Do coding agents recommend Fly Machines?
Coding agents raised Fly Machines in 81 of 520 judged code sandboxes sessions and chose it in none of them.
Coding agents raised Fly Machines in 81 of 520 judged code sandboxes sessions and chose it in none of them.
This page reports what happened when Claude Code, Codex, Cursor, Grok Build CLI and Muse Code had to solve a problem in code sandboxes inside a realistic codebase. Not what a chat assistant says about Fly Machines. What an agent actually installed.
The numbers
| Category | Code sandboxes |
| Sessions in the category | 520 |
| Sessions where Fly Machines was chosen | 0 |
| Install share | 0% |
| Raised as a candidate, not chosen | 81 |
| Chosen when considered | 0% |
| Site | fly.io |
Which agents raised Fly Machines
Every agent considered it and none adopted it. Claude Code raised it most often, in 26% of its code sandboxes sessions.
| Agent | Sessions | Raised Fly Machines | Chose it |
|---|---|---|---|
| Claude Code | 129 | 33 (26%) | 0 |
| Codex | 170 | 10 (6%) | 0 |
| Cursor | 136 | 28 (21%) | 0 |
| Grok Build CLI | 34 | 2 (6%) | 0 |
| Muse Code | 51 | 8 (16%) | 0 |
Which buyers it came up for
It surfaced most for requests written as senior engineer, in 17% of those sessions. Knowing which buyer already has the product in mind tells you which pages to fix first.
| Who is asking | Sessions | Raised it |
|---|---|---|
| Senior engineer | 464 | 78 (17%) |
| Enterprise team | 56 | 3 (5%) |
What Fly Machines was up against
The full ranking in code sandboxes, from the same sessions:
| # | Product | Runs won | Share |
|---|---|---|---|
| 1 | E2B | 227 | 44% |
| 2 | Modal | 131 | 25% |
| 3 | Vercel Sandbox | 81 | 16% |
| 4 | Daytona | 73 | 14% |
| 5 | Anthropic Code Execution | 3 | 1% |
| 6 | Runloop Devboxes | 3 | 1% |
| 7 | Cloudflare Workers | 2 | 0% |
What this means
Raised 81 times and chosen none is a specific, diagnosable result, and a better starting position than being unknown. The agent has the product in mind. It reached the shortlist 81 times. Something then lost every one of those sessions.
In our data the causes, in the order they occur:
- The quickstart does not run when pasted, so the agent abandoned it mid-integration.
- The documentation describes an interface that changed, so the generated code failed.
- The product name and the package name differ, so the install step went wrong.
- The fit was genuinely wrong for the repository, which is fine and worth knowing.
All but the last are fixable in days, and the reason is written down in the session transcript.
Where these numbers come from
The 520 sessions in code sandboxes are part of a published set of 15,051, run with real coding agents inside realistic codebases and judged blind. The full method is on one page: how we measured this.
Every code sandboxes run can be replayed on the board.
If you work on Fly Machines: the judge recorded a reason for every session where it was raised and passed over. Those reasons are in the transcripts.
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Common questions
Do coding agents recommend Fly Machines?
They raise it but do not choose it. Across 81 sessions where Fly Machines came up as a candidate, agents chose something else every time.
Does Claude Code recommend Fly Machines?
In 0 of the 129 sessions in code sandboxes run with Claude Code, which is 0%.
Do different coding agents treat Fly Machines differently?
Not much. Claude Code, Codex, Cursor, Grok Build CLI and Muse Code chose it at similar rates, between 0% and 0% of their runs.
How was this measured?
Real coding agents at pinned versions were run in sandboxes inside 92 realistic codebases and asked to solve real tasks. A simulated project owner approved or questioned each recommendation before any code was written, and a judge from a model family that builds none of the agents read every session blind.
Where this comes from
Armature ran 15,051 judged sessions with Claude Code, Codex, Cursor, Grok Build CLI and Muse Code inside 92 realistic codebases, and published every run. The numbers on this page come from that work.