Which coding agent should you optimise for?

Why the answer is not "all of them"

If the agents differed only slightly you would do the same work and stop worrying. They do not.

And they disagree about outcomes. The three did not all name the same leader in 18 of the 29 categories all three ran. Email: Postmark, Resend, Resend. Sandboxes: E2B, Modal, E2B. Authentication: WorkOS AuthKit, Auth0, WorkOS AuthKit.

So "optimise for coding agents" is not one job.

What each one needs

Claude Code. Content reaches it in the moment in about three sessions in ten. Your levers are the repository and the training data. Ship official templates for the stacks your users run, get a maintained framework integration, be the default in a scaffolder. And beat the hand-written implementation, because Claude Code writes its own more than twice as often as Codex: name the failure modes and the year-two maintenance cost, with numbers, in the documentation.

Codex. It goes and looks in almost every session, so what you publish changes outcomes in weeks. Write the pages it actually searches for: a complete configuration reference, limits and quotas as numbers, pricing in units, production setup, self-hosting specifics, and every error message with its cause and fix. Its queries are long and often site-scoped, and they keep containing the word "official".

Cursor. It works with the project open and indexed, and in our sessions it reached for the option that needed the least new infrastructure. Shorten the distance between install and a first working call. Every step that happens outside the editor, an account, a dashboard, a deployed service, is a place the session ends.

How to find out which one matters to you

You do not need precision. The recommendation only changes at the extremes.

• Ask your users. A one-question survey in your onboarding or your community.
• Look at your issues and integration requests. People name their tools.
• Check the user agent on your documentation traffic.
• Look at what your own team runs, then discount it, because your team is not representative.

If it is roughly even, do both, in this order: repository first because it is largest and slowest, content second because it is fastest to move.

The answer if you refuse to choose

Get into the repository.

It is the largest lever for every agent, and it is the only one that reaches the sessions in which the agent does not search. In our tests the same email request went to Resend in 38 of 51 sessions on TypeScript codebases and to SendGrid in 16 of 17 on a Python codebase. A written instruction naming a preferred product was followed 16 times out of 18, and lost 2 times out of 3 once a rival library was installed in the same repository.

Templates, framework integrations, official examples, platform defaults. Slow, unglamorous, and it works on all three.

The mistake to avoid

Measuring one agent and reporting the number as your position.

A blended install share is an average across markets that behave differently. It can tell you that you hold 22% of a category while hiding that you hold 40% with one agent and 5% with another, and those two situations need completely different work.

Split the number. See how to measure install share.