Runtimes

Runtimes

A package declares which runtimes it supports in manifest.runtimes. The install command (openagents add) picks the install directory from this table, either from an explicit --runtime flag or by auto-detecting the current runtime from marker directories already present in your project.

Detection checks the list top-to-bottom against the target directory (--dir, default the current directory) and stops at the first match; generic is the fallback so openagents add always succeeds even in a project with no runtime-specific directory yet.

How each runtime picks the files up

Installing a package copies its files into the table above, then openagents add writes a runtime-specific discovery shim so the target runtime actually finds it — a directory of files alone isn't enough for Claude Code or Cursor to notice a package.

• Claude Code discovers skills only via a SKILL.md with name/description YAML frontmatter. add writes .claude/skills/<name>/SKILL.md with frontmatter generated from the manifest (name, description from summary) pointing at entry — if entry already is a bare SKILL.md with no frontmatter, the CLI prepends the frontmatter to it instead of creating a second file. After install, add prints a hint to restart Claude Code (or reload the window) so it picks up the new skill.
• Codex uses the same SKILL.md-with-frontmatter convention as Claude Code; add writes it the same way under .codex/skills/<name>/SKILL.md.
• Cursor discovers rules only via a top-level .mdc file under .cursor/rules/. add writes .cursor/rules/<name>.mdc — a small frontmatter'd rule file that references @.cursor/rules/<name>/<entry> — alongside the full package contents at .cursor/rules/<name>/, so Cursor's rule index picks it up without needing every supporting file flattened to the top level. add prints a hint to check Cursor's rules panel after install.
• OpenAI Agents SDK projects typically load instruction files explicitly (e.g. via a system prompt include or a tool that reads from disk) — point your project's own bootstrap at <install-dir>/<entry>. No shim is generated; add prints a hint with the exact path to wire in.
• LangGraph graphs commonly load rules/workflow text as a node's system prompt or as a tool's documentation — same pattern: read <install-dir>/<entry> from wherever your graph is constructed. No shim is generated; add prints the path.
• Generic (.openagents/<name>/) is the runtime-agnostic fallback: a plain directory with the manifest and files, for any setup that isn't one of the above (a custom harness, a script-based agent, or manual reading by a human). There's no automatic pickup — treat it as "the files are here, wire them in yourself."

Multi-runtime packages

Most seed packages list several runtimes (all list claude-code and generic at minimum) because the content — markdown instructions, templates — is runtime-agnostic; only the install location differs. A package that genuinely needs runtime-specific mechanics (e.g. a harness relying on a specific SDK's hook system) should scope runtimes down to only the ones it actually works correctly in, rather than listing everything.

Installing for a specific runtime

openagents add openagents/pr-reviewer --runtime cursor

If a package's manifest doesn't list the runtime you asked for, the install still proceeds (the file format is generally portable) — but check the package's README for any runtime-specific caveats first.