[Init] Initial commit - NetMesh terminal manager

packages/plugin-cli/package.json

@@ -0,0 +1,31 @@
+{
+  "name": "@netcatty/plugin-cli",
+  "version": "0.1.0-internal",
+  "private": true,
+  "type": "module",
+  "license": "GPL-3.0-or-later",
+  "files": ["dist"],
+  "bin": {
+    "netcatty-plugin": "./dist/cli.js"
+  },
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    }
+  },
+  "scripts": {
+    "build": "tsc -p tsconfig.build.json"
+  },
+  "dependencies": {
+    "@netcatty/plugin-contract": "0.1.0-internal",
+    "ajv": "8.18.0",
+    "ajv-formats": "3.0.1",
+    "semver": "^7.7.3",
+    "yauzl": "^3.2.0"
+  },
+  "devDependencies": {
+    "@types/semver": "^7.7.1",
+    "@types/yauzl": "^2.10.3"
+  }
+}

packages/plugin-cli/src/archive.ts

@@ -0,0 +1,796 @@
+import { createHash, randomUUID } from "node:crypto";
+import { constants, createReadStream, createWriteStream } from "node:fs";
+import {
+  chmod,
+  lstat,
+  mkdir,
+  open,
+  opendir,
+  realpath,
+  rename,
+  rm,
+  stat,
+} from "node:fs/promises";
+import path from "node:path";
+import { once } from "node:events";
+
+import type { IconReference, PluginManifest } from "@netcatty/plugin-contract";
+import yauzl, { type Entry, type ZipFile } from "yauzl";
+
+import { IGNORED_ROOT_ENTRIES, PACKAGE_LIMITS } from "./constants.js";
+import {
+  parseAndValidateManifestContents,
+  readValidatedManifestSource,
+  type ValidatedManifestSource,
+} from "./manifest.js";
+import { assertSafePackagePath, PackagePathRegistry } from "./packagePath.js";
+
+const CRC32_TABLE = new Uint32Array(256);
+const EXECUTABLE_EXTENSIONS = new Set([".bat", ".cmd", ".com", ".exe", ".ps1"]);
+for (let index = 0; index < CRC32_TABLE.length; index += 1) {
+  let value = index;
+  for (let bit = 0; bit < 8; bit += 1) {
+    value = (value & 1) === 1 ? 0xedb88320 ^ (value >>> 1) : value >>> 1;
+  }
+  CRC32_TABLE[index] = value >>> 0;
+}
+
+interface ScannedFile {
+  readonly absolutePath: string;
+  readonly packagePath: string;
+  readonly size: number;
+  readonly crc32: number;
+  readonly sha256: string;
+  readonly executable: boolean;
+}
+
+interface ScannedManifestIdentity {
+  readonly size: number;
+  readonly sha256: string;
+}
+
+export function assertManifestSnapshotMatches(
+  source: Pick<ValidatedManifestSource, "size" | "sha256">,
+  scanned: ScannedManifestIdentity | undefined,
+): void {
+  if (!scanned || scanned.size !== source.size || scanned.sha256 !== source.sha256) {
+    throw new Error("Plugin manifest changed after validation");
+  }
+}
+
+export interface PackageBuildResult {
+  readonly outputPath: string;
+  readonly fileCount: number;
+  readonly uncompressedBytes: number;
+  readonly archiveBytes: number;
+  readonly sha256: string;
+  readonly contentSha256: string;
+}
+
+export interface PackageValidationResult {
+  readonly manifest: PluginManifest;
+  readonly fileCount: number;
+  readonly uncompressedBytes: number;
+  readonly contentSha256: string;
+}
+
+export type PluginDirectoryValidationResult = PackageValidationResult;
+
+function updateCrc32(current: number, chunk: Buffer): number {
+  let crc = current;
+  for (const byte of chunk) crc = CRC32_TABLE[(crc ^ byte) & 0xff] ^ (crc >>> 8);
+  return crc >>> 0;
+}
+
+async function readRegularFile(
+  filePath: string,
+  maxBytes: number,
+  onChunk: (chunk: Buffer) => void,
+): Promise<{ size: number; mode: number }> {
+  const noFollow = "O_NOFOLLOW" in constants
+    ? constants.O_NOFOLLOW
+    : 0;
+  const handle = await open(filePath, constants.O_RDONLY | noFollow);
+  try {
+    const fileStats = await handle.stat();
+    if (!fileStats.isFile()) throw new Error(`Package source is not a regular file: ${filePath}`);
+    let size = 0;
+    const stream = createReadStream(filePath, { fd: handle.fd, autoClose: false });
+    for await (const chunk of stream) {
+      const buffer = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk);
+      size += buffer.byteLength;
+      if (size > maxBytes) {
+        throw new Error(`Package source exceeds ${maxBytes} bytes while reading: ${filePath}`);
+      }
+      onChunk(buffer);
+    }
+    return { size, mode: fileStats.mode };
+  } finally {
+    await handle.close();
+  }
+}
+
+export async function hashFile(
+  filePath: string,
+  maxBytes: number,
+): Promise<{ crc32: number; sha256: string; size: number; mode: number }> {
+  const sha256 = createHash("sha256");
+  let crc = 0xffffffff;
+  const file = await readRegularFile(filePath, maxBytes, (buffer) => {
+    sha256.update(buffer);
+    crc = updateCrc32(crc, buffer);
+  });
+  return {
+    crc32: (crc ^ 0xffffffff) >>> 0,
+    sha256: sha256.digest("hex"),
+    size: file.size,
+    mode: file.mode,
+  };
+}
+
+function sortPackagePaths(left: ScannedFile, right: ScannedFile): number {
+  return Buffer.compare(Buffer.from(left.packagePath), Buffer.from(right.packagePath));
+}
+
+interface PackageContentIdentity {
+  readonly packagePath: string;
+  readonly size: number;
+  readonly sha256: string;
+  readonly executable: boolean;
+}
+
+/**
+ * Hash the logical package contents instead of the ZIP representation. This
+ * keeps integrity checks stable across valid ZIP encoders and compression
+ * choices while binding every path, byte length, executable bit, and file
+ * digest into one versioned identity.
+ */
+export function computePackageContentSha256(
+  entries: readonly PackageContentIdentity[],
+): string {
+  const hash = createHash("sha256");
+  hash.update("netcatty-plugin-content-v1\0", "utf8");
+  const ordered = [...entries].sort((left, right) => (
+    Buffer.compare(Buffer.from(left.packagePath), Buffer.from(right.packagePath))
+  ));
+  for (const entry of ordered) {
+    const packagePath = Buffer.from(entry.packagePath, "utf8");
+    const header = Buffer.allocUnsafe(13);
+    header.writeUInt32BE(packagePath.byteLength, 0);
+    header.writeBigUInt64BE(BigInt(entry.size), 4);
+    header.writeUInt8(entry.executable ? 1 : 0, 12);
+    hash.update(header);
+    hash.update(packagePath);
+    hash.update(Buffer.from(entry.sha256, "hex"));
+  }
+  return hash.digest("hex");
+}
+
+function isExecutablePackageFile(packagePath: string, mode: number): boolean {
+  return (mode & 0o111) !== 0
+    || EXECUTABLE_EXTENSIONS.has(path.posix.extname(packagePath).toLowerCase());
+}
+
+function packageIconPaths(icon: IconReference | undefined): string[] {
+  if (icon?.kind !== "package") return [];
+  return icon.dark
+    ? [icon.light, icon.dark]
+    : [icon.light];
+}
+
+function isSameOrDescendantPath(parentPath: string, candidatePath: string): boolean {
+  const relativePath = path.relative(parentPath, candidatePath);
+  return relativePath === ""
+    || (!path.isAbsolute(relativePath)
+      && relativePath !== ".."
+      && !relativePath.startsWith(`..${path.sep}`));
+}
+
+async function resolveThroughExistingAncestor(targetPath: string): Promise<string> {
+  let currentPath = targetPath;
+  const missingSegments: string[] = [];
+  while (true) {
+    try {
+      const resolvedAncestor = await realpath(currentPath);
+      return path.join(resolvedAncestor, ...missingSegments.reverse());
+    } catch (error) {
+      if (!(error instanceof Error && "code" in error && error.code === "ENOENT")) throw error;
+      const parentPath = path.dirname(currentPath);
+      if (parentPath === currentPath) throw error;
+      missingSegments.push(path.basename(currentPath));
+      currentPath = parentPath;
+    }
+  }
+}
+
+async function scanPackageDirectory(
+  pluginDirectory: string,
+  manifestSource: ValidatedManifestSource,
+  options: { allowIgnoredRootEntries?: boolean } = {},
+): Promise<ScannedFile[]> {
+  const { manifest } = manifestSource;
+  const registry = new PackagePathRegistry();
+  const companionPaths = new Map(
+    (manifest.companionExecutables ?? []).flatMap((companion) => (
+      companion.variants.map((variant) => [variant.path, variant] as const)
+    )),
+  );
+  const files: ScannedFile[] = [];
+  let totalBytes = 0;
+
+  async function visit(directory: string, relativeDirectory: string): Promise<void> {
+    const entries = [];
+    for await (const entry of await opendir(directory)) entries.push(entry);
+    entries.sort((left, right) => Buffer.compare(Buffer.from(left.name), Buffer.from(right.name)));
+    for (const entry of entries) {
+      if (
+        relativeDirectory === ""
+        && (IGNORED_ROOT_ENTRIES.has(entry.name) || entry.name.endsWith(".ncpkg"))
+      ) {
+        if (options.allowIgnoredRootEntries === false) {
+          throw new Error(`Installed plugin contains an unpackaged root entry: ${entry.name}`);
+        }
+        continue;
+      }
+      const relativePath = relativeDirectory
+        ? `${relativeDirectory}/${entry.name}`
+        : entry.name;
+      const packagePath = assertSafePackagePath(relativePath);
+      const absolutePath = path.join(directory, entry.name);
+      const fileStats = await lstat(absolutePath);
+      if (fileStats.isSymbolicLink()) {
+        throw new Error(`Symbolic links are not allowed in plugin packages: ${packagePath}`);
+      }
+      if (fileStats.isDirectory()) {
+        await visit(absolutePath, packagePath);
+        continue;
+      }
+      if (!fileStats.isFile()) {
+        throw new Error(`Only regular files are allowed in plugin packages: ${packagePath}`);
+      }
+      registry.add(packagePath);
+      if (files.length + 1 > PACKAGE_LIMITS.fileCount) {
+        throw new Error(`Plugin package exceeds ${PACKAGE_LIMITS.fileCount} files`);
+      }
+      if (fileStats.size > PACKAGE_LIMITS.singleFileBytes) {
+        throw new Error(`Plugin file exceeds ${PACKAGE_LIMITS.singleFileBytes} bytes: ${packagePath}`);
+      }
+      totalBytes += fileStats.size;
+      if (totalBytes > PACKAGE_LIMITS.uncompressedBytes) {
+        throw new Error(
+          `Plugin package exceeds ${PACKAGE_LIMITS.uncompressedBytes} uncompressed bytes`,
+        );
+      }
+      const hashes = await hashFile(absolutePath, PACKAGE_LIMITS.singleFileBytes);
+      if (hashes.size !== fileStats.size || hashes.mode !== fileStats.mode) {
+        throw new Error(`Package source changed while it was being scanned: ${packagePath}`);
+      }
+      const isExecutable = isExecutablePackageFile(packagePath, hashes.mode);
+      if (isExecutable && !companionPaths.has(packagePath)) {
+        throw new Error(`Executable file is not declared as a companion: ${packagePath}`);
+      }
+      const companion = companionPaths.get(packagePath);
+      if (companion && companion.sha256 !== hashes.sha256) {
+        throw new Error(`Companion SHA-256 mismatch: ${packagePath}`);
+      }
+      files.push({
+        absolutePath,
+        packagePath,
+        size: fileStats.size,
+        executable: Boolean(companion),
+        crc32: hashes.crc32,
+        sha256: hashes.sha256,
+      });
+    }
+  }
+
+  await visit(pluginDirectory, "");
+  assertManifestSnapshotMatches(
+    manifestSource,
+    files.find(({ packagePath }) => packagePath === "netcatty.plugin.json"),
+  );
+  const packagedPaths = new Set(files.map(({ packagePath }) => packagePath));
+  const requiredPaths = [
+    "netcatty.plugin.json",
+    manifest.main.browser,
+    manifest.main.node,
+    ...(manifest.contributes?.views ?? []).map(({ entry }) => entry),
+    ...(manifest.contributes?.commands ?? []).flatMap(({ icon }) => packageIconPaths(icon)),
+    ...(manifest.contributes?.menus ?? []).flatMap(({ icon }) => packageIconPaths(icon)),
+    ...(manifest.contributes?.views ?? []).flatMap(({ icon }) => packageIconPaths(icon)),
+    ...companionPaths.keys(),
+  ].filter((entryPath): entryPath is string => Boolean(entryPath));
+  for (const requiredPath of requiredPaths) {
+    if (!packagedPaths.has(requiredPath)) {
+      throw new Error(`Manifest references a missing package file: ${requiredPath}`);
+    }
+  }
+  return files.sort(sortPackagePaths);
+}
+
+function makeLocalHeader(file: ScannedFile): Buffer {
+  const name = Buffer.from(file.packagePath, "utf8");
+  const header = Buffer.alloc(30 + name.byteLength);
+  header.writeUInt32LE(0x04034b50, 0);
+  header.writeUInt16LE(20, 4);
+  header.writeUInt16LE(0x0800, 6);
+  header.writeUInt16LE(0, 8);
+  header.writeUInt16LE(0, 10);
+  header.writeUInt16LE(33, 12);
+  header.writeUInt32LE(file.crc32, 14);
+  header.writeUInt32LE(file.size, 18);
+  header.writeUInt32LE(file.size, 22);
+  header.writeUInt16LE(name.byteLength, 26);
+  header.writeUInt16LE(0, 28);
+  name.copy(header, 30);
+  return header;
+}
+
+function makeCentralHeader(file: ScannedFile, localOffset: number): Buffer {
+  const name = Buffer.from(file.packagePath, "utf8");
+  const header = Buffer.alloc(46 + name.byteLength);
+  header.writeUInt32LE(0x02014b50, 0);
+  header.writeUInt16LE(0x0314, 4);
+  header.writeUInt16LE(20, 6);
+  header.writeUInt16LE(0x0800, 8);
+  header.writeUInt16LE(0, 10);
+  header.writeUInt16LE(0, 12);
+  header.writeUInt16LE(33, 14);
+  header.writeUInt32LE(file.crc32, 16);
+  header.writeUInt32LE(file.size, 20);
+  header.writeUInt32LE(file.size, 24);
+  header.writeUInt16LE(name.byteLength, 28);
+  header.writeUInt16LE(0, 30);
+  header.writeUInt16LE(0, 32);
+  header.writeUInt16LE(0, 34);
+  header.writeUInt16LE(0, 36);
+  const mode = file.executable ? 0o100755 : 0o100644;
+  header.writeUInt32LE((mode << 16) >>> 0, 38);
+  header.writeUInt32LE(localOffset, 42);
+  name.copy(header, 46);
+  return header;
+}
+
+function makeEndOfCentralDirectory(
+  entryCount: number,
+  centralSize: number,
+  centralOffset: number,
+): Buffer {
+  const footer = Buffer.alloc(22);
+  footer.writeUInt32LE(0x06054b50, 0);
+  footer.writeUInt16LE(0, 4);
+  footer.writeUInt16LE(0, 6);
+  footer.writeUInt16LE(entryCount, 8);
+  footer.writeUInt16LE(entryCount, 10);
+  footer.writeUInt32LE(centralSize, 12);
+  footer.writeUInt32LE(centralOffset, 16);
+  footer.writeUInt16LE(0, 20);
+  return footer;
+}
+
+async function writeBuffer(output: ReturnType<typeof createWriteStream>, buffer: Buffer) {
+  if (!output.write(buffer)) await once(output, "drain");
+}
+
+async function writeArchive(files: readonly ScannedFile[], outputPath: string): Promise<void> {
+  await mkdir(path.dirname(outputPath), { recursive: true });
+  const temporaryPath = `${outputPath}.tmp-${process.pid}-${randomUUID()}`;
+  const output = createWriteStream(temporaryPath, { flags: "wx", mode: 0o600 });
+  const centralHeaders: Buffer[] = [];
+  let offset = 0;
+  try {
+    await once(output, "open");
+    for (const file of files) {
+      const localHeader = makeLocalHeader(file);
+      centralHeaders.push(makeCentralHeader(file, offset));
+      await writeBuffer(output, localHeader);
+      offset += localHeader.byteLength;
+      const sha256 = createHash("sha256");
+      let crc = 0xffffffff;
+      let writtenBytes = 0;
+      const input = await open(
+        file.absolutePath,
+        constants.O_RDONLY | ("O_NOFOLLOW" in constants ? constants.O_NOFOLLOW : 0),
+      );
+      try {
+        const inputStats = await input.stat();
+        if (!inputStats.isFile() || inputStats.size !== file.size) {
+          throw new Error(`Package source changed before archive write: ${file.packagePath}`);
+        }
+        const stream = createReadStream(file.absolutePath, { fd: input.fd, autoClose: false });
+        for await (const chunk of stream) {
+          const buffer = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk);
+          writtenBytes += buffer.byteLength;
+          if (writtenBytes > file.size) {
+            throw new Error(`Package source changed while it was being written: ${file.packagePath}`);
+          }
+          sha256.update(buffer);
+          crc = updateCrc32(crc, buffer);
+          await writeBuffer(output, buffer);
+          offset += buffer.byteLength;
+        }
+      } finally {
+        await input.close();
+      }
+      if (
+        writtenBytes !== file.size
+        || ((crc ^ 0xffffffff) >>> 0) !== file.crc32
+        || sha256.digest("hex") !== file.sha256
+      ) {
+        throw new Error(`Package source changed while it was being written: ${file.packagePath}`);
+      }
+    }
+    const centralOffset = offset;
+    for (const centralHeader of centralHeaders) {
+      await writeBuffer(output, centralHeader);
+      offset += centralHeader.byteLength;
+    }
+    await writeBuffer(
+      output,
+      makeEndOfCentralDirectory(files.length, offset - centralOffset, centralOffset),
+    );
+    output.end();
+    await once(output, "close");
+    const archiveStats = await stat(temporaryPath);
+    if (archiveStats.size > PACKAGE_LIMITS.archiveBytes) {
+      throw new Error(`Plugin archive exceeds ${PACKAGE_LIMITS.archiveBytes} bytes`);
+    }
+    await rename(temporaryPath, outputPath);
+  } catch (error) {
+    output.destroy();
+    await rm(temporaryPath, { force: true });
+    throw error;
+  }
+}
+
+export async function buildPluginPackage(
+  pluginDirectory: string,
+  outputPath: string,
+): Promise<PackageBuildResult> {
+  const sourceDirectory = path.resolve(pluginDirectory);
+  const resolvedOutputPath = path.resolve(outputPath);
+  if (!resolvedOutputPath.endsWith(".ncpkg")) {
+    throw new Error("Plugin package output must use the .ncpkg extension");
+  }
+  const canonicalSourceDirectory = await realpath(sourceDirectory);
+  const canonicalOutputPath = await resolveThroughExistingAncestor(resolvedOutputPath);
+  if (
+    isSameOrDescendantPath(sourceDirectory, resolvedOutputPath)
+    || isSameOrDescendantPath(canonicalSourceDirectory, canonicalOutputPath)
+  ) {
+    throw new Error("Plugin package output must be outside the plugin source directory");
+  }
+  const manifestSource = await readValidatedManifestSource(sourceDirectory);
+  const files = await scanPackageDirectory(sourceDirectory, manifestSource);
+  await writeArchive(files, resolvedOutputPath);
+  const outputStats = await stat(resolvedOutputPath);
+  const archiveHash = await hashFile(resolvedOutputPath, PACKAGE_LIMITS.archiveBytes);
+  return {
+    outputPath: resolvedOutputPath,
+    fileCount: files.length,
+    uncompressedBytes: files.reduce((sum, file) => sum + file.size, 0),
+    archiveBytes: outputStats.size,
+    sha256: archiveHash.sha256,
+    contentSha256: computePackageContentSha256(files),
+  };
+}
+
+export async function validatePluginDirectory(
+  pluginDirectory: string,
+  options: { allowIgnoredRootEntries?: boolean } = {},
+): Promise<PluginDirectoryValidationResult> {
+  const sourceDirectory = path.resolve(pluginDirectory);
+  const manifestSource = await readValidatedManifestSource(sourceDirectory);
+  const files = await scanPackageDirectory(sourceDirectory, manifestSource, options);
+  return {
+    manifest: manifestSource.manifest,
+    fileCount: files.length,
+    uncompressedBytes: files.reduce((sum, file) => sum + file.size, 0),
+    contentSha256: computePackageContentSha256(files),
+  };
+}
+
+function openZip(filePath: string): Promise<ZipFile> {
+  return new Promise((resolve, reject) => {
+    yauzl.open(
+      filePath,
+      // Security invariant: for deflated entries, validateEntrySizes inserts an
+      // AssertByteCountStream that rejects an overflowing chunk before it is
+      // forwarded to readEntry(). Combined with the metadata limits below,
+      // captured manifest contents cannot exceed PACKAGE_LIMITS.manifestBytes.
+      { lazyEntries: true, decodeStrings: true, strictFileNames: true, validateEntrySizes: true },
+      (error, zipFile) => {
+        if (error || !zipFile) reject(error ?? new Error("Unable to open plugin archive"));
+        else resolve(zipFile);
+      },
+    );
+  });
+}
+
+interface ReadArchiveEntryResult {
+  readonly bytes: number;
+  readonly crc32: number;
+  readonly sha256: string;
+  readonly contents?: Buffer;
+}
+
+interface LocalFileHeader {
+  readonly generalPurposeBitFlag: number;
+  readonly compressionMethod: number;
+  readonly crc32: number;
+  readonly compressedSize: number;
+  readonly uncompressedSize: number;
+  readonly fileName: Buffer;
+}
+
+interface ZipEntryWithRawName extends Entry {
+  readonly fileNameRaw?: Buffer;
+}
+
+interface ZipFileWithLocalHeader extends ZipFile {
+  readLocalFileHeader(
+    entry: Entry,
+    callback: (error: Error | null, header?: LocalFileHeader) => void,
+  ): void;
+}
+
+function readLocalFileHeader(zipFile: ZipFile, entry: Entry): Promise<LocalFileHeader> {
+  return new Promise((resolve, reject) => {
+    (zipFile as ZipFileWithLocalHeader).readLocalFileHeader(entry, (error, header) => {
+      if (error || !header) {
+        reject(error ?? new Error(`Unable to read local ZIP header: ${entry.fileName}`));
+      } else {
+        resolve(header);
+      }
+    });
+  });
+}
+
+async function validateLocalFileHeader(
+  zipFile: ZipFile,
+  entry: Entry,
+  packagePath: string,
+): Promise<void> {
+  if ((entry.generalPurposeBitFlag & 0x0800) === 0) {
+    throw new Error(`ZIP entry name must use UTF-8 encoding: ${packagePath}`);
+  }
+  if ((entry.generalPurposeBitFlag & 0x0008) !== 0) {
+    throw new Error(`ZIP data descriptors are not allowed: ${packagePath}`);
+  }
+  const centralName = (entry as ZipEntryWithRawName).fileNameRaw;
+  if (!centralName || !centralName.equals(Buffer.from(entry.fileName, "utf8"))) {
+    throw new Error(`ZIP central entry name is not canonical UTF-8: ${packagePath}`);
+  }
+  const local = await readLocalFileHeader(zipFile, entry);
+  if (!local.fileName.equals(centralName)) {
+    throw new Error(`ZIP local and central entry names differ: ${packagePath}`);
+  }
+  if (local.generalPurposeBitFlag !== entry.generalPurposeBitFlag) {
+    throw new Error(`ZIP local and central entry flags differ: ${packagePath}`);
+  }
+  if (local.compressionMethod !== entry.compressionMethod) {
+    throw new Error(`ZIP local and central compression methods differ: ${packagePath}`);
+  }
+  if (
+    local.crc32 !== entry.crc32
+    || local.compressedSize !== entry.compressedSize
+    || local.uncompressedSize !== entry.uncompressedSize
+  ) {
+    throw new Error(`ZIP local and central integrity metadata differ: ${packagePath}`);
+  }
+}
+
+async function readEntry(
+  zipFile: ZipFile,
+  entry: Entry,
+  captureContents: boolean,
+  outputPath?: string,
+): Promise<ReadArchiveEntryResult> {
+  const stream = await new Promise<NodeJS.ReadableStream>((resolve, reject) => {
+    zipFile.openReadStream(entry, (error, stream) => {
+      if (error || !stream) {
+        reject(error ?? new Error(`Unable to read archive entry: ${entry.fileName}`));
+        return;
+      }
+      resolve(stream);
+    });
+  });
+  const chunks: Buffer[] = [];
+  const sha256 = createHash("sha256");
+  let crc = 0xffffffff;
+  let bytes = 0;
+  let outputHandle;
+  try {
+    if (outputPath) {
+      await mkdir(path.dirname(outputPath), { recursive: true, mode: 0o700 });
+      outputHandle = await open(outputPath, "wx", 0o600);
+    }
+    for await (const chunk of stream) {
+      const buffer = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk);
+      bytes += buffer.byteLength;
+      if (bytes > PACKAGE_LIMITS.singleFileBytes) {
+        throw new Error(`Plugin file exceeds size limit: ${entry.fileName}`);
+      }
+      sha256.update(buffer);
+      crc = updateCrc32(crc, buffer);
+      if (captureContents) chunks.push(buffer);
+      if (outputHandle) {
+        let written = 0;
+        while (written < buffer.length) {
+          const result = await outputHandle.write(buffer, written, buffer.length - written);
+          if (result.bytesWritten === 0) {
+            throw new Error(`Unable to extract the complete archive entry: ${entry.fileName}`);
+          }
+          written += result.bytesWritten;
+        }
+      }
+    }
+    if (outputHandle) await outputHandle.sync();
+    return {
+      bytes,
+      crc32: (crc ^ 0xffffffff) >>> 0,
+      sha256: sha256.digest("hex"),
+      contents: captureContents ? Buffer.concat(chunks) : undefined,
+    };
+  } finally {
+    await outputHandle?.close();
+  }
+}
+
+async function inspectPluginPackage(
+  archivePath: string,
+  extractionDirectory?: string,
+): Promise<PackageValidationResult> {
+  const archiveStats = await stat(archivePath);
+  if (archiveStats.size > PACKAGE_LIMITS.archiveBytes) {
+    throw new Error(`Plugin archive exceeds ${PACKAGE_LIMITS.archiveBytes} bytes`);
+  }
+  const zipFile = await openZip(archivePath);
+  const registry = new PackagePathRegistry();
+  const entries = new Map<string, {
+    contents?: Buffer;
+    mode: number;
+    sha256: string;
+    size: number;
+  }>();
+  let totalBytes = 0;
+
+  await new Promise<void>((resolve, reject) => {
+    const fail = (error: unknown) => {
+      zipFile.close();
+      reject(error);
+    };
+    zipFile.once("error", fail);
+    zipFile.once("end", resolve);
+    zipFile.on("entry", (entry: Entry) => {
+      void (async () => {
+        try {
+          const packagePath = registry.add(entry.fileName);
+          if (entries.size + 1 > PACKAGE_LIMITS.fileCount) {
+            throw new Error(`Plugin package exceeds ${PACKAGE_LIMITS.fileCount} files`);
+          }
+          if ((entry.generalPurposeBitFlag & 1) !== 0) {
+            throw new Error(`Encrypted ZIP entries are not allowed: ${packagePath}`);
+          }
+          if (entry.compressionMethod !== 0 && entry.compressionMethod !== 8) {
+            throw new Error(`Unsupported ZIP compression method: ${packagePath}`);
+          }
+          await validateLocalFileHeader(zipFile, entry, packagePath);
+          const mode = (entry.externalFileAttributes >>> 16) & 0xffff;
+          const fileType = mode & 0o170000;
+          if (fileType !== 0 && fileType !== 0o100000) {
+            throw new Error(`Only regular files are allowed: ${packagePath}`);
+          }
+          if (entry.uncompressedSize > PACKAGE_LIMITS.singleFileBytes) {
+            throw new Error(`Plugin file exceeds size limit: ${packagePath}`);
+          }
+          if (
+            packagePath === "netcatty.plugin.json"
+            && entry.uncompressedSize > PACKAGE_LIMITS.manifestBytes
+          ) {
+            throw new Error(`Plugin manifest exceeds ${PACKAGE_LIMITS.manifestBytes} bytes`);
+          }
+          totalBytes += entry.uncompressedSize;
+          if (totalBytes > PACKAGE_LIMITS.uncompressedBytes) {
+            throw new Error("Plugin package exceeds the uncompressed size limit");
+          }
+          const result = await readEntry(
+            zipFile,
+            entry,
+            packagePath === "netcatty.plugin.json",
+            extractionDirectory ? path.join(extractionDirectory, ...packagePath.split("/")) : undefined,
+          );
+          if (result.bytes !== entry.uncompressedSize || result.crc32 !== entry.crc32) {
+            throw new Error(`ZIP entry integrity check failed: ${packagePath}`);
+          }
+          entries.set(packagePath, {
+            contents: result.contents,
+            mode,
+            sha256: result.sha256,
+            size: result.bytes,
+          });
+          zipFile.readEntry();
+        } catch (error) {
+          fail(error);
+        }
+      })();
+    });
+    zipFile.readEntry();
+  });
+
+  const manifestEntry = entries.get("netcatty.plugin.json");
+  if (!manifestEntry?.contents) throw new Error("Plugin package is missing netcatty.plugin.json");
+  const manifest = parseAndValidateManifestContents(manifestEntry.contents);
+  const declaredCompanions = new Map(
+    (manifest.companionExecutables ?? []).flatMap((companion) => (
+      companion.variants.map((variant) => [variant.path, variant] as const)
+    )),
+  );
+  for (const [packagePath, entry] of entries) {
+    const isExecutable = isExecutablePackageFile(packagePath, entry.mode);
+    if (isExecutable && !declaredCompanions.has(packagePath)) {
+      throw new Error(`Executable file is not declared as a companion: ${packagePath}`);
+    }
+  }
+  const requiredPaths = [
+    manifest.main.browser,
+    manifest.main.node,
+    ...(manifest.contributes?.views ?? []).map(({ entry }) => entry),
+    ...(manifest.contributes?.commands ?? []).flatMap(({ icon }) => packageIconPaths(icon)),
+    ...(manifest.contributes?.menus ?? []).flatMap(({ icon }) => packageIconPaths(icon)),
+    ...(manifest.contributes?.views ?? []).flatMap(({ icon }) => packageIconPaths(icon)),
+  ].filter((entryPath): entryPath is string => Boolean(entryPath));
+  for (const requiredPath of requiredPaths) {
+    if (!entries.has(requiredPath)) {
+      throw new Error(`Manifest references a missing package file: ${requiredPath}`);
+    }
+  }
+  for (const [companionPath, companion] of declaredCompanions) {
+    const entry = entries.get(companionPath);
+    if (!entry) throw new Error(`Manifest references a missing companion: ${companionPath}`);
+    if (entry.sha256 !== companion.sha256) {
+      throw new Error(`Companion SHA-256 mismatch: ${companionPath}`);
+    }
+  }
+  if (extractionDirectory) {
+    for (const [packagePath] of entries) {
+      await chmod(
+        path.join(extractionDirectory, ...packagePath.split("/")),
+        declaredCompanions.has(packagePath) ? 0o700 : 0o600,
+      );
+    }
+  }
+  const contentSha256 = computePackageContentSha256(
+    [...entries].map(([packagePath, entry]) => ({
+      packagePath,
+      size: entry.size,
+      sha256: entry.sha256,
+      executable: declaredCompanions.has(packagePath),
+    })),
+  );
+  return { manifest, fileCount: entries.size, uncompressedBytes: totalBytes, contentSha256 };
+}
+
+export async function validatePluginPackage(
+  archivePath: string,
+): Promise<PackageValidationResult> {
+  return inspectPluginPackage(archivePath);
+}
+
+/**
+ * Validates and extracts an immutable package snapshot into a new directory.
+ * Failed or incomplete destinations are always removed so only callers that
+ * receive a successful result can atomically publish the staged directory.
+ */
+export async function extractPluginPackage(
+  archivePath: string,
+  destinationDirectory: string,
+): Promise<PackageValidationResult> {
+  await mkdir(destinationDirectory, { recursive: false, mode: 0o700 });
+  try {
+    return await inspectPluginPackage(archivePath, destinationDirectory);
+  } catch (error) {
+    await rm(destinationDirectory, { recursive: true, force: true });
+    throw error;
+  }
+}

