{"schema_version":1,"experiment_id":"eoa_inverse_innovation_exp09_archetype_breadth150_20260804","cell_id":"representation_independent_interface_contract__computer_science","arm":"BREADTH_PROBE_ONE_SHOT","candidate_id":"representation_independent_interface_contract__computer_science__P1","proposal_index":1,"version":0,"title":"Behavioral Contract for Substitutable Idempotency Registries","problem":"A service platform permits applications to replace an idempotency-key registry backed by local memory, SQL, or a distributed key-value store, but specifies only record-reading and record-writing methods. Each backend consequently chooses different behavior for concurrent claims, key reuse with a different request fingerprint, completion, failure, and expiration. Middleware that relies on backend-specific fields, lock timing, or deletion order can admit duplicate execution or reject valid retries when the backend is replaced.","actors":["Application developers using idempotency middleware","Platform team maintaining the registry interface","Teams supplying in-memory, SQL, or distributed-store implementations","Site reliability engineers operating backend migrations","Clients retrying service requests"],"observable_state":"For a given scope and idempotency key, black-box operation traces reveal whether a claim is acquired, rejected as already in progress, replayed from a completed result, rejected for a fingerprint conflict, or treated as expired; they also reveal returned result identity, error category, expiry boundary, and externally visible side effects.","consequence":"A nominally compatible backend substitution can change which caller owns a key or whether a completed operation is replayed, allowing duplicate side effects, inconsistent retry responses, or migration-specific outages.","affected_objective":"Preserve at-most-one admitted execution and deterministic retry treatment across idempotency-registry implementations without freezing their storage schemas, locking algorithms, or cleanup strategies.","intervention":"Define an opaque IdempotencyRegistry abstract data type with operations such as claim(scope,key,fingerprint,lease), complete(claim_token,result), release(claim_token,reason), and observe(scope,key). Specify its abstract states, transition laws, concurrency outcomes, fingerprint-conflict rule, expiry semantics, error taxonomy, and permitted side effects. Keep rows, lock primitives, cache entries, clocks, and garbage-collection procedures non-contractual. Admit an implementation only after it passes the same state-machine and concurrent black-box conformance oracle within a declared clock and consistency envelope.","structural_mapping":[{"archetype_element":"abstract_component_boundary","domain_realization":"The IdempotencyRegistry is treated as one opaque stateful component between retry middleware and any persistence backend."},{"archetype_element":"observable_operation_surface","domain_realization":"Claim, complete, release, and observe operations expose categorized outcomes and claim tokens, not database records or lock handles."},{"archetype_element":"abstract_state_model","domain_realization":"Each scoped key is modeled as Absent, Active(fingerprint,token,expiry), or Completed(fingerprint,result,retention_expiry), with explicit allowed transitions."},{"archetype_element":"representation_hiding_boundary","domain_realization":"Table layouts, Redis commands, mutexes, indexes, serialization, cleanup jobs, and cache topology remain private to each adapter."},{"archetype_element":"representation_invariant","domain_realization":"At most one unexpired active claim token exists for a scoped key, and only its holder can complete or release that claim."},{"archetype_element":"conformance_oracle","domain_realization":"A black-box state-machine harness compares sequential and concurrent operation histories with the contract's allowed outcomes."},{"archetype_element":"substitutability_acceptance_rule","domain_realization":"A backend is substitutable only if it passes the oracle under its declared consistency, clock-resolution, capacity, and failure envelope."},{"archetype_element":"observable_leakage_watchlist","domain_realization":"Tests watch for dependencies on record IDs, error strings, scan order, exact cleanup timing, lock duration, and backend-specific metadata."},{"archetype_element":"versioned_contract_record","domain_realization":"Changes to transitions, outcomes, retention semantics, or side-effect limits require a contract version and migration review."}],"mechanism_mapping":[{"mechanism_slug":"abstract_data_type_specification","role":"Defines registry meaning through operations, abstract states, transition laws, and invariants rather than persistence procedures.","counterfactual_removal":"Without the abstract specification, adapters can share method names while assigning different meanings to claims, completion, and expiry."},{"mechanism_slug":"property_based_conformance_test","role":"Generates operation sequences, including retries, fingerprint conflicts, expiry boundaries, and invalid-token actions, and checks them against the state model.","counterfactual_removal":"Without generated sequence testing, uncommon state transitions can diverge while ordinary examples still pass."},{"mechanism_slug":"black_box_contract_test_suite","role":"Applies identical observable tests to every adapter without inspecting its schema or locking implementation.","counterfactual_removal":"Without a shared black-box oracle, acceptance depends on implementation-owner assertions or backend-specific tests and does not establish substitutability."},{"mechanism_slug":"representation_leakage_probe","role":"Detects client or test reliance on private record fields, ordering, error wording, and cleanup timing.","counterfactual_removal":"Without leakage probes, accidental observables can harden into dependencies that defeat later backend replacement."