AI agents are only as capable as the tools they can call. The Model Context Protocol (MCP) is how an agent discovers and invokes those tools. The catch: most of the software your work depends on has no API, so it has no tool, and the agent is stuck. Here is how to give an agent a real tool for any website.
What MCP is, in one paragraph
MCP is a small, open protocol for connecting AI models to tools and data. A client (Claude, Cursor, your own agent) connects to an MCP server, which advertises a set of typed tools. The model can then call a tool with structured arguments and get a structured result back. It is the clean, standard interface agents have been missing.
Why most sites are not MCP tools yet
To be an MCP tool, a capability needs a callable interface. A REST API can become one easily. But the supplier portal, the internal admin panel, the booking system behind a login: none of those have an API, so none of them can be a tool. That is exactly the gap Writ fills.
Turning a site into a tool
You build a workflow once (by recording the task in a real browser, describing the goal to
AI, or discovering the underlying calls) and publish it. Writ exposes it as a REST endpoint
at /v1/{slug}/{path} and as an MCP tool, from the same definition.
{
"mcpServers": {
"writ": {
"url": "https://api.usewrit.app/mcp",
"headers": { "Authorization": "Bearer wt_8f3a…" }
}
}
} Connecting Claude, Cursor, and other clients
Drop that config into your MCP client and your published workflows appear as tools. The agent reads the tool's typed inputs and calls it like any other function, except this tool drives a real browser session on a site that never had an API.
User: pull this month's open invoices from the supplier portal
Agent → tool: writ.portal_export({ account_id: "AC-19284", since: "2026-06-01" })
tool → agent: { invoices: [ { id: "INV-5521", amount: 1840.00 }, … ] }
Agent: You have 2 open invoices totaling $2,460.50. Keeping agent actions safe
Giving an agent the ability to act is powerful, so the controls matter. Writ runs the workflow on your own account, and the agent never sees your credentials, which stay encrypted at rest. A dry-run preview and a confirm-gate are on by default, and write-style actions can be held for your approval, so an autonomous action always stays inside limits you set.
The payoff: your agent gains a tool for any authenticated site, with the same authorization and spend controls as a human operator. See how the MCP layer works
Give your agent a tool for any site
Publish a workflow as an MCP tool, callable with a wt_ key.
Common questions
Do I need to write an MCP server myself?
Can the agent see my credentials?
Which MCP clients work?
Related reading
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