packages/plugin-cli/src/cli.test.ts

@@ -0,0 +1,943 @@
+import assert from "node:assert/strict";
+import { execFile } from "node:child_process";
+import { createHash } from "node:crypto";
+import {
+  mkdir,
+  mkdtemp,
+  readFile,
+  rm,
+  symlink,
+  truncate,
+  writeFile,
+} from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { promisify } from "node:util";
+import { fileURLToPath } from "node:url";
+import { deflateRawSync } from "node:zlib";
+import test from "node:test";
+
+import {
+  assertManifestSnapshotMatches,
+  buildPluginPackage,
+  extractPluginPackage,
+  hashFile,
+  validatePluginDirectory,
+  validatePluginPackage,
+} from "./archive.ts";
+import { checkPluginCompatibility } from "./compatibility.ts";
+import { PACKAGE_LIMITS } from "./constants.ts";
+import { initPlugin } from "./commands.ts";
+import {
+  parseAndValidateManifestContents,
+  readAndValidateManifest,
+  validateManifestValue,
+} from "./manifest.ts";
+import { assertSafePackagePath, PackagePathRegistry } from "./packagePath.ts";
+
+const execFileAsync = promisify(execFile);
+const cliPath = fileURLToPath(new URL("./cli.ts", import.meta.url));
+const repositoryRoot = fileURLToPath(new URL("../../../", import.meta.url));
+
+function crc32(contents: Buffer): number {
+  let crc = 0xffffffff;
+  for (const byte of contents) {
+    crc ^= byte;
+    for (let bit = 0; bit < 8; bit += 1) {
+      crc = (crc & 1) === 1 ? 0xedb88320 ^ (crc >>> 1) : crc >>> 1;
+    }
+  }
+  return (crc ^ 0xffffffff) >>> 0;
+}
+
+function createZipEntry(
+  entryName: string,
+  contents: Buffer,
+  options: {
+    readonly compressionMethod?: 0 | 8;
+    readonly declaredUncompressedSize?: number;
+  } = {},
+): Buffer {
+  const compressionMethod = options.compressionMethod ?? 0;
+  const encodedContents = compressionMethod === 8 ? deflateRawSync(contents) : contents;
+  const declaredUncompressedSize = options.declaredUncompressedSize ?? contents.byteLength;
+  const encodedName = Buffer.from(entryName);
+  const checksum = crc32(contents);
+  const localHeader = Buffer.alloc(30 + encodedName.byteLength);
+  localHeader.writeUInt32LE(0x04034b50, 0);
+  localHeader.writeUInt16LE(20, 4);
+  localHeader.writeUInt16LE(0x0800, 6);
+  localHeader.writeUInt16LE(compressionMethod, 8);
+  localHeader.writeUInt16LE(0, 10);
+  localHeader.writeUInt16LE(33, 12);
+  localHeader.writeUInt32LE(checksum, 14);
+  localHeader.writeUInt32LE(encodedContents.byteLength, 18);
+  localHeader.writeUInt32LE(declaredUncompressedSize, 22);
+  localHeader.writeUInt16LE(encodedName.byteLength, 26);
+  encodedName.copy(localHeader, 30);
+
+  const centralHeader = Buffer.alloc(46 + encodedName.byteLength);
+  centralHeader.writeUInt32LE(0x02014b50, 0);
+  centralHeader.writeUInt16LE(20, 4);
+  centralHeader.writeUInt16LE(20, 6);
+  centralHeader.writeUInt16LE(0x0800, 8);
+  centralHeader.writeUInt16LE(compressionMethod, 10);
+  centralHeader.writeUInt16LE(0, 12);
+  centralHeader.writeUInt16LE(33, 14);
+  centralHeader.writeUInt32LE(checksum, 16);
+  centralHeader.writeUInt32LE(encodedContents.byteLength, 20);
+  centralHeader.writeUInt32LE(declaredUncompressedSize, 24);
+  centralHeader.writeUInt16LE(encodedName.byteLength, 28);
+  centralHeader.writeUInt32LE((0o100644 << 16) >>> 0, 38);
+  centralHeader.writeUInt32LE(0, 42);
+  encodedName.copy(centralHeader, 46);
+
+  const centralOffset = localHeader.byteLength + encodedContents.byteLength;
+  const end = Buffer.alloc(22);
+  end.writeUInt32LE(0x06054b50, 0);
+  end.writeUInt16LE(1, 8);
+  end.writeUInt16LE(1, 10);
+  end.writeUInt32LE(centralHeader.byteLength, 12);
+  end.writeUInt32LE(centralOffset, 16);
+  return Buffer.concat([localHeader, encodedContents, centralHeader, end]);
+}
+
+function replaceCentralEntryMode(archive: Buffer, entryName: string, mode: number): Buffer {
+  const result = Buffer.from(archive);
+  const endOffset = result.lastIndexOf(Buffer.from([0x50, 0x4b, 0x05, 0x06]));
+  if (endOffset < 0) throw new Error("Missing ZIP end record");
+  const entryCount = result.readUInt16LE(endOffset + 10);
+  let offset = result.readUInt32LE(endOffset + 16);
+  for (let entry = 0; entry < entryCount; entry += 1) {
+    if (result.readUInt32LE(offset) !== 0x02014b50) throw new Error("Invalid central ZIP entry");
+    const nameLength = result.readUInt16LE(offset + 28);
+    const extraLength = result.readUInt16LE(offset + 30);
+    const commentLength = result.readUInt16LE(offset + 32);
+    const name = result.subarray(offset + 46, offset + 46 + nameLength).toString("utf8");
+    if (name === entryName) {
+      result.writeUInt32LE((mode << 16) >>> 0, offset + 38);
+      return result;
+    }
+    offset += 46 + nameLength + extraLength + commentLength;
+  }
+  throw new Error(`Missing central ZIP entry: ${entryName}`);
+}
+
+function manifest(overrides: Record<string, unknown> = {}) {
+  return {
+    manifestVersion: 1,
+    id: "com.example.package-test",
+    name: "package-test",
+    version: "1.0.0",
+    publisher: "example",
+    engines: { netcatty: ">=1.0.0 <2.0.0", api: ">=0.1.0-internal <0.2.0" },
+    main: { browser: "dist/index.js" },
+    ...overrides,
+  };
+}
+
+async function createPlugin(root: string): Promise<string> {
+  const directory = path.join(root, "plugin");
+  await mkdir(path.join(directory, "dist"), { recursive: true });
+  await Promise.all([
+    writeFile(
+      path.join(directory, "netcatty.plugin.json"),
+      `${JSON.stringify(manifest(), null, 2)}\n`,
+    ),
+    writeFile(path.join(directory, "dist/index.js"), "export default {};\n"),
+    writeFile(path.join(directory, "README.md"), "# Package test\n"),
+  ]);
+  return directory;
+}
+
+test("path validation rejects traversal, platform aliases, and duplicates", () => {
+  for (const unsafe of [
+    "../escape",
+    "/absolute",
+    "C:/drive",
+    "a\\b",
+    "a/../b",
+    "CON",
+    "assets/PRN.txt",
+    "file.",
+    "folder/file ",
+    "folder/file?.js",
+    "a//b",
+    "a／b",
+    "a＼b",
+    "．．/x",
+    "．．",
+    "Ｃ：/x",
+    "assets/ＣＯＮ.txt",
+    "file．",
+    "😀".repeat(129),
+  ]) {
+    assert.throws(() => assertSafePackagePath(unsafe));
+  }
+  assert.equal(assertSafePackagePath("😀".repeat(128)), "😀".repeat(128));
+  assert.equal(assertSafePackagePath("assets/fullwidth-Ｓ.txt"), "assets/fullwidth-Ｓ.txt");
+  const registry = new PackagePathRegistry();
+  registry.add("dist/Plugin.js");
+  assert.throws(() => registry.add("dist/plugin.js"), /case-colliding/);
+
+  for (const [first, second] of [
+    ["assets/Straße.txt", "assets/STRASSE.txt"],
+    ["assets/fullwidth-Ｓ.txt", "assets/fullwidth-S.txt"],
+  ]) {
+    const unicodeRegistry = new PackagePathRegistry();
+    unicodeRegistry.add(first);
+    assert.throws(() => unicodeRegistry.add(second), /case-colliding/);
+  }
+
+  for (const paths of [
+    ["dist", "dist/index.js"],
+    ["dist/index.js", "dist"],
+    ["DIST", "dist/index.js"],
+    ["dist/index.js", "DIST"],
+  ]) {
+    const collisionRegistry = new PackagePathRegistry();
+    collisionRegistry.add(paths[0]);
+    assert.throws(
+      () => collisionRegistry.add(paths[1]),
+      /File\/directory package path collision/,
+    );
+  }
+});
+
+test("manifest validation reports permission and contribution mistakes", () => {
+  const result = validateManifestValue(manifest({
+    permissions: {
+      required: [{ permission: "network", resources: ["https://example.com"] }],
+      optional: ["network"],
+    },
+    contributes: {
+      commands: [{ id: "com.example.package-test.run", title: "Run" }],
+      menus: [{ command: "com.example.package-test.missing", location: "commandPalette" }],
+    },
+  }));
+  assert.equal(result.valid, false);
+  assert.match(result.errors.join("\n"), /both required and optional/);
+  assert.match(result.errors.join("\n"), /undeclared command/);
+});
+
+test("text setting defaults must satisfy their declared pattern", () => {
+  const result = validateManifestValue(manifest({
+    permissions: { required: ["settings.read", "settings.write"] },
+    contributes: {
+      settings: [{
+        id: "com.example.package-test.channel",
+        label: "Channel",
+        control: "text",
+        scope: "application",
+        pattern: "^(stable|beta)$",
+        default: "nightly",
+      }],
+    },
+  }));
+
+  assert.equal(result.valid, false);
+  assert.match(result.errors.join("\n"), /default does not match its pattern/u);
+});
+
+test("resource-scoped required permissions must declare activation-time bounds", () => {
+  for (const [permission, resource] of [
+    ["network", "https://example.com"],
+    ["filesystem.read", "/tmp/plugin-read"],
+    ["filesystem.write", "/tmp/plugin-write"],
+    ["companion.execute", "com.example.package-test.helper"],
+  ] as const) {
+    const unbounded = validateManifestValue(manifest({
+      permissions: { required: [permission] },
+    }));
+    assert.equal(unbounded.valid, false, permission);
+    assert.match(unbounded.errors.join("\n"), /must declare explicit resources/u);
+
+    const bounded = validateManifestValue(manifest({
+      permissions: { required: [{ permission, resources: [resource] }] },
+    }));
+    assert.equal(bounded.valid, true, bounded.errors.join("\n"));
+
+    const wildcard = validateManifestValue(manifest({
+      permissions: { required: [{ permission, resources: ["*"] }] },
+    }));
+    assert.equal(wildcard.valid, false, permission);
+    assert.match(wildcard.errors.join("\n"), /must not use the wildcard resource/u);
+
+    const optional = validateManifestValue(manifest({
+      permissions: { optional: [permission] },
+    }));
+    assert.equal(optional.valid, true, optional.errors.join("\n"));
+  }
+});
+
+test("manifest validation applies the runtime resource limit for each permission", () => {
+  for (const [permission, length, expectedLimit] of [
+    ["network", 2_049, 2_048],
+    ["storage", 2_049, 2_048],
+    ["companion.execute", 193, 192],
+  ] as const) {
+    const result = validateManifestValue(manifest({
+      permissions: permission === "storage"
+        ? { optional: [{ permission, resources: ["x".repeat(length)] }] }
+        : { required: [{ permission, resources: ["x".repeat(length)] }] },
+    }));
+    assert.equal(result.valid, false);
+    assert.match(
+      result.errors.join("\n"),
+      new RegExp(`Permission resource for ${permission.replace(".", "\\.")} exceeds ${expectedLimit}`),
+    );
+  }
+
+  const filesystem = validateManifestValue(manifest({
+    permissions: {
+      required: [{ permission: "filesystem.read", resources: [`/${"x".repeat(4_096)}`] }],
+    },
+  }));
+  assert.equal(filesystem.valid, true, filesystem.errors.join("\n"));
+});
+
+test("Node utility entrypoints require the explicit advanced-runtime permission", () => {
+  const missing = validateManifestValue(manifest({
+    main: { node: "dist/index.js" },
+  }));
+  assert.equal(missing.valid, false);
+  assert.match(missing.errors.join("\n"), /requires declared permission: runtime\.advanced/);
+
+  const declared = validateManifestValue(manifest({
+    main: { node: "dist/index.js" },
+    permissions: { required: ["runtime.advanced"] },
+  }));
+  assert.equal(declared.valid, true, declared.errors.join("\n"));
+});
+
+test("manifest byte parsing rejects invalid UTF-8 before JSON validation", () => {
+  const validContents = new TextEncoder().encode(JSON.stringify(manifest()));
+  assert.equal(parseAndValidateManifestContents(validContents).id, "com.example.package-test");
+  assert.throws(
+    () => parseAndValidateManifestContents(Uint8Array.from([0x7b, 0x22, 0xff, 0x22, 0x7d])),
+    /not valid UTF-8 JSON/,
+  );
+});
+
+test("manifest validation safely rejects excessive JSON nesting", () => {
+  let nested: unknown = null;
+  for (let depth = 0; depth < 5_000; depth += 1) {
+    nested = [nested];
+  }
+  const result = validateManifestValue(manifest({
+    permissions: { required: ["commands"] },
+    contributes: {
+      commands: [{ id: "com.example.package-test.run", title: "Run" }],
+      keybindings: [{
+        command: "com.example.package-test.run",
+        key: "ctrl+x",
+        args: nested,
+      }],
+    },
+  }));
+  assert.equal(result.valid, false);
+  assert.match(result.errors.join("\n"), /must not exceed .* levels/);
+
+  const wideResult = validateManifestValue(manifest({
+    permissions: { required: ["commands"] },
+    contributes: {
+      commands: [{ id: "com.example.package-test.run", title: "Run" }],
+      keybindings: [{
+        command: "com.example.package-test.run",
+        key: "ctrl+x",
+        args: Array.from({ length: 100_000 }, () => null),
+      }],
+    },
+  }));
+  assert.equal(wideResult.valid, false);
+  assert.match(wideResult.errors.join("\n"), /must not contain more than .* nodes/);
+});
+
+test("manifest validation rejects duplicate companion executable paths", () => {
+  const result = validateManifestValue(manifest({
+    companionExecutables: [
+      {
+        id: "com.example.package-test.helper-one",
+        variants: [{
+          path: "bin/helper",
+          platforms: ["linux-x64"],
+          sha256: "0".repeat(64),
+        }],
+      },
+      {
+        id: "com.example.package-test.helper-two",
+        variants: [{
+          path: "bin/helper",
+          platforms: ["darwin-arm64"],
+          sha256: "1".repeat(64),
+        }],
+      },
+    ],
+  }));
+
+  assert.equal(result.valid, false);
+  assert.match(result.errors.join("\n"), /Duplicate companion executable path: bin\/helper/);
+});
+
+test("manifest validation supports platform-specific companion variants", () => {
+  const result = validateManifestValue(manifest({
+    main: { browser: "dist/index.js", node: "dist/index.js" },
+    permissions: {
+      required: [
+        "runtime.advanced",
+        {
+          permission: "companion.execute",
+          resources: ["com.example.package-test.helper"],
+        },
+      ],
+    },
+    companionExecutables: [{
+      id: "com.example.package-test.helper",
+      variants: [
+        {
+          path: "bin/helper-darwin",
+          platforms: ["darwin-arm64", "darwin-x64"],
+          sha256: "0".repeat(64),
+        },
+        {
+          path: "bin/helper-linux",
+          platforms: ["linux-arm64", "linux-x64"],
+          sha256: "1".repeat(64),
+        },
+      ],
+    }],
+  }));
+  assert.equal(result.valid, true, result.errors.join("\n"));
+
+  const duplicatePlatform = validateManifestValue(manifest({
+    main: { browser: "dist/index.js", node: "dist/index.js" },
+    permissions: {
+      required: [
+        "runtime.advanced",
+        {
+          permission: "companion.execute",
+          resources: ["com.example.package-test.helper"],
+        },
+      ],
+    },
+    companionExecutables: [{
+      id: "com.example.package-test.helper",
+      variants: [
+        {
+          path: "bin/helper-one",
+          platforms: ["linux-x64"],
+          sha256: "0".repeat(64),
+        },
+        {
+          path: "bin/helper-two",
+          platforms: ["linux-x64"],
+          sha256: "1".repeat(64),
+        },
+      ],
+    }],
+  }));
+  assert.equal(duplicatePlatform.valid, false);
+  assert.match(duplicatePlatform.errors.join("\n"), /Duplicate companion platform/);
+});
+
+test("companion executables require an advanced utility placement", () => {
+  const companionExecutables = [{
+    id: "com.example.package-test.helper",
+    variants: [{
+      path: "bin/helper",
+      platforms: ["linux-x64"],
+      sha256: "0".repeat(64),
+    }],
+  }];
+  const companionPermission = {
+    permission: "companion.execute" as const,
+    resources: ["com.example.package-test.helper"],
+  };
+
+  const browserOnly = validateManifestValue(manifest({
+    permissions: { required: [companionPermission] },
+    companionExecutables,
+  }));
+  assert.equal(browserOnly.valid, false);
+  assert.match(browserOnly.errors.join("\n"), /require a Node utility entrypoint/u);
+
+  const missingAdvanced = validateManifestValue(manifest({
+    main: { browser: "dist/index.js", node: "dist/index.js" },
+    permissions: { required: [companionPermission] },
+    companionExecutables,
+  }));
+  assert.equal(missingAdvanced.valid, false);
+  assert.match(missingAdvanced.errors.join("\n"), /requires declared permission: runtime\.advanced/u);
+});
+
+test("packaging treats contributed package icons as required safe files", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-icons-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = await createPlugin(root);
+  const manifestPath = path.join(directory, "netcatty.plugin.json");
+  await writeFile(manifestPath, `${JSON.stringify(manifest({
+    permissions: { required: ["commands"] },
+    contributes: {
+      commands: [{
+        id: "com.example.package-test.run",
+        title: "Run",
+        icon: {
+          kind: "package",
+          light: "assets/run-light.svg",
+          dark: "assets/run-dark.svg",
+        },
+      }],
+    },
+  }), null, 2)}\n`);
+
+  await assert.rejects(
+    buildPluginPackage(directory, path.join(root, "missing-icons.ncpkg")),
+    /missing package file: assets\/run-light\.svg/,
+  );
+
+  await mkdir(path.join(directory, "assets"));
+  await Promise.all([
+    writeFile(path.join(directory, "assets/run-light.svg"), "<svg></svg>"),
+    writeFile(path.join(directory, "assets/run-dark.svg"), "<svg></svg>"),
+  ]);
+  const output = path.join(root, "with-icons.ncpkg");
