APPLICATION_CONTRACTS

Application-service contracts

Status: implemented for the 0.3.0 release candidate. These contracts are the framework-independent boundary shared by the current terminal adapters and the future FastAPI/Electron adapters. ARCHITECTURE.md owns the repository-wide dependency graph and current-versus-target status.

Public boundary

The public boundary is intentionally small:

Module	Ownership
ancestryllm.application.dto	Strict, immutable, deterministic JSON DTOs, opaque artifact and secret capabilities, and decision/progress records.
ancestryllm.application.operations	One exact request/result pair for every DispatchKey.
ancestryllm.application.ports	Cancellation, progress, decision, identity-resolution, and quality-resolution protocols.
ancestryllm.application.errors	Complete mapping from pure domain failures to stable coded application errors and transport envelopes.
ancestryllm.domain.errors	Framework-independent failure categories and bounded safe detail values.

The private modules application._artifacts and application._compat belong to adapter composition. They are not an alternate service API.

Every boundary dataclass is frozen and slotted. BoundaryDTO.to_json() emits a versioned envelope with sorted keys, finite JSON numbers, and a one-megabyte limit. BoundaryDTO.from_json() requires the exact DTO type and rejects unknown, missing, or incorrectly typed fields. Requests and results contain no Click, prompt-toolkit, Rich, FastAPI/Pydantic, Electron, provider-SDK, database-session, callback, exception, or host-filesystem objects.

Operation inventory

OPERATION_CONTRACTS pairs each command dispatch identity with one request and one result. Import-time and test-time drift checks require exact equality with the shared command specifications:

Command	Operations
Modules	modules.list, modules.enable, modules.disable
RootsMagic	rootsmagic.list, rootsmagic.query, rootsmagic.export
GEDCOM	gedcom.merge, gedcom.subtree, gedcom.quality, gedcom.sync
Prompts	prompts.list, prompts.save, prompts.show, prompts.render
People	people.list, people.add
Providers	providers.list, providers.create, providers.consent, providers.revoke
Secrets	secrets.set, secrets.delete, secrets.status
OCR	ocr.extract
Database	database.backup, database.diagnose

This inventory is the only application-operation registry. Terminal, HTTP, and desktop adapters may translate their inputs into these requests but must not create a second UI-specific registry or redefine result semantics.

Ports and adapter responsibilities

Services depend on five narrow structural protocols:

• CancellationPort checks for cooperative cancellation at safe boundaries.
• ProgressPort emits operation/stage codes, bounded counters, sequence numbers, and optional opaque artifact IDs. It cannot carry genealogy content, SQL, credentials, host paths, or arbitrary messages.
• DecisionPort returns one declared coded option or explicit cancellation.
• IdentityResolutionPort resolves only opaque source/candidate references.
• QualityResolutionPort returns one declared coded resolution or cancellation.

The current job and cancellation objects are translated by private compatibility adapters. Future FastAPI and Electron code must implement the same protocols at their adapter boundary. A port implementation may collect user input or update presentation state; it does not acquire genealogy, provider, persistence, or publication ownership.

Artifact and secret capabilities

Host paths never cross the public application boundary. A trusted adapter registers a selected input or destination with the private artifact registry and passes an ArtifactGrantRef to a request. Each unpredictable grant is scoped to one operation and one access mode, can be revoked, and resolves to a path only inside the owning process. Results return an ArtifactRef containing an unpredictable identity, media type, artifact type, status, bounded size, and optional digest—not a path.

Output publication is staged, claimed, cancellation-checked, and atomically published through the hardened publication helpers. Cancellation before publication removes the staged artifact and preserves any previous destination. Publication failures map to a sanitized code; partial external outputs and raw exception details are not returned.

Secrets use a separate write-only SecretGrantRef. Secret values remain in the owning adapter/secret-store boundary and never enter a request, result, error, progress event, or deterministic JSON envelope. Secret results expose presence only.

Provider and genealogy safety

ProviderSelection contains identifiers only. The explicit none provider is network-disabled even when credentials or provider SDKs are present. A cloud selection is not authorization: existing provider policy must still require a matching explicit consent grant before any disclosure or network call.

The operation DTOs expose deterministic change, conflict, quality, and provenance records. The implemented service-owned genealogy aggregate owns the rules that produce those records. Adapters only translate and render them. RootsMagic inputs remain immutable and RootsMagic/GEDCOM outputs remain loss-visible and atomically published.

Stable failure contract

DomainFailureCode is complete for the application boundary. Every member has one DOMAIN_ERROR_MAPPINGS entry defining its stable public code, sanitized message, optional remediation, and exit status. Mapping ignores raw exception text and admits only allowlisted, bounded, path-free scalar details. Unknown exceptions are caught at the owning boundary and converted to the generic internal category before transport rendering.

CLI and REPL compatibility continues to use the existing coded-error rendering. Future transports serialize the corresponding ErrorEnvelope; they must not invent transport-specific domain codes or expose tracebacks, filesystem locations, SQL, provider payloads, credentials, or genealogy content.

Contract validation

tests/modular/test_application_contracts.py proves:

• exact operation coverage and deterministic round trips for every request and result;
• immutable DTOs and forbidden dependency/type exclusion;
• framework-free imports in an isolated interpreter;
• structural port conformance and legacy cancellation mapping;
• strict JSON, finite-number, bounded-value, and path/content rejection;
• complete stable failure mapping with sanitized envelopes;
• scoped, revocable, opaque artifact grants;
• atomic publication, cancellation preservation, and absence of partial external output;
• write-only secret capability use.

The core-contract characterization suite remains the compatibility authority for shipped CLI/REPL behavior, JSON, errors, consent, network-free none, RootsMagic immutability, rooted/loss-minimal GEDCOM behavior, and existing artifact/report behavior.