@sellable/install/lib/sellable-agent/fly-capabilities-bridge-exec.mjs

One-command installer for Sellable MCP in Claude Code, Codex, and Hermes

#!/usr/bin/env node

import { resolve } from "node:path";
import { fileURLToPath } from "node:url";

import {
  CAPABILITIES_REQUEST_MAX_BYTES,
  FlyCapabilitiesBridgeError,
  executeExternalCapabilitiesBridgeOperation,
} from "./fly-capabilities-bridge.mjs";

export const FLY_CAPABILITIES_EXEC_ARGUMENT_MAX_BYTES = 96 * 1024;
export const FLY_CAPABILITIES_EXEC_ARGUMENT_MAX_COUNT = 2;

const BASE64URL_CHUNK = /^[A-Za-z0-9_-]+$/;
const ENCODED_MAX_BYTES = Math.ceil(CAPABILITIES_REQUEST_MAX_BYTES / 3) * 4;

export function decodeFlyCapabilitiesExecArguments(args) {
  if (!Array.isArray(args) || args.length === 0)
    throw new FlyCapabilitiesBridgeError("capabilities_request_rejected");
  if (args.length > FLY_CAPABILITIES_EXEC_ARGUMENT_MAX_COUNT)
    throw new FlyCapabilitiesBridgeError("capabilities_request_too_large");
  let encoded = "";
  for (const chunk of args) {
    if (typeof chunk !== "string" || !BASE64URL_CHUNK.test(chunk))
      throw new FlyCapabilitiesBridgeError("capabilities_request_rejected");
    if (
      Buffer.byteLength(chunk, "utf8") >
      FLY_CAPABILITIES_EXEC_ARGUMENT_MAX_BYTES
    )
      throw new FlyCapabilitiesBridgeError("capabilities_request_too_large");
    encoded += chunk;
    if (encoded.length > ENCODED_MAX_BYTES)
      throw new FlyCapabilitiesBridgeError("capabilities_request_too_large");
  }
  let bytes;
  try {
    bytes = Buffer.from(encoded, "base64url");
  } catch {
    throw new FlyCapabilitiesBridgeError("capabilities_request_rejected");
  }
  if (
    bytes.toString("base64url") !== encoded ||
    bytes.byteLength > CAPABILITIES_REQUEST_MAX_BYTES
  )
    throw new FlyCapabilitiesBridgeError("capabilities_request_rejected");
  try {
    return JSON.parse(new TextDecoder("utf-8", { fatal: true }).decode(bytes));
  } catch {
    throw new FlyCapabilitiesBridgeError("capabilities_request_rejected");
  }
}

export async function runFlyCapabilitiesBridgeExecCli() {
  try {
    const request = decodeFlyCapabilitiesExecArguments(process.argv.slice(2));
    const result = executeExternalCapabilitiesBridgeOperation(request);
    process.stdout.write(`${JSON.stringify(result)}\n`);
    process.exitCode = result.ok ? 0 : 2;
  } catch (error) {
    process.stdout.write(
      `${JSON.stringify({
        ok: false,
        code:
          error instanceof FlyCapabilitiesBridgeError
            ? error.code
            : "capabilities_bridge_failed",
      })}\n`
    );
    process.exitCode = 2;
  }
}

if (
  resolve(process.argv[1] ?? "") === resolve(fileURLToPath(import.meta.url))
) {
  await runFlyCapabilitiesBridgeExecCli();
}