A portable Agent Skill that searches and downloads ebooks from Z-Library via the eAPI — usable by any AI agent that can read a SKILL.md and run a script (Claude Code, Codex, Cursor, Gemini CLI, custom agents…), or straight from the shell. It is not tied to any single agent. It uses the Python standard library only — runs on Python >= 3.10 with no third-party dependencies.

holo-zlib/
├── skills/
│   └── holo-zlib/              # canonical, self-contained skill (this is what ships)
│       ├── SKILL.md            # skill entry point (loaded by the agent)
│       ├── scripts/
│       │   ├── client.py       # eAPI client (requests / auth / path resolution)
│       │   ├── zlib.py         # CLI (search / download)
│       │   └── requirements.txt# stdlib-only marker (no runtime deps)
│       └── references/
│           └── eapi.md         # eAPI endpoints / fields reference
├── src/holo_zlib/             # dev harness (validation + packaging; not shipped)
├── tests/                     # pytest unit + layout tests
├── evals/evals.json           # skill-creator eval set
├── CLAUDE.md                  # guidance for Claude Code
├── pyproject.toml             # dev tooling only (pytest, ruff); runtime needs none
└── uv.lock

The skill is portable and dependency-free at runtime. Credentials and downloads live outside the skill directory (at your project root) so they never ship with the skill.

Invocation uses python; on Linux/macOS where only python3 exists, substitute it. On Windows, python (from a venv or the Microsoft Store) works; the py launcher is not always installed, so don't rely on py -3.

Claude Code discovers skills as directories — there is no install command and no .skill import step. Place the skill folder in one of these locations and it is picked up automatically (Claude consults it based on the description in its SKILL.md frontmatter, or you can invoke it by name):

• Project (commit it to share with the repo): <project>/.claude/skills/holo-zlib/
• Personal (available in all your projects): ~/.claude/skills/holo-zlib/

git clone <repo-url>
mkdir -p .claude/skills
cp -r holo-zlib/skills/holo-zlib .claude/skills/holo-zlib   # or symlink it

Credentials: create credentials/zlib.json at your project root (the script walks upward to find it; the .claude sibling counts as an ancestor).

The packaged .skill (a zip built by uv run holo-zlib-package → dist/holo-zlib.skill) is for these platforms — not Claude Code:

• claude.ai: upload the .skill in settings (the Capabilities/Features area, on a plan with code execution enabled).
• Claude API: upload via the /v1/skills endpoints (currently beta — header skills-2025-10-02).

Any agent that can read SKILL.md and run a script can use this skill — it isn't tied to Claude Code. git clone <repo-url>; work inside the repo or place skills/holo-zlib/ where the agent can see it (point the agent at skills/holo-zlib/SKILL.md), then call the CLI directly — stdlib only, nothing to install:

python skills/holo-zlib/scripts/zlib.py search "title" --ext epub --limit 5

Credentials: same as above — credentials/zlib.json at the repo/project root.

Paste this to Claude Code or Codex to set it up and use it end to end:

Install and use the holo-zlib skill (Z-Library ebook search/download, pure Python stdlib):
1. If .claude/skills/holo-zlib/ does not exist in this project, git clone <repo-url> and
   copy its skills/holo-zlib/ into .claude/skills/holo-zlib/.
2. Create credentials/zlib.json at the project root:
   {"remix_userid": "YOUR_USERID", "remix_userkey": "YOUR_USERKEY"}
   (log in at https://z-library.sk and take remix_userid / remix_userkey from cookies).
3. Search Z-Library for an epub of "The Three-Body Problem", top 5, pick the best
   match, and show me its book_id and hash.
4. Ensure an ebooks/ directory exists at the project root (create it if missing — that is
   where the default download location resolves), then after I confirm, download the one
   I pick into it and tell me the final file path.
(Invocation: python skills/holo-zlib/scripts/zlib.py search/download … — on Linux/macOS
substitute python3 if needed.)

Replace <repo-url> with the actual repository URL once it is pushed.

# 1. Create the credentials file (log in to https://z-library.sk, copy two cookie values)
mkdir -p credentials
cat > credentials/zlib.json <<'EOF'
{"remix_userid": "YOUR_USERID", "remix_userkey": "YOUR_USERKEY"}
EOF

# 2. (optional) create ebooks/ here so downloads default to the project root
mkdir -p ebooks

# 3. Try it (use python; on Linux/macOS substitute python3 if needed)
python skills/holo-zlib/scripts/zlib.py search "The Three-Body Problem" --ext epub --limit 3

The download default resolves to the first existing ebooks/ found while walking up from the skill directory. If none exists, it falls back to <skill>/ebooks/ inside the skill itself — create an ebooks/ at your project root (as above) to keep downloads out of the skill, or pass --output <dir> per call.

Dependency and script management uses uv (dev only; the skill runtime needs none):

uv sync                                  # install the pinned dev environment
uv run holo-zlib-validate                # validate skill layout + frontmatter + banned names
uv run ruff check .                      # lint
uv run python -m pytest -p no:cacheprovider  # run the test suite
uv run holo-zlib-package                 # build dist/holo-zlib.skill (with a credential danger gate)

MIT — see LICENSE.