+  await buildPluginPackage(directory, output);
+  const result = await validatePluginPackage(output);
+  assert.equal(result.manifest.id, "com.example.package-test");
+});
+
+test("compatibility checks engine ranges and negotiates declared features", () => {
+  const pluginManifest = manifest({
+    features: {
+      required: ["netcatty.rpc.progress"],
+      optional: ["netcatty.stream.binary", "netcatty.view.theme"],
+    },
+  });
+  const compatible = checkPluginCompatibility(pluginManifest, {
+    netcattyVersion: "1.4.0",
+    features: ["netcatty.rpc.progress", "netcatty.stream.binary"],
+  });
+  assert.equal(compatible.compatible, true);
+  assert.deepEqual(compatible.enabledFeatures, [
+    "netcatty.rpc.progress",
+    "netcatty.stream.binary",
+  ]);
+
+  const incompatible = checkPluginCompatibility(pluginManifest, {
+    netcattyVersion: "2.0.0",
+    apiVersion: "0.2.0",
+    features: [],
+  });
+  assert.equal(incompatible.compatible, false);
+  assert.deepEqual(incompatible.missingRequiredFeatures, ["netcatty.rpc.progress"]);
+  assert.match(incompatible.errors.join("\n"), /does not satisfy/);
+  assert.match(incompatible.errors.join("\n"), /Missing required features/);
+
+  const nextApiPrerelease = checkPluginCompatibility(pluginManifest, {
+    netcattyVersion: "1.4.0",
+    apiVersion: "0.2.0-alpha.1",
+    features: ["netcatty.rpc.progress"],
+  });
+  assert.equal(nextApiPrerelease.compatible, false);
+  assert.match(nextApiPrerelease.errors.join("\n"), /plugin API version .* does not satisfy/);
+});
+
+test("compatibility CLI checks a validated plugin target", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-compatibility-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = await createPlugin(root);
+
+  const compatible = await execFileAsync(process.execPath, [
+    "--import",
+    "tsx",
+    cliPath,
+    "compatibility",
+    directory,
+    "--netcatty",
+    "1.5.0",
+  ]);
+  assert.match(compatible.stdout, /Compatible: com\.example\.package-test@1\.0\.0/);
+
+  await assert.rejects(
+    execFileAsync(process.execPath, [
+      "--import",
+      "tsx",
+      cliPath,
+      "compatibility",
+      directory,
+      "--netcatty",
+      "2.0.0",
+    ]),
+    /Plugin is incompatible/,
+  );
+});
+
+test("example README commands use repository-root CLI paths", async () => {
+  const readme = await readFile(
+    path.join(repositoryRoot, "examples/plugins/hello-netcatty/README.md"),
+    "utf8",
+  );
+
+  assert.match(readme, /npm run build:plugin-packages/);
+  assert.match(
+    readme,
+    /npm exec -- netcatty-plugin validate examples\/plugins\/hello-netcatty/,
+  );
+  assert.match(
+    readme,
+    /npm exec -- netcatty-plugin compatibility examples\/plugins\/hello-netcatty --netcatty 0\.0\.0/,
+  );
+  assert.doesNotMatch(readme, /npm exec --workspace @netcatty\/plugin-cli/);
+});
+
+test("init creates a valid TypeScript plugin skeleton", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-init-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = path.join(root, "created");
+
+  await initPlugin(directory, { id: "com.example.created", name: "Created" });
+
+  const createdManifest = await readAndValidateManifest(directory);
+  assert.equal(createdManifest.id, "com.example.created");
+  assert.match(await readFile(path.join(directory, "src/index.ts"), "utf8"), /definePlugin/);
+});
+
+test("init safely serializes the display name in generated TypeScript", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-init-escape-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = path.join(root, "created");
+  const displayName = 'A "quoted" \\ plugin\nnext line';
+
+  await initPlugin(directory, { id: "com.example.escaped", name: displayName });
+
+  const source = await readFile(path.join(directory, "src/index.ts"), "utf8");
+  assert.ok(
+    source.includes(`context.logger.info(${JSON.stringify(`${displayName} activated`)});`),
+  );
+});
+
+test("packing is deterministic and the archive validates", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-pack-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = await createPlugin(root);
+  const first = path.join(root, "first.ncpkg");
+  const second = path.join(root, "second.ncpkg");
+
+  const firstResult = await buildPluginPackage(directory, first);
+  await buildPluginPackage(directory, second);
+  const firstBytes = await readFile(first);
+  const secondBytes = await readFile(second);
+
+  assert.deepEqual(firstBytes, secondBytes);
+  assert.equal(
+    firstResult.sha256,
+    createHash("sha256").update(firstBytes).digest("hex"),
+  );
+  const validation = await validatePluginPackage(first);
+  const directoryValidation = await validatePluginDirectory(directory);
+  assert.equal(validation.manifest.id, "com.example.package-test");
+  assert.equal(validation.fileCount, 3);
+  assert.equal(firstResult.contentSha256, validation.contentSha256);
+  assert.equal(validation.contentSha256, directoryValidation.contentSha256);
+  assert.match(validation.contentSha256, /^[a-f0-9]{64}$/u);
+});
+
+test("logical content identity follows companion declarations across ZIP mode encoders", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-companion-mode-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = await createPlugin(root);
+  const companionContents = Buffer.from("portable companion\n");
+  const companionPath = path.join(directory, "bin/helper");
+  await mkdir(path.dirname(companionPath), { recursive: true });
+  await writeFile(companionPath, companionContents);
+  await writeFile(
+    path.join(directory, "netcatty.plugin.json"),
+    `${JSON.stringify(manifest({
+      main: { browser: "dist/index.js", node: "dist/index.js" },
+      permissions: {
+        required: [
+          "runtime.advanced",
+          {
+            permission: "companion.execute",
+            resources: ["com.example.package-test.helper"],
+          },
+        ],
+      },
+      companionExecutables: [{
+        id: "com.example.package-test.helper",
+        variants: [{
+          path: "bin/helper",
+          platforms: ["linux-x64"],
+          sha256: createHash("sha256").update(companionContents).digest("hex"),
+        }],
+      }],
+    }), null, 2)}\n`,
+  );
+  const builtPath = path.join(root, "built.ncpkg");
+  const portablePath = path.join(root, "portable.ncpkg");
+  const extracted = path.join(root, "extracted");
+  await buildPluginPackage(directory, builtPath);
+  await writeFile(
+    portablePath,
+    replaceCentralEntryMode(await readFile(builtPath), "bin/helper", 0o100644),
+  );
+
+  const archiveValidation = await extractPluginPackage(portablePath, extracted);
+  const directoryValidation = await validatePluginDirectory(extracted, {
+    allowIgnoredRootEntries: false,
+  });
+  assert.equal(archiveValidation.contentSha256, directoryValidation.contentSha256);
+});
+
+test("validated extraction creates an isolated tree and removes partial output on failure", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-extract-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = await createPlugin(root);
+  const archive = path.join(root, "plugin.ncpkg");
+  const extracted = path.join(root, "extracted");
+  await buildPluginPackage(directory, archive);
+
+  const result = await extractPluginPackage(archive, extracted);
+  assert.equal(result.manifest.id, "com.example.package-test");
+  assert.equal(
+    await readFile(path.join(extracted, "dist/index.js"), "utf8"),
+    "export default {};\n",
+  );
+  await assert.rejects(extractPluginPackage(archive, extracted));
+  assert.equal(
+    await readFile(path.join(extracted, "dist/index.js"), "utf8"),
+    "export default {};\n",
+  );
+
+  const invalidArchive = path.join(root, "invalid.ncpkg");
+  const failedDestination = path.join(root, "failed-extraction");
+  await writeFile(invalidArchive, "not a zip");
+  await assert.rejects(extractPluginPackage(invalidArchive, failedDestination));
+  await assert.rejects(readFile(failedDestination), /ENOENT/);
+});
+
+test("archive validation rejects oversized manifests before buffering", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-archive-manifest-limit-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const oversizedPath = path.join(root, "oversized-manifest.ncpkg");
+  const oversizedBytes = createZipEntry(
+    "netcatty.plugin.json",
+    Buffer.alloc(PACKAGE_LIMITS.manifestBytes + 1, 0x20),
+  );
+  await writeFile(oversizedPath, oversizedBytes);
+
+  await assert.rejects(
+    validatePluginPackage(oversizedPath),
+    new RegExp(`Plugin manifest exceeds ${PACKAGE_LIMITS.manifestBytes} bytes`),
+  );
+
+  const forgedSizePath = path.join(root, "forged-size-manifest.ncpkg");
+  const forgedSizeBytes = createZipEntry(
+    "netcatty.plugin.json",
+    Buffer.alloc(PACKAGE_LIMITS.manifestBytes + 1, 0x20),
+    {
+      compressionMethod: 8,
+      declaredUncompressedSize: PACKAGE_LIMITS.manifestBytes,
+    },
+  );
+  await writeFile(forgedSizePath, forgedSizeBytes);
+
+  await assert.rejects(
+    validatePluginPackage(forgedSizePath),
+    new RegExp(
+      `too many bytes in the stream\\. expected ${PACKAGE_LIMITS.manifestBytes}\\. got at least ${PACKAGE_LIMITS.manifestBytes + 1}`,
+    ),
+  );
+});
+
+test("archive validation rejects duplicate names and CRC corruption", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-archive-safety-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = await createPlugin(root);
+  await Promise.all([
+    writeFile(path.join(directory, "a.txt"), "first\n"),
+    writeFile(path.join(directory, "b.txt"), "second\n"),
+  ]);
+  await mkdir(path.join(directory, "bbbbb"));
+  await Promise.all([
+    writeFile(path.join(directory, "aaaaa"), "parent-file\n"),
+    writeFile(path.join(directory, "bbbbb/file"), "child-file\n"),
+  ]);
+  const validPath = path.join(root, "valid.ncpkg");
+  await buildPluginPackage(directory, validPath);
+  const validBytes = await readFile(validPath);
+
+  const duplicateBytes = Buffer.from(validBytes);
+  const originalName = Buffer.from("b.txt");
+  const duplicateName = Buffer.from("a.txt");
+  let replacements = 0;
+  for (let offset = duplicateBytes.indexOf(originalName); offset !== -1;) {
+    duplicateName.copy(duplicateBytes, offset);
+    replacements += 1;
+    offset = duplicateBytes.indexOf(originalName, offset + originalName.byteLength);
+  }
+  assert.equal(replacements, 2, "ZIP should contain the local and central entry names");
+  const duplicatePath = path.join(root, "duplicate.ncpkg");
+  await writeFile(duplicatePath, duplicateBytes);
+  await assert.rejects(validatePluginPackage(duplicatePath), /Duplicate or case-colliding/);
+
+  const prefixCollisionBytes = Buffer.from(validBytes);
+  let prefixReplacements = 0;
+  for (const [source, target] of [
+    [Buffer.from("aaaaa"), Buffer.from("distx")],
+    [Buffer.from("bbbbb/file"), Buffer.from("distx/file")],
+  ]) {
+    for (let offset = prefixCollisionBytes.indexOf(source); offset !== -1;) {
+      target.copy(prefixCollisionBytes, offset);
+      prefixReplacements += 1;
+      offset = prefixCollisionBytes.indexOf(source, offset + source.byteLength);
+    }
+  }
+  assert.equal(prefixReplacements, 4, "ZIP should contain both local and central names");
+  const prefixCollisionPath = path.join(root, "prefix-collision.ncpkg");
+  await writeFile(prefixCollisionPath, prefixCollisionBytes);
+  await assert.rejects(
+    validatePluginPackage(prefixCollisionPath),
+    /File\/directory package path collision/,
+  );
+
+  const corruptedBytes = Buffer.from(validBytes);
+  const content = Buffer.from("# Package test\n");
+  const contentOffset = corruptedBytes.indexOf(content);
+  assert.notEqual(contentOffset, -1);
+  corruptedBytes[contentOffset] ^= 0x01;
+  const corruptedPath = path.join(root, "corrupted.ncpkg");
+  await writeFile(corruptedPath, corruptedBytes);
+  await assert.rejects(validatePluginPackage(corruptedPath), /integrity check failed/);
+
+  const splitNameBytes = Buffer.from(validBytes);
+  const localName = Buffer.from("README.md");
+  const conflictingLocalName = Buffer.from("renamed.x");
+  assert.equal(localName.byteLength, conflictingLocalName.byteLength);
+  const localNameOffset = splitNameBytes.indexOf(localName);
+  assert.notEqual(localNameOffset, -1);
+  conflictingLocalName.copy(splitNameBytes, localNameOffset);
+  const splitNamePath = path.join(root, "split-name.ncpkg");
+  await writeFile(splitNamePath, splitNameBytes);
+  await assert.rejects(
+    validatePluginPackage(splitNamePath),
+    /local and central entry names differ/,
+  );
+});
+
+test("packer rejects symbolic links and undeclared executables", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-safety-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = await createPlugin(root);
+  await assert.rejects(
+    buildPluginPackage(directory, path.join(root, "wrong-extension.zip")),
+    /\.ncpkg extension/,
+  );
+  if (process.platform !== "win32") {
+    await symlink("README.md", path.join(directory, "linked-readme"));
+    await assert.rejects(
+      buildPluginPackage(directory, path.join(root, "symlink.ncpkg")),
+      /Symbolic links/,
+    );
+    await rm(path.join(directory, "linked-readme"));
+  }
+  await mkdir(path.join(directory, "bin"));
+  const executablePath = path.join(directory, "bin/tool.exe");
+  await writeFile(executablePath, "not-a-real-executable\n");
+  await assert.rejects(
+    buildPluginPackage(directory, path.join(root, "executable.ncpkg")),
+    /not declared as a companion/,
+  );
+});
+
+test("packer ignores root dev artifacts without dropping nested runtime dependencies", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-runtime-deps-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = await createPlugin(root);
+  await Promise.all([
+    mkdir(path.join(directory, "node_modules/dev-only"), { recursive: true }),
+    mkdir(path.join(directory, "dist/node_modules/runtime-dependency"), { recursive: true }),
+  ]);
+  await Promise.all([
+    writeFile(path.join(directory, "node_modules/dev-only/index.js"), "dev only\n"),
+    writeFile(
+      path.join(directory, "dist/node_modules/runtime-dependency/index.js"),
+      "export const runtime = true;\n",
+    ),
+  ]);
+  const packagePath = path.join(root, "runtime-deps.ncpkg");
+
+  const build = await buildPluginPackage(directory, packagePath);
+  const validation = await validatePluginPackage(packagePath);
+
+  assert.equal(build.fileCount, 4);
+  assert.equal(validation.fileCount, 4);
+});
+
+test("packer rejects outputs inside the plugin source tree", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-output-containment-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const directory = await createPlugin(root);
+  const nestedOutput = path.join(directory, "dist/plugin.ncpkg");
+  await writeFile(nestedOutput, "previous package output\n");
+
+  await assert.rejects(
+    buildPluginPackage(directory, nestedOutput),
+    /output must be outside the plugin source directory/,
+  );
+
+  if (process.platform !== "win32") {
+    const outputAlias = path.join(root, "output-alias");
+    await symlink(path.join(directory, "dist"), outputAlias);
+    await assert.rejects(
+      buildPluginPackage(directory, path.join(outputAlias, "plugin.ncpkg")),
+      /output must be outside the plugin source directory/,
+    );
+  }
+});
+
+test("manifest byte limit is enforced before JSON parsing", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-limit-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const manifestPath = path.join(root, "netcatty.plugin.json");
+  await writeFile(manifestPath, "{}");
+  await truncate(manifestPath, PACKAGE_LIMITS.manifestBytes * 4);
+  await assert.rejects(readAndValidateManifest(root), /manifest exceeds/);
+});
+
+test("manifest validation refuses symlinked source manifests", async (context) => {
+  if (process.platform === "win32") return;
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-manifest-link-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const target = path.join(root, "target.json");
+  await writeFile(target, JSON.stringify(manifest()));
+  await symlink(target, path.join(root, "netcatty.plugin.json"));
+  await assert.rejects(readAndValidateManifest(root), /must be a regular file/);
+});
+
+test("validated manifest snapshots reject changed package bytes", () => {
+  const snapshot = { size: 128, sha256: "a".repeat(64) };
+  assert.doesNotThrow(() => assertManifestSnapshotMatches(snapshot, snapshot));
+  assert.throws(
+    () => assertManifestSnapshotMatches(snapshot, { ...snapshot, size: 129 }),
+    /manifest changed after validation/,
+  );
+  assert.throws(
+    () => assertManifestSnapshotMatches(snapshot, { ...snapshot, sha256: "b".repeat(64) }),
+    /manifest changed after validation/,
+  );
+  assert.throws(
+    () => assertManifestSnapshotMatches(snapshot, undefined),
+    /manifest changed after validation/,
+  );
+});
+
+test("source hashing enforces its byte budget while reading", async (context) => {
+  const root = await mkdtemp(path.join(tmpdir(), "netcatty-plugin-source-limit-"));
+  context.after(() => rm(root, { recursive: true, force: true }));
+  const filePath = path.join(root, "growing.bin");
+  await writeFile(filePath, "1234");
+
+  await assert.rejects(hashFile(filePath, 3), /source exceeds 3 bytes while reading/);
+  assert.equal((await hashFile(filePath, 4)).size, 4);
+});

