Buy versus build is rarely binary. Most durable products combine purchased models and components with custom orchestration, retrieval, UX, and governance that reflect how your company actually works.

Start from the job-to-be-done

Write the user story without naming technology. If the outcome is a commodity—generic summarization of public text—buying may suffice. If the outcome depends on proprietary workflows, metrics definitions, or compliance rules, you will own integration and policy code regardless of who hosts the model.

Score the decision

• Differentiation: Will a packaged tool ever encode your edge, or are you paying for parity?
• Data: Do you have unique, permissioned data that improves quality when grounded?
• Velocity: Can a vendor ship faster than your team can integrate safely?
• Cost structure: Project token, GPU, and support load at realistic adoption, not demo traffic.
• Risk: What happens if the vendor changes pricing, terms, or model behavior overnight?

Practical hybrid pattern

Use vendor APIs for baseline language capabilities while you build the retrieval layer, evaluation harness, and product workflows that are genuinely yours. Revisit the decision quarterly as your volumes and regulatory posture evolve.