docs(#751): Publish native Kanban/SOT canon (#752)

docs/native-kanban-sot/contracts/health-state.v1.ts

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+/**
+ * Mosaic Native Kanban — frozen health/error contract v1.
+ * Publication contract only; no runtime implementation is included here.
+ *
+ * PostgreSQL is the sole writable SOT. Public health DTOs are observations,
+ * never write authority. Only an internal transaction-local proof produced by
+ * the PostgreSQL adapter may authorize a mutation.
+ */
+
+export const KANBAN_CONTRACT_VERSION = '1.0.0' as const;
+
+export const kanbanHealthStates = ['healthy', 'read-only-degraded', 'write-unavailable'] as const;
+export type KanbanHealthState = (typeof kanbanHealthStates)[number];
+
+interface KanbanHealthBaseV1 {
+  contractVersion: typeof KANBAN_CONTRACT_VERSION;
+  checkedAt: string;
+  /** Observation expires at this RFC 3339 instant; it still never authorizes writes. */
+  validUntil: string;
+  policyRevision: string;
+  reasons: string[];
+}
+
+export interface HealthyKanbanHealthResponseV1 extends KanbanHealthBaseV1 {
+  state: 'healthy';
+  readHealthProven: true;
+  writeHealthProven: true;
+}
+
+export interface ReadOnlyDegradedKanbanHealthResponseV1 extends KanbanHealthBaseV1 {
+  state: 'read-only-degraded';
+  readHealthProven: true;
+  writeHealthProven: false;
+}
+
+export interface WriteUnavailableKanbanHealthResponseV1 extends KanbanHealthBaseV1 {
+  state: 'write-unavailable';
+  readHealthProven: false;
+  writeHealthProven: false;
+}
+
+/** Public, discriminated observation. Contradictory combinations are unrepresentable. */
+export type KanbanHealthResponseV1 =
+  | HealthyKanbanHealthResponseV1
+  | ReadOnlyDegradedKanbanHealthResponseV1
+  | WriteUnavailableKanbanHealthResponseV1;
+
+/** Pure evaluation context. It cannot authorize a mutation. */
+export interface KanbanEvaluationContextV1 {
+  contractVersion: typeof KANBAN_CONTRACT_VERSION;
+  workspaceId: string;
+  correlationId: string;
+  now: string;
+  policyRevision: string;
+  observedHealth: KanbanHealthResponseV1;
+}
+
+/**
+ * Non-exported brand: public DTO deserialization cannot construct this type.
+ * The PostgreSQL adapter mints it only after a fresh write probe inside the same
+ * transaction and validates checkedAt <= now < validUntil and policy revision.
+ */
+declare const postgresWriteHealthProofBrand: unique symbol;
+export interface PostgresWriteHealthProofV1 {
+  readonly [postgresWriteHealthProofBrand]: true;
+  readonly source: 'postgres-transaction-local-write-probe';
+  readonly transactionId: string;
+  readonly checkedAt: string;
+  readonly validUntil: string;
+  readonly policyRevision: string;
+}
+
+/** Internal mutation context; MUST NOT appear in REST/MCP/CLI request DTOs. */
+export interface InternalKanbanMutationContextV1 {
+  contractVersion: typeof KANBAN_CONTRACT_VERSION;
+  workspaceId: string;
+  correlationId: string;
+  causationId?: string;
+  idempotencyKey: string;
+  now: string;
+  expectedPolicyRevision: string;
+  writeProof: PostgresWriteHealthProofV1;
+}
+
+interface MutationFailureBaseV1 {
+  contractVersion: typeof KANBAN_CONTRACT_VERSION;
+  retryable: false;
+  requestOutcome: 'not_applied';
+  idempotencyKey: string;
+  correlationId: string;
+  message: string;
+}
+
+/** KCR-016: code/state pairing is exact and cannot cross-map. */
+export interface ReadOnlyWriteHealthDenialV1 extends MutationFailureBaseV1 {
+  kind: 'deliberate_fail_closed_denial';
+  code: 'KANBAN_WRITE_HEALTH_UNPROVEN';
+  healthState: 'read-only-degraded';
+  checkedAt: string;
+}
+
+export interface WriteUnavailableDenialV1 extends MutationFailureBaseV1 {
