/**
 * A2A Handoff Observation Extension Schema (v0.14.1).
 *
 * Records observational events emitted alongside A2A v1.0 task lifecycle
 * transitions. Strictly observational: helpers do NOT verify Agent Card
 * signatures, do NOT fetch upstream events, and do NOT derive auth or trust
 * decisions. PEAC records what an external A2A v1 host or client attested.
 *
 * Extension namespace: `org.peacprotocol/a2a-handoff`.
 *
 * Type URIs (10):
 *   - org.peacprotocol/a2a-agent-card-observation
 *   - org.peacprotocol/a2a-task-submitted
 *   - org.peacprotocol/a2a-task-accepted
 *   - org.peacprotocol/a2a-task-rejected
 *   - org.peacprotocol/a2a-task-state-changed
 *   - org.peacprotocol/a2a-task-completed
 *   - org.peacprotocol/a2a-task-failed
 *   - org.peacprotocol/a2a-human-review-requested
 *   - org.peacprotocol/a2a-human-approved
 *   - org.peacprotocol/a2a-human-rejected
 *
 * Schema invariants:
 *   - `card_ref` (3 places: top-level, from_agent, to_agent) is a strict
 *     `sha256:<64 lowercase hex>` digest. Agent Cards are stable artifacts;
 *     digest references are portable across vendors.
 *   - `task_id`, `parent_task_id`, `upstream_event_ref`, `method_ref`,
 *     `observed_by_ref` are opaque references validated by `OpaqueRefSchema`
 *     (multi-prefix grammar: `ref:` `urn:` `did:` `sha256:` `peac:` `https://`).
 *   - `event` and `type` MUST agree per the 9 task-event variants.
 *   - All observation-payload schemas are `strict()` (extra keys rejected).
 *   - `validateA2AHandoff()` returns structured `{ ok: false, errors: [{code,path,message}] }`
 *     mapping common failures to stable error codes.
 */
import { z } from 'zod';
export declare const A2A_HANDOFF_EXTENSION_KEY: "org.peacprotocol/a2a-handoff";
export declare const A2A_AGENT_CARD_OBSERVATION_TYPE: "org.peacprotocol/a2a-agent-card-observation";
export declare const A2A_TASK_EVENT_TYPES: readonly ["task.submitted", "task.accepted", "task.rejected", "task.state_changed", "task.completed", "task.failed", "human.review_requested", "human.approved", "human.rejected"];
export type A2ATaskEvent = (typeof A2A_TASK_EVENT_TYPES)[number];
export declare const A2A_TASK_TYPE_URIS: Record<A2ATaskEvent, string>;
/** All 10 type URIs (Agent Card observation + 9 task-lifecycle events). */
export declare const A2A_HANDOFF_TYPE_URIS: readonly ["org.peacprotocol/a2a-agent-card-observation", ...string[]];
/** Stable error codes for `validateA2AHandoff`. */
export declare const A2A_HANDOFF_ERROR_CODES: {
    readonly observationDecisionBlocked: "a2a.observation_decision_blocked";
    readonly cardRefDigestInvalid: "a2a.card_ref_digest_invalid";
    readonly opaqueRefGrammarViolation: "a2a.opaque_ref_grammar_violation";
    readonly legacySignatureShapeBlocked: "a2a.legacy_signature_shape_blocked";
    readonly typeEventMismatch: "a2a.type_event_mismatch";
    readonly timestampInvalid: "a2a.timestamp_invalid";
    readonly unknownField: "a2a.unknown_field";
    readonly schemaRejection: "a2a.schema_rejection";
};
/** Agent Card observation payload. */
export declare const A2AAgentCardObservationSchema: z.ZodObject<{
    type: z.ZodLiteral<"org.peacprotocol/a2a-agent-card-observation">;
    card_ref: z.ZodString;
    selected_interface_url: z.ZodOptional<z.ZodString>;
    signature_observation: z.ZodObject<{
        present: z.ZodBoolean;
        caller_reported_verification: z.ZodEnum<{
            verified: "verified";
            unverified: "unverified";
            not_checked: "not_checked";
        }>;
        method_ref: z.ZodOptional<z.ZodString>;
        kid: z.ZodOptional<z.ZodString>;
        observed_by_ref: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    discovered_at: z.ZodString;
    discovery_path: z.ZodEnum<{
        "/.well-known/agent-card.json": "/.well-known/agent-card.json";
        "/.well-known/peac.json": "/.well-known/peac.json";
        "header-probe": "header-probe";
    }>;
}, z.core.$strict>;
/**
 * Nine explicit per-event schemas. Used as members of the discriminated union
 * so `type` and `event` cannot drift apart.