packages/plugin-cli/src/cli.ts

@@ -0,0 +1,92 @@
+#!/usr/bin/env node
+
+import process from "node:process";
+
+import { checkPluginCompatibility } from "./compatibility.js";
+import { buildPlugin, initPlugin, packPlugin, validateTarget } from "./commands.js";
+
+const USAGE = `Netcatty plugin CLI (API 0.1.0-internal)
+
+Usage:
+  netcatty-plugin init <directory> --id <reverse.dns.id> [--name <display name>]
+  netcatty-plugin validate <directory|package.ncpkg>
+  netcatty-plugin compatibility <directory|package.ncpkg> --netcatty <version> [--api <version>] [--features <id,id,...>]
+  netcatty-plugin build <directory>
+  netcatty-plugin pack <directory> [--out <package.ncpkg>]
+`;
+
+function optionValue(args: readonly string[], name: string): string | undefined {
+  const index = args.indexOf(name);
+  if (index === -1) return undefined;
+  const value = args[index + 1];
+  if (!value || value.startsWith("--")) throw new Error(`Missing value for ${name}`);
+  return value;
+}
+
+async function main(args: readonly string[]): Promise<void> {
+  const [command, target] = args;
+  if (!command || command === "help" || command === "--help" || command === "-h") {
+    process.stdout.write(USAGE);
+    return;
+  }
+  if (!target) throw new Error(`Missing target for ${command}`);
+
+  if (command === "init") {
+    const id = optionValue(args, "--id");
+    if (!id) throw new Error("init requires --id <reverse.dns.id>");
+    const directory = await initPlugin(target, { id, name: optionValue(args, "--name") });
+    process.stdout.write(`Initialized plugin in ${directory}\n`);
+    return;
+  }
+  if (command === "validate") {
+    const result = await validateTarget(target);
+    process.stdout.write(
+      `Valid ${result.kind}: ${result.manifest.id}@${result.manifest.version}\n`,
+    );
+    return;
+  }
+  if (command === "compatibility") {
+    const netcattyVersion = optionValue(args, "--netcatty");
+    if (!netcattyVersion) {
+      throw new Error("compatibility requires --netcatty <version>");
+    }
+    const targetResult = await validateTarget(target);
+    const features = optionValue(args, "--features")
+      ?.split(",")
+      .map((feature) => feature.trim())
+      .filter(Boolean);
+    const result = checkPluginCompatibility(targetResult.manifest, {
+      netcattyVersion,
+      apiVersion: optionValue(args, "--api"),
+      features,
+    });
+    if (!result.compatible) {
+      throw new Error(`Plugin is incompatible:\n- ${result.errors.join("\n- ")}`);
+    }
+    const featureSummary = result.enabledFeatures.length > 0
+      ? result.enabledFeatures.join(", ")
+      : "none";
+    process.stdout.write(
+      `Compatible: ${targetResult.manifest.id}@${targetResult.manifest.version}\nEnabled features: ${featureSummary}\n`,
+    );
+    return;
+  }
+  if (command === "build") {
+    await buildPlugin(target);
+    process.stdout.write("Plugin build completed.\n");
+    return;
+  }
+  if (command === "pack") {
+    const result = await packPlugin(target, optionValue(args, "--out"));
+    process.stdout.write(
+      `Packed ${result.fileCount} files to ${result.outputPath}\nSHA-256 ${result.sha256}\n`,
+    );
+    return;
+  }
+  throw new Error(`Unknown command: ${command}`);
+}
+
+main(process.argv.slice(2)).catch((error: unknown) => {
+  process.stderr.write(`${error instanceof Error ? error.message : String(error)}\n`);
+  process.exitCode = 1;
+});

packages/plugin-cli/src/commands.ts

@@ -0,0 +1,137 @@
+import { spawn } from "node:child_process";
+import { mkdir, readdir, stat, writeFile } from "node:fs/promises";
+import path from "node:path";
+
+import type { PluginManifest } from "@netcatty/plugin-contract";
+
+import {
+  buildPluginPackage,
+  validatePluginDirectory,
+  validatePluginPackage,
+} from "./archive.js";
+import { readAndValidateManifest } from "./manifest.js";
+
+export interface InitPluginOptions {
+  readonly id: string;
+  readonly name?: string;
+}
+
+export async function initPlugin(
+  targetDirectory: string,
+  options: InitPluginOptions,
+): Promise<string> {
+  const directory = path.resolve(targetDirectory);
+  await mkdir(directory, { recursive: true });
+  const existingEntries = await readdir(directory);
+  if (existingEntries.length > 0) {
+    throw new Error(`Target directory is not empty: ${directory}`);
+  }
+  const displayName = options.name?.trim() || options.id.split(".").at(-1) || options.id;
+  const activationMessage = JSON.stringify(`${displayName} activated`);
+  const packageName = options.id.replaceAll(".", "-");
+  const manifest: PluginManifest = {
+    $schema: "https://netcatty.com/schemas/plugins/0.1.0-internal/plugin-contract.schema.json",
+    manifestVersion: 1,
+    id: options.id,
+    name: displayName,
+    displayName,
+    description: "A Netcatty plugin",
+    version: "0.1.0",
+    publisher: options.id.split(".")[0] || "local",
+    engines: {
+      netcatty: ">=0.0.0",
+      api: ">=0.1.0-internal <0.2.0",
+    },
+    main: { browser: "dist/index.js" },
+    activationEvents: ["onStartupFinished"],
+    permissions: { required: [], optional: [] },
+  };
+  await mkdir(path.join(directory, "src"), { recursive: true });
+  await Promise.all([
+    writeFile(
+      path.join(directory, "netcatty.plugin.json"),
+      `${JSON.stringify(manifest, null, 2)}\n`,
+      "utf8",
+    ),
+    writeFile(
+      path.join(directory, "package.json"),
+      `${JSON.stringify({
+        name: packageName,
+        version: "0.1.0",
+        private: true,
+        type: "module",
+        scripts: { build: "tsc -p tsconfig.json" },
+        dependencies: { "@netcatty/plugin-sdk": "0.1.0-internal" },
+        devDependencies: { typescript: "^5.9.0" },
+      }, null, 2)}\n`,
+      "utf8",
+    ),
+    writeFile(
+      path.join(directory, "tsconfig.json"),
+      `${JSON.stringify({
+        compilerOptions: {
+          target: "ES2022",
+          module: "ESNext",
+          moduleResolution: "Bundler",
+          strict: true,
+          declaration: true,
+          rootDir: "src",
+          outDir: "dist",
+        },
+        include: ["src/**/*.ts"],
+      }, null, 2)}\n`,
+      "utf8",
+    ),
+    writeFile(
+      path.join(directory, "src/index.ts"),
+      `import { definePlugin } from "@netcatty/plugin-sdk";\n\nexport default definePlugin({\n  activate(context) {\n    context.logger.info(${activationMessage});\n  },\n});\n`,
+      "utf8",
+    ),
+  ]);
+  await readAndValidateManifest(directory);
+  return directory;
+}
+
+export async function validateTarget(target: string) {
+  const resolved = path.resolve(target);
+  const targetStats = await stat(resolved);
+  if (targetStats.isDirectory()) {
+    const result = await validatePluginDirectory(resolved);
+    return { kind: "directory" as const, ...result };
+  }
+  if (targetStats.isFile() && resolved.endsWith(".ncpkg")) {
+    const result = await validatePluginPackage(resolved);
+    return { kind: "package" as const, ...result };
+  }
+  throw new Error("Validation target must be a plugin directory or .ncpkg file");
+}
+
+export async function buildPlugin(pluginDirectory: string): Promise<void> {
+  const directory = path.resolve(pluginDirectory);
+  await readAndValidateManifest(directory);
+  const npmCommand = process.platform === "win32" ? "npm.cmd" : "npm";
+  await new Promise<void>((resolve, reject) => {
+    const child = spawn(npmCommand, ["run", "build", "--if-present"], {
+      cwd: directory,
+      env: process.env,
+      shell: false,
+      stdio: "inherit",
+      windowsHide: true,
+    });
+    child.once("error", reject);
+    child.once("exit", (code, signal) => {
+      if (code === 0) resolve();
+      else reject(new Error(`Plugin build failed (${signal ?? `exit ${String(code)}`})`));
+    });
+  });
+  await validatePluginDirectory(directory);
+}
+
+export async function packPlugin(pluginDirectory: string, outputPath?: string) {
+  const directory = path.resolve(pluginDirectory);
+  const manifest = await readAndValidateManifest(directory);
+  const resolvedOutput = outputPath
+    ? path.resolve(outputPath)
+    : path.join(path.dirname(directory), `${manifest.id}-${manifest.version}.ncpkg`);
+  return buildPluginPackage(directory, resolvedOutput);
+}