+  kind: 'deliberate_fail_closed_denial';
+  code: 'KANBAN_WRITE_UNAVAILABLE';
+  healthState: 'write-unavailable';
+  checkedAt: string;
+}
+
+export type DeliberateWriteDenialV1 = ReadOnlyWriteHealthDenialV1 | WriteUnavailableDenialV1;
+
+export const transportErrorCodes = [
+  'GATEWAY_UNREACHABLE',
+  'GATEWAY_TIMEOUT',
+  'UPSTREAM_BAD_GATEWAY',
+] as const;
+export type TransportErrorCode = (typeof transportErrorCodes)[number];
+
+/** Client-normalized transport uncertainty; never an authoritative 503 body. */
+export interface RetryableTransportErrorV1 {
+  contractVersion: typeof KANBAN_CONTRACT_VERSION;
+  kind: 'retryable_transport_error';
+  code: TransportErrorCode;
+  retryable: true;
+  requestOutcome: 'unknown';
+  /** Retry MUST reuse this exact key. */
+  idempotencyKey: string;
+  correlationId: string;
+  message: string;
+}
+
+export interface VersionConflictV1 {
+  contractVersion: typeof KANBAN_CONTRACT_VERSION;
+  kind: 'version_conflict';
+  code: 'AGGREGATE_VERSION_CONFLICT';
+  retryable: false;
+  requestOutcome: 'not_applied';
+  aggregateType: 'project' | 'mission' | 'milestone' | 'task' | 'change_proposal';
+  aggregateId: string;
+  expectedVersion: number;
+  actualVersion: number;
+  idempotencyKey: string;
+  correlationId: string;
+  message: string;
+}
+
+export type KanbanMutationFailureV1 =
+  | DeliberateWriteDenialV1
+  | RetryableTransportErrorV1
+  | VersionConflictV1;
+
+export const kanbanHealthCapabilities: Readonly<
+  Record<KanbanHealthState, { canonicalReads: boolean; mutations: boolean }>
+> = {
+  healthy: { canonicalReads: true, mutations: true },
+  'read-only-degraded': { canonicalReads: true, mutations: false },
+  'write-unavailable': { canonicalReads: false, mutations: false },
+};
+
+/** Exact HTTP/error normalization freeze; 503, transport, and 409 cannot cross-map. */
+export const kanbanFailureHttpMapV1 = {
+  KANBAN_WRITE_HEALTH_UNPROVEN: {
+    httpStatus: 503,
+    kind: 'deliberate_fail_closed_denial',
+    requestOutcome: 'not_applied',
+    retryable: false,
+  },
+  KANBAN_WRITE_UNAVAILABLE: {
+    httpStatus: 503,
+    kind: 'deliberate_fail_closed_denial',
+    requestOutcome: 'not_applied',
+    retryable: false,
+  },
+  AGGREGATE_VERSION_CONFLICT: {
+    httpStatus: 409,
+    kind: 'version_conflict',
+    requestOutcome: 'not_applied',
+    retryable: false,
+  },
+  GATEWAY_UNREACHABLE: {
+    httpStatus: 502,
+    kind: 'retryable_transport_error',
+    requestOutcome: 'unknown',
+    retryable: true,
+  },
+  GATEWAY_TIMEOUT: {
+    httpStatus: 504,
+    kind: 'retryable_transport_error',
+    requestOutcome: 'unknown',
+    retryable: true,
+  },
+  UPSTREAM_BAD_GATEWAY: {
+    httpStatus: 502,
+    kind: 'retryable_transport_error',
+    requestOutcome: 'unknown',
+    retryable: true,
+  },
+} as const;
+
+/**
+ * Required negative contract tests:
+ * - contradictory state/proof booleans fail type/schema validation;
+ * - expired internal proof and policy mismatch deny before mutation;
+ * - Valkey-only liveness cannot mint PostgresWriteHealthProofV1;
+ * - public/caller-forged `healthy` cannot enter InternalKanbanMutationContextV1;
+ * - authoritative 503, transport 502/504/timeout, and 409 mappings are exhaustive.
+ */

docs/native-kanban-sot/contracts/mechanical-coordinator.v1.ts

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+/**
+ * Mosaic Native Kanban — frozen Mechanical Coordinator contracts v1.
+ *
+ * The pure decision engine and persistence/orchestration service are separate.
+ * Neither surface can create scope, edit acceptance, waive gates, certify,
+ * merge, release a deployment, or close a provider issue.
