# Best Agent tools & infrastructure — The Agents Index

> Source: https://theagentsindex.com/category/agent-tools (curated, quality-gated, re-verified)

What agents run on rather than what they are: MCP servers and tool APIs built for an agent to call, plus the memory, sandboxing, evaluation and orchestration layers underneath them. These are listed as tooling and never ranked against autonomous agents.

12 quality-gated agents in this category. Each name links to its answer-first markdown twin.

| Name | What it is | Pricing | API |
| --- | --- | --- | --- |
| [SkaleAgents](https://theagentsindex.com/skaleagents.md) | Hosted MCP server and specialist DevOps bots for reviewing code and infrastructure text. | freemium | — |
| [Aident Loadout](https://theagentsindex.com/aident-loadout.md) | Managed capability layer that connects any AI agent to 1,000+ apps through one reusable, audited setup. | freemium | Yes |
| [Xquik](https://theagentsindex.com/xquik.md) | X (Twitter) scraper API, one-second monitors and account automation via REST, SDKs, webhooks and MCP. | paid | Yes |
| [API.market](https://theagentsindex.com/api-market.md) | API marketplace and gateway for 600+ AI, data and media APIs, each also exposed as an MCP server. | paid | Yes |
| [HOL Guard](https://theagentsindex.com/hol-guard.md) | Local-first runtime security layer that allows, asks or blocks risky AI coding-agent actions before they run. | freemium | Yes |
| [NeverApply](https://theagentsindex.com/neverapply.md) | Consumer job-search agent that finds matching roles, tailors your resume and submits applications for you. | paid | Yes |
| [Firecrawl](https://theagentsindex.com/firecrawl.md) | Web data API that turns search, scrape and browser interaction into agent-ready Markdown or JSON. | freemium | Yes |
| [sipgate flow](https://theagentsindex.com/sipgate-flow.md) | EU-hosted real-time voice and telephony API that puts your own AI agent on the phone. | paid | Yes |
| [AgentBridge](https://theagentsindex.com/agentbridge.md) | Local MIT bridge connecting Claude Code and Codex as live peers in one session. | free | Yes |
| [TinyFish](https://theagentsindex.com/tinyfish.md) | Web infrastructure for AI agents: search, page fetch, cloud browsers and goal-driven web automation. | freemium | Yes |
| [Browserbase](https://theagentsindex.com/browserbase.md) | Cloud headless browsers, search/fetch APIs and managed browser agents behind one API key. | freemium | Yes |
| [SalesTouch](https://theagentsindex.com/salestouch.md) | OAuth-protected remote MCP server that gives AI agents LinkedIn search, messaging and publishing tools. | paid | Yes |