9 Best AI Agent Tool Integration Platforms of 2026

Composio ranks first because it pairs a large catalog with the most generous free allowance on this list. The Hobby plan includes 100,000 tool calls, 50,000 triggers, unlimited connected accounts and three team members a month without a credit card, and every plan gets the full set of 1,500+ toolkits. Composio handles OAuth consent, token storage, refresh and scopes for each connected account, and exposes tools through SDKs, a CLI for coding agents and a managed MCP gateway. Triggers start background agents from events in connected apps, and the Firewall feature blocks instructions hidden in tool results before the agent reads them. Pro costs $29 a month, includes $29 in monthly credits that do not roll over, and adds unlimited team members and spend controls. The main caveat is the shared OAuth apps: Composio says they work in production but are not built for production scale, so plan to register your own apps before launch.

Arcade.dev positions itself as the actions runtime between agents and the systems they reach, and its focus is authorization. Authentication runs against your identity provider, authorization is delegated so the agent acts as its user without exceeding its scope, and your policies are enforced in the path of every action, outside the model where a prompt cannot undo them. The catalog covers 8,000+ permission-aware tools, plus custom MCP servers you build or bring, and Tool Recommendation exposes the full catalog while cutting token costs by up to 37% by Arcade's figure. Every action leaves a record naming the agent, the user and the system. The Free plan includes 2,000 tool calls a month, and Team costs $25 a month plus $0.01 per call, which is cheap for low volume but adds up for chatty agents. Enterprise adds VPC or air-gapped deployment, SSO, RBAC and a private registry. Arcade also now runs the Smithery MCP directory.

Pipedream Connect has the broadest catalog here: managed auth for 3,000+ APIs and 10,000+ prebuilt actions and triggers, all published on GitHub so you can extend any tool or write your own. Agents can reach them through one remote MCP endpoint with built-in tool discovery, or through the SDK, and each tool runs with the connected account of the user the agent acts for. When no prebuilt tool fits, the Connect proxy sends any HTTP request to a supported API and attaches the user's credentials, which keeps tokens out of your servers. Hosted Connect Link flows mean there is no auth UI to build, and you can bring your own OAuth clients. The free tier includes every feature but only in development. Going live needs the Startup plan at $99 a month, which covers 100 external users and 10,000 usage credits, then $2 per user and $0.012 per credit. That makes it slightly pricier than Composio for small launches.

Nango is the most code-first platform on this list. It ships pre-built authentication, credential storage and token refresh for 1,200+ APIs and MCPs, along with 10k+ pre-built tools, triggers and syncs, but its strength is letting you extend those templates or write fully custom integrations that run on Nango's infrastructure. Real-time webhooks feed triggers, embeddable UI components handle account authorization, and white labeling removes Nango's name from the auth flow. Pricing is unusual: the Pay-as-you-go plan is $50 a month in credits, then $0.29 per connection, $0.72 per compute hour and $0.50 per GB of data transfer. That is cheap for products with a modest number of connected accounts, though you need to estimate compute for syncs. The free plan caps you at 10 connections, which is enough to test but not to launch. Nango is SOC 2 Type II certified, and Enterprise adds self-hosting, BYOC and HIPAA.

Scalekit AgentKit focuses on the plumbing between agents and the tools they call on a user's behalf. It offers 600+ connectors and 30,000+ ready-to-call tools that Scalekit says are schema-optimized for LLMs rather than thin wrappers over REST endpoints, with auth, retries and rate limits handled on each call. From one config it generates a per-user authenticated MCP URL that any MCP client can use, and you can define custom tools against any endpoint of an existing connector. Tokens live in an isolated per-tenant vault and are injected at runtime, so the agent never sees them. Tool bundles let you give each agent only the tools it needs, which Scalekit claims cuts token overhead by up to 80%. The free plan includes 10,000 tool calls and unlimited connected accounts. Growth costs $99 a month with 100,000 calls, custom connectors and private Slack support, and EU data residency is a $99 add-on.

Zapier MCP is the easiest route on this list: add it to Claude, ChatGPT, Cursor or another MCP client, choose your apps, and the agent can act in them. It draws on Zapier's directory of 9,000+ apps and 66,000+ triggers and actions, and rather than making you pick every tool up front, the agent searches for the right action from your goal. When no standard action fits, Zapier says it writes and runs code to reach an internal API or reshape data. Auth and permissions come from your Zapier account, and useful workflows can be saved as Skills or deployed as Zaps. Zapier MCP is included in every plan, and each tool call uses two tasks from the shared pool, so the free plan's 100 tasks covers about 50 calls. Professional starts at $19.99 a month. The limit for developers is scope: it is designed around your own connected accounts, with an embed option and SDK, rather than a full multi-tenant auth layer for your customers.

Merge Agent Handler brings Merge's integration background to agent tool calling. It offers thousands of pre-built connectors that Merge maintains with detailed error handling, plus built-in authentication that guides a user through connecting a tool when the agent tries to act on an unauthenticated connector. Tool Packs bundle the exact connectors each agent needs, scoped by agent type, customer tier or environment, so agents only see tools they can call. On the security side, every tool call can be scanned for sensitive data, with policies that block, redact or mask it before it reaches a model or third party, and audit logs are on all plans. Agent Handler is built on MCP, so it works with Claude, Cursor, ChatGPT or any framework. Merge says it is free to start and priced by monthly credits consumed by tool calls, but the public pricing page did not show Agent Handler figures when we checked, so cost is hard to compare.

StackOne describes itself as an AI agent integration platform, and it puts governance at the center. One connection gives an agent access to 44,000+ actions across 640+ enterprise apps, and every connector is included on every plan. StackOne handles OAuth, SAML and API key auth, forwards provider webhooks to trigger agent workflows, and connects through MCP, A2A or its API, so it works with Claude, Copilot Studio, Gemini, Glean, Cursor and n8n. Defender Core, its open source prompt-injection defense, scans tool responses before they reach the model on all plans, and Tool Policies set permissions down to the field. The Gateway offer is for your own employees and internal agents, with a free Starter plan of 1,000 credits per seat a month, while an OEM offer covers embedding in your product. Team pricing is seat-based and the figure on the page changes with seat count, so we left the starting price pending. Custom connectors need a paid plan.

Paragon ActionKit is aimed at SaaS companies that want their AI product to act in customers' external apps. It exposes 1000+ integration actions through one API and an MCP server, with a uniform interface across integrations and schemas tuned either for agents or for UI. At query time your agent calls ActionKit to fetch available actions and parameters, and Paragon's embedded UI components or headless SDK handle each user's authentication inside your product. ActionKit is part of a broader platform: every plan also includes Managed Sync for high-volume data ingestion, with a Permissions API for access control in RAG, and Workflows for asynchronous logic in TypeScript or a low-code editor. That breadth suits products that need integrations beyond tool calling. The downside is cost visibility. Pricing is custom and scales with connected customer orgs, both plans say to talk to sales, and there is no self-serve paid tier to compare with the leaders.