/**
 * The ACP (Agent Client Protocol) wire vocabulary — ADR 0062, slice 2.
 *
 * This is the **harness-facing** half of the ACP ingestion backend: the JSON-RPC
 * method names, the protocol-version constant, and the small set of runtime
 * guards that turn the untyped JSON a harness sends over the wire into the typed
 * shapes {@link ./normalize.ts} and {@link ./client.ts} consume. Exactly like
 * `../events.ts`' `parseSessionEvent`, every guard *builds* a typed value field
 * by field and fails loudly on a malformed one — it never uses an `as`-cast to
 * fabricate a shape (AGENTS.md: the `as T` ban applies at every untyped boundary).
 *
 * The shapes mirror ACP **protocol version 1** — the version `opencode acp`
 * speaks and the one ADR 0062 §5 resolves as the preferred harness protocol.
 * Method names are verified against the canonical schema
 * (`zed-industries/agent-client-protocol`, `schema/v1/meta.json`) and confirmed
 * present in the opencode binary: `initialize`, `session/new|load|prompt|cancel`,
 * `session/update`.
 */
/** The ACP protocol version this client negotiates (integer, per the spec). */
export declare const ACP_PROTOCOL_VERSION = 1;
/** Agent-handled JSON-RPC methods (client → agent requests / notifications). */
export declare const ACP_METHOD: {
    readonly initialize: "initialize";
    readonly sessionNew: "session/new";
    readonly sessionLoad: "session/load";
    readonly sessionPrompt: "session/prompt";
    /** A notification — no response is expected. */
    readonly sessionCancel: "session/cancel";
};
/** Client-handled JSON-RPC methods (agent → client requests / notifications). */
export declare const ACP_CLIENT_METHOD: {
    /** Streamed session activity — a notification the agent pushes to the client. */
    readonly sessionUpdate: "session/update";
    /** The agent asks the client to approve a tool call. */
    readonly requestPermission: "session/request_permission";
};
/** A JSON object with unknown-typed values — the raw wire shape before guarding. */
export type JsonRecord = Record<string, unknown>;
/** Narrow an unknown value to a plain (non-array) object. */
export declare function isRecord(value: unknown): value is JsonRecord;
/**
 * The prompt-content capabilities an agent advertises (`agentCapabilities`
 * sub-object). All optional booleans, defaulting to `false` when absent.
 */
export interface AcpPromptCapabilities {
    readonly image: boolean;
    readonly audio: boolean;
    readonly embeddedContext: boolean;
}
/**
 * The subset of `agentCapabilities` this slice reads from the `initialize`
 * handshake. `loadSession` is the ADR 0062 §5 durable-resume probe; the rest is
 * retained verbatim in {@link AcpInitializeResult.rawAgentCapabilities} for
 * consumers that need more.
 */
export interface AcpAgentCapabilities {
    /** Whether the agent supports `session/load` — the durable-resume signal. */
    readonly loadSession: boolean;
    readonly promptCapabilities: AcpPromptCapabilities;
}
/** The negotiated result of an `initialize` handshake, guarded off the wire. */
export interface AcpInitializeResult {
    readonly protocolVersion: number;
    readonly agentCapabilities: AcpAgentCapabilities;
    /** The full, unmodified `agentCapabilities` object (opaque passthrough). */
    readonly rawAgentCapabilities: unknown;
}
/** Raised when an ACP wire message is not the well-formed shape its method requires. */
export declare class AcpProtocolError extends Error {
    constructor(message: string);
}
/**
 * Parse an `initialize` result. The agent MAY answer with a lower
 * `protocolVersion` than requested (down-negotiation); we surface whatever it
 * reports and let the caller decide. A missing `agentCapabilities` is treated as
 * "no capabilities" (every flag `false`) rather than an error, matching the ACP
 * schema's `x-deserialize-default-on-error` default.
 */
export declare function parseInitializeResult(value: unknown): AcpInitializeResult;
/**
 * Extract the session id from a `session/new` result (`{ sessionId }`).
 * `session/load` carries the id from the request and returns only session
 * metadata, so this guards the `session/new` case.
 */
export declare function parseSessionId(value: unknown): string;
/**
 * Flatten an ACP `ContentBlock` (or an array of them) to plain text — the only
 * projection the canonical `SessionEvent` model needs from a message/thought
 * chunk. A `text` block contributes its `text`; a `resource` block with embedded
 * text contributes that; every other block type (image/audio/resource_link)
 * contributes nothing. Returns `null` when no text could be recovered so the
 * caller can distinguish "empty text" from "no textual content at all".
 */
export declare function contentBlockText(value: unknown): string | null;