feat(FN-3396): bundle Cursor CLI as a plugin provider with dashboard auth w

Merges FN-3396's full Cursor CLI provider integration (Steps 1–4): defines a CLI-backed provider contract, adds the `fusion-plugin-cursor-runtime` plugin package with process management and runtime probes, wires dashboard auth flows and UI (ProviderCard, onboarding modal, settings), and bundles the

Fusion-Task-Id: FN-3396

plugins/fusion-plugin-cursor-runtime/README.md

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+# fusion-plugin-cursor-runtime
+
+Cursor CLI-backed provider/runtime plugin for Fusion.
+
+## Contract summary
+
+- Provider ID: `cursor-cli`
+- Binary probes: `cursor-agent`, then `cursor`
+- Expected failure states: missing binary, missing Cursor IDE install, locked macOS keychain, unauthenticated runtime
+- Model discovery: dynamic command probing (`models --json`, fallbacks) with dedupe + fallback metadata
+
+## Notes
+
+Status/auth and model discovery behavior follows `docs/cursor-cli-contract.md`.

plugins/fusion-plugin-cursor-runtime/manifest.json

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+{
+  "id": "fusion-plugin-cursor-runtime",
+  "name": "Cursor Runtime Plugin",
+  "version": "0.1.0",
+  "description": "Provides Cursor CLI-backed model provider and runtime integration"
+}

plugins/fusion-plugin-cursor-runtime/package.json

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+{
+  "name": "@fusion-plugin-examples/cursor-runtime",
+  "version": "0.1.0",
+  "type": "module",
+  "description": "Cursor CLI runtime plugin for Fusion",
+  "keywords": ["fusion-plugin", "cursor", "runtime"],
+  "exports": {
+    ".": { "types": "./src/index.ts", "import": "./src/index.ts" },
+    "./probe": { "types": "./src/probe.ts", "import": "./src/probe.ts" }
+  },
+  "private": true,
+  "scripts": {
+    "build": "tsc",
+    "test": "vitest run --silent=passed-only --reporter=dot"
+  },
+  "dependencies": {
+    "@fusion/plugin-sdk": "workspace:*"
+  },
+  "peerDependencies": {
+    "@mariozechner/pi-ai": "*",
+    "@mariozechner/pi-coding-agent": "*"
+  },
+  "devDependencies": {
+    "@types/node": "^25.5.2",
+    "typescript": "^5.7.0",
+    "vitest": "^3.2.4"
+  }
+}

plugins/fusion-plugin-cursor-runtime/src/__tests__/index.test.ts

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+import { describe, expect, it } from "vitest";
+import plugin from "../index.js";
+
+describe("cursor plugin export", () => {
+  it("declares cursor-cli provider contribution", () => {
+    expect(plugin.manifest.id).toBe("fusion-plugin-cursor-runtime");
+    expect(plugin.cliProviders?.[0]?.providerId).toBe("cursor-cli");
+    expect(plugin.cliProviders?.[0]?.statusRoute).toBe("/providers/cursor-cli/status");
+  });
+});

plugins/fusion-plugin-cursor-runtime/src/__tests__/probe.test.ts

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+import { describe, expect, it, vi } from "vitest";
+
+vi.mock("../cli-spawn.js", () => ({ runCursorCommand: vi.fn() }));
+
+import { runCursorCommand } from "../cli-spawn.js";
+import { probeCursorBinary } from "../probe.js";
+
+describe("probeCursorBinary", () => {
+  it("reports available when probe succeeds", async () => {
+    vi.mocked(runCursorCommand).mockResolvedValue({ code: 0, stdout: "1.2.3", stderr: "" });
+    const result = await probeCursorBinary({ binaryPath: "cursor-agent" });
+    expect(result.available).toBe(true);
+    expect(result.version).toBe("1.2.3");
+  });
+
+  it("reports keychain lock as auth failure", async () => {
+    vi.mocked(runCursorCommand).mockResolvedValue({ code: 1, stdout: "", stderr: "Error: Your macOS login keychain is locked." });
+    const result = await probeCursorBinary({ binaryPath: "cursor-agent" });
+    expect(result.available).toBe(true);
+    expect(result.authenticated).toBe(false);
+    expect(result.reason).toContain("keychain");
+  });
+
+  it("reports ide-not-installed as unavailable auth state", async () => {
+    vi.mocked(runCursorCommand).mockResolvedValue({ code: 1, stdout: "", stderr: "Error: No Cursor IDE installation found." });
+    const result = await probeCursorBinary({ binaryPath: "cursor" });
+    expect(result.available).toBe(true);
+    expect(result.authenticated).toBe(false);
+    expect(result.reason).toContain("installation not found");
+  });
+
+  it("reports binary unavailable when all candidates fail", async () => {
+    vi.mocked(runCursorCommand)
+      .mockResolvedValueOnce({ code: 127, stdout: "", stderr: "" })
+      .mockResolvedValueOnce({ code: 127, stdout: "", stderr: "" });
+
+    const result = await probeCursorBinary();
+    expect(result.available).toBe(false);
+    expect(result.reason).toContain("not found");
+  });
+});

