feat: add Pi Coding Agent extension

[ruttybob]

Description

Adds Pi Coding Agent extension support to CLI-Anything, enabling AI agents to build CLI harnesses for any GUI application directly from the Pi TUI.

Closes #179

Type of Change

• New Feature — adds Pi Coding Agent extension with 5 slash commands

---

What This Adds

Extension (.pi-extension/cli-anything/index.ts)

• Registers 5 slash commands: /cli-anything, /cli-anything:refine, /cli-anything:test, /cli-anything:validate, /cli-anything:list
• Injects HARNESS.md methodology + command specs into agent session via sendUserMessage()
• Path remapping from containerized environment to local system

Global Install (.pi-extension/cli-anything/install.sh)

• Copies extension + all assets (HARNESS.md, commands, guides, scripts, templates, tests) from cli-anything-plugin/ into ~/.pi/agent/extensions/cli-anything/ for all-project availability
• Supports --uninstall flag

Tests

• cli-anything-plugin/tests/test_skill_generator.py — 31 pytest tests covering metadata extraction, SKILL.md generation, and edge cases (lives next to skill_generator.py)
• .pi-extension/cli-anything/tests/test_extension.test.ts — 8 Vitest tests for command registration

---

Review Feedback Addressed

1. Path mismatch in docs

• Renamed pi-extension/ to .pi-extension/ to match Pi's expected convention
• Updated root README install instructions to reflect actual path (.pi-extension/cli-anything/) and the install.sh-based workflow instead of incorrect .pi-extension/extensions/cli-anything/
• Updated extension README directory tree to show only files that actually live in the extension dir (command specs, guides, scripts, templates come from cli-anything-plugin/ via install.sh)

2. test_skill_generator.py can now run standalone

• Moved test_skill_generator.py from .pi-extension/cli-anything/tests/ to cli-anything-plugin/tests/ (next to skill_generator.py)
• Simplified import resolution — no more fragile parent-navigation fallback
• install.sh copies tests into the installed extension so they work there too
• 31/31 tests pass

---

Single Source of Truth

All shared files are referenced from their canonical locations — no duplicates:

File	Canonical Location	How Extension Accesses It
HARNESS.md	cli-anything-plugin/HARNESS.md	install.sh copies it alongside extension; readAsset() reads from __dirname
skill_generator.py	cli-anything-plugin/skill_generator.py	install.sh copies to scripts/; test imports from parent dir
repl_skin.py	cli-anything-plugin/repl_skin.py	install.sh copies to scripts/
Commands, guides, templates	cli-anything-plugin/{commands,guides,templates}/	install.sh copies them into the extension

---

Changes to Existing Files

• README.md (repo root) — added Pi as a supported platform; fixed install instructions
• .gitignore — whitelisted .pi-extension/ directory

---

General Checklist

• Code follows existing patterns and conventions
• --json flag is supported on any new commands (/cli-anything:list)
• Commit messages follow the conventional format (feat:, fix:, docs:, test:)
• I have tested my changes locally

Test Results

Python tests (31 passed)

$ cd cli-anything-plugin && python3 -m pytest tests/test_skill_generator.py -v

31 passed in 0.06s

Install script verified

$ bash .pi-extension/cli-anything/install.sh
✓ commands copied from .../cli-anything-plugin/commands
✓ guides copied from .../cli-anything-plugin/guides
✓ templates copied from .../cli-anything-plugin/templates
✓ HARNESS.md copied from .../cli-anything-plugin/HARNESS.md
✓ repl_skin.py copied from .../cli-anything-plugin/repl_skin.py
✓ skill_generator.py copied from .../cli-anything-plugin/skill_generator.py
✓ tests copied from .../cli-anything-plugin/tests
✓ CLI-Anything extension installed globally!

$ bash .pi-extension/cli-anything/install.sh --uninstall
✓ CLI-Anything extension uninstalled

[omerarslan0]

Hey @ruttybob, looked through the PR. Pi support is a welcome addition but a few things need fixing before merge.

Blockers:

1. HARNESS.md duplication — The 592-line HARNESS.md is copied into .pi-extension/ but the file itself says "do NOT duplicate it." I understand the Pi extension needs a local copy for readAsset(), but if we update the original in .claude-plugin/, this one goes stale silently. Move the shared file to the repo root or add a sync mechanism so we don't maintain two copies.

2. No tests — 3289 lines added, zero tests. CONTRIBUTING.md requires tests for new functionality. skill_generator.py alone has 527 lines of regex-heavy parsing logic that needs coverage. At minimum: a test that commands register correctly and that the generator can parse a sample harness.

3. Hardcoded path in setup-cli-anything.sh — HARNESS_PATH="/root/cli-anything/HARNESS.md" is a container path, won't exist on real machines. Leftover from the Claude plugin setup that wasn't adapted.

4. Syntax error in commands/list.md — The glob scanning example has broken indentation:

   for init_file in glob.glob(pattern, recursive=True):
   parts = Path(init_file).parts  # not inside the loop

   Anyone copying this gets a SyntaxError.

Should fix:

5. No error handling in readAsset() — readFileSync in index.ts will crash the entire extension if any file is missing. Needs a try/catch.

6. No linked issue — CONTRIBUTING.md asks to open an issue before starting feature work.

7. PR template incomplete — "I have tested my changes locally" isn't checked.

Minor:

8. repl_skin.py under scripts/ is the standard copy, fine for now — but same drift problem as HARNESS.md. All shared files need a single-source-of-truth strategy.

Fix 1-4 and this is good to go.

[ruttybob]

@omerarslan0
hello, im so sorry...

The PR turned out quite messy, as there are currently a lot of duplicates in the repository. I understand, however, that PI has a different installation method since this is TypeScript—it installs packages from NPM or a separate GitHub repository.

In this case, would it make more sense to add support here as a separate directory, or should I publish the package to NPM and reference it in the README.md of this repository instead?

Apologies for opening such a messy PR intentionally.

I’m very new to the open-source community, and I feel quite embarrassed about how I handled this. I hope I haven’t taken up too much of your time. 😢

[omerarslan0]

@ruttybob Good progress — you've addressed all 4 blockers from the previous review. Tests added, HARNESS.md duplication resolved, indentation fixed, hardcoded path removed. Appreciated.

Still needs fixes before merge:

1. Path mismatch in docs — The root README install instructions reference .pi-extension/extensions/cli-anything/ but the actual directory is pi-extension/cli-anything/. Pi auto-discovery won't work with this path. Either move the directory to .pi-extension/extensions/cli-anything/ or update the docs to reflect the correct path + manual symlink step.

2. test_skill_generator.py can't run standalone — It depends on skill_generator.py which only exists after install.sh copies it from cli-anything-plugin/. Add the script to the extension directory or adjust the test to import from the canonical location.

3. Re: your NPM question — Keeping it in-repo under pi-extension/ is fine for now. If Pi's ecosystem matures to support NPM-based extensions natively, we can extract it later. No need to over-engineer the distribution at this stage.

And no need to feel embarrassed — the first PR is always the hardest. You responded to feedback quickly and addressed every blocker, that's exactly how open-source works. Keep contributing.

Fix 1-2 and this is ready to merge.

[ruttybob]

@omerarslan0
By default, Pi loads extensions from the .pi/extensions/ directory.
However, if an extension is structured this way and its code depends on paths within the repository, it effectively becomes project-specific rather than global.

That’s why I decided to add an install.sh script that installs the extension globally for Pi.

[yuh-yang]

The current status LGTM. It's okay to include a bash script for installing if certain coding agents need that.

[omerarslan0]

LGTM! Thx for this.