Cursor Agent Host

@ask-llm/plugin ships a Cursor Plugin adapter in .cursor-plugin/plugin.json. Cursor loads exactly the two Cursor-adapted skills (/codex-pair, /grok-pair) through its Agent Skills surface and the unified Ask LLM server through mcp.json; the manifest sets agents: [], commands: [], and hooks: {} (Cursor's manifest schema accepts a path or array for agents/commands and a path or object for hooks, and a present field replaces folder discovery) so Claude-only reviewer agents and the Claude-format hooks/hooks.json are never auto-discovered by Cursor. The remaining review/brainstorm/compare skills still use Claude-only mechanics and are deferred to separate Cursor-compatibility work. It does not consume Claude Code's hook registration, ${CLAUDE_PLUGIN_ROOT}, AskUserQuestion, or Claude MCP namespace conventions.

Start from source

yarn install --immutable
yarn build
agent --plugin-dir ./packages/claude-plugin

Installed plugins expose only /codex-pair and /grok-pair in Cursor's / skill menu. The Cursor manifest deliberately omits /codex-pair-ack, /codex-pair-pause, and /codex-pair-resume: those toggle the Claude Code/Pi background per-edit reviewer through .codex-pair/state sentinels, and Cursor's on-demand session has no background reviewer for them to act on. If you only want MCP setup, copy the packages/claude-plugin/mcp.json entry to project .cursor/mcp.json or user ~/.cursor/mcp.json, then restart/reload Cursor Agent. The adapter bundles exactly one server:

• ask-llm → @ask-llm/mcp (ask-cursor-agent plus the unified ask-llm tool, which pair skills call only fully pinned — provider, harness, exact model, effort, include directories, session — never as a generic fallback).

Keep one registration per server: if the plugin is loaded, do not add a second ask-llm entry in .cursor/mcp.json. The split servers are optional user installs, not plugin bundles — codex → @ask-llm/codex-mcp (ask-codex) and grok → @ask-llm/grok-mcp (ask-grok); when such a deterministic leaf is exposed the pair skills prefer it, otherwise they use only fully pinned unified calls and never fall back between tools.

/codex-pair on Cursor

Cursor's /codex-pair is an on-demand iterative pair session. Cursor remains the editor; an authenticated Codex CLI is the explicit read-only reviewer. Both model=<exact ID> and effort=low|medium|high|xhigh|max are required: the adapter cannot safely infer environment defaults inside a separately spawned MCP server. If either is omitted, pairing stops before extra context is read or consent is requested. Before calling the provider it reports those exact choices, bounded files, relative include directories, quota/data boundary, and asks for consent.

The first Codex call (ask-codex when user-installed, otherwise the fully pinned unified ask-llm with provider: "codex") passes sessionId: "" to create a persisted thread and may pass up to 32 safe relative includeDirs. Follow-ups reuse the returned structured Thread ID and omit includeDirs, because codex exec resume does not support --add-dir; a resumed call that still passes includeDirs is rejected by every Codex transport (split ask-codex, unified ask-llm) rather than silently dropping the directories. Feedback is relayed and source-verified before Cursor edits. Interrupts cancel the MCP call; unavailable tools/models, partial failures, and any Codex quota fallback are reported rather than hidden.

Example:

/codex-pair model=gpt-5.6-sol effort=high include=packages/api,packages/shared review this migration

With the plugin loaded, the unified ask-llm tool is the bundled transport: /codex-pair uses it with provider: "codex" and every option pinned; unsupported combinations (including includeDirs on a resumed thread) are rejected instead of stripped. A separately user-installed ask-codex leaf is preferred when exposed. If neither is present, install the recommended unified server instead of making a generic call:

{
  "mcpServers": {
    "ask-llm": { "command": "npx", "args": ["-y", "@ask-llm/mcp"] }
  }
}

Save it in project .cursor/mcp.json or user ~/.cursor/mcp.json, authenticate codex, then reload the server from Cursor Settings → Tools & MCP or restart Cursor Agent. A codex entry using @ask-llm/codex-mcp remains the optional user-installed split-tool alternative.

/grok-pair route safety

When Cursor itself is the host, /grok-pair does not recursively invoke Cursor Agent. Select xai-api or grok-cli through the bundled unified ask-llm with provider, harness, exact model, and effort all pinned, or through a separately user-installed ask-grok leaf when exposed; there is no fallback. Claude Code may instead select Grok through the model-neutral ask-cursor-agent tool; that route keeps host, provider, Cursor harness, exact catalog ID, and optional display label separate and refuses Auto or cross-provider substitution.

If neither direct leaf is exposed, configure the recommended unified server and reload Cursor MCP:

{
  "mcpServers": {
    "ask-llm": { "command": "npx", "args": ["-y", "@ask-llm/mcp"] }
  }
}

Save it in project .cursor/mcp.json or user ~/.cursor/mcp.json. The xai-api route needs XAI_API_KEY in the MCP process environment; keep literal secrets in user-level configuration and never commit them. The grok-cli route needs authenticated Grok Build with headless JSON flags visible in grok --help. Reload from Cursor Settings → Tools & MCP or restart Cursor Agent, then invoke /grok-pair again. Unified startup probes both direct harnesses, so a CLI-only login works without setting ASK_GROK_HARNESS=grok-cli; the request still pins harness: "grok-cli", and no API fallback occurs. A CLI-only call that omits harness fails with a diagnostic naming that pin (or ASK_GROK_HARNESS=grok-cli), and an explicit ASK_GROK_HARNESS makes startup readiness track that harness alone.

Lifecycle differences

Capability	Claude Code	Cursor Agent
/codex-pair	Marker-gated continuous hooks plus dashboard	On-demand skill-backed persisted reviewer session
Registration	Claude plugin + .mcp.json (Codex only)	Cursor Plugin Agent Skills + mcp.json (unified ask-llm only; split servers user-installed)
Include directories	Per-edit context from marker/project	Explicit safe relative includeDirs on first Codex call
Completion gate	Optional Claude Stop hook	Explicit completed/cancelled/failed session report
Cancellation	Claude hook/provider process lifecycle	Cursor MCP AbortSignal/interrupt
Pause / resume / ack	/codex-pair-pause, /codex-pair-resume, /codex-pair-ack toggle the background hook	Not exposed — no background reviewer; end or restart the on-demand session

The portable contract is canonical in packages/claude-plugin/skills/pairing-contract.md; host adapters must not claim lifecycle guarantees their host does not provide.