packages/plugin-cli/src/compatibility.ts

@@ -0,0 +1,72 @@
+import {
+  type PluginManifest,
+} from "@netcatty/plugin-contract";
+import { satisfies, valid, validRange } from "semver";
+
+const DEFAULT_PLUGIN_API_VERSION = "0.1.0-internal";
+
+export interface PluginCompatibilityTarget {
+  readonly netcattyVersion: string;
+  readonly apiVersion?: string;
+  readonly features?: readonly string[];
+}
+
+export interface PluginCompatibilityResult {
+  readonly compatible: boolean;
+  readonly apiVersion: string;
+  readonly enabledFeatures: readonly string[];
+  readonly missingRequiredFeatures: readonly string[];
+  readonly errors: readonly string[];
+}
+
+function checkEngineVersion(
+  label: string,
+  version: string,
+  range: string,
+  errors: string[],
+): void {
+  if (valid(version) === null) {
+    errors.push(`Host ${label} version is not valid semver: ${version}`);
+    return;
+  }
+  const normalizedRange = validRange(range);
+  if (normalizedRange === null) {
+    errors.push(`Plugin ${label} range is not valid semver: ${range}`);
+    return;
+  }
+  if (!satisfies(version, normalizedRange)) {
+    errors.push(`Host ${label} version ${version} does not satisfy ${range}`);
+  }
+}
+
+export function checkPluginCompatibility(
+  manifest: PluginManifest,
+  target: PluginCompatibilityTarget,
+): PluginCompatibilityResult {
+  const apiVersion = target.apiVersion ?? DEFAULT_PLUGIN_API_VERSION;
+  const errors: string[] = [];
+  checkEngineVersion("Netcatty", target.netcattyVersion, manifest.engines.netcatty, errors);
+  checkEngineVersion("plugin API", apiVersion, manifest.engines.api, errors);
+
+  const supportedFeatures = new Set(target.features ?? []);
+  const requiredFeatures = manifest.features?.required ?? [];
+  const optionalFeatures = manifest.features?.optional ?? [];
+  const missingRequiredFeatures = requiredFeatures
+    .filter((feature) => !supportedFeatures.has(feature))
+    .sort((left, right) => left.localeCompare(right, "en"));
+  if (missingRequiredFeatures.length > 0) {
+    errors.push(`Missing required features: ${missingRequiredFeatures.join(", ")}`);
+  }
+
+  const enabledFeatures = [...new Set([...requiredFeatures, ...optionalFeatures])]
+    .filter((feature) => supportedFeatures.has(feature))
+    .sort((left, right) => left.localeCompare(right, "en"));
+
+  return {
+    compatible: errors.length === 0,
+    apiVersion,
+    enabledFeatures,
+    missingRequiredFeatures,
+    errors,
+  };
+}

packages/plugin-cli/src/constants.ts

@@ -0,0 +1,15 @@
+export const PACKAGE_LIMITS = Object.freeze({
+  archiveBytes: 100 * 1024 * 1024,
+  uncompressedBytes: 250 * 1024 * 1024,
+  singleFileBytes: 50 * 1024 * 1024,
+  manifestBytes: 1024 * 1024,
+  fileCount: 5_000,
+  pathCharacters: 128,
+  pathBytes: 512,
+});
+
+export const IGNORED_ROOT_ENTRIES = new Set([
+  ".DS_Store",
+  ".git",
+  "node_modules",
+]);

packages/plugin-cli/src/index.ts

@@ -0,0 +1,28 @@
+export { PACKAGE_LIMITS } from "./constants.js";
+export {
+  buildPluginPackage,
+  extractPluginPackage,
+  validatePluginDirectory,
+  validatePluginPackage,
+  type PackageBuildResult,
+  type PackageValidationResult,
+  type PluginDirectoryValidationResult,
+} from "./archive.js";
+export {
+  buildPlugin,
+  initPlugin,
+  packPlugin,
+  validateTarget,
+  type InitPluginOptions,
+} from "./commands.js";
+export {
+  checkPluginCompatibility,
+  type PluginCompatibilityResult,
+  type PluginCompatibilityTarget,
+} from "./compatibility.js";
+export {
+  readAndValidateManifest,
+  validateManifestValue,
+  type ManifestValidationResult,
+} from "./manifest.js";
+export { assertSafePackagePath, PackagePathRegistry } from "./packagePath.js";

