claude-engineering-plugin/docs/specs/cursor.md

Cursor Spec (Plugin Marketplace, Rules, Commands, Skills, MCP)

Last verified: 2026-02-12

Primary sources

https://docs.cursor.com/context/rules
https://docs.cursor.com/context/rules-for-ai
https://docs.cursor.com/customize/model-context-protocol

Plugin Marketplace

Compound Engineering is published through the Cursor Plugin Marketplace.

In Cursor Agent chat, install with:

/add-plugin compound-engineering

Users can also search for "compound engineering" in the plugin marketplace.

The repo-owned marketplace files are:

.cursor-plugin/marketplace.json
plugins/compound-engineering/.cursor-plugin/plugin.json

Do not use the old custom Bun converter/install path for Cursor.

Config locations

Scope	Path
Project rules	.cursor/rules/*.mdc
Project commands	.cursor/commands/*.md
Project skills	.cursor/skills/*/SKILL.md
Project MCP	.cursor/mcp.json
Project CLI permissions	.cursor/cli.json
Global MCP	~/.cursor/mcp.json
Global CLI config	~/.cursor/cli-config.json
Legacy rules	.cursorrules (deprecated)

Rules (.mdc files)

• Rules are Markdown files with the .mdc extension stored in .cursor/rules/.
• Each rule has YAML frontmatter with three fields: description, globs, alwaysApply.
• Rules have four activation types based on frontmatter configuration:

Type	alwaysApply	globs	description	Behavior
Always	true	ignored	optional	Included in every conversation
Auto Attached	false	set	optional	Included when matching files are in context
Agent Requested	false	empty	set	AI decides based on description relevance
Manual	false	empty	empty	Only included via @rule-name mention

• Precedence: Team Rules > Project Rules > User Rules > Legacy .cursorrules > AGENTS.md.

Commands (slash commands)

• Custom commands are Markdown files stored in .cursor/commands/.
• Commands are plain markdown with no YAML frontmatter support.
• The filename (without .md) becomes the command name.
• Commands are invoked by typing / in the chat UI.
• Commands support parameterized arguments via $1, $2, etc.

Skills (Agent Skills)

• Skills follow the open SKILL.md standard, identical to Claude Code and Codex.
• A skill is a folder containing SKILL.md plus optional scripts/, references/, and assets/.
• SKILL.md uses YAML frontmatter with required name and description fields.
• Skills can be repo-scoped in .cursor/skills/ or user-scoped in ~/.cursor/skills/.
• At startup, only each skill's name/description is loaded; full content is injected on invocation.

MCP (Model Context Protocol)

• MCP configuration lives in .cursor/mcp.json (project) or ~/.cursor/mcp.json (global).
• Each server is configured under the mcpServers key.
• STDIO servers support command (required), args, and env.
• Remote servers support url (required) and optional headers.
• Cursor infers transport type from whether command or url is present.

Example:

{
  "mcpServers": {
    "server-name": {
      "command": "npx",
      "args": ["-y", "package-name"],
      "env": { "KEY": "value" }
    }
  }
}

CLI (cursor-agent)

• Cursor CLI launched August 2025 as cursor-agent.
• Supports interactive mode, headless mode (-p), and cloud agents.
• Reads .cursor/rules/, .cursorrules, and AGENTS.md for instructions.
• CLI permissions controlled via .cursor/cli.json with allow/deny lists.
• Permission tokens: Shell(command), Read(path), Write(path), Delete(path), Grep(path), LS(path).