 */
export declare const A2A_TASK_EVENT_SCHEMAS: {
    readonly 'task.submitted': z.ZodObject<{
        type: z.ZodLiteral<string>;
        event: z.ZodLiteral<"task.submitted">;
        task_id: z.ZodString;
        parent_task_id: z.ZodOptional<z.ZodString>;
        from_agent: z.ZodObject<{
            card_ref: z.ZodString;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>;
        to_agent: z.ZodOptional<z.ZodObject<{
            card_ref: z.ZodOptional<z.ZodString>;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>>;
        state: z.ZodOptional<z.ZodString>;
        reason: z.ZodOptional<z.ZodString>;
        observed_at: z.ZodString;
        upstream_event_ref: z.ZodOptional<z.ZodString>;
        upstream_event_digest: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    readonly 'task.accepted': z.ZodObject<{
        type: z.ZodLiteral<string>;
        event: z.ZodLiteral<"task.accepted">;
        task_id: z.ZodString;
        parent_task_id: z.ZodOptional<z.ZodString>;
        from_agent: z.ZodObject<{
            card_ref: z.ZodString;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>;
        to_agent: z.ZodOptional<z.ZodObject<{
            card_ref: z.ZodOptional<z.ZodString>;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>>;
        state: z.ZodOptional<z.ZodString>;
        reason: z.ZodOptional<z.ZodString>;
        observed_at: z.ZodString;
        upstream_event_ref: z.ZodOptional<z.ZodString>;
        upstream_event_digest: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    readonly 'task.rejected': z.ZodObject<{
        type: z.ZodLiteral<string>;
        event: z.ZodLiteral<"task.rejected">;
        task_id: z.ZodString;
        parent_task_id: z.ZodOptional<z.ZodString>;
        from_agent: z.ZodObject<{
            card_ref: z.ZodString;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>;
        to_agent: z.ZodOptional<z.ZodObject<{
            card_ref: z.ZodOptional<z.ZodString>;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>>;
        state: z.ZodOptional<z.ZodString>;
        reason: z.ZodOptional<z.ZodString>;
        observed_at: z.ZodString;
        upstream_event_ref: z.ZodOptional<z.ZodString>;
        upstream_event_digest: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    readonly 'task.state_changed': z.ZodObject<{
        type: z.ZodLiteral<string>;
        event: z.ZodLiteral<"task.state_changed">;
        task_id: z.ZodString;
        parent_task_id: z.ZodOptional<z.ZodString>;
        from_agent: z.ZodObject<{
            card_ref: z.ZodString;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>;
        to_agent: z.ZodOptional<z.ZodObject<{
            card_ref: z.ZodOptional<z.ZodString>;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>>;
        state: z.ZodOptional<z.ZodString>;
        reason: z.ZodOptional<z.ZodString>;
        observed_at: z.ZodString;
        upstream_event_ref: z.ZodOptional<z.ZodString>;
        upstream_event_digest: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    readonly 'task.completed': z.ZodObject<{
        type: z.ZodLiteral<string>;
        event: z.ZodLiteral<"task.completed">;
        task_id: z.ZodString;
        parent_task_id: z.ZodOptional<z.ZodString>;
        from_agent: z.ZodObject<{
            card_ref: z.ZodString;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>;
        to_agent: z.ZodOptional<z.ZodObject<{
            card_ref: z.ZodOptional<z.ZodString>;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>>;
        state: z.ZodOptional<z.ZodString>;
        reason: z.ZodOptional<z.ZodString>;
        observed_at: z.ZodString;
        upstream_event_ref: z.ZodOptional<z.ZodString>;
        upstream_event_digest: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    readonly 'task.failed': z.ZodObject<{
        type: z.ZodLiteral<string>;
        event: z.ZodLiteral<"task.failed">;
        task_id: z.ZodString;
        parent_task_id: z.ZodOptional<z.ZodString>;
        from_agent: z.ZodObject<{
            card_ref: z.ZodString;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>;
        to_agent: z.ZodOptional<z.ZodObject<{
            card_ref: z.ZodOptional<z.ZodString>;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>>;
        state: z.ZodOptional<z.ZodString>;
        reason: z.ZodOptional<z.ZodString>;
        observed_at: z.ZodString;
        upstream_event_ref: z.ZodOptional<z.ZodString>;
        upstream_event_digest: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    readonly 'human.review_requested': z.ZodObject<{
        type: z.ZodLiteral<string>;
        event: z.ZodLiteral<"human.review_requested">;
        task_id: z.ZodString;
        parent_task_id: z.ZodOptional<z.ZodString>;
        from_agent: z.ZodObject<{
            card_ref: z.ZodString;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>;
        to_agent: z.ZodOptional<z.ZodObject<{
            card_ref: z.ZodOptional<z.ZodString>;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>>;
        state: z.ZodOptional<z.ZodString>;
        reason: z.ZodOptional<z.ZodString>;
        observed_at: z.ZodString;
        upstream_event_ref: z.ZodOptional<z.ZodString>;
        upstream_event_digest: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    readonly 'human.approved': z.ZodObject<{
        type: z.ZodLiteral<string>;
        event: z.ZodLiteral<"human.approved">;