packages/plugin-cli/src/manifest.ts

@@ -0,0 +1,804 @@
+import { createHash } from "node:crypto";
+import { createRequire } from "node:module";
+import {
+  lstat,
+  open,
+  readFile,
+} from "node:fs/promises";
+import path from "node:path";
+
+import type {
+  IconReference,
+  PermissionDeclaration,
+  PluginManifest,
+  PluginPermission,
+} from "@netcatty/plugin-contract";
+import Ajv2020, { type ErrorObject } from "ajv/dist/2020.js";
+import addFormats from "ajv-formats";
+import { valid, validRange } from "semver";
+
+import { PACKAGE_LIMITS } from "./constants.js";
+import { assertSafePackagePath } from "./packagePath.js";
+
+const require = createRequire(import.meta.url);
+const schemaPath = require.resolve(
+  "@netcatty/plugin-contract/schema/plugin-contract.schema.json",
+);
+interface PluginContractSchema extends Record<string, unknown> {
+  readonly $defs: {
+    readonly JsonValueLimits: {
+      readonly const: {
+        readonly maxDepth: number;
+        readonly maxNodes: number;
+      };
+    };
+    readonly ResourceScopedPermission: {
+      readonly enum: readonly PluginPermission[];
+    };
+  };
+}
+
+const contractSchema = JSON.parse(
+  await readFile(schemaPath, "utf8"),
+) as PluginContractSchema;
+const manifestJsonLimits = contractSchema.$defs.JsonValueLimits.const;
+if (!Number.isSafeInteger(manifestJsonLimits.maxDepth) || manifestJsonLimits.maxDepth < 1
+  || !Number.isSafeInteger(manifestJsonLimits.maxNodes) || manifestJsonLimits.maxNodes < 1) {
+  throw new Error("Plugin contract JSON value limits are invalid");
+}
+const ajv = new Ajv2020({ allErrors: true, strict: true });
+addFormats(ajv);
+const validateSchema = ajv.compile<PluginManifest>(contractSchema);
+const utf8Decoder = new TextDecoder("utf-8", { fatal: true });
+const MAX_SETTING_PATTERN_LENGTH = 512;
+const MAX_RESTRICTED_SCHEMA_DEPTH = 8;
+const MAX_RESTRICTED_SCHEMA_NODES = 256;
+const RESTRICTED_SCHEMA_TYPES = new Set(["array", "boolean", "integer", "null", "number", "object", "string"]);
+const RESTRICTED_SCHEMA_KEYWORDS = new Set([
+  "additionalProperties", "const", "enum", "items", "maxItems", "maxLength", "maximum",
+  "minItems", "minLength", "minimum", "properties", "required", "type",
+]);
+const FORBIDDEN_SCHEMA_PROPERTY_NAMES = new Set(["__proto__", "constructor", "prototype"]);
+
+export interface ManifestValidationResult {
+  readonly valid: boolean;
+  readonly manifest?: PluginManifest;
+  readonly errors: readonly string[];
+}
+
+export interface ValidatedManifestSource {
+  readonly manifest: PluginManifest;
+  readonly size: number;
+  readonly sha256: string;
+}
+
+function formatAjvError(error: ErrorObject): string {
+  const location = error.instancePath || "/";
+  return `${location} ${error.message ?? "is invalid"}`;
+}
+
+function plainRecord(value: unknown): value is Record<string, unknown> {
+  if (!value || typeof value !== "object" || Array.isArray(value)) return false;
+  const prototype = Object.getPrototypeOf(value);
+  return prototype === Object.prototype || prototype === null;
+}
+
+function settingPatternError(source: string): string | null {
+  if (source.length < 1 || source.length > MAX_SETTING_PATTERN_LENGTH
+    || /\(\?/u.test(source) || /\\(?:[1-9]|k<)/u.test(source)
+    || /\)(?:[*+?]|\{\d+(?:,\d*)?\})/u.test(source)) {
+    return "pattern uses an unsafe regular-expression feature";
+  }
+  try { new RegExp(source, "u"); }
+  catch { return "pattern is invalid"; }
+  return null;
+}
+
+function restrictedSettingSchemaErrors(root: unknown, rootType: "array" | null = "array"): string[] {
+  const errors: string[] = [];
+  const stack: Array<{ schema: unknown; depth: number }> = [{ schema: root, depth: 0 }];
+  let nodes = 0;
+  while (stack.length > 0) {
+    const current = stack.pop();
+    if (!current || !plainRecord(current.schema)) {
+      errors.push("valueSchema must contain plain schema objects");
+      continue;
+    }
+    nodes += 1;
+    if (nodes > MAX_RESTRICTED_SCHEMA_NODES || current.depth > MAX_RESTRICTED_SCHEMA_DEPTH) {
+      errors.push("valueSchema is too complex");
+      break;
+    }
+    const schema = current.schema;
+    for (const keyword of Object.keys(schema)) {
+      if (!RESTRICTED_SCHEMA_KEYWORDS.has(keyword)) errors.push(`valueSchema keyword is not allowed: ${keyword}`);
+    }
+    if (!RESTRICTED_SCHEMA_TYPES.has(schema.type as string)) {
+      errors.push("every valueSchema node must declare one supported type");
+    }
+    if (current.depth === 0 && rootType && schema.type !== rootType) {
+      errors.push(`valueSchema root must use type ${rootType}`);
+    }
+    if (schema.type === "array") {
+      if (!plainRecord(schema.items)) errors.push("array valueSchema nodes require one items schema");
+      else stack.push({ schema: schema.items, depth: current.depth + 1 });
+    } else if (schema.items !== undefined || schema.minItems !== undefined || schema.maxItems !== undefined) {
+      errors.push("valueSchema array keywords require type array");
+    }
+    if (schema.type === "object") {
+      if (!plainRecord(schema.properties)) errors.push("object valueSchema nodes require properties");
+      else {
+        for (const [name, child] of Object.entries(schema.properties)) {
+          if (name.length < 1 || name.length > 128 || name.includes("\0")
+            || FORBIDDEN_SCHEMA_PROPERTY_NAMES.has(name)) {
+            errors.push(`valueSchema property name is invalid: ${name}`);
+          }
+          stack.push({ schema: child, depth: current.depth + 1 });
+        }
+        if (schema.required !== undefined && (!Array.isArray(schema.required)
+          || new Set(schema.required).size !== schema.required.length
+          || schema.required.some((name) => typeof name !== "string" || !Object.hasOwn(schema.properties as object, name)))) {
+          errors.push("valueSchema required fields are invalid");
+        }
+      }
+      if (schema.additionalProperties !== false) errors.push("object valueSchema nodes must deny additionalProperties");
+    } else if (schema.properties !== undefined || schema.required !== undefined || schema.additionalProperties !== undefined) {
+      errors.push("valueSchema object keywords require type object");
+    }
+    for (const name of ["minItems", "maxItems", "minLength", "maxLength"] as const) {
+      if (schema[name] !== undefined && (!Number.isSafeInteger(schema[name]) || (schema[name] as number) < 0)) {
+        errors.push(`valueSchema ${name} must be a non-negative safe integer`);
+      }
+    }
+    for (const name of ["minimum", "maximum"] as const) {
+      if (schema[name] !== undefined && (typeof schema[name] !== "number" || !Number.isFinite(schema[name]))) {
+        errors.push(`valueSchema ${name} must be finite`);
+      }
+    }
+    if (typeof schema.minItems === "number" && typeof schema.maxItems === "number" && schema.minItems > schema.maxItems) {
+      errors.push("valueSchema minItems must not exceed maxItems");
+    }
+    if (typeof schema.minLength === "number" && typeof schema.maxLength === "number" && schema.minLength > schema.maxLength) {
+      errors.push("valueSchema minLength must not exceed maxLength");
+    }
+    if (typeof schema.minimum === "number" && typeof schema.maximum === "number" && schema.minimum > schema.maximum) {
+      errors.push("valueSchema minimum must not exceed maximum");
+    }
+    if (schema.type === "integer" && typeof schema.minimum === "number" && typeof schema.maximum === "number"
+      && Math.ceil(schema.minimum) > Math.floor(schema.maximum)) {
+      errors.push("valueSchema integer range must contain a valid integer");
+    }
+    if (schema.type !== "string" && (schema.minLength !== undefined || schema.maxLength !== undefined)) {
+      errors.push("valueSchema string keywords require type string");
+    }
+    if (!["integer", "number"].includes(String(schema.type))
+      && (schema.minimum !== undefined || schema.maximum !== undefined)) {
+      errors.push("valueSchema numeric keywords require type number or integer");
+    }
+    if (schema.enum !== undefined && (!Array.isArray(schema.enum) || schema.enum.length < 1 || schema.enum.length > 256)) {
+      errors.push("valueSchema enum is invalid");
+    }
+  }
+  return [...new Set(errors)];
+}
+
+function assertManifestJsonStructure(root: unknown): void {
+  const stack: Array<{ value: unknown; depth: number }> = [{ value: root, depth: 0 }];
+  const seen = new WeakSet<object>();
+  let nodes = 0;
+  while (stack.length > 0) {
+    const current = stack.pop();
+    if (!current) break;
+    if (current.depth > manifestJsonLimits.maxDepth) {
+      throw new RangeError(
+        `JSON values must not exceed ${manifestJsonLimits.maxDepth} levels of nesting`,
+      );
+    }
+    nodes += 1;
+    if (nodes > manifestJsonLimits.maxNodes) {
+      throw new RangeError(
+        `JSON values must not contain more than ${manifestJsonLimits.maxNodes} nodes`,
+      );
+    }
+    const { value } = current;
+    if (value === null || typeof value === "string" || typeof value === "boolean") continue;
+    if (typeof value === "number") {
+      if (!Number.isFinite(value)) throw new TypeError("JSON numbers must be finite");
+      continue;
+    }
+    if (typeof value !== "object") {
+      throw new TypeError(`Unsupported JSON value type: ${typeof value}`);
+    }
+    if (seen.has(value)) throw new TypeError("JSON values must not contain shared references");
+    seen.add(value);
+    const nextDepth = current.depth + 1;
+    if (Array.isArray(value)) {
+      const keys = Object.keys(value);
+      const ownKeys = Reflect.ownKeys(value);
+      if (keys.length !== value.length || ownKeys.length !== value.length + 1) {
+        throw new TypeError("JSON arrays must be dense and contain no named properties");
+      }
+      for (let index = value.length - 1; index >= 0; index -= 1) {
+        const descriptor = Object.getOwnPropertyDescriptor(value, String(index));
+        if (!descriptor || !("value" in descriptor) || !descriptor.enumerable) {
+          throw new TypeError("JSON arrays must contain enumerable data properties only");
+        }
+        stack.push({ value: descriptor.value, depth: nextDepth });
+      }
+      continue;
+    }
+    const prototype = Object.getPrototypeOf(value);
+    if (prototype !== Object.prototype && prototype !== null) {
+      throw new TypeError("JSON objects must be plain records");
+    }
+    const stringKeys = Object.keys(value);
+    const ownKeys = Reflect.ownKeys(value);
+    if (ownKeys.length !== stringKeys.length) {
+      throw new TypeError("JSON objects must not contain symbols or non-enumerable properties");
+    }
+    for (let index = stringKeys.length - 1; index >= 0; index -= 1) {
+      const key = stringKeys[index];
+      const descriptor = Object.getOwnPropertyDescriptor(value, key);
+      if (!descriptor || !("value" in descriptor)) {
+        throw new TypeError("JSON objects must not contain accessor properties");
+      }
+      stack.push({ value: descriptor.value, depth: nextDepth });
+    }
+  }
+}
+
+function permissionName(declaration: PermissionDeclaration): PluginPermission {
+  return typeof declaration === "string" ? declaration : declaration.permission;
+}
+
+function permissionResourceLimit(permission: PluginPermission): number {
+  if (permission === "filesystem.read" || permission === "filesystem.write") return 8_192;
+  if (permission === "companion.execute") return 192;
+  return 2_048;
+}
+
+const resourceScopedPermissions = new Set<PluginPermission>(
+  contractSchema.$defs.ResourceScopedPermission.enum,
+);
+
+function validateRequiredPermissionBounds(value: unknown): string[] {
+  if (!value || typeof value !== "object" || Array.isArray(value)) return [];
+  const permissions = (value as { permissions?: unknown }).permissions;
+  if (!permissions || typeof permissions !== "object" || Array.isArray(permissions)) return [];
+  const required = (permissions as { required?: unknown }).required;
+  if (!Array.isArray(required)) return [];
+  return required.flatMap((declaration) => {
+    if (typeof declaration === "string") {
+      return resourceScopedPermissions.has(declaration as PluginPermission)
+        ? [`Required permission ${declaration} must declare explicit resources`]
+        : [];
+    }
+    if (!declaration || typeof declaration !== "object" || Array.isArray(declaration)) return [];
+    const permission = (declaration as { permission?: unknown }).permission;
+    const resources = (declaration as { resources?: unknown }).resources;
+    return typeof permission === "string"
+      && resourceScopedPermissions.has(permission as PluginPermission)
+      && Array.isArray(resources)
+      && resources.includes("*")
+      ? [`Required permission ${permission} must not use the wildcard resource`]
+      : [];
+  });
+}
+
+function validatePermissionResourceLimits(manifest: PluginManifest): string[] {
+  const errors: string[] = [];
+  for (const declaration of [
+    ...(manifest.permissions?.required ?? []),
+    ...(manifest.permissions?.optional ?? []),
+  ]) {
+    if (typeof declaration === "string") continue;
+    const maximum = permissionResourceLimit(declaration.permission);
+    for (const resource of declaration.resources) {
+      if (resource.length > maximum) {
+        errors.push(
+          `Permission resource for ${declaration.permission} exceeds ${maximum} characters`,
+        );
+      }
+    }
+  }
+  return errors;
+}
+
+function findDuplicateIds(manifest: PluginManifest): string[] {
+  const errors: string[] = [];
+  const groups = [
+    ["settings", manifest.contributes?.settings],
+    ["commands", manifest.contributes?.commands],
+    ["views", manifest.contributes?.views],
+    ["providers", manifest.contributes?.providers],
+    ["companionExecutables", manifest.companionExecutables],
+  ] as const;
+  const ids = new Map<string, string>();
+  for (const [groupName, contributions] of groups) {
+    for (const contribution of contributions ?? []) {
+      const previousGroup = ids.get(contribution.id);
+      if (previousGroup) {
+        errors.push(
+          `Duplicate contribution id across ${previousGroup} and ${groupName}: ${contribution.id}`,
+        );
+      } else {
+        ids.set(contribution.id, groupName);
+      }
+    }
+  }
+  return errors;
+}
+
+function validateOwnedContributionIds(manifest: PluginManifest): string[] {
+  const errors: string[] = [];
+  const expectedPrefix = `${manifest.id}.`;
+  const groups = [
+    ["setting", manifest.contributes?.settings],
+    ["command", manifest.contributes?.commands],
+    ["view", manifest.contributes?.views],
+    ["provider", manifest.contributes?.providers],
+    ["companion executable", manifest.companionExecutables],
+  ] as const;
+  for (const [kind, contributions] of groups) {
+    for (const contribution of contributions ?? []) {
+      if (!contribution.id.startsWith(expectedPrefix)) {
+        errors.push(
+          `${kind} id must start with the owning plugin id '${expectedPrefix}': ${contribution.id}`,
+        );
+      }
+    }
+  }
+  return errors;
+}
+
+function validateSemantics(manifest: PluginManifest): string[] {
+  const errors = [
+    ...findDuplicateIds(manifest),
+    ...validateOwnedContributionIds(manifest),
+    ...validatePermissionResourceLimits(manifest),
+  ];
+  for (const [engine, range] of Object.entries(manifest.engines)) {
+    if (validRange(range) === null) {
+      errors.push(`Invalid ${engine} engine semver range: ${range}`);
+    }
+  }
+  if (valid(manifest.version) === null) {
+    errors.push(`Invalid plugin semantic version: ${manifest.version}`);
+  }
+
+  const requiredFeatures = new Set(manifest.features?.required ?? []);
+  for (const feature of manifest.features?.optional ?? []) {
+    if (requiredFeatures.has(feature)) {
+      errors.push(`Feature cannot be both required and optional: ${feature}`);
+    }
+  }
+
+  const companionPaths = new Set<string>();
+  for (const companion of manifest.companionExecutables ?? []) {
+    const companionPlatforms = new Set<string>();
+    for (const variant of companion.variants) {
+      if (companionPaths.has(variant.path)) {
+        errors.push(`Duplicate companion executable path: ${variant.path}`);
+      }
+      companionPaths.add(variant.path);
+      for (const platform of variant.platforms) {
+        if (companionPlatforms.has(platform)) {
+          errors.push(`Duplicate companion platform for ${companion.id}: ${platform}`);
+        }
+        companionPlatforms.add(platform);
+      }
+    }
+  }
+  const requiredPermissions = new Set(
+    (manifest.permissions?.required ?? []).map(permissionName),
+  );
+  if (requiredPermissions.size !== (manifest.permissions?.required ?? []).length) {
+    errors.push("Required permissions must not contain duplicate permission names");
+  }
+  const optionalPermissions = new Set(
+    (manifest.permissions?.optional ?? []).map(permissionName),
+  );
+  if (optionalPermissions.size !== (manifest.permissions?.optional ?? []).length) {
+    errors.push("Optional permissions must not contain duplicate permission names");
+  }
+  const declaredPermissions = new Set([
+    ...requiredPermissions,
+    ...optionalPermissions,
+  ]);