+ */
+
+import type {
+  DeliberateWriteDenialV1,
+  InternalKanbanMutationContextV1,
+  KanbanEvaluationContextV1,
+  KanbanMutationFailureV1,
+  RetryableTransportErrorV1,
+  VersionConflictV1,
+} from './health-state.v1.js';
+
+export const COORDINATOR_CONTRACT_VERSION = '1.0.0' as const;
+export type Uuid = string;
+export type IsoTimestamp = string;
+/** PostgreSQL bigint-safe decimal string; never a JavaScript number. */
+export type FencingTokenV1 = string;
+
+export const specialistRoles = [
+  'planning',
+  'enhance',
+  'coder',
+  'review',
+  'security-review',
+  'pr-monitor',
+  'certifier',
+] as const;
+export type SpecialistRole = (typeof specialistRoles)[number];
+
+/** One vocabulary shared with task_assignment_state_v1 in the Drizzle schema. */
+export const assignmentStates = [
+  'awaiting_approval',
+  'policy_pre_authorized',
+  'approved',
+  'rejected',
+  'leased',
+  'released',
+  'expired',
+  'superseded',
+] as const;
+export type AssignmentStateV1 = (typeof assignmentStates)[number];
+
+export const readinessStates = [
+  'dependency-gated',
+  'schedule-gated',
+  'policy-gated',
+  'lease-available',
+  'leased',
+  'retry-delayed',
+  'exhausted',
+  'quarantined',
+] as const;
+export type ReadinessState = (typeof readinessStates)[number];
+
+export interface RetryStateSnapshotV1 {
+  disposition: 'available' | 'retry_delayed' | 'quarantined' | 'exhausted';
+  attemptCount: number;
+  maxAttempts: number;
+  nextEligibleAt: IsoTimestamp | null;
+  idempotent: boolean;
+  terminalReason: string | null;
+  version: number;
+}
+
+export interface TaskEligibilitySnapshotV1 {
+  workspaceId: Uuid;
+  taskId: Uuid;
+  taskVersion: number;
+  projectId: Uuid;
+  projectActive: boolean;
+  missionId: Uuid | null;
+  missionActive: boolean;
+  status: 'ready';
+  priority: 'critical' | 'high' | 'medium' | 'low';
+  boardRank: string;
+  dueAt: IsoTimestamp | null;
+  notBeforeAt: IsoTimestamp | null;
+  createdAt: IsoTimestamp;
+  requiredRole: SpecialistRole;
+  requiredCapabilities: readonly string[];
+  blockingDependencies: readonly {
+    taskId: Uuid;
+    done: boolean;
+    completionConditionSatisfied: boolean;
+  }[];
+  releaseApproval: {
+    decisionId: Uuid;
+    approved: boolean;
+    policyRevision: string;
+  } | null;
+  activeLeaseId: Uuid | null;
+  retry: RetryStateSnapshotV1;
+}
+
+export interface AgentSessionSnapshotV1 {
+  workspaceId: Uuid;
+  agentId: Uuid;
+  sessionId: Uuid;
+  state: 'available' | 'busy';
+  roles: readonly SpecialistRole[];
+  capabilities: readonly string[];
+  capacity: number;
+  activeLeaseCount: number;
+  heartbeatAt: IsoTimestamp;
+}
+
+export interface EligibilityExplanationV1 {
+  taskId: Uuid;
+  eligible: boolean;
+  readiness: ReadinessState;
+  reasons: readonly {
+    gate:
+      | 'status'
+      | 'project'
+      | 'mission'
+      | 'dependency'
+      | 'schedule'
+      | 'retry'
+      | 'approval'
+      | 'lease'
+      | 'capability'
+      | 'capacity'
+      | 'health';
+    satisfied: boolean;
+    code: string;
+    detail: string;
+  }[];
+  policyRevision: string;
+  evaluatedAt: IsoTimestamp;
+}
+
+export interface AssignmentProposalDecisionV1 {
+  workspaceId: Uuid;
+  taskId: Uuid;
+  taskVersion: number;
+  targetAgentId: Uuid;
+  targetSessionId: Uuid;
+  specialistRole: SpecialistRole;
+  initialState: 'awaiting_approval' | 'policy_pre_authorized';
+  policyRevision: string;
+  explanation: EligibilityExplanationV1;
+  expiresAt: IsoTimestamp;
+}
+
+export interface AssignmentCycleSnapshotV1 {
+  context: KanbanEvaluationContextV1;
+  tasks: readonly TaskEligibilitySnapshotV1[];
+  sessions: readonly AgentSessionSnapshotV1[];
+  workspaceFairness: Readonly<Record<Uuid, number>>;
+  limit: number;
+}
+
+export interface AssignmentCycleDecisionV1 {
+  evaluatedTaskCount: number;
+  proposals: readonly AssignmentProposalDecisionV1[];
+  explanations: readonly EligibilityExplanationV1[];
+}
+
+export interface LeaseExpirySnapshotV1 {
+  workspaceId: Uuid;
+  taskId: Uuid;
+  taskVersion: number;
+  leaseId: Uuid;
+  assignmentId: Uuid;
+  sessionId: Uuid;
+  fencingToken: FencingTokenV1;
+  state: 'pending_ack' | 'active';
+  acknowledgeBy: IsoTimestamp;
+  expiresAt: IsoTimestamp;
+  lastHeartbeatAt: IsoTimestamp | null;
+  retry: RetryStateSnapshotV1;
+}
+
+export interface LeaseExpiryDecisionV1 {
+  leaseId: Uuid;
+  action: 'retain' | 'release' | 'retry' | 'quarantine' | 'exhaust';
+  reason: string;
+  nextEligibleAt: IsoTimestamp | null;
+}
+
+/** Pure package owned by KBN-200. It receives complete immutable snapshots. */
+export interface MechanicalCoordinatorDecisionEngineV1 {
+  evaluateAssignmentCycle(snapshot: AssignmentCycleSnapshotV1): AssignmentCycleDecisionV1;
+  explainEligibility(
+    context: KanbanEvaluationContextV1,
+    task: TaskEligibilitySnapshotV1,
+    sessions: readonly AgentSessionSnapshotV1[],
+  ): EligibilityExplanationV1;
+  decideLeaseExpiry(
+    context: KanbanEvaluationContextV1,
+    lease: LeaseExpirySnapshotV1,
+  ): LeaseExpiryDecisionV1;
+}
+
+export interface PersistedAssignmentV1 {
+  assignmentId: Uuid;
+  workspaceId: Uuid;
+  taskId: Uuid;
+  taskVersion: number;
+  targetAgentId: Uuid;
+  targetSessionId: Uuid;
+  specialistRole: SpecialistRole;
+  state: AssignmentStateV1;
+  policyRevision: string;
+  proposedBy: { kind: 'user' | 'agent'; id: Uuid };
+  reason: string;
+  createdAt: IsoTimestamp;
+  expiresAt: IsoTimestamp;
+}
+
+export interface TaskLeaseV1 {
+  leaseId: Uuid;
+  workspaceId: Uuid;
+  taskId: Uuid;
+  taskVersion: number;
+  assignmentId: Uuid;
+  agentId: Uuid;
+  sessionId: Uuid;
+  state: 'pending_ack' | 'active';
+  fencingToken: FencingTokenV1;
+  attempt: number;
+  acquiredAt: IsoTimestamp;
+  acknowledgeBy: IsoTimestamp;
+  lastHeartbeatAt: IsoTimestamp | null;
+  expiresAt: IsoTimestamp;
+}
+
+interface ServiceCommandBaseV1 {
+  context: InternalKanbanMutationContextV1;
+  taskId: Uuid;
+  expectedTaskVersion: number;
+}
+
+export interface AcquireApprovedLeaseCommandV1 extends ServiceCommandBaseV1 {
+  assignmentId: Uuid;
+  approvalDecisionId: Uuid;
+  targetSessionId: Uuid;
+  leaseTtlSeconds: number;
+}
+
+export interface LeaseCommandV1 extends ServiceCommandBaseV1 {
+  leaseId: Uuid;
+  sessionId: Uuid;
+  fencingToken: FencingTokenV1;
+}
+
+export interface HeartbeatLeaseCommandV1 extends LeaseCommandV1 {
+  extendSeconds: number;
+}
+
+export interface CheckpointCommandV1 extends LeaseCommandV1 {
+  sequence: number;
+  resumableSummary: string;
+  artifactIds: readonly Uuid[];
+  contextUsagePercent: number;
+}
+
+export interface SubmitForReviewCommandV1 extends LeaseCommandV1 {
+  artifactIds: readonly Uuid[];
+  summary: string;
+}
+
+export interface ReleaseLeaseCommandV1 extends LeaseCommandV1 {
+  reason:
+    | 'worker_requested'
+    | 'ack_timeout'
+    | 'heartbeat_timeout'
+    | 'task_submitted'
+    | 'policy_revoked'
+    | 'shutdown';
+}
+
+export interface AssignmentCycleCommandV1 {
+  context: InternalKanbanMutationContextV1;
+  limit: number;
+}
+
+export interface ExpirySweepCommandV1 {
+  context: InternalKanbanMutationContextV1;
+  limit: number;
+}
+
+export interface RecoverCoordinatorCommandV1 {
+  context: InternalKanbanMutationContextV1;
+}
+
+interface CoordinatorRejectionBaseV1 {
+  kind: 'coordinator_rejection';
+  retryable: false;
+  requestOutcome: 'not_applied';
+  correlationId: Uuid;
+  idempotencyKey: string;
+  message: string;
+}
+
+export type CoordinatorPolicyRejectionV1 =
+  | (CoordinatorRejectionBaseV1 & { code: 'WORKSPACE_MISMATCH' })
+  | (CoordinatorRejectionBaseV1 & {
+      code: 'TASK_NOT_ELIGIBLE';
+      explanation: EligibilityExplanationV1;
+    })
+  | (CoordinatorRejectionBaseV1 & { code: 'APPROVAL_REQUIRED' })
+  | (CoordinatorRejectionBaseV1 & { code: 'APPROVAL_STALE' })
+  | (CoordinatorRejectionBaseV1 & { code: 'ASSIGNMENT_STALE' })
+  | (CoordinatorRejectionBaseV1 & { code: 'ASSIGNMENT_TARGET_MISMATCH' })
+  | (CoordinatorRejectionBaseV1 & { code: 'POLICY_REVISION_MISMATCH' })
+  | (CoordinatorRejectionBaseV1 & { code: 'ARTIFACT_WORKSPACE_MISMATCH' })
+  | (CoordinatorRejectionBaseV1 & { code: 'LEASE_ALREADY_ACTIVE' })
+  | (CoordinatorRejectionBaseV1 & { code: 'LEASE_NOT_FOUND' })
+  | (CoordinatorRejectionBaseV1 & { code: 'LEASE_NOT_ACTIVE' })
+  | (CoordinatorRejectionBaseV1 & {
+      code: 'ACK_DEADLINE_EXPIRED';
+      expiredAt: IsoTimestamp;
+    })
+  | (CoordinatorRejectionBaseV1 & {
+      code: 'FENCING_TOKEN_STALE';
+      currentFencingToken: FencingTokenV1;
+    })
+  | (CoordinatorRejectionBaseV1 & { code: 'SESSION_MISMATCH' })
+  | (CoordinatorRejectionBaseV1 & {
+      code: 'HEARTBEAT_EXPIRED';
+      expiredAt: IsoTimestamp;
+    })
+  | (CoordinatorRejectionBaseV1 & {
+      code: 'CHECKPOINT_SEQUENCE_CONFLICT';
+      currentSequence: number;
+    })
+  | (CoordinatorRejectionBaseV1 & { code: 'RETRY_EXHAUSTED' })
+  | (CoordinatorRejectionBaseV1 & {
+      code: 'NON_IDEMPOTENT_RETRY_REQUIRES_ORCHESTRATOR';
+    });
+
+/** Explicit mapping to the Gateway mutation failure union; no arbitrary booleans. */
+export type CoordinatorFailureV1 =
+  | DeliberateWriteDenialV1
+  | VersionConflictV1
+  | RetryableTransportErrorV1
+  | CoordinatorPolicyRejectionV1;
+
+export interface CoordinatorSuccessV1<T> {
+  ok: true;
+  value: T;
+  correlationId: Uuid;
+}
+export interface CoordinatorFailureResultV1 {
+  ok: false;
+  failure: CoordinatorFailureV1;
+}
+export type CoordinatorResultV1<T> = CoordinatorSuccessV1<T> | CoordinatorFailureResultV1;
+
+export interface ExpirySweepResultV1 {
+  examined: number;
+  released: readonly Uuid[];
+  retryScheduled: readonly Uuid[];
+  quarantined: readonly Uuid[];
+  exhausted: readonly Uuid[];
+}
+
+export interface RestartRecoveryResultV1 {
+  activeLeaseIds: readonly Uuid[];
+  expiredLeaseIds: readonly Uuid[];
+  pendingAssignmentIds: readonly Uuid[];
+  pendingOutboxEventIds: readonly Uuid[];
+}
+
+/** Persistence/Gateway adapter owned by KBN-210. */
+export interface MechanicalCoordinatorServicePortV1 {
+  /** Loads immutable snapshots, invokes pure engine, and persists proposals atomically. */
+  runAssignmentCycle(
+    command: AssignmentCycleCommandV1,
+  ): Promise<CoordinatorResultV1<{ assignments: readonly PersistedAssignmentV1[] }>>;
+
+  /** Query path loads by ID; public health observation cannot authorize mutation. */
+  getEligibilityExplanation(
+    context: KanbanEvaluationContextV1,
+    taskId: Uuid,
+  ): Promise<CoordinatorResultV1<EligibilityExplanationV1>>;
+
+  /**
+   * Accepts IDs only. Implementation reloads and locks assignment + approval +
+   * task + target session in PostgreSQL, then verifies workspace, task version,
+   * target agent/session, state, expiry, policy revision, and current approval.
+   */
+  acquireApprovedLease(
+    command: AcquireApprovedLeaseCommandV1,
+  ): Promise<CoordinatorResultV1<TaskLeaseV1>>;
+
+  acknowledgeLease(command: LeaseCommandV1): Promise<CoordinatorResultV1<TaskLeaseV1>>;
+  heartbeatLease(command: HeartbeatLeaseCommandV1): Promise<CoordinatorResultV1<TaskLeaseV1>>;
+  appendCheckpoint(
+    command: CheckpointCommandV1,
+  ): Promise<CoordinatorResultV1<{ checkpointId: Uuid }>>;
+  submitForReview(
+    command: SubmitForReviewCommandV1,
+  ): Promise<CoordinatorResultV1<{ taskVersion: number; status: 'in_review' }>>;
+  releaseLease(command: ReleaseLeaseCommandV1): Promise<CoordinatorResultV1<{ released: true }>>;
+  expireAndRecover(
+    command: ExpirySweepCommandV1,
+  ): Promise<CoordinatorResultV1<ExpirySweepResultV1>>;
+  recoverFromPostgres(
+    command: RecoverCoordinatorCommandV1,
+  ): Promise<CoordinatorResultV1<RestartRecoveryResultV1>>;
+}
+
+/** Compile-time mapping guarantee: Coordinator Gateway failures are Kanban failures or exact policy rejections. */
+export function isKanbanMutationFailureV1(
+  failure: CoordinatorFailureV1,
+): failure is KanbanMutationFailureV1 {
+  return (
+    failure.kind === 'deliberate_fail_closed_denial' ||
+    failure.kind === 'retryable_transport_error' ||
+    failure.kind === 'version_conflict'
+  );
+}

docs/native-kanban-sot/contracts/recovery-posture.v1.ts

@@ -0,0 +1,369 @@
+/**
+ * Mosaic Native Kanban — frozen recovery-posture contract v1.
+ * Recovery posture is configurable; SOT, write-health, Coordinator authority,
+ * and gate semantics are not fields and cannot be overridden.
+ */
+
+export const RECOVERY_POSTURE_CONTRACT_VERSION = '1.0.0' as const;
+export const recoveryTiers = ['lite', 'standard', 'high-assurance'] as const;
+export type RecoveryTier = (typeof recoveryTiers)[number];
+
+export interface OffClusterStorageV1 {
+  required: true;
+  encrypted: true;
+  separateFailureDomain: true;
+  minimumCopies: number;
+  storageClass: 'encrypted-object-storage' | 'encrypted-backup-target';
+}
+
+export interface RecoveryPostureV1 {
+  contractVersion: typeof RECOVERY_POSTURE_CONTRACT_VERSION;
+  tier: RecoveryTier;
+  targetRpoMinutes: number;
+  targetRtoMinutes: number;
+  baseBackupIntervalHours: number;
+  /** null means WAL archival/PITR is disabled. */
+  walArchiveIntervalMinutes: number | null;
+  /** 0 means PITR is disabled. */
+  pitrRetentionDays: number;
+  restoreTestIntervalDays: number;
+  breakGlassDrillIntervalDays: number;
+  offClusterStorage: OffClusterStorageV1;
+}
+
+export const recoveryPostureDefaults: Readonly<Record<RecoveryTier, RecoveryPostureV1>> = {
+  lite: {
+    contractVersion: RECOVERY_POSTURE_CONTRACT_VERSION,
+    tier: 'lite',
+    targetRpoMinutes: 24 * 60,
+    targetRtoMinutes: 24 * 60,
+    baseBackupIntervalHours: 24,
+    walArchiveIntervalMinutes: null,
+    pitrRetentionDays: 0,
+    restoreTestIntervalDays: 90,
+    breakGlassDrillIntervalDays: 365,
+    offClusterStorage: {
+      required: true,
+      encrypted: true,
+      separateFailureDomain: true,
+      minimumCopies: 1,
+      storageClass: 'encrypted-backup-target',
+    },
+  },
+  standard: {
+    contractVersion: RECOVERY_POSTURE_CONTRACT_VERSION,
+    tier: 'standard',
+    targetRpoMinutes: 60,
+    targetRtoMinutes: 8 * 60,
+    baseBackupIntervalHours: 24,
+    walArchiveIntervalMinutes: 15,
+    pitrRetentionDays: 14,
+    restoreTestIntervalDays: 90,
+    breakGlassDrillIntervalDays: 180,
+    offClusterStorage: {
+      required: true,
+      encrypted: true,
+      separateFailureDomain: true,
+      minimumCopies: 1,
+      storageClass: 'encrypted-object-storage',
+    },
+  },
+  'high-assurance': {
+    contractVersion: RECOVERY_POSTURE_CONTRACT_VERSION,
+    tier: 'high-assurance',
+    targetRpoMinutes: 15,
+    targetRtoMinutes: 4 * 60,
+    baseBackupIntervalHours: 24,
+    walArchiveIntervalMinutes: 5,
+    pitrRetentionDays: 35,
+    restoreTestIntervalDays: 30,
+    breakGlassDrillIntervalDays: 90,
+    offClusterStorage: {
+      required: true,
+      encrypted: true,
+      separateFailureDomain: true,
+      minimumCopies: 1,
+      storageClass: 'encrypted-object-storage',
+    },
+  },
+};
+
+/** Shape schema. Normative cross-field semantics are enforced by validateRecoveryPostureV1. */
+export const recoveryPostureJsonSchemaV1 = {
+  $id: 'https://mosaicstack.dev/contracts/recovery-posture.v1.schema.json',
+  $schema: 'https://json-schema.org/draft/2020-12/schema',
+  type: 'object',
+  additionalProperties: false,
+  required: [
+    'contractVersion',
+    'tier',
+    'targetRpoMinutes',
+    'targetRtoMinutes',
+    'baseBackupIntervalHours',
+    'walArchiveIntervalMinutes',
+    'pitrRetentionDays',
+    'restoreTestIntervalDays',
+    'breakGlassDrillIntervalDays',
+    'offClusterStorage',
+  ],
+  properties: {
+    contractVersion: { const: RECOVERY_POSTURE_CONTRACT_VERSION },
+    tier: { enum: recoveryTiers },
+    targetRpoMinutes: { type: 'integer', minimum: 1 },
+    targetRtoMinutes: { type: 'integer', minimum: 1 },
+    baseBackupIntervalHours: { type: 'integer', minimum: 1 },
+    walArchiveIntervalMinutes: {
+      anyOf: [{ type: 'integer', minimum: 1 }, { type: 'null' }],
+    },
+    pitrRetentionDays: { type: 'integer', minimum: 0 },
