One manifest can now install skills and rules for Cursor

Cursor recognizes the same SKILL.md packages as other coding agents, but its native project paths are its own. Skills live under .cursor/skills. Project rules live under .cursor/rules, where a .mdc extension and YAML frontmatter determine whether Cursor loads them.

Skillfold now has a first-class cursor target for both:

targets: [claude, codex, cursor]

The target landed on main in pull request 574. It lets one manifest and lockfile materialize the same declared configuration into each tool's native layout, then check every copy for drift.

What gets installed

Cursor's Agent Skills documentation lists .cursor/skills and .agents/skills as project discovery roots, with matching user-level roots under the home directory. Skillfold deliberately uses Cursor's named path for the Cursor target:

Project skills keep the standard directory shape. Supporting files such as scripts, references, and assets travel with SKILL.md, and composed skills are generated the same way they are for the Claude and Codex targets.

The lockfile records cursor among its targets. Remote sources still resolve to an exact Git commit or npm version, with a content hash stored beside the pin. Local sources remain local. skillfold check walks .cursor/skills and reports a missing or modified copy even when the copies installed for other agents are intact.

Plain Markdown in, valid Cursor rules out

Skillfold rule sources are plain Markdown files. Cursor project rules are not: the Cursor Rules documentation says project rules must use .mdc and frontmatter. A plain .md file inside .cursor/rules is ignored.

For the Cursor target, skillfold wraps each rule source with generated metadata:

---
description: "Managed by skillfold: code-style"
alwaysApply: true
---

...the declared rule source, unchanged...

That conversion preserves the meaning rules already have in a skillfold manifest. A declared rule is standing guidance, so the generated Cursor rule uses alwaysApply: true. The original Markdown body remains the content whose integrity is pinned and checked. If someone edits the body or generated frontmatter in place, skillfold check reports drift and skillfold install repairs it.

This design also keeps one source usable across targets. The same rules/code-style.md can become a plain file under .claude/rules, a managed section in Codex's AGENTS.md, and an always-on .mdc file for Cursor.

Adding Cursor to an existing manifest

Add the target, run a normal install, and commit the lockfile change:

# edit skillfold.yaml: targets: [claude, codex, cursor]
skillfold install
skillfold check
git add skillfold.yaml skillfold.lock

Do not use install --frozen for the first run after changing targets. Frozen mode correctly rejects manifest and lockfile disagreement. Once the normal install records the new target, frozen installs become valid again.

Existing files in .cursor/skills and .cursor/rules do not silently become skillfold's property. When the target is new, the previous lockfile names nothing there as managed. Byte-identical content can be adopted. A same-named file with different content stops the install unless you explicitly pass --force. Unrelated hand-authored files remain untouched.

Per-skill and per-rule target selectors continue to work. A project can enable Cursor globally while keeping one tool-specific item out of its paths:

targets: [claude, codex, cursor]

skills:
  shared-reviewer: npm:skillfold/code-review
  claude-only:
    source: ./skills/claude-only
    targets: [claude]

rules:
  shared-style: ./rules/style.md

The full path and selector contract is in the manifest reference.

Where the target stops

Cursor's global User Rules are configured in Customize > Rules. They are not ordinary files under ~/.cursor, so skillfold does not pretend it can manage them. Global mode installs Cursor skills to ~/.cursor/skills, but rejects a rule selected for the Cursor target with an explanation instead of writing a file Cursor would ignore.

The target also does not expose Cursor's rule activation modes. Skillfold rules become always-on project guidance. It does not currently map globs, manual activation, or "Apply Intelligently" descriptions from the manifest. If a rule needs those Cursor-specific semantics, keep that .mdc file hand-authored outside skillfold's managed names. That boundary is intentional in this first version.

There is one more practical overlap: Cursor discovers .agents/skills as well as .cursor/skills. If a manifest enables both codex and cursor, the same skill is installed in both roots because each target serves its named tool. Cursor's documentation does not define a precedence rule for same-named copies across those roots. Do not enable the Codex target solely to serve Cursor; use cursor for Cursor and codex when the project also needs Codex.

Finally, this code is merged but not yet in the npm package. The current npm release remains 2.6.0. The Cursor target will become available to npm users in the next skillfold release; until then, the post documents the behavior on main, not a capability in 2.6.0.