+  for (const declaration of manifest.permissions?.optional ?? []) {
+    const permission = permissionName(declaration);
+    if (requiredPermissions.has(permission)) {
+      errors.push(`Permission cannot be both required and optional: ${permission}`);
+    }
+  }
+
+  const requirePermission = (condition: boolean, permission: PluginPermission, reason: string) => {
+    if (condition && !declaredPermissions.has(permission)) {
+      errors.push(`${reason} requires declared permission: ${permission}`);
+    }
+  };
+  requirePermission(
+    Boolean(manifest.contributes?.settings?.length),
+    "settings.read",
+    "Setting contributions",
+  );
+  requirePermission(
+    Boolean(manifest.main.node),
+    "runtime.advanced",
+    "Node utility entrypoints",
+  );
+  requirePermission(
+    Boolean(manifest.contributes?.commands?.length),
+    "commands",
+    "Command contributions",
+  );
+  requirePermission(Boolean(manifest.contributes?.menus?.length), "menus", "Menu contributions");
+  requirePermission(Boolean(manifest.contributes?.views?.length), "views", "View contributions");
+  requirePermission(
+    Boolean(manifest.companionExecutables?.length),
+    "companion.execute",
+    "Companion executables",
+  );
+  requirePermission(
+    Boolean(manifest.companionExecutables?.length),
+    "runtime.advanced",
+    "Companion executables",
+  );
+  if (manifest.companionExecutables?.length && !manifest.main.node) {
+    errors.push("Companion executables require a Node utility entrypoint");
+  }
+  const providerPermissions = new Map<string, readonly PluginPermission[]>([
+    ["terminal.completion", ["provider.terminal", "terminal.complete"]],
+    ["terminal.decoration", ["provider.terminal", "terminal.output", "terminal.decorate"]],
+    ["terminal.link", ["provider.terminal", "terminal.output", "terminal.decorate"]],
+    ["terminal.hover", ["provider.terminal", "terminal.output", "terminal.decorate"]],
+    ["terminal.matcher", ["provider.terminal", "terminal.output", "terminal.decorate"]],
+    ["terminal.semantic", ["provider.terminal", "terminal.input", "terminal.decorate"]],
+    ["terminal.prompt", ["provider.terminal", "terminal.output", "terminal.decorate"]],
+    ["terminal.background", ["provider.terminal", "terminal.decorate"]],
+    ["terminal.theme", ["provider.terminal", "terminal.decorate"]],
+    ["terminal.interceptor.input", ["provider.terminal", "terminal.intercept.input"]],
+    ["terminal.interceptor.output", ["provider.terminal", "terminal.intercept.output"]],
+    ["connection", ["provider.connection"]],
+    ["authentication", ["provider.authentication"]],
+    ["sync", ["provider.sync"]],
+    ["importer", ["provider.importer"]],
+  ]);
+  for (const provider of manifest.contributes?.providers ?? []) {
+    for (const permission of providerPermissions.get(provider.kind) ?? ["provider.terminal"]) {
+      requirePermission(true, permission, `Provider ${provider.id}`);
+    }
+    if (provider.kind === "terminal.interceptor.input"
+      || provider.kind === "terminal.interceptor.output") {
+      requirePermission(true, "runtime.advanced", `Provider ${provider.id}`);
+      if (!manifest.main.node) {
+        errors.push(`Provider ${provider.id} requires a Node utility entrypoint`);
+      }
+    }
+    if (provider.configurationSchema !== undefined) {
+      const schemaErrors = restrictedSettingSchemaErrors(provider.configurationSchema, null);
+      for (const error of schemaErrors) {
+        errors.push(`Provider ${provider.id} configurationSchema ${error}`);
+      }
+    }
+  }
+  for (const companion of manifest.companionExecutables ?? []) {
+    for (const permission of companion.permissions ?? []) {
+      requirePermission(
+        true,
+        permission,
+        `Companion executable ${companion.id}`,
+      );
+    }
+  }
+
+  const commandIds = new Set((manifest.contributes?.commands ?? []).map(({ id }) => id));
+  const viewIds = new Set((manifest.contributes?.views ?? []).map(({ id }) => id));
+  const providerIds = new Set((manifest.contributes?.providers ?? []).map(({ id }) => id));
+  for (const menu of manifest.contributes?.menus ?? []) {
+    if (!commandIds.has(menu.command)) {
+      errors.push(`Menu references an undeclared command: ${menu.command}`);
+    }
+    if (menu.alt && !commandIds.has(menu.alt)) {
+      errors.push(`Menu references an undeclared alternate command: ${menu.alt}`);
+    }
+  }
+  for (const keybinding of manifest.contributes?.keybindings ?? []) {
+    if (!commandIds.has(keybinding.command)) {
+      errors.push(`Keybinding references an undeclared command: ${keybinding.command}`);
+    }
+  }
+  for (const activationEvent of manifest.activationEvents ?? []) {
+    const targets = [
+      ["onCommand:", "command", commandIds],
+      ["onView:", "view", viewIds],
+      ["onProvider:", "provider", providerIds],
+    ] as const;
+    for (const [prefix, kind, ids] of targets) {
+      if (activationEvent.startsWith(prefix)) {
+        const id = activationEvent.slice(prefix.length);
+        if (!ids.has(id)) errors.push(`Activation event references an undeclared ${kind}: ${id}`);
+      }
+    }
+  }
+
+  for (const setting of manifest.contributes?.settings ?? []) {
+    if (setting.secret && setting.default !== undefined) {
+      errors.push(`Secret setting must not declare a default value: ${setting.id}`);
+    }
+    if (["radio", "select", "multiselect"].includes(setting.control)
+      && !setting.options?.length) {
+      errors.push(`${setting.control} setting requires options: ${setting.id}`);
+    }
+    const optionValues = new Set<string>();
+    for (const option of setting.options ?? []) {
+      if (optionValues.has(option.value)) {
+        errors.push(`${setting.control} setting has duplicate option value '${option.value}': ${setting.id}`);
+      }
+      optionValues.add(option.value);
+    }
+    if (!["radio", "select", "multiselect"].includes(setting.control)
+      && setting.options !== undefined) {
+      errors.push(`${setting.control} setting must not declare options: ${setting.id}`);
+    }
+    if (["number", "slider"].includes(setting.control) && setting.minimum !== undefined
+      && setting.maximum !== undefined && setting.minimum > setting.maximum) {
+      errors.push(`${setting.control} setting minimum exceeds maximum: ${setting.id}`);
+    }
+    if (setting.control === "slider"
+      && (setting.minimum === undefined || setting.maximum === undefined)) {
+      errors.push(`slider setting requires minimum and maximum: ${setting.id}`);
+    }
+    if (!["number", "slider"].includes(setting.control)
+      && (setting.minimum !== undefined
+        || setting.maximum !== undefined
+        || setting.step !== undefined)) {
+      errors.push(`${setting.control} setting must not declare numeric bounds: ${setting.id}`);
+    }
+    if (setting.pattern !== undefined
+      && !["text", "textarea", "password"].includes(setting.control)) {
+      errors.push(`${setting.control} setting must not declare a text pattern: ${setting.id}`);
+    }
+    if (setting.pattern !== undefined) {
+      const patternError = settingPatternError(setting.pattern);
+      if (patternError) errors.push(`${setting.control} setting ${patternError}: ${setting.id}`);
+      else if (typeof setting.default === "string"
+        && !new RegExp(setting.pattern, "u").test(setting.default)) {
+        errors.push(`${setting.control} setting default does not match its pattern: ${setting.id}`);
+      }
+    }
+    if (setting.control === "password" && !setting.secret) {
+      errors.push(`password setting must be marked secret: ${setting.id}`);
+    }
+    if (setting.secret && setting.control !== "password") {
+      errors.push(`Secret setting must use the password control: ${setting.id}`);
+    }
+    if (setting.secret && setting.sync) {
+      errors.push(`Secret setting must not be cloud-synced: ${setting.id}`);
+    }
+    if (setting.sync && ["device", "session"].includes(setting.scope)) {
+      errors.push(`${setting.scope}-scoped setting must not be cloud-synced: ${setting.id}`);
+    }
+    if (setting.sync && ["file", "directory"].includes(setting.control)) {
+      errors.push(`${setting.control} setting paths must not be cloud-synced: ${setting.id}`);
+    }
+    if (["list", "table"].includes(setting.control) && setting.valueSchema === undefined) {
+      errors.push(`${setting.control} setting requires valueSchema: ${setting.id}`);
+    }
+    if (["list", "table"].includes(setting.control) && setting.valueSchema !== undefined) {
+      const schemaErrors = restrictedSettingSchemaErrors(setting.valueSchema);
+      for (const error of schemaErrors) errors.push(`${setting.control} setting ${error}: ${setting.id}`);
+      if (schemaErrors.length === 0) {
+        try {
+          const validateDefault = ajv.compile(setting.valueSchema as object);
+          if (setting.default !== undefined && !validateDefault(setting.default)) {
+            errors.push(`${setting.control} setting default does not match valueSchema: ${setting.id}`);
+          }
+        } catch (error) {
+          errors.push(`${setting.control} setting valueSchema is invalid: ${setting.id}: ${error instanceof Error ? error.message : String(error)}`);
+        }
+      }
+    }
+    if (!["list", "table"].includes(setting.control) && setting.valueSchema !== undefined) {
+      errors.push(`${setting.control} setting must not declare valueSchema: ${setting.id}`);
+    }
+    if (!["list", "table"].includes(setting.control) && setting.sortable) {
+      errors.push(`${setting.control} setting must not be sortable: ${setting.id}`);
+    }
+    if (setting.default !== undefined) {
+      const stringControls = [
+        "radio",
+        "select",
+        "text",
+        "textarea",
+        "password",
+        "color",
+        "font",
+        "file",
+        "directory",
+        "keybinding",
+      ];
+      if (setting.control === "switch" && typeof setting.default !== "boolean") {
+        errors.push(`switch setting default must be boolean: ${setting.id}`);
+      }
+      if (stringControls.includes(setting.control) && typeof setting.default !== "string") {
+        errors.push(`${setting.control} setting default must be a string: ${setting.id}`);
+      }
+      if (["number", "slider"].includes(setting.control)
+        && (typeof setting.default !== "number" || !Number.isFinite(setting.default))) {
+        errors.push(`${setting.control} setting default must be a finite number: ${setting.id}`);
+      }
+      if (["list", "table"].includes(setting.control) && !Array.isArray(setting.default)) {
+        errors.push(`${setting.control} setting default must be an array: ${setting.id}`);
+      }
+      if (setting.control === "multiselect") {
+        if (!Array.isArray(setting.default)
+          || setting.default.some((value) => typeof value !== "string")) {
+          errors.push(`multiselect setting default must be a string array: ${setting.id}`);
+        } else {
+          const selected = new Set<string>();
+          for (const value of setting.default as string[]) {
+            if (!optionValues.has(value)) {
+              errors.push(`multiselect setting default uses an undeclared option '${value}': ${setting.id}`);
+            }
+            if (selected.has(value)) {
+              errors.push(`multiselect setting default repeats option '${value}': ${setting.id}`);
+            }
+            selected.add(value);
+          }
+        }
+      }
+      if (["radio", "select"].includes(setting.control)
+        && typeof setting.default === "string"
+        && !optionValues.has(setting.default)) {
+        errors.push(`${setting.control} setting default uses an undeclared option '${setting.default}': ${setting.id}`);
+      }
+      if (typeof setting.default === "number" && Number.isFinite(setting.default)) {
+        if (setting.minimum !== undefined && setting.default < setting.minimum) {
+          errors.push(`${setting.control} setting default is below minimum: ${setting.id}`);
+        }
+        if (setting.maximum !== undefined && setting.default > setting.maximum) {
+          errors.push(`${setting.control} setting default is above maximum: ${setting.id}`);
+        }
+        if (setting.step !== undefined) {
+          const offset = setting.default - (setting.minimum ?? 0);
+          const steps = offset / setting.step;
+          if (Math.abs(steps - Math.round(steps)) > 1e-9) {
+            errors.push(`${setting.control} setting default does not align to step: ${setting.id}`);
+          }
+        }
+      }
+    }
+  }
+
+  for (const entryPath of [
+    manifest.main.browser,
+    manifest.main.node,
+    ...(manifest.contributes?.views ?? []).map(({ entry }) => entry),
+    ...(manifest.contributes?.commands ?? []).flatMap(({ icon }) => packageIconPaths(icon)),
+    ...(manifest.contributes?.menus ?? []).flatMap(({ icon }) => packageIconPaths(icon)),
+    ...(manifest.contributes?.views ?? []).flatMap(({ icon }) => packageIconPaths(icon)),
+    ...(manifest.companionExecutables ?? []).flatMap(({ variants }) => (
+      variants.map(({ path: companionPath }) => companionPath)
+    )),
+  ]) {
+    if (entryPath) {
+      try {
+        assertSafePackagePath(entryPath);
+      } catch (error) {
+        errors.push(error instanceof Error ? error.message : String(error));
+      }
+    }
+  }
+  return errors;
+}
+
+function packageIconPaths(icon: IconReference | undefined): string[] {
+  if (icon?.kind !== "package") return [];
+  return icon.dark
+    ? [icon.light, icon.dark]
+    : [icon.light];
+}
+
+export function validateManifestValue(value: unknown): ManifestValidationResult {
+  try {
+    assertManifestJsonStructure(value);
+  } catch (error) {
+    return {
+      valid: false,
+      errors: [error instanceof Error ? error.message : String(error)],
+    };
+  }
+  const requiredPermissionErrors = validateRequiredPermissionBounds(value);
+  if (requiredPermissionErrors.length > 0) {
+    return { valid: false, errors: requiredPermissionErrors };
+  }
+  if (!validateSchema(value)) {
+    return {
+      valid: false,
+      errors: (validateSchema.errors ?? []).map(formatAjvError),
+    };
+  }
+  const semanticErrors = validateSemantics(value);
+  return semanticErrors.length === 0
+    ? { valid: true, manifest: value, errors: [] }
+    : { valid: false, errors: semanticErrors };
+}
+
+export function parseAndValidateManifestContents(contents: Uint8Array): PluginManifest {
+  if (contents.byteLength > PACKAGE_LIMITS.manifestBytes) {
+    throw new Error(`Plugin manifest exceeds ${PACKAGE_LIMITS.manifestBytes} bytes`);
+  }
+  let value: unknown;
+  try {
+    value = JSON.parse(utf8Decoder.decode(contents));
+  } catch (error) {
+    throw new Error(
+      `Plugin manifest is not valid UTF-8 JSON: ${error instanceof Error ? error.message : String(error)}`,
+    );
+  }
+  const result = validateManifestValue(value);
+  if (!result.valid || !result.manifest) {
+    throw new Error(`Plugin manifest is invalid:\n- ${result.errors.join("\n- ")}`);
+  }
+  return result.manifest;
+}
+
+export async function readValidatedManifestSource(
+  pluginDirectory: string,
+): Promise<ValidatedManifestSource> {
+  const manifestPath = path.join(pluginDirectory, "netcatty.plugin.json");
+  const initialStats = await lstat(manifestPath);
+  if (!initialStats.isFile()) {
+    throw new Error("Plugin manifest must be a regular file");
+  }
+  if (initialStats.size > PACKAGE_LIMITS.manifestBytes) {
+    throw new Error(`Plugin manifest exceeds ${PACKAGE_LIMITS.manifestBytes} bytes`);
+  }
+  const handle = await open(manifestPath, "r");
+  let contents: Uint8Array;
+  try {
+    const [openedStats, currentStats] = await Promise.all([
+      handle.stat(),
+      lstat(manifestPath),
+    ]);
+    if (!openedStats.isFile() || !currentStats.isFile()) {
+      throw new Error("Plugin manifest must be a regular file");
+    }
+    if (openedStats.dev !== currentStats.dev || openedStats.ino !== currentStats.ino) {
+      throw new Error("Plugin manifest changed while being opened");
+    }
+    if (openedStats.size > PACKAGE_LIMITS.manifestBytes) {
+      throw new Error(`Plugin manifest exceeds ${PACKAGE_LIMITS.manifestBytes} bytes`);
+    }
+    const buffer = new Uint8Array(PACKAGE_LIMITS.manifestBytes + 1);
+    let bytesRead = 0;
+    while (bytesRead < buffer.byteLength) {
+      const result = await handle.read(
+        buffer,
+        bytesRead,
+        buffer.byteLength - bytesRead,
+        null,
+      );
+      if (result.bytesRead === 0) break;
+      bytesRead += result.bytesRead;
+    }
+    if (bytesRead > PACKAGE_LIMITS.manifestBytes) {
+      throw new Error(`Plugin manifest exceeds ${PACKAGE_LIMITS.manifestBytes} bytes`);
+    }
+    contents = buffer.subarray(0, bytesRead);
+  } finally {
+    await handle.close();
+  }
+  return {
+    manifest: parseAndValidateManifestContents(contents),
+    size: contents.byteLength,
+    sha256: createHash("sha256").update(contents).digest("hex"),
+  };
+}
+
+export async function readAndValidateManifest(
+  pluginDirectory: string,
+): Promise<PluginManifest> {
+  return (await readValidatedManifestSource(pluginDirectory)).manifest;
+}

