Bottom line: for a core tool, no API is close to a dealbreaker; MCP almost as important but slightly less critical because you can build your own MCP on an API.
Business software is usually purchased to solve an immediate problem with leads, jobs, orders, or customer work. The harder question arrives after people have built their routines around it: how will the rest of the company read and use what is inside?
That may mean connecting the tool to a report, another system, or an AI workflow. By then the company already depends on it, so a bad answer is expensive.
A CSV export helps with a one-time analysis. It is not a live connection. If someone has to export the same file, clean it, and move it every week, that person has become part of the integration.
For a tool that will sit at the core of the business for years, a usable API is close to non-negotiable. An API is simply a structured way for other software to read from the tool and, when you allow it, write back. Without one, every future report, integration, and AI workflow depends on manual exports and brittle workarounds. I would only accept a core tool with no API if it were the best option by a wide margin.
MCP is almost as important, and it will keep getting more important as more of the work is handed to AI. MCP gives an AI system a standard way to see what a tool can do and take those actions inside the permissions you set. It ranks just below the API for one practical reason: you can build your own MCP on top of an API later, but you cannot add an API to a tool that was never built to be read from. Both sit near the top of how I choose operating software now.
When a tool will hold an important part of the business, I ask the vendor a few direct questions before signing. What data can another system read? What can it change? How do permissions control that access? Can the tool tell another system when something important happens? And if we ever leave, how do we export the full history in a usable format? The answers tell you whether the tool is built to work with the rest of your systems, or to keep your data locked inside itself.
This is not a reason to replace every closed system already in use. Migrations are expensive, and a tool the team understands may be safer than a rushed replacement. The stricter rule is for the next purchase, before years of operating memory accumulate inside it.
If the software will hold an important part of the business, access belongs in the buying decision, not in a technical conversation saved for later.
Always expect friction.