How it works
SkillMaxx answers one question: will this skill work in my agent, and what's the install command? Here's exactly how we answer it, and where we stop short.
1. Where the data comes from
- Anthropic's official Claude Code plugin marketplace
- OpenAI's official Codex plugin marketplace
- xAI's official Grok Build plugin marketplace
- The official MCP reference servers
- MCP server packages published on npm
2. What the statuses mean
✓ Verified from docs: an official source (the agent's own docs or marketplace) publishes the install method. Every one of these links to that source on the skill's page.
Not yet tested: we found no official docs for that agent. It may still work. If you know it does, tell us.
Tested ✓: our test harness installed it in that agent's real CLI, inside a throwaway sandbox with an empty home folder and no accounts or API keys, and the agent then listed it as enabled or loaded. For MCP servers, the agent's own health check had to connect.
✕ Failed: the install or load check didn't pass. Common reasons are a required account, API key or extra arguments. Every result shows its date and a log excerpt.
3. Hands-on tests
Last run: 2026-10-16 21:46-04:00. 810 of 901 install checks passed.
| Agent | CLI version | What we test | Passed | Failed |
|---|---|---|---|---|
| Claude Code | 2.1.197 (Claude Code) | Official marketplace plugins (installed, then must show as enabled) and MCP servers (`claude mcp list` health check) | 341 | 26 |
| Codex | codex-cli 0.163.0 | Plugins from a local mirror of the official openai/plugins marketplace (must show installed, enabled). MCP servers aren't tested: the CLI can't health-check them without signing in. | 65 | 0 |
| Grok Build | grok 1.0.62 (1474f9cbdd91) | xAI marketplace plugins, plus Claude Code plugins loaded through Grok's documented Claude marketplace support (must show as installed) | 317 | 13 |
| Cursor | 2026.10.16-e3cb207 | MCP servers in ~/.cursor/mcp.json (must report ready and list tools). Cursor CLI has no plugin installer. | 30 | 22 |
| Pi | pi 0.73.1 | Plugins with their own GitHub repo, installed as a Pi package. Pi must find skills/ by its discovery rules. No MCP or hooks in Pi. | 57 | 30 |
The harness (testing/run_tests.py) is built to run every night. It doesn't run on a schedule yet: the latest results come from a manual run. "Tested ✓" means install and load only. We don't run your prompts or check each tool's output.
4. Special cases
- Grok Build + Claude Code plugins: xAI's docs say Grok Build reads Claude Code plugins automatically, so we count those as verified from docs. Our hands-on test overrides that: the 12 Claude Code LSP plugins and Learn with Coursera failed to install in Grok Build, and they show ✕ Failed.
- npm MCP packages: we show commands in each agent's general MCP setup format. They only count as verified from docs when the package's own docs confirm them. Where our sandbox could start the server and list its tools, the listing shows Tested ✓.
5. Independence
SkillMaxx isn't affiliated with Anthropic, OpenAI, xAI, Anysphere or Pi. Sponsored placements are labeled, limited to one per row, and never change a status.
Last checked against official docs: 2026-10-16.