Open-source MCP Agents tools

The best open-source MCP Agents tools, curated: 11 in the registry, including ACI.dev (Aipolabs), CLI-Anything, Composio. Every tool is open-source; each entry lists license, self-hostability, and links.

11 tools · ← all categories · JSON

• ACI.dev (Aipolabs) — tool, 2026-09-03
  OSS alt to Composio (proprietary), Zapier-for-agents; ~4900 stars; complements Composio, Nango, Klavis; Apache-2.0. Open infra: multi-tenant auth, 600+ tools, and a Unified MCP server + VibeOps. Connectors use each app's official OAuth/API keys -> ethical_risk empty.
• CLI-Anything — tool, 2026-09-03
  Framework and registry for making existing software agent-native through structured CLIs; seven-phase harness generator, CLI-Hub package manager, JSON output, tests, SKILL.md generation, and maintained harnesses for creative, productivity, engineering, GIS, media, and developer applications; ~47.6k stars; generated CLIs execute the permissions of their wrapped software — review before agent use
• Composio — tool, 2026-09-03
  OSS alt to Zapier-for-agents, proprietary tool platforms; ~29600 stars; complements ACI.dev, Nango, Pipedream, MCP servers; Root LICENSE is MIT (some managed-server subdirectories carry Elastic-2.0). Handles OAuth/managed-auth to 250+ apps and exposes them as agent tools/MCP; uses each app's official credentials -> ethical_risk empty. Cloud offering is separate.
• Klavis AI — tool, 2026-09-03
  OSS alt to Composio MCP, proprietary MCP hubs; ~5800 stars; complements modelcontextprotocol/servers, ACI.dev, MetaMCP; Apache-2.0. Fleet of per-app MCP servers with built-in OAuth flows (Gmail/Slack/GitHub/Notion/Jira/etc.); uses each provider's official OAuth -> platform-tos empty. Self-hostable or hosted.
• MCPJungle — tool, 2026-09-03
  OSS alt to proprietary MCP gateways; ~1200 stars; complements MetaMCP, lasso mcp-gateway; MPL-2.0 (weak copyleft). Self-hosted registry+gateway: register servers once, expose one endpoint to Claude/Cursor/Codex/agents with access control. Auth delegated to registered servers. No per-platform ToS flag.
• MetaMCP — tool, 2026-09-03
  OSS alt to proprietary MCP gateways; MCP Context Forge (XREF); ~2600 stars; complements MCPJungle, lasso mcp-gateway, Klavis; MIT (successor to metatool-app). Groups MCP servers into namespaces, exposes unified SSE/HTTP/OpenAPI endpoints with middlewares + API-key/OIDC auth, Docker-packaged. It fronts other servers; auth is delegated to them. No per-platform ToS flag.
• modelcontextprotocol/servers — tool, 2026-09-03
  OSS alt to proprietary agent-tool plugins; ~89000 stars; complements Klavis, awesome-mcp-servers, MCP Context Forge (XREF); Reference servers under MIT, transitioning to Apache-2.0 (new contributions Apache-2.0; unrelicensed MIT contributions stay MIT) -> OSI-open either way. Each server uses the target service's official auth. No per-platform ToS flag.
• MCP Registry REST API v0.1 frozen — update, 2026-09-03
  The MCP Registry's REST read API reached a frozen v0.1: GET /v0.1/servers with cursor pagination and an updated_since delta filter. Agents can now build stable clients against a versioned contract instead of tracking an in-flux surface.
• ToolHive Registry Catalog — tool, 2026-09-03
  Open-source registry catalog of MCP servers from Stacklok. Demonstrates twin catalog streams — servers for executable components and skills for reusable prompt workflows — with an allowedTools array that bounds which tools a skill may invoke.
• Model Context Protocol Registry — tool, 2026-09-03
  Community-driven registry service for Model Context Protocol servers. Provides a stateless REST read API (v0.1) with cursor pagination and updated_since delta sync, plus the server.json entry schema that standardizes tool distribution metadata.
• Google Agent Skills — tool, 2026-08-25
  Google's official collection of Agent Skills across infrastructure, databases, AI/ML, security, and developer tools (incl. Google Ads/Analytics developer workflows). Installable via `npx skills add google/skills`. Broad, not marketing-only.