Should I connect my AI agent tools through MCP or REST?
Choose MCP or REST for Agentik tool access based on your client and application.
By Agentik · Updated
Use MCP when a compatible assistant or agent runtime can connect to a tool server. Use REST when your application needs to make and control the requests directly. Agentik exposes discovery, inspection, execution and run retrieval across those interfaces; the task’s authorization, tool schemas and billing still need to be handled in either design.
On this page
Choose the interface your runtime supports
For an interactive assistant, start with the specific client installation guide and complete its supported authentication flow. Verify discovery and inspection after connecting. A saved server address is not proof that the intended workspace has authorized execution.
For a backend service, REST can fit existing request validation, logging and job orchestration. Keep credentials in the application’s secret handling rather than in prompts or browser code. Choose the interface for the integration you control, not a claim that one transport changes provider quality.
Map the operation lifecycle in either interface
MCP uses discover_tools, inspect_tool, run_tool and get_run. REST uses the documented discovery, tool inspection, execution and run endpoints. Consult the quickstart for their exact payloads and authentication requirements.
Your application still has to preserve the execution identity and validate final output. Neither transport makes an asynchronous provider job synchronous, removes account consent or includes the model’s own usage in the tool price.
Define ownership when both interfaces are used
A team can use an assistant for exploration and a backend for a repeated workflow. Give those jobs appropriate execution keys and retain which client submitted each run. Avoid two independent components submitting the same intended operation.
Keep the task contract consistent across the handoff: selected tool, validated input, spending authority and existing run ID. If a backend takes over retrieval, it should follow the original run rather than create a duplicate.
What you pay for
Supported paid tools use Agentik's prepaid workspace balance. Inspect the selected tool's pricing units and maximum before approving a run; a reservation can differ from its settled charge. Funding fees, taxes and your model's usage are separate. Current terms are on the Pricing and Billing pages linked below.
Choose an interface for two application shapes
The table compares integration responsibilities, not measured performance. Both designs must respect the same selected tool contract.
On a small screen, scroll to see every column.
| Integration | Typical interface | Work you retain |
|---|---|---|
| Assistant with MCP support | Authenticated MCP connection. | Task scope, approvals and result review. |
| Custom backend worker | REST requests from the server. | Secrets, orchestration, persistence and retries. |
| Interactive-to-backend handoff | Explicit handoff between components. | Original input, authority and run identity. |
A prompt to try
Connect Codex, then use this prompt with your connected assistant. Keep credentials in the authorized connection.
Give this to your agent
Recommend MCP or REST for [client or application architecture] using Agentik. Check the supported connection guide or quickstart and explain discovery, inspection, authentication, execution and run retrieval. Identify where credentials, spending approval and persistent run state belong. If both interfaces are used, define a single submission owner and an explicit handoff. Return the architecture before executing provider tools or changing credentials.
Your agent should inspect the tools and ask for missing inputs before proposing any paid work.
A related workflow
The companies in the space, their pricing pages, Google search demand for the category, and what buyers say on Hacker News and X.
One market in the United States, 25 companies found, 10 pricing pages read, 50 keywords measured, 5 trend terms, 50 Hacker News comments and 50 posts on X.
This catalog-based reservation maximum belongs to the playbook’s inputs, separately from this guide’s worked example. It is not an executed charge. Optional calls, funding fees, taxes and model usage are excluded.
- Exa web searchExa
- Scrape a web page to markdownFirecrawl
- Browser Use autonomous browser taskBrowser Use
Questions
Are MCP tools and REST tools billed differently?
The selected tool’s pricing contract governs usage. Inspect the actual operation and funding terms rather than assuming a transport-specific discount.
Does REST include a hosted workflow scheduler?
Do not assume so. Your application owns scheduling and orchestration unless a documented product capability explicitly supplies it.
Sources and next steps
Agentik publishes this guide. References below describe the product, its billing and the alternatives discussed. This page was updated on ; provider terms and tool availability can change.