packages/plugin-cli/src/packagePath.ts

@@ -0,0 +1,102 @@
+import { PACKAGE_LIMITS } from "./constants.js";
+
+const WINDOWS_RESERVED_NAME = /^(?:con|prn|aux|nul|com[1-9]|lpt[1-9])(?:\..*)?$/i;
+const WINDOWS_SPECIAL = /[<>:"|?*]/;
+
+function containsControlCharacter(value: string): boolean {
+  return [...value].some((character) => character.charCodeAt(0) <= 0x1f);
+}
+
+function portablePathKey(value: string): string {
+  return value
+    .normalize("NFKC")
+    .toUpperCase()
+    .toLowerCase()
+    .normalize("NFKC");
+}
+
+function assertPortablePathSyntax(value: string, originalInput: string): string[] {
+  if (value.startsWith("/") || /^[A-Za-z]:/.test(value) || value.includes("\\")) {
+    throw new Error(`Package path must be relative POSIX syntax: ${originalInput}`);
+  }
+  const segments = value.split("/");
+  if (segments.some((segment) => segment === "" || segment === "." || segment === "..")) {
+    throw new Error(`Package path contains an unsafe segment: ${originalInput}`);
+  }
+  for (const segment of segments) {
+    if (
+      segment.endsWith(".")
+      || segment.endsWith(" ")
+      || WINDOWS_RESERVED_NAME.test(segment)
+      || WINDOWS_SPECIAL.test(segment)
+      || containsControlCharacter(segment)
+    ) {
+      throw new Error(`Package path is not portable across supported platforms: ${originalInput}`);
+    }
+  }
+  return segments;
+}
+
+export function assertSafePackagePath(input: string): string {
+  if (!input || input !== input.normalize("NFC")) {
+    throw new Error(`Package path must be non-empty NFC text: ${JSON.stringify(input)}`);
+  }
+  if ([...input].length > PACKAGE_LIMITS.pathCharacters) {
+    throw new Error(
+      `Package path exceeds ${PACKAGE_LIMITS.pathCharacters} Unicode characters: ${input}`,
+    );
+  }
+  if (Buffer.byteLength(input, "utf8") > PACKAGE_LIMITS.pathBytes) {
+    throw new Error(`Package path exceeds ${PACKAGE_LIMITS.pathBytes} UTF-8 bytes: ${input}`);
+  }
+  const rawSegments = assertPortablePathSyntax(input, input);
+  const compatibilitySegments = assertPortablePathSyntax(input.normalize("NFKC"), input);
+  if (compatibilitySegments.length !== rawSegments.length) {
+    throw new Error(
+      `Package path changes directory structure after Unicode compatibility normalization: ${input}`,
+    );
+  }
+  return input;
+}
+
+export class PackagePathRegistry {
+  readonly #filesExact = new Set<string>();
+  readonly #filesPortable = new Set<string>();
+  readonly #directoriesExact = new Set<string>();
+  readonly #directoriesPortable = new Set<string>();
+
+  add(input: string): string {
+    const safePath = assertSafePackagePath(input);
+    const portableKey = portablePathKey(safePath);
+    if (this.#filesExact.has(safePath) || this.#filesPortable.has(portableKey)) {
+      throw new Error(`Duplicate or case-colliding package path: ${safePath}`);
+    }
+    if (
+      this.#directoriesExact.has(safePath)
+      || this.#directoriesPortable.has(portableKey)
+    ) {
+      throw new Error(`File/directory package path collision: ${safePath}`);
+    }
+
+    const segments = safePath.split("/");
+    const ancestors: string[] = [];
+    for (let index = 1; index < segments.length; index += 1) {
+      const ancestor = segments.slice(0, index).join("/");
+      if (
+        this.#filesExact.has(ancestor)
+        || this.#filesPortable.has(portablePathKey(ancestor))
+      ) {
+        throw new Error(`File/directory package path collision: ${safePath}`);
+      }
+      ancestors.push(ancestor);
+    }
+
+    this.#filesExact.add(safePath);
+    this.#filesPortable.add(portableKey);
+    for (const ancestor of ancestors) {
+      this.#directoriesExact.add(ancestor);
+      this.#directoriesPortable.add(portablePathKey(ancestor));
+    }
+    return safePath;
+  }
+}

packages/plugin-cli/tsconfig.build.json

@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "strict": true,
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "rootDir": "src",
+    "outDir": "dist",
+    "skipLibCheck": true,
+    "esModuleInterop": true
+  },
+  "include": ["src/**/*.ts"],
+  "exclude": ["src/**/*.test.ts"]
+}