Cursor vs Claude Code for production — the question that matters is neither

Teams comparing Cursor and Claude Code for production work usually argue about the wrong variable. Whichever agent you pick, the artifact that reaches production is a diff written by a language model at a speed nobody fully reviews — and the risk that matters is not which model wrote it, but whether anything proved the changed lines actually ran under test before merging. That gate is agent-agnostic, and it is the piece most workflows are missing.

Why not just pick the better agent?

Pick whichever fits your team — editor-centric or terminal-centric, and both are moving targets that improve monthly. The comparison this post refuses to fake is a feature-by-feature scorecard: those go stale in weeks and rarely survive contact with your actual codebase. What does not change, whichever you choose, is the shape of the output: plausible code, produced fast, accompanied by a sincere-sounding claim that it works.

What do both agents have in common?

The properties that matter for production safety are identical:

• They write the code and the test in one loop. So the test tends to exercise what the agent believes it built. A suite can pass while executing none of the changed lines — we've measured real changes where the suite was green and 3 of 4 changed lines had never run.
• Their "done" is an assertion. "All tests pass and the feature works" costs a model nothing to say, in either tool. Without a mechanical check, the true and false versions of that sentence are indistinguishable.
• Their output volume moves the bottleneck to verification. The scarce resource stops being code production and becomes knowing what the code actually does.

None of this is a criticism of either tool. It is the structure of agent-written code, and it is why the production-readiness question sits *behind* the agent, not inside it.

What does an agent-agnostic gate look like?

A verification layer that treats every agent identically, because it never reads the agent's claims at all:

• Runs the repository's own test suite, measures which changed lines executed, and signs the result.
• Computes a deterministic verdict from that signed evidence — the same diff and the same evidence produce the same answer, with no model in the loop.
• Speaks a machine contract, so whichever agent you use drives itself: ask what to do, do exactly that, repeat until PASS. Both Cursor's and Claude Code's agents can follow it, because it requires no cleverness — read action.command, run it, branch on the exit code.
• Stops and fetches a human for the one decision no agent may make: vouching for a signing key.

That is what Relay is. It does not care which agent wrote the diff, which model version it ran, or what the agent said about its own work — the verdict consumes only measured inputs, so switching agents (or running several) changes nothing about the gate.

So which one should you pick?

Whichever your team works faster with — sincerely. Run a two-week trial of each if the choice matters to you. But put the same gate behind both trials, because then the comparison gets honest too: instead of judging agents by how confident their summaries sound, you judge them by measured evidence — how often their changes arrive with every changed line actually executed. The gate that protects production turns out to be the same instrument that makes the agent comparison meaningful. Start with one command that writes nothing: relayevals try, in the docs.