Borrowing it
Nothing to install: this file belongs to rubys/roundhouse. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/rubys/roundhouse/main/AGENTS.mdgit clone --depth 1 https://github.com/rubys/roundhouseWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/rubys/roundhouse/agents-md)<a href="https://agentmods.dev/instructions/rubys/roundhouse/agents-md"><img src="https://agentmods.dev/badge/instructions/rubys/roundhouse/agents-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/rubys/roundhouse/agents-md"><img src="https://agentmods.dev/badge/instructions/rubys/roundhouse/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.01647 | $0.01647 |
| Opus 5.5 | $0.00659 | $0.00659 |
| Sonnet 5.5 | $0.00329 | $0.00329 |
| Haiku 4.5 | $0.00165 | $0.00165 |
Grade A, and why
roundhouse AGENTS.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Working on Roundhouse (agents & contributors)
Roundhouse reads Rails source and emits standalone projects in ~12 target languages, plus an inference engine (LSP/MCP/in-browser IDE) that types Rails without annotations. This file is the orientation an AI agent or new contributor needs before touching the code: where to look, and the invariants not to break.
Current implementation and executed CI are authoritative for behavior.
RELEASES.md records dated snapshot claims, not a live main
status page. The user guide describes product usage;
the bench page carries measurements.
Start here
| You want… | Read |
|---|---|
| What the project is | README.md — the landing page |
| Release snapshots and their known gaps | RELEASES.md |
| Using it (check / editor / MCP / transpile / Spinel) | docs/guide/ |
| Set up a checkout | docs/development/README.md |
Choose tests or use bin/rh verify |
docs/development/testing.md |
| Inspect AST, IR, or emitted output | docs/development/debugging.md |
| Change IR, lowering, runtime, or an emitter | docs/development/compiler-changes.md |
| Read/request hosted checks | docs/ci/README.md |
| Pipeline internals (analyze / lower / specialization / emit / runtime / verification) | docs/pipeline/ — architecture, not status |
| Compiler inputs (Ruby+ERB, schema/routes/seeds, method catalog, DB adapter) | docs/data/ |
| Why do this at all (the argument, option value) | WHY.md |
| Why this attempt is different (lineage, the three bets, risks) | BETS.md |
Pipeline shape: Ruby AST → analyze (typed IR) → lower (target-neutral IR) → emit (per-target project + runtime/<target>/ glue). The
ownership map locates each stage.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago Changed · -2 tokens per session eaa668c6e49e
- 15d ago Changed · +8 lines · +148 tokens per session 991afd90dce3
- 25d ago Changed · +2 tokens per session 877f68bf0a57
- 1mo ago Changed · -27 lines · -460 tokens per session 6118c080f2df
- 1mo ago Changed · +7 lines · +112 tokens per session d9598684b600
- 1mo ago Changed · +16 lines · +246 tokens per session e209d2a07e47
- 1mo ago Changed · +16 lines · +264 tokens per session 7efec74ac670
- 1mo ago Changed · +5 lines · +117 tokens per session d59948050369
- 2mo ago First seen · 88 lines · 1,220 tokens per session scan A fc82d5562116
roundhouse AGENTS.md is an instructions file published in the GitHub repository rubys/roundhouse (517 stars, last pushed 5d ago), licensed Apache-2.0. It adds 1,647 tokens to every session, about $0.0066 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
roundhouse AGENTS.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| roundhouse AGENTS.mdrubys/roundhouse | Instructions file | 517 | 5d ago | Apache-2.0 | A | 1,647 | Codex, OpenCode |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | today | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | yesterday | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |