/**
 * Bounded-cardinality observability recorder for the `ownership: 'workflow-lease'`
 * per-workflow claim protocol described in
 * [ADR 0002 § Observability](../../../documentation/contributing/architecture-decisions/0002-multiengine-per-workflow-ownership.md#observability).
 *
 * This module is a standalone recorder, not wired into
 * `src/observability/metrics.ts`/`metrics-catalog.ts` — those files already
 * document a "keeping this as an interface" plug-point idiom for exactly this
 * situation (see `PrometheusExporter` there), and the existing `METRICS`
 * catalogue and `MetricsCollector` have no concept of a labelled series at
 * all: every entry is a flat, unlabelled name. Folding `outcome` into that
 * shape would require editing `metrics-catalog.ts` and `metrics.ts`, which is
 * out of scope for this stage (see the module-level follow-up note below).
 * Instead this module defines the same three signals as a small, injectable,
 * structurally-typed recorder that a later stage can either back the existing
 * exporter with directly, or bridge into `MetricsCollector` by fanning
 * `snapshot().attempts` out into five unlabelled counter names.
 *
 * The ADR states twice that workflow ids are never Prometheus metric labels.
 * That is enforced here at the type level, not by convention: the only value
 * {@link WorkflowClaimMetricsRecorder.recordClaimAttempt} accepts is
 * {@link WorkflowClaimAttemptOutcome}, a closed union of exactly five string
 * literals. A workflow id — an arbitrary `string` — is not a member of that
 * union, so passing one is a compile error, not a runtime cardinality bug
 * waiting to happen. See `workflow-claim-metrics.test-d.ts` for the pinned
 * proof.
 *
 * **Follow-up (not built here):** wiring this recorder's snapshot into the
 * server's `/v1/metrics` `PrometheusExporter` (`src/observability/metrics.ts`)
 * requires editing that file, which is owned by a different in-flight patch
 * for this stage. {@link WorkflowClaimMetricsRecorder} is deliberately
 * structural so that wiring can happen later without reshaping this module.
 *
 * @module core/engine/workflow-claim-metrics
 */
/**
 * The exact, closed set of outcomes {@link WorkflowClaimMetricsRecorder.recordClaimAttempt}
 * accepts. Matches `weft_workflow_claim_attempts_total`'s `outcome` label
 * value set in ADR 0002 § Observability — five fixed values, nothing else.
 */
export type WorkflowClaimAttemptOutcome = 'acquired' | 'takeover' | 'lost_race' | 'deposed' | 'backoff_skipped';
/**
 * Every {@link WorkflowClaimAttemptOutcome} value, in declaration order. The
 * single source of truth for the label's cardinality bound — both the
 * recorder's internal counter map and the Prometheus serializer iterate this
 * tuple rather than re-listing the five values.
 */
export declare const WORKFLOW_CLAIM_ATTEMPT_OUTCOMES: readonly ["acquired", "takeover", "lost_race", "deposed", "backoff_skipped"];
/** One count per {@link WorkflowClaimAttemptOutcome}, always present (zero-filled when never recorded). */
export type WorkflowClaimAttemptCounts = Readonly<Record<WorkflowClaimAttemptOutcome, number>>;
/** A point-in-time read of everything this module tracks. */
export type WorkflowClaimMetricsSnapshot = {
    /** Per-outcome attempt counts. Mirrors `weft_workflow_claim_attempts_total{outcome="..."}`. */
    attempts: WorkflowClaimAttemptCounts;
    /** Mirrors `weft_workflow_claims_active` — workflows this engine currently holds a claim for. */
    activeClaims: number;
    /** Mirrors `weft_workflow_claim_renewal_failures_total`. */
    renewalFailures: number;
};
/**
 * Structural recorder interface for the three ADR 0002 observability signals.
 * Defined as an interface — not just the concrete {@link WorkflowClaimMetricsCollector}
 * class — so a caller can satisfy it with any implementation (a bridge into
 * `MetricsCollector`, an OpenTelemetry adapter, a test double) without
 * depending on this module's storage choices.
 *
 * `recordClaimAttempt`'s parameter type is the whole point of this interface:
 * it is impossible to express "pass a workflow id here" without a type error,
 * because the parameter is {@link WorkflowClaimAttemptOutcome}, not `string`.
 */
export interface WorkflowClaimMetricsRecorder {
    /** Record one claim-attempt outcome. Increments only that outcome's series. */
    recordClaimAttempt(outcome: WorkflowClaimAttemptOutcome): void;
    /**
     * Set the absolute count of workflows this engine currently holds a claim
     * for. An absolute set (not a delta), matching the existing
     * `MetricsCollector.gauge()` idiom in `src/observability/metrics.ts`. Must
     * be a safe, non-negative integer.
     */
    setActiveClaims(count: number): void;
    /** Record one renewal-failure occurrence. */
    recordClaimRenewalFailure(): void;
}
/**
 * In-memory implementation of {@link WorkflowClaimMetricsRecorder}, one per
 * engine process — matching the ADR's "single counter/gauge per engine
 * process" cardinality note for these three signals.
 *
 * @example
 * ```ts
 * import { WorkflowClaimMetricsCollector } from './workflow-claim-metrics.ts';
 *
 * const collector = new WorkflowClaimMetricsCollector();
 * collector.recordClaimAttempt('acquired');
 * collector.setActiveClaims(1);
 * console.log(collector.snapshot().attempts.acquired); // 1
 * ```
 */
export declare class WorkflowClaimMetricsCollector implements WorkflowClaimMetricsRecorder {
    #private;
    constructor();
    recordClaimAttempt(outcome: WorkflowClaimAttemptOutcome): void;
    setActiveClaims(count: number): void;
    recordClaimRenewalFailure(): void;
    /** Return a point-in-time snapshot of all three signals. */
    snapshot(): WorkflowClaimMetricsSnapshot;
    /** Clear all collected values back to zero. */
    reset(): void;
}
/**
 * Serialize a {@link WorkflowClaimMetricsSnapshot} as Prometheus text format,
 * using the exact metric names ADR 0002 § Observability specifies. Every
 * outcome always emits a line — including zero-valued ones — so a scraper
 * sees a stable schema regardless of which outcomes have occurred yet,
 * matching the stable-schema behavior of
 * `serializeMetricsSnapshotForPrometheus` in `src/observability/metrics.ts`.
 *
 * @example
 * ```ts
 * import {
 *   WorkflowClaimMetricsCollector,
 *   serializeWorkflowClaimMetricsForPrometheus,
 * } from './workflow-claim-metrics.ts';
 *
 * const collector = new WorkflowClaimMetricsCollector();
 * collector.recordClaimAttempt('acquired');
 * const body = serializeWorkflowClaimMetricsForPrometheus(collector.snapshot());
 * console.log(body.includes('weft_workflow_claim_attempts_total{outcome="acquired"} 1'));
 * ```
 */
export declare function serializeWorkflowClaimMetricsForPrometheus(snapshot: WorkflowClaimMetricsSnapshot): string;