+    restoreTestIntervalDays: { type: 'integer', minimum: 1 },
+    breakGlassDrillIntervalDays: { type: 'integer', minimum: 1 },
+    offClusterStorage: {
+      type: 'object',
+      additionalProperties: false,
+      required: ['required', 'encrypted', 'separateFailureDomain', 'minimumCopies', 'storageClass'],
+      properties: {
+        required: { const: true },
+        encrypted: { const: true },
+        separateFailureDomain: { const: true },
+        minimumCopies: { type: 'integer', minimum: 1 },
+        storageClass: {
+          enum: ['encrypted-object-storage', 'encrypted-backup-target'],
+        },
+      },
+    },
+  },
+} as const;
+
+export const recoveryValidationCodes = [
+  'INVALID_SHAPE',
+  'UNKNOWN_FIELD',
+  'PITR_REQUIRES_WAL',
+  'WAL_REQUIRES_PITR',
+  'RPO_BETTER_THAN_MECHANISM',
+  'OFF_CLUSTER_REQUIRED',
+  'HIGH_ASSURANCE_WEAKENED',
+] as const;
+export type RecoveryValidationCode = (typeof recoveryValidationCodes)[number];
+
+export interface RecoveryValidationIssueV1 {
+  code: RecoveryValidationCode;
+  path: string;
+  message: string;
+}
+export type RecoveryValidationResultV1 =
+  | { ok: true; value: RecoveryPostureV1 }
+  | { ok: false; issues: RecoveryValidationIssueV1[] };
+
+const topLevelFields = new Set([
+  'contractVersion',
+  'tier',
+  'targetRpoMinutes',
+  'targetRtoMinutes',
+  'baseBackupIntervalHours',
+  'walArchiveIntervalMinutes',
+  'pitrRetentionDays',
+  'restoreTestIntervalDays',
+  'breakGlassDrillIntervalDays',
+  'offClusterStorage',
+]);
+const storageFields = new Set([
+  'required',
+  'encrypted',
+  'separateFailureDomain',
+  'minimumCopies',
+  'storageClass',
+]);
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value);
+}
+function isPositiveInteger(value: unknown): value is number {
+  return Number.isInteger(value) && Number(value) > 0;
+}
+function isNonnegativeInteger(value: unknown): value is number {
+  return Number.isInteger(value) && Number(value) >= 0;
+}
+
+/**
+ * Normative parser/refinement. Deployment code MUST call this function (or a
+ * byte-for-byte behaviorally equivalent generated validator), not JSON Schema
+ * shape validation alone.
+ */
+export function validateRecoveryPostureV1(input: unknown): RecoveryValidationResultV1 {
+  const issues: RecoveryValidationIssueV1[] = [];
+  if (!isRecord(input)) {
+    return {
+      ok: false,
+      issues: [{ code: 'INVALID_SHAPE', path: '$', message: 'posture must be an object' }],
+    };
+  }
+
+  for (const key of Object.keys(input)) {
+    if (!topLevelFields.has(key)) {
+      issues.push({ code: 'UNKNOWN_FIELD', path: `$.${key}`, message: 'unknown field' });
+    }
+  }
+
+  const tier = input['tier'];
+  const storage = input['offClusterStorage'];
+  const integerFields = [
+    'targetRpoMinutes',
+    'targetRtoMinutes',
+    'baseBackupIntervalHours',
+    'restoreTestIntervalDays',
+    'breakGlassDrillIntervalDays',
+  ] as const;
+
+  if (input['contractVersion'] !== RECOVERY_POSTURE_CONTRACT_VERSION) {
+    issues.push({
+      code: 'INVALID_SHAPE',
+      path: '$.contractVersion',
+      message: `must equal ${RECOVERY_POSTURE_CONTRACT_VERSION}`,
+    });
+  }
+  if (!recoveryTiers.includes(tier as RecoveryTier)) {
+    issues.push({ code: 'INVALID_SHAPE', path: '$.tier', message: 'unknown recovery tier' });
+  }
+  for (const field of integerFields) {
+    if (!isPositiveInteger(input[field])) {
+      issues.push({
+        code: 'INVALID_SHAPE',
+        path: `$.${field}`,
+        message: 'must be a positive integer',
+      });
+    }
+  }
+  if (!isNonnegativeInteger(input['pitrRetentionDays'])) {
+    issues.push({
+      code: 'INVALID_SHAPE',
+      path: '$.pitrRetentionDays',
+      message: 'must be a nonnegative integer',
+    });
+  }
+  if (
+    input['walArchiveIntervalMinutes'] !== null &&