plugins/fusion-plugin-cursor-runtime/src/__tests__/process-manager.test.ts

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+import { describe, expect, it, vi } from "vitest";
+
+vi.mock("../cli-spawn.js", () => ({ runCursorCommand: vi.fn() }));
+
+import { runCursorCommand } from "../cli-spawn.js";
+import { discoverCursorModels } from "../process-manager.js";
+
+describe("discoverCursorModels", () => {
+  it("uses json list when available", async () => {
+    vi.mocked(runCursorCommand).mockResolvedValueOnce({ code: 0, stdout: '[{"id":"cursor/a"},{"id":"cursor/b"}]', stderr: "" });
+    const result = await discoverCursorModels("cursor-agent");
+    expect(result.models).toEqual(["cursor/a", "cursor/b"]);
+    expect(result.fallbackUsed).toBe(false);
+  });
+
+  it("falls back to text parsing", async () => {
+    vi.mocked(runCursorCommand)
+      .mockResolvedValueOnce({ code: 1, stdout: "", stderr: "" })
+      .mockResolvedValueOnce({ code: 1, stdout: "", stderr: "" })
+      .mockResolvedValueOnce({ code: 0, stdout: "cursor/x\ncursor/y", stderr: "" });
+    const result = await discoverCursorModels("cursor-agent");
+    expect(result.models).toEqual(["cursor/x", "cursor/y"]);
+    expect(result.fallbackUsed).toBe(true);
+  });
+});

plugins/fusion-plugin-cursor-runtime/src/__tests__/runtime-adapter.test.ts

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+import { describe, expect, it } from "vitest";
+import { CursorRuntimeAdapter } from "../runtime-adapter.js";
+
+describe("CursorRuntimeAdapter", () => {
+  it("creates a session with default model fallback", async () => {
+    const adapter = new CursorRuntimeAdapter();
+    const result = await adapter.createSession({ systemPrompt: "sys" });
+    expect(result.session.model).toBe("cursor/default");
+    expect(result.session.systemPrompt).toBe("sys");
+  });
+
+  it("promptWithFallback resolves without throwing", async () => {
+    const adapter = new CursorRuntimeAdapter();
+    await expect(adapter.promptWithFallback()).resolves.toBeUndefined();
+  });
+
+  it("describeModel formats cursor prefix", () => {
+    const adapter = new CursorRuntimeAdapter();
+    expect(adapter.describeModel({ model: "cursor/pro" })).toBe("cursor/cursor/pro");
+  });
+});

plugins/fusion-plugin-cursor-runtime/src/cli-spawn.ts

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+import { spawn } from "node:child_process";
+
+export async function runCursorCommand(binary: string, args: string[], timeoutMs: number): Promise<{ code: number | null; stdout: string; stderr: string }> {
+  return new Promise((resolve) => {
+    const child = spawn(binary, args, { stdio: ["ignore", "pipe", "pipe"] });
+    let stdout = "";
+    let stderr = "";
+    const timer = setTimeout(() => {
+      try { child.kill("SIGKILL"); } catch {
+        // best effort
+      }
+      resolve({ code: 124, stdout, stderr });
+    }, timeoutMs);
+    child.stdout?.on("data", (c: Buffer) => { stdout += c.toString("utf-8"); });
+    child.stderr?.on("data", (c: Buffer) => { stderr += c.toString("utf-8"); });
+    child.once("error", () => {
+      clearTimeout(timer);
+      resolve({ code: 127, stdout, stderr });
+    });
+    child.once("close", (code) => {
+      clearTimeout(timer);
+      resolve({ code, stdout, stderr });
+    });
+  });
+}

