add-license-header

name	add-license-header
description	Add the project's canonical SPDX license header to source files that don't already have one. Use when asked to add a license header to a file or directory of files.

Add License Header

Procedure

1. Identify target files from the user's request -- either a single path or all source files under a given directory.

2. For each target file, read its first 20 lines and check whether the string SPDX-License-Identifier is already present.

3. If the header is already present, skip that file. Never add a second header to a file that already has one.

4. If no header is present, insert this exact two-line header at line 1 of the file -- above all existing content, including shebangs, comments, or blank lines:

   // SPDX-License-Identifier: Apache-2.0
   // Copyright (c) 2026 Acme Corp
   

5. After processing all files, report which files were changed and which were skipped (already had a header).

Constraints

• Never duplicate a header. If SPDX-License-Identifier already appears in the first 20 lines, the file is considered done -- do not touch it.
• Always insert at the very top. The header must be the first content in the file, above any shebang (#!), existing comment, or code. Do not place it after existing content.