+    !isPositiveInteger(input['walArchiveIntervalMinutes'])
+  ) {
+    issues.push({
+      code: 'INVALID_SHAPE',
+      path: '$.walArchiveIntervalMinutes',
+      message: 'must be null or a positive integer',
+    });
+  }
+
+  if (!isRecord(storage)) {
+    issues.push({
+      code: 'INVALID_SHAPE',
+      path: '$.offClusterStorage',
+      message: 'must be an object',
+    });
+  } else {
+    for (const key of Object.keys(storage)) {
+      if (!storageFields.has(key)) {
+        issues.push({
+          code: 'UNKNOWN_FIELD',
+          path: `$.offClusterStorage.${key}`,
+          message: 'unknown field',
+        });
+      }
+    }
+    if (
+      storage['required'] !== true ||
+      storage['encrypted'] !== true ||
+      storage['separateFailureDomain'] !== true
+    ) {
+      issues.push({
+        code: 'OFF_CLUSTER_REQUIRED',
+        path: '$.offClusterStorage',
+        message: 'storage must be required, encrypted, and in a separate failure domain',
+      });
+    }
+    if (!isPositiveInteger(storage['minimumCopies'])) {
+      issues.push({
+        code: 'INVALID_SHAPE',
+        path: '$.offClusterStorage.minimumCopies',
+        message: 'must be a positive integer',
+      });
+    }
+    if (
+      storage['storageClass'] !== 'encrypted-object-storage' &&
+      storage['storageClass'] !== 'encrypted-backup-target'
+    ) {
+      issues.push({
+        code: 'INVALID_SHAPE',
+        path: '$.offClusterStorage.storageClass',
+        message: 'unsupported storage class',
+      });
+    }
+  }
+
+  const wal = input['walArchiveIntervalMinutes'];
+  const pitr = input['pitrRetentionDays'];
+  if (pitr !== 0 && wal === null) {
+    issues.push({
+      code: 'PITR_REQUIRES_WAL',
+      path: '$.pitrRetentionDays',
+      message: 'PITR retention requires WAL archival',
+    });
+  }
+  if (wal !== null && pitr === 0) {
+    issues.push({
+      code: 'WAL_REQUIRES_PITR',
+      path: '$.walArchiveIntervalMinutes',
+      message: 'WAL archival requires positive PITR retention',
+    });
+  }
+
+  if (
+    isPositiveInteger(input['targetRpoMinutes']) &&
+    isPositiveInteger(input['baseBackupIntervalHours']) &&
+    (wal === null || isPositiveInteger(wal))
+  ) {
+    const mechanismMinutes = wal === null ? input['baseBackupIntervalHours'] * 60 : wal;
+    if (mechanismMinutes > input['targetRpoMinutes']) {
+      issues.push({
+        code: 'RPO_BETTER_THAN_MECHANISM',
+        path: '$.targetRpoMinutes',
+        message: `configured mechanism can only support ${mechanismMinutes} minutes`,
+      });
+    }
+  }
+
+  if (tier === 'high-assurance') {
+    const weakened =
+      !isPositiveInteger(input['targetRpoMinutes']) ||
+      input['targetRpoMinutes'] > 15 ||
+      !isPositiveInteger(input['targetRtoMinutes']) ||
+      input['targetRtoMinutes'] > 4 * 60 ||
+      !isPositiveInteger(input['baseBackupIntervalHours']) ||
+      input['baseBackupIntervalHours'] > 24 ||
+      !isPositiveInteger(wal) ||
+      wal > 5 ||
+      !isNonnegativeInteger(pitr) ||
+      pitr < 35 ||
+      !isPositiveInteger(input['restoreTestIntervalDays']) ||
+      input['restoreTestIntervalDays'] > 30 ||
+      !isPositiveInteger(input['breakGlassDrillIntervalDays']) ||
+      input['breakGlassDrillIntervalDays'] > 90;
+    if (weakened) {
+      issues.push({
+        code: 'HIGH_ASSURANCE_WEAKENED',
+        path: '$',
+        message: 'high-assurance posture may be strengthened but not weakened',
+      });
+    }
+  }
+
+  if (issues.length > 0) return { ok: false, issues };
+  return { ok: true, value: input as unknown as RecoveryPostureV1 };
+}
+
+export interface RecoveryPostureOverrideAuditV1 {
+  actorId: string;
+  reason: string;
+  effectiveAt: string;
+  policyRevision: string;
+  previous: RecoveryPostureV1;
+  next: RecoveryPostureV1;
+}