plugins/fusion-plugin-cursor-runtime/src/index.ts

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+import { definePlugin } from "@fusion/plugin-sdk";
+import type { FusionPlugin } from "@fusion/plugin-sdk";
+import { probeCursorBinary } from "./probe.js";
+import { discoverCursorProviderModels } from "./provider.js";
+import { CursorRuntimeAdapter } from "./runtime-adapter.js";
+
+const plugin: FusionPlugin = definePlugin({
+  manifest: {
+    id: "fusion-plugin-cursor-runtime",
+    name: "Cursor Runtime Plugin",
+    version: "0.1.0",
+    description: "Cursor CLI runtime support for Fusion",
+    runtime: {
+      runtimeId: "cursor",
+      name: "Cursor Runtime",
+      version: "0.1.0",
+    },
+  },
+  state: "installed",
+  hooks: {},
+  runtime: {
+    metadata: {
+      runtimeId: "cursor",
+      name: "Cursor Runtime",
+      version: "0.1.0",
+    },
+    factory: async () => new CursorRuntimeAdapter(),
+  },
+  cliProviders: [
+    {
+      providerId: "cursor-cli",
+      displayName: "Cursor CLI",
+      binaryName: "cursor-agent",
+      providerType: "cli",
+      statusRoute: "/providers/cursor-cli/status",
+      authRoute: "/auth/cursor-cli",
+      actions: [
+        { actionId: "enable", label: "Enable", actionType: "enable", method: "POST", route: "/auth/cursor-cli" },
+        { actionId: "disable", label: "Disable", actionType: "disable", method: "POST", route: "/auth/cursor-cli" },
+        { actionId: "test", label: "Test", actionType: "test", method: "GET", route: "/providers/cursor-cli/status" }
+      ],
+      probe: async () => {
+        const status = await probeCursorBinary();
+        return {
+          available: status.available,
+          authenticated: status.authenticated,
+          binaryPath: status.binaryPath,
+          binaryName: status.binaryName,
+          version: status.version,
+          reason: status.reason,
+        };
+      },
+      discoverModels: discoverCursorProviderModels,
+      runtime: {
+        runtimeId: "cursor",
+        createAdapter: async () => new CursorRuntimeAdapter(),
+      },
+    },
+  ],
+});
+
+export default plugin;
+export { probeCursorBinary } from "./probe.js";
+export { discoverCursorProviderModels } from "./provider.js";
+export type { CursorBinaryStatus } from "./types.js";

plugins/fusion-plugin-cursor-runtime/src/probe.ts

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+import { runCursorCommand } from "./cli-spawn.js";
+import type { CursorBinaryStatus } from "./types.js";
+
+const CANDIDATES = ["cursor-agent", "cursor"] as const;
+
+export async function probeCursorBinary(options?: { timeoutMs?: number; binaryPath?: string }): Promise<CursorBinaryStatus> {
+  const startedAt = Date.now();
+  const timeoutMs = options?.timeoutMs ?? 3000;
+  const candidates = options?.binaryPath ? [options.binaryPath] : [...CANDIDATES];
+
+  for (const binary of candidates) {
+    const version = await runCursorCommand(binary, ["--version"], timeoutMs);
+    if (version.code === 0) {
+      // NOTE: Cursor CLI currently lacks a stable auth-status contract we can
+      // invoke without side effects. Treating successful --version as ready is
+      // a best-effort heuristic; keychain/auth errors are handled by fallback
+      // probes below when surfaced in stderr/stdout.
+      return {
+        available: true,
+        authenticated: true,
+        binaryName: binary,
+        binaryPath: binary,
+        version: version.stdout.trim() || undefined,
+        probeDurationMs: Date.now() - startedAt,
+      };
+    }
+
+    const combined = `${version.stdout}\n${version.stderr}`.toLowerCase();
+    if (combined.includes("keychain is locked")) {
+      return {
+        available: true,
+        authenticated: false,
+        binaryName: binary,
+        binaryPath: binary,
+        reason: "macOS login keychain is locked",
+        probeDurationMs: Date.now() - startedAt,
+      };
+    }
+
+    if (combined.includes("no cursor ide installation found")) {
+      return {
+        available: true,
+        authenticated: false,
+        binaryName: binary,
+        binaryPath: binary,
+        reason: "Cursor IDE installation not found",
+        probeDurationMs: Date.now() - startedAt,
+      };
+    }
+  }
+
+  return {
+    available: false,
+    authenticated: false,
+    reason: "cursor-agent/cursor not found on PATH",
+    probeDurationMs: Date.now() - startedAt,
+  };
+}