        task_id: z.ZodString;
        parent_task_id: z.ZodOptional<z.ZodString>;
        from_agent: z.ZodObject<{
            card_ref: z.ZodString;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>;
        to_agent: z.ZodOptional<z.ZodObject<{
            card_ref: z.ZodOptional<z.ZodString>;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>>;
        state: z.ZodOptional<z.ZodString>;
        reason: z.ZodOptional<z.ZodString>;
        observed_at: z.ZodString;
        upstream_event_ref: z.ZodOptional<z.ZodString>;
        upstream_event_digest: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    readonly 'human.rejected': z.ZodObject<{
        type: z.ZodLiteral<string>;
        event: z.ZodLiteral<"human.rejected">;
        task_id: z.ZodString;
        parent_task_id: z.ZodOptional<z.ZodString>;
        from_agent: z.ZodObject<{
            card_ref: z.ZodString;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>;
        to_agent: z.ZodOptional<z.ZodObject<{
            card_ref: z.ZodOptional<z.ZodString>;
            selected_interface_url: z.ZodOptional<z.ZodString>;
        }, z.core.$strict>>;
        state: z.ZodOptional<z.ZodString>;
        reason: z.ZodOptional<z.ZodString>;
        observed_at: z.ZodString;
        upstream_event_ref: z.ZodOptional<z.ZodString>;
        upstream_event_digest: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
};
/** Aggregate task-observation schema (union over the 9 strict per-event variants). */
export declare const A2ATaskObservationSchema: z.ZodUnion<readonly [z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.submitted">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.accepted">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.rejected">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.state_changed">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.completed">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.failed">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"human.review_requested">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"human.approved">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"human.rejected">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>]>;
/**
 * A2A handoff extension payload: discriminated union over Agent Card vs the
 * 9 strict per-event task observations.
 */
export declare const A2AHandoffSchema: z.ZodDiscriminatedUnion<[z.ZodObject<{
    type: z.ZodLiteral<"org.peacprotocol/a2a-agent-card-observation">;
    card_ref: z.ZodString;
    selected_interface_url: z.ZodOptional<z.ZodString>;
    signature_observation: z.ZodObject<{
        present: z.ZodBoolean;
        caller_reported_verification: z.ZodEnum<{
            verified: "verified";
            unverified: "unverified";
            not_checked: "not_checked";
        }>;
        method_ref: z.ZodOptional<z.ZodString>;
        kid: z.ZodOptional<z.ZodString>;
        observed_by_ref: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    discovered_at: z.ZodString;
    discovery_path: z.ZodEnum<{
        "/.well-known/agent-card.json": "/.well-known/agent-card.json";
        "/.well-known/peac.json": "/.well-known/peac.json";
        "header-probe": "header-probe";
    }>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.submitted">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.accepted">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.rejected">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.state_changed">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.completed">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"task.failed">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"human.review_requested">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"human.approved">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>, z.ZodObject<{
    type: z.ZodLiteral<string>;
    event: z.ZodLiteral<"human.rejected">;
    task_id: z.ZodString;
    parent_task_id: z.ZodOptional<z.ZodString>;
    from_agent: z.ZodObject<{
        card_ref: z.ZodString;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>;
    to_agent: z.ZodOptional<z.ZodObject<{
        card_ref: z.ZodOptional<z.ZodString>;
        selected_interface_url: z.ZodOptional<z.ZodString>;
    }, z.core.$strict>>;
    state: z.ZodOptional<z.ZodString>;
    reason: z.ZodOptional<z.ZodString>;
    observed_at: z.ZodString;
    upstream_event_ref: z.ZodOptional<z.ZodString>;
    upstream_event_digest: z.ZodOptional<z.ZodString>;
}, z.core.$strict>], "type">;
export type A2AAgentCardObservation = z.infer<typeof A2AAgentCardObservationSchema>;
export type A2ATaskObservation = z.infer<typeof A2ATaskObservationSchema>;
export type A2AHandoffPayload = z.infer<typeof A2AHandoffSchema>;
export interface A2AValidationError {
    code: string;
    path?: string;
    message?: string;
}
export type A2AValidationResult = {
    ok: true;
    value: A2AHandoffPayload;
} | {
    ok: false;
    errors: A2AValidationError[];
};
/**
 * Validate an A2A handoff payload (Agent Card observation or task observation).
 *
 * Returns a structured result with stable error codes for downstream
 * conformance vector assertions. The mapping prioritizes the most specific
 * applicable code when multiple issues are present in the same payload.
 */
export declare function validateA2AHandoff(data: unknown): A2AValidationResult;
//# sourceMappingURL=a2a-handoff.d.ts.map