Cursor consumes RAC on two surfaces — a generated context file Cursor reads, and the lore MCP server it connects to. A stranger can reproduce this from the file alone.

pip install rac-core   # the `rac` CLI and the `lore` MCP server

A repository with a RAC corpus under decisions/ (run decided quickstart, or use this repository's own decisions/).

decided export decisions/ --agent-rules

This writes several agent-context files, two of which Cursor reads:

• AGENTS.md (recommended). Cursor reads AGENTS.md at the project root as plain instructions — the simplest, glob-free path, and the one to rely on here.
• .cursor/rules. RAC also writes this legacy single rules file. Modern Cursor's rules system is a .cursor/rules/*.mdc directory with metadata (description/globs/alwaysApply), so the single-file form may be ignored by current Cursor — prefer AGENTS.md above until RAC emits an .mdc rule. Either way the decisions reach Cursor through AGENTS.md.

The managed block keeps your own content intact; re-run on change (decided export decisions/ --agent-rules --check fails CI on drift).

Add .cursor/mcp.json in the repo root (project-scoped; a sample is in mcp.example.json):

{
  "mcpServers": {
    "asdecided": { "command": "decided-mcp", "args": ["--root", "."] }
  }
}

• Project: .cursor/mcp.json (commit it to share with the team).
• Global: ~/.cursor/mcp.json — use an absolute --root path.

Enable the server in Cursor's MCP settings if prompted. It exposes the five read-only lore tools (get_summary, search_artifacts, get_artifact, get_related, find_decisions); the server re-reads the corpus on every call and never writes to the repo.

RAC supplies context and enforces after the edit (ADR-067). There is no platform API to veto a Cursor agent edit before it lands, so Cursor relies on the post-edit guard: decided validate / decided relationships --validate and the GitHub Action / pre-merge gate, the same as any contributor. (The pre-edit veto is Claude-Code-specific — see examples/claude-code/.)

Run the bundled grounding demo — same task twice, once unconnected and once with lore connected — and watch the connected run respect a recorded decision the unconnected run violates: examples/guide/.