import type { AgentEvent, AgentExecuteParams, AgentRuntime } from "./types.js";
/**
 * Abstract base class encapsulating shared subprocess machinery for CLI-based agent runtimes.
 *
 * Concrete runtimes (Claude, Gemini, Codex, OpenCode) extend this and implement only
 * the CLI-specific parts: argument construction, event extraction, and environment setup.
 */
export declare abstract class CLIRuntimeBase implements AgentRuntime {
    /** CLI command name (e.g., "claude", "gemini", "codex", "opencode"). */
    protected readonly command: string;
    /** Subprocess timeout in milliseconds (default: 5 minutes). */
    protected readonly timeoutMs: number;
    /** Threshold above which prompts are delivered via stdin instead of CLI argument. */
    private static readonly STDIN_PROMPT_THRESHOLD;
    /**
     * In-flight subprocess counts per CLI backend. Shared across all instances
     * of a given runtime so the gauge reflects total concurrency, not per-instance.
     */
    private static readonly inflightCounts;
    constructor(
    /** CLI command name (e.g., "claude", "gemini", "codex", "opencode"). */
    command: string, 
    /** Subprocess timeout in milliseconds (default: 5 minutes). */
    timeoutMs?: number);
    /**
     * Whether to sample subprocess RSS during in-flight execution.
     * Default `false`. Multi-process backends (Gemini/Codex/OpenCode) override
     * to `true`. Claude's per-session 1-process-per-turn model has different
     * topology, so RSS sampling is not applied there.
     */
    protected get shouldSampleRss(): boolean;
    /** RSS sampling interval in milliseconds (default 5s). */
    protected get rssSampleIntervalMs(): number;
    /**
     * Emit a single structured metric line via the debug logger.
     *
     * Format: `[agent-runtime] metric=<name> backend=<cmd> value=<n> [extra=...]`
     *
     * Intentionally line-oriented and grep-aggregatable so no metrics backend
     * is required at the call site. See `src/middleware/README.md` for the
     * full metric vocabulary.
     */
    protected emitMetric(name: string, value: number, extras?: Record<string, string | number>): void;
    /**
     * Run an MCP-config manager's `setup()` with timing instrumentation.
     * Emits the `mcp_config_setup_ms` metric on completion (success or failure).
     */
    protected timedMcpSetup(manager: {
        setup(): Promise<void>;
    } | null): Promise<void>;
    /**
     * Run an MCP-config manager's `teardown()` with timing instrumentation.
     * Emits the `mcp_config_teardown_ms` metric on completion (always — teardown
     * is invoked from `finally` blocks even on the failure path).
     */
    protected timedMcpTeardown(manager: {
        teardown(): Promise<void>;
    } | null): Promise<void>;
    /**
     * Sample resident set size of a child process via `ps -o rss= -p <pid>`.
     * Returns RSS in megabytes, or `undefined` if sampling failed (e.g., the
     * child has already exited or `ps` is unavailable on the host).
     */
    protected sampleRssMb(pid: number): Promise<number | undefined>;
    /** Construct CLI-specific command-line arguments. */
    protected abstract buildArgs(params: AgentExecuteParams): string[];
    /** Parse a single NDJSON line into an AgentEvent (or null to skip). */
    protected abstract extractEvent(line: string): AgentEvent | null;
    /** Construct provider-specific environment variables. */
    protected abstract buildEnv(params: AgentExecuteParams): Record<string, string>;
    /**
     * Compose the full prompt from structured parts (system + extra context + user).
     * Runtimes that support separate system prompt delivery (e.g. Claude) should
     * override or bypass this and handle the parts individually.
     */
    protected composePrompt(params: AgentExecuteParams): string;
    /**
     * Construct a custom stdin payload for the subprocess.
     * When this returns a string, it is written to stdin instead of
     * the default large-prompt fallback.  Subclasses may override.
     */
    protected buildStdinPayload(_params: AgentExecuteParams): string | undefined;
    /** Whether this CLI accepts prompts via stdin. Subclasses may override. */
    protected get supportsStdinPrompt(): boolean;
    /**
     * Which subprocess stream carries NDJSON output.
     * Defaults to `"stdout"`. Override to `"stderr"` for CLIs (like Claude)
     * that emit structured output on stderr.
     */
    protected get ndjsonStream(): "stdout" | "stderr";
    execute(params: AgentExecuteParams): AsyncIterable<AgentEvent>;
}