},{"mechanism_slug":"substitutability_trial_or_canary","role":"Exercises a candidate adapter on isolated mirrored traces before it is eligible for production selection.","counterfactual_removal":"Without a bounded trial, conformance under modeled traces may miss differences induced by the deployment envelope."}],"causal_chain":["A storage-shaped interface leaves concurrency, expiry, conflict, and completion semantics unspecified.","Backend adapters fill those gaps differently, while middleware learns accidental details from the current adapter.","A representation-independent state machine makes the permitted observable behavior and invariants explicit.","Opaque claim tokens and a leakage audit prevent clients from depending on storage representation or locking artifacts.","A shared property-based black-box oracle rejects adapters whose operation histories violate the abstract model.","Adapters that pass within the declared context envelope can be trialed without granting equivalence outside that envelope.","Backend replacement can then preserve the specified retry behavior while allowing independent changes to storage and synchronization internals."],"baseline":"A CRUD-style plugin interface exposes get, put, and delete over idempotency records, with example-driven tests for the default backend. Concurrency resolution, fingerprint conflicts, clock boundaries, failure recovery, retention, and error categories are left to adapter convention, and migration review compares schemas rather than observable histories.","nearest_rivals":["Mandating one canonical SQL schema and transaction recipe, which aligns implementations by freezing representation rather than defining an opaque behavioral surface.","Providing a generic storage repository interface, which decouples calls but does not specify the idempotency state machine or substitutability laws.","Running backend-specific integration tests, which may validate each implementation's intended behavior without proving a common contract.","Standardizing only the middleware's external HTTP idempotency response, which does not govern the internal registry transitions that determine duplicate admission."],"remaining_contrastive_claim":"The candidate's distinctive claim is that safe registry replacement depends on a representation-independent, sequence-level contract for claim ownership, completion, conflicts, and expiry, enforced by one black-box oracle; shared CRUD signatures, schemas, or isolated adapter tests do not by themselves establish that relation.","authority_safety":{"decision_authority":"The platform interface steward may define an experimental contract version, build its oracle, and approve adapters for isolated conformance testing; application owners retain authority over production adoption and migration.","authorized_first_step":"Model the abstract states and run a non-production conformance harness against test instances using synthetic keys and inert result payloads.","excluded_actions":["Changing production idempotency semantics","Migrating or deleting production registry records","Mirroring sensitive request bodies or credentials","Enabling a candidate adapter for live write admission","Claiming an adapter is substitutable outside its tested context envelope"],"halt_rollback":"Stop the trial on any duplicate admitted owner, unauthorized completion, unexplained outcome mismatch, or test spillover. Disable the experimental adapter, discard only its isolated synthetic data, and retain the existing production adapter and contract version unchanged."},"negative_tests":{"strongest_counterevidence":"Observed backend replacements already preserve all sequential and concurrent operation histories despite the sparse interface, and no clients or tests depend on backend representation across a representative set of migrations.","problem_falsifier":"Trace comparison shows that the supposedly interchangeable registries are never actually substituted, or that they serve intentionally different retry semantics explicitly selected by callers rather than one shared abstraction.","intervention_falsifier":"Two implementations pass the proposed oracle and declared envelope yet produce contract-relevant differences during an isolated mirrored-trace canary, showing that the state model or oracle is insufficient for substitution.","risks":["An incomplete abstract state model could certify adapters that differ on unmodeled crash or partition histories.","Over-specifying timing, consistency, or retention could freeze useful implementation choices.","A reference implementation could become an accidental specification despite contradictory written laws.","Concurrency tests may be nondeterministic or fail to explore decisive interleavings.","Opaque claim tokens and normalized errors can reduce diagnostic detail unless a separately governed introspection path exists.","Canary mirroring could leak request-derived data or create side effects if synthetic inputs and inert sinks are not enforced."]},"next_evidence_step":"In an isolated test environment, write a minimal executable state model and generate at most 200 traces of no more than 20 operations each, including paired concurrent claims, conflicting fingerprints, completion, stale-token actions, and expiry boundaries. Run the identical traces against two available test adapters or, if only one exists, against that adapter and a deliberately simple model adapter. Record outcome and invariant mismatches without changing either implementation; proceed only to refine the contract or reject the intervention based on those bounded results.","prior_art_status":"UNSEARCHED","diversity_from_prior_proposals":"No other experiment candidates or proposals were inspected or used; this one-shot candidate is derived solely from the supplied archetype and computer-science domain card.","revision_record":{"parent_version":null,"progress_targets_addressed":[],"conceptual_changes":[],"operational_changes":[],"evidence_changes":[],"claim_changes":[]}}