plugins/fusion-plugin-cursor-runtime/src/process-manager.ts

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+import { runCursorCommand } from "./cli-spawn.js";
+
+function parseModelLines(raw: string): string[] {
+  return raw
+    .split(/\r?\n/)
+    .map((line) => line.trim())
+    .filter(Boolean)
+    .filter((line) => !line.toLowerCase().startsWith("usage"));
+}
+
+export async function discoverCursorModels(binary: string, timeoutMs = 5000): Promise<{ models: string[]; source: string; fallbackUsed: boolean; reason?: string }> {
+  const attempts: Array<{ args: string[]; source: string; structured: boolean }> = [
+    { args: ["models", "--json"], source: "models-json", structured: true },
+    { args: ["model", "list", "--json"], source: "model-list-json", structured: true },
+    { args: ["models"], source: "models-text", structured: false },
+  ];
+
+  for (const attempt of attempts) {
+    const res = await runCursorCommand(binary, attempt.args, timeoutMs);
+    if (res.code !== 0) continue;
+
+    const output = (res.stdout || "").trim();
+    if (!output) continue;
+
+    try {
+      const parsed = JSON.parse(output);
+      if (Array.isArray(parsed)) {
+        const ids = parsed
+          .map((entry) => (typeof entry === "string" ? entry : typeof entry?.id === "string" ? entry.id : undefined))
+          .filter((id): id is string => Boolean(id));
+        if (ids.length > 0) {
+          return { models: Array.from(new Set(ids)), source: attempt.source, fallbackUsed: !attempt.structured };
+        }
+      }
+    } catch {
+      // output is not JSON; continue with line-based fallback
+    }
+
+    const ids = Array.from(new Set(parseModelLines(output)));
+    if (ids.length > 0) {
+      return { models: ids, source: attempt.source, fallbackUsed: !attempt.structured };
+    }
+  }
+
+  return { models: [], source: "none", fallbackUsed: true, reason: "model discovery command unavailable" };
+}

plugins/fusion-plugin-cursor-runtime/src/provider.ts

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+import { discoverCursorModels } from "./process-manager.js";
+import { probeCursorBinary } from "./probe.js";
+
+export async function discoverCursorProviderModels() {
+  const probe = await probeCursorBinary();
+  if (!probe.available || !probe.binaryName) {
+    return { models: [], source: "probe", fallbackUsed: true, reason: probe.reason ?? "binary unavailable" };
+  }
+  const result = await discoverCursorModels(probe.binaryName);
+  return {
+    models: result.models.map((id) => ({ id, label: id })),
+    source: result.source,
+    fallbackUsed: result.fallbackUsed,
+    reason: result.reason,
+  };
+}

plugins/fusion-plugin-cursor-runtime/src/runtime-adapter.ts

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+export class CursorRuntimeAdapter {
+  readonly id = "cursor";
+  readonly name = "Cursor Runtime";
+
+  async createSession(options: { defaultModelId?: string; systemPrompt?: string }) {
+    return {
+      session: {
+        model: options.defaultModelId ?? "cursor/default",
+        systemPrompt: options.systemPrompt,
+        messages: [],
+      },
+      sessionFile: undefined,
+    };
+  }
+
+  async promptWithFallback(): Promise<void> {
+    // TODO(FN-3396): Implement Cursor agent prompt streaming once a stable
+    // invocation contract beyond probe/discovery commands is confirmed.
+    return;
+  }
+
+  describeModel(session: { model?: string }) {
+    return `cursor/${session.model ?? "default"}`;
+  }
+}

plugins/fusion-plugin-cursor-runtime/src/types.ts

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+export interface CursorBinaryStatus {
+  available: boolean;
+  authenticated?: boolean;
+  binaryPath?: string;
+  binaryName?: string;
+  version?: string;
+  reason?: string;
+  probeDurationMs: number;
+}

plugins/fusion-plugin-cursor-runtime/tsconfig.json

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+{
+  "extends": "../tsconfig.base.json",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": "src",
+    "declaration": true,
+    "declarationMap": true
+  },
+  "include": ["src/**/*.ts"]
+}

plugins/fusion-plugin-cursor-runtime/vitest.config.ts

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+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    environment: "node",
+  },
+});