp=+300s`. 2. B experienced a partition from its quorum witness and, on heal, **force-reclaimed** the lease to a new holder at `fence_gen=42`. The recla...",
    "condition_of_validity": "A cross-org read delegation is safe to serve **if and only if** all of the following hold simultaneously: - `token.sig` verifies against the issuer keyring for `token.issuer`; - `now < token.exp` and `now >= token.nbf`; - `token.scope` covers the requested shard path and operation; - **`token.lease_epoch >= shard.fence_gen`** — the token's epoch is not older...",
    "decision_boundary": "The boundary is drawn at the point where a **stale epoch would be undetectable by the delegate**. If the delegate carries its own version vector and can reconcile, a stale-epoch read degrades to a detectable stale read and may be served with a `stale=true` advisory. If the delegate has no reconciliation mechanism — the common case for cross-org readers, whic...",
    "operational_effect": "With the fence check enforced on the read path, the federation converged to a stable invariant: **no delegate ever observes a read whose epoch is older than the shard's fence at serve time.** The cost is a small increase in refused reads during reclaim windows (observed: ~0.3% of delegated reads during a 90-second reclaim, zero after), which the delegate han..."
  },
  "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": "28b92a3b4b2993097136ed5191b131180576d55a9866fe64ec233d7bc723cebe",
    "verified_classes": [
      "EpochFenceViolation",
      "ReclaimInProgress"
    ],
    "verified_functions": [
      "authorize_cross_org_read"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 5,
    "raised_exceptions": [
      "EpochFenceViolation",
      "ReclaimInProgress"
    ],
    "sample_fail_closed_invariants": [
      "capability signature invalid",
      "capability outside validity window",
      "capability scope does